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How to Optimize Results While Machining with Miniature End Mills

 The machining industry generally considers miniature end mills to be any end mill with a diameter under 1/8 of an inch. This is also often the point where tolerances must be held to a tighter window. Because the diameter of a tool is directly related to the strength of a tool, miniature end mills are considerably weaker than their larger counterparts, and therefore, lack of strength must be accounted for when machining with them. If you are using these tools in a repetitive application, then optimization of this process is key.

Key Cutting Differences between Conventional and Miniature End Mills

Runout

Runout during an operation has a much greater effect on miniature tools, as even a very small amount can have a large impact on the tool engagement and cutting forces. Runout causes the cutting forces to increase due to the uneven engagement of the flutes, prompting some flutes to wear faster than others in conventional tools, and breakage in miniature tools. Tool vibration also impacts the tool life, as the intermittent impacts can cause the tool to chip or, in the case of miniature tools, break. It is extremely important to check the runout of a setup before starting an operation. The example below demonstrates how much of a difference .001” of runout is between a .500” diameter tool and a .031” diameter tool.

The runout of an operation should not exceed 2% of the tool diameter. Excess runout will lead to a poor surface finish.

Chip Thickness

The ratio between the chip thickness and the edge radius (the edge prep) is much smaller for miniature tools. This phenomena is sometimes called “the size effect” and often leads to an error in the prediction of cutting forces. When the chip thickness-to-edge radius ratio is smaller, the cutter will be more or less ploughing the material rather than shearing it. This ploughing effect is essentially due to the negative rake angle created by the edge radius when cutting a chip with a small thickness.

If this thickness is less than a certain value (this value depends of the tool being used), the material will squeeze underneath the tool. Once the tool passes and there is no chip formation, part of the plowed material recovers elastically. This elastic recovery causes there to be higher cutting forces and friction due to the increased contact area between the tool and the workpiece. These two factors ultimately lead to a greater amount of tool wear and surface roughness.

Figure 1: (A) Miniature tool operation where the edge radius is greater than the chip thickness (B) Conventional operation where the edge radius is small than the chip thickness

Tool Deflection

Tool deflection has a much greater impact on the formation of chips and accuracy of the operation in miniature operations, when compared to conventional operations. Cutting forces concentrated on the side of the tool cause it to bend in the direction opposite the feed. The magnitude of this deflection depends upon the rigidity of the tool and its distance extended from the spindle. Small diameter tools are inherently less stiff compared to larger diameter tools because they have much less material holding them in place during the operation. In theory, doubling the length sticking out of the holder will result in 8 times more deflection. Doubling the diameter of an end mill it will result in 16 times less deflection. If a miniature cutting tool breaks on the first pass, it is most likely due to the deflection force overcoming the strength of the carbide. Here are some ways you can minimize tool deflection.

Workpiece Homogeny

Workpiece homogeny becomes a questionable factor with decreasing tool diameter. This means that a material may not have uniform properties at an exceptionally small scale due to a number of factors, such as container surfaces, insoluble impurities, grain boundaries, and dislocations. This assumption is generally saved for tools that have a cutter diameter below .020”, as the cutting system needs to be extremely small in order for the homogeny of the microstructure of the material to be called into question.

Surface Finish

Micromachining may result in an increased amount of burrs and surface roughness when compared to conventional machining. In milling, burring increases as feed increases, and decreases as speed increases. During a machining operation, chips are created by the compression and shearing of the workpiece material along the primary shear zone. This shear zone can be seen in Figure 2 below. As stated before, the chip thickness-to-edge radius ratio is much higher in miniature applications. Therefore, plastic and elastic deformation zones are created during cutting and are located adjacent to the primary shear zone (Figure 2a). Consequently, when the cutting edge is close to the border of the workpiece, the elastic zone also reaches this border (Figure 2b). Plastic deformation spreads into this area as the cutting edge advances, and more plastic deformation forms at the border due to the connecting elastic deformation zones (Figure 2c). A permanent burr begins to form when the plastic deformation zones connect (Figure 2d) and are expanded once a chip cracks along the slip line (Figure 2e). When the chips finally break off from the edge of the workpiece, a burr is left behind (Figure 2f).

Tool Path Best Practices for Miniature End Mills

Because of the fragility of miniature tools, the tool path must be programmed in such a way as to avoid a sudden amount of cutting force, as well as permit the distribution of cutting forces along multiple axes. For these reasons, the following practices should be considered when writing a program for a miniature tool path:

Ramping Into a Part

Circular ramping is the best practice for moving down axially into a part, as it evenly distributes cutting forces along the x, y, and z planes. If you have to move into a part radially at a certain depth of cut, consider an arching tool path as this gradually loads cutting forces onto the tool instead of all at once.

Machining in Circular Paths

You should not use the same speeds and feed for a circular path as you would for a linear path. This is because of an effect called compounded angular velocity. Each tooth on a cutting tool has its own angular velocity when it is active in the spindle. When a circular tool path is used, another angular velocity component is added to the system and, therefore, the teeth on the outer portion of tool path are traveling at a substantially different speed than expected. The feed of the tool must be adjusted depending on whether it is an internal or external circular operation. To find out how to adjust your feed, check out this article on running in circles.

Slotting with a Miniature Tool

Do not approach a miniature slot the same way as you would a larger slot. With a miniature slot, you want as many flutes on the tool as possible, as this increases the rigidity of the tool through a larger core. This decreases the possibility of the tool breaking due to deflection. Because there is less room for chips to evacuate with a higher number of flutes, the axial engagement must be decreased. With larger diameter tools you may be stepping down 50% – 100% of the tool diameter. But when using miniatures with a higher flute count, only step down between 5% – 15%, depending on the size of the diameter and risk of deflection. The feed rate should be increased to compensate for the decreased axial engagement. The feed can be increased even high when using a ball nose end mill as chip thinning occurs at these light depths of cut and begins to act like a high feed mill.

Slowing Down Your Feed Around Corners

Corners of a part create an additional amount of cutting forces as more of the tool becomes engaged with the part. For this reason it is beneficial to slow down your feed when machining around corners to gradually introduce the tool to these forces.

Climb Milling vs. Conventional Milling

This is somewhat of a tricky question to answer when it comes to micromachining. Climb milling should be utilized whenever a quality surface finish is called for on the part print. This type of tool path ultimately leads to more predictable/lower cutting forces and therefore higher quality surface finish. In climb milling, the cutter engages the maximum chip thickness at the beginning of the cut, giving it a tendency to push away from the workpiece. This can potentially cause chatter issues if the setup does not have enough rigidity.  In conventional milling, as the cutter rotates back into the cut it pulls itself into the material and increases cutting forces. Conventional milling should be utilized for parts with long thin walls as well as delicate operations.

Combined Roughing and Finishing Operations

These operations should be considered when micromachining tall thin walled parts as in some cases there is not sufficient support for the part for a finishing pass.

Helpful Tips for Achieving Successful Micromachining Operations

Try to minimize runout and deflection as much as possible.This can be achieved by using a shrink-fit or press-fit tool holder. Maximize the amount of shank contact with the collet while minimizing the amount of stick-out during an operation. Double check your print and make sure that you have the largest possible end mill because bigger tools mean less deflection.

  • Choose an appropriate depth of cut so that the chip thickness to edge radius ratio is not too small as this will cause a ploughing effect.
  • If possible, test the hardness of the workpiece before machining to confirm the mechanical properties of the material advertised by the vender. This gives the operator an idea of the quality of the material.
  • Use a coated tool if possible when working in ferrous materials due to the excess amount of heat that is generated when machining these types of metals. Tool coatings can increase tool life between 30%-200% and allows for higher speeds, which is key in micro-machining.
  • Consider using a support material to control the advent of burrs during a micro milling application. The support material is deposited on the workpiece surface to provide auxiliary support force as well as increase the stiffness of the original edge of the workpiece. During the operation, the support material burrs and is plastically deformed rather than the workpiece.
  • Use flood coolant to lower cutting forces and a greater surface finish.
  • Scrutinize the tool path that is to be applied as a few adjustments can go a long way in extending the life of a miniature tool.
  • Double-check tool geometry to make sure it is appropriate for the material you are machining. When available, use variable pitch and variable helix tools as this will reduce harmonics at the exceptionally high RPMs that miniature tools are typically run at.
Figure 3: Variable pitch tool (yellow) vs. a non-variable pitch tool (black)

TOMI Engineering INC – Featured Customer

Since its beginning in 1977, brothers Tony and Mike Falbo have made the focal point of TOMI Engineering to deliver quality, competitively-priced parts on time. TOMI Engineering has earned a reputation through the years as being a world-class manufacturer of precision machined components and assemblies for aerospace, defense, commercial and other advanced technology industries. They are fortunate to have the highest level of engineering, quality and programming personnel on staff, and, with over 40 years in the industry, there isn’t a problem TOMI hasn’t experienced.

With all the years of experience, TOMI Engineering has a lot of knowledge to share. We had the pleasure of sitting down with Tony and Mike Falbo to ask them about their experiences, techniques, tooling and a lot more.

How was TOMI Engineering INC started?

TOMI Engineering, Inc. began in 1977 when we (Tony and Mike) teamed up and got a loan from our father to purchase our first machine.  The machine was used in the garage of our parents’ home, which still resides in Tustin, California.  Forty years, 20 current machines, and countless parts later, TOMI Engineering proudly serves the defense, airline, medical and commercial industries.  We machine just about any type of product thrown our way.  Over the years, we have made wing tips for the F16 fighter jet, enclosures for GPS housings, manifolds that help transport fluids, support frames for Gulfstream, cabin brackets for Airbus, ammunition feeders for tanks, and many, many others.

At TOMI Engineering, we aim to be a one-stop shop for our customers.  Once we receive blueprints, we can program, machine, deburr, inspect, process and assemble most parts.  We utilize a mixture of 3-and-4-axis machines in order to increase efficiency, which helps us to cut down costs to our customer.  In our temperature-controlled assembly room, we can assemble bearings, bushings, rivets, nut plates, gaskets and sealants.  We also hope to add additive machining to our repertoire soon.

What machines are you currently using in your shop?

Our 21,250 square foot facility houses 20 CNC machines.  Most of our machines are Kitamura, OKK and Okuma.  The purchase dates of these machines range from 1987 to December of 2019.  With our large machine diversity, we can machine parts smaller than a penny, and as large as 30 x 60 inches. Most of the material that makes its way through our shop is aluminum.  Whether it is 6061 or aircraft grade 7000 series, we aim to have most of our parts be aluminum.  However, we do see a large amount of 6AL-4V titanium, along with 17-4 and 15-5 steel. We are currently utilizing Mastercam 2020 for most of our programming needs and are staying up to date with software upgrades and progression.

What sets TOMI Engineering apart from the rest of the competition?

We believe our greatest asset is our experience.  Here at TOMI, we have been machining parts since 1977.  In those 40-plus years, a lot of parts have come and gone through our doors and we have helped our customers solve a large array of problems.  Most of our machinists have been with us for over 10 years, while some are approaching 20 years!  Our programmers easily boast over 60 years of experience! With so many of our employees working together for so many years, it has really helped everyone to understand what helps us quickly machine our products, while being held accountable to the high standards of AS9100. 

Where did your passion for machining start?

We grew up with machines in our garage and it wasn’t until we needed money to pay for college that our dad realized he could show us the basics of operating a milling machine, which allowed us to pay our tuition while working at home in the evenings and weekends. Machining was more of a necessity than a passion at the time. However, after nearly 40 years in the business, it has been amazing to see the strides in technology from a Bridgeport Mill to the multi-axis lights-out machining that is available today.

My favorite part of the job has always been the flexibility it has allowed me. I had the opportunity to watch my kids grow up and be a part of their lives by going to their school plays, coaching them, and being home at night to help them with anything they needed. Most importantly, I’ve had the opportunity to work with my brother, my business partner, who also shares the same ideals about being with family, so we could always cover for each while the other was gone and spending time with their family. The business would not have worked without both of us understanding the importance of each other’s input. The challenge of running a business keeps me going, and working with all of the different personalities was an added bonus.

Who is the most famous contact that you have worked on a project with? What is the most interesting product youve made?

At TOMI, we do not work with specific individuals, so we can’t really name drop.  However, a vast majority of our work is for Airbus, Boeing, or the military. So it’s pretty gratifying to say that we supply parts to some of the biggest companies in the world and that our work helps to defend this country.

The most interesting product we have made here at TOMI is a GPS housing for a defense contractor.  This part encompasses everything that we can do at TOMI: precision machining, complex/multi detail assemblies, gasket assembly, and pressure testing fluid transportation components. 

Why is high quality tool performance important to you?

High quality tool performance is important to us in many ways.  Purchasing high quality tools allow us to constantly achieve premium surface finishes, push our machines to the high speeds and feeds that they are capable of, and enjoy noticeably longer tool life.

Every part, day-in and day-out, is different.   Because of our vast array of products, our tools are always changing.  But when we are picking out Helical End Mills for Aluminum, we always go with their 3-flute variable helix cutters, and we have always been happy with them.

What sort of tolerances do you work in on a daily basis?

The tolerances we typically work with are ± tenths of an inch, as well as very tight true position cal louts. We can hold and achieve these close tolerance dimensions through our very experienced Mastercam programmers, as well as our superior quality department.  Our quality inspectors have over 30 years of experience in the industry and utilize two Zeiss Contura G2 coordinate measuring machines (CMMs).  While in their temperature controlled environment, the CMMs are capable of measuring close tolerance dimensions and are used to generate data for inspection reports.

Are you guys using High Efficiency Milling (HEM) techniques to improve cycle times? What advice do you have for others who want to try HEM?

Yes, we are using HEM techniques to improve cycle times while roughing to increase our MRR while increasing tool life. If you have CAM/CAD software that supports HEM, then go for it!  Machine Advisor Pro (MAP) is VERY helpful with the suggested speeds and feeds as a starting point.  Over time though, and through experience, we have learned that every single machine is a bit different and often needs a different approach with speeds and feeds.  Start with a smaller than suggested RDOC and physically go out to your machine and see how it sounds and what is going on.  Then, start increasing and find that sweet spot that your particular machine runs well on.  Many programmers in the industry will not take the time to go out and watch how their part is sounding and cutting on the machine and going out and doing that is the best way to really find out what you and the machine are capable of achieving.

If you could give one piece of advice to a new machinist ready to take the #PlungeIntoMachining, what would it be?

Ask questions!  Don’t be afraid to talk to programmers and fellow coworkers about what is trying to be achieved and WHY the programmer is holding tolerances a certain way.  Learn from them and watch what every cutter is doing during your cycles.  The more you learn, the more you can contribute to the machining process and move up in your business.  Sometimes it takes just one good suggestion about the machining approach that can change the set-up process from aggravating to very easy.  Lastly, be open minded to new ideas and approaches.  As we said earlier, there are a ton of ways to make good parts in a constantly evolving industry.

Please take the time to check out the TOMI Engineering INC website or follow them on social media!

Titan Ring Design – Featured Customer

Officially started in 2015, Titan Ring Design is a high quality machine shop that designs rings, as well as mechanical tie clips, art based designs, and freelance custom designs. While working at a machine shop that produced top notch parts for just about every type of field you can imagine, now owner of Titan Ring Design, Trevor Hirschi, noticed that the machining industry is mostly about cranking out a mass quantity of the highest quality parts as quickly as possible. This often resulted in compromised tolerances and part finishes, something Trevor aimed to change. Quality always comes first in his projects.

Whether you are looking for a band for an upcoming wedding, looking to replace or upgrade your current wedding ring, or just want something unique and beautiful, Trevor’s designs are different than anything else. Trevor was able to take the time and answer some questions for us about his business, machining techniques, tooling, and a lot more.

How was Titan Ring Design started?

Titan Ring Designs is a part time, passion/hobby business of mine that I sort of started at the time I was ring shopping for a wedding ring back in 2013. I didn’t like what was available on the market and was inspired by a former Oakley designer to machine my own. I had been introduced to machining in High School at a technical college and had been working as a machinist since graduating in 2007, so I decided to make my own wedding ring. It sort of snowballed into my business in 2015, after finally deciding to make it official with a business license and some sales. Some further work experience in California for McWhinney Designs brought me greater motivation and encouragement to keep going and helped me get to where I am today. I now offer several different CNC Milled [wedding] rings, as well as a mechanical tie clip, some occasional art based designs, and freelance custom design and mill work. I also teach machining full time  at the same tech college I graduated from in my own education and enjoy sharing my knowledge and love for machining with those interested in the career.

What capabilities does your shop have?

Custom Design in CAD/CAM, 3axis CNC Mill work, Small Scale Lathe Work, Tumbling, Finishing, Assembling, 3D Printing/Rapid Prototyping. I cut 6-4 Titanium primarily, but also work with Stainless Steel for fasteners, Aluminum and some Steel for fixtures, and Polycarbonate for prototyping ideas. I teach machining technology full time, so I have access to SolidWorks, MasterCam, Fusion360, and NC Simul. We currently have a Haas OfficeMill 3axis, Levin High Precision Instrument Maker’s Lathe, Prusa i3 MK2S 3D Printer in the shop.

What sets Titan Ring Design apart from the competition?

There are lots of people making interesting rings today, but most are done on lathes. Anyone can make a round part on a lathe. Very few of them make rings on a mill, and I feel that gives the opportunity to be creative and allows you to think outside the box more. I try to stand out in that field by offering something that makes you think about the value of the design process more by interrupting and challenging the norm. I also like to take on work that is outside of jewelry, but still highly design related. Most other ring makers stick with just rings.

What is your favorite part of the job and what other passions do you have?

Making cool stuff! Most machinists only end up making whatever comes through the shop, which can be cool, but most of the time you have no idea what you’re making, just some part for Customer X, Y, or Z. Being a small, design centered business, I get to come up with ideas for what to make next, and most of the time I start out making something that wasn’t ever intended to be marketed, it was simply something I wanted for myself that I found others were interested in too. I discovered machining in high school and fell in love with it when I started making parts for my dirt bikes and truck. I’ve been hooked ever since but I do have other passions. I’ve always had a big interest in LED lighting and flashlights. I’m perpetually working on different ideas for making one of my own, which will happen eventually. I’m also a bit of a health-nut and enjoy being outdoors and spending time with my family.

Who is the most famous contact that you have worked on a project with?

I made a ring for an NFL player once, but I don’t follow football and his name didn’t stick out to me so I’ve forgotten who he was. I also had the privilege of working for McWhinney Designs and made some truly remarkable products in the openable wedding ring niche market. I gained more skill in design, machining, craftsmanship, and engineering while working for Jeff McWhinney. We’re good friends and often work together to help each other when one of us gets stumped on something.

What is the most difficult project you have worked on?

I was commissioned to design from the ground up and machine was a custom set of all-titanium cabinet door handle pulls for a very high end wine cabinet. Each handle was an assembly of 32 pieces, all machined from billet 6-4 Titanium. They required over 400 individual CAM toolpath operations, 35 unique machine setups, and well over 300 hours to complete, including finishing and assembly. More than anything, it was extremely time intensive in programming, set up, and machine time. The design was a fair bit challenging in my mind and initial modeling, but didn’t compete with what it took to actually produce them. I grossly underestimated and underbid the job. But in the end, I really enjoyed making a truly one of a kind, Tour-De-Force product, even if it was completely overkill for its purpose. I enjoy making that kind of stuff, and the lessons you learn from it.

What is your favorite project you have worked on?

It’s really simple and was initially designed just because I wanted it for myself, but I have a mechanical titanium tie clip that I really enjoy making. It’s quite unique in that, as far as I know, to this day, it is the only CNC machined mechanical titanium tie clip you’ll find anywhere in the world. It puts a little bling in your formal attire, for those times you have to go full suit and tie.

Why is high quality tool performance important to you?

Because I cut mostly titanium, tools wear out quickly if you don’t have a rigid set up, the right coolant, proper feeds & speeds, and of course, high quality tooling. Harvey Tool makes such a wide variety of micro tooling that works so well in the industry of making small titanium parts, where I like to fit into. I’ve used a fair spread across Harvey’s offering and have always been impressed with performance and the feeds and speeds guides are top notch too. I had an application that required a .0035” internal corner radius which landed me with a .007” end mill. It’s still hard to comprehend tooling in this league. My machine actually recommends only tooling under 1/4” shank size, so I don’t get into Helical’s range too often. But I’ve used Helical 1/2” end mills extensively at other job shops and they are definitely made for eating metal. I was using another tool brand’s key cutters for some undercut hinges and would wear through them much more often than I thought was reasonable. When I finally decided to try Harvey’s key cutters, I was blown away with how much longer they have lasted me. Truly a game changer!

If you could give one piece of advice to a new machinist ready to take the #PlungeIntoMachining, what would it be?

Be creative. Machining is such a rewarding career that has limitless possibilities of what you can achieve. Follow your passion and have fun with it! If you end up in a dead end shop doing something you don’t like, go somewhere else. There are so many shops that need help right now and chances are good that you can find a better shop that suits your style.

Is there anything else you would like to share with the In The Loupe community?

To those machine shops out in industry, do whatever you can to be supportive of your local trade schools that are teaching the upcoming machinist workforce. They really need your support and in turn will bring you the employees you depend on.

Please take the time to check out Titan Ring Designs website or follow them on Instagram @titanringdesigns

Titanium Machining Cost Savings with Helical Solutions

When the manufacturing team at Geospace Technologies was looking for better tool life and improved performance on a Titanium CNC milling job, they turned to Harvey Performance Company and local Application Engineer Mike Kanigowski to dial in some Helical Solutions End Mills. With Mike’s help, Geospace Technologies, led by Lead Mill Programmer Tranquilino Sosa, achieved massive success and cost-savings, which led them to completely shift their tooling repertoire to Helical’s high-performance end mills in their shop.

Struggling with Tool Life

Prior to switching to Helical, Geospace Technologies was experiencing trouble with tool life on a job that required both roughing and finishing toolpaths on a Titanium (Ti-6AL-4V) part. For their roughing pass, Geospace was using a competitor’s 4 flute, 3/8” diameter end mill with a 30° helix angle and TiALN coating. In traditional roughing toolpaths, this tool was running at 1,750 RPM with a 10 IPM feed rate. The tool would take four step downs, three with an axial depth of cut of .200”, and a final pass at .100” for a total depth of .700”.

When finishing, the team used a 1/2” version of the same competitor tool, running at 900 RPM with an 8 IPM feed rate. This would take two passes, one at .400” deep and the last down to the bottom of the part at .700”.

geospace technologies

With this strategy and tooling, the team was creating high-quality parts at a cycle time of 15 minutes and 22 seconds per part, but were only seeing the roughing tool last for 60 parts on average, and the finishing tool for around 120 parts. This was causing tool costs to be higher than they would like, and costing the team precious time with frequent tool changes.

Sosa had seen some of the success that other shops were having with Titanium milling using Helical Solutions end mills, and so they reached out to Kanigowski to see how Helical could help them lower their cost per part while achieving an even better finish.

Dialing in Tool Selection

When Mike got in touch with the team at Geospace, he knew there were some immediate benefits to changing the toolpaths used in this job. Using their ESPRIT software, the team was able to dial in a new program using high efficiency milling (HEM) toolpaths through ESPRIT’s “Profit Milling” technology.

With HEM toolpaths in place, Geospace was going to need new high performance tools to take full advantage of the programming adjustments. After much testing and evaluating several options from Helical’s extensive line of end mills for Titanium, Geospace settled on two solid tools.

Helical offers many different options for Titanium milling in HEM toolpaths. During testing, the team at Geospace decided on Helical EDP 59424, a 3/8” diameter, 7 flute, corner radius end mill. This tool features variable pitch geometry and offset chipbreakers for optimal chip evacuation, reduced harmonics, and minimized tool pressure, as well as Helical’s Aplus coating for high temperature resistance, decreased wear, and improved tool life.

7 flute chipbreaker
7 Flute Chipbeaker Tools Fresh Off the Grinder

When looking at the finishing toolpath, Geospace decided on Helical EDP 82566, a 3/8”, 6 flute, square end mill from Helical’s well known HEV-6 product line. This tool featured a variable pitch design to help mitigate chatter and leave a superior finish. While Helical also offers several tools for finishing toolpaths in Titanium, during testing this tool provided Geospace with the best finish for their specific part geometry.

HEV-6
Example of a Tool from Helical Solutions HEV-6 Tooling Line

Experiencing the “Helical Difference”

With the new tools in place, Sosa’s team reached out to Helical for help dialing in speeds and feeds. The Helical tech team was able to get them set up on Machining Advisor Pro, an advanced speeds and feeds calculator developed by the experts behind Helical Solutions tooling. With this “miracle worker” application in their arsenal, the team was able to easily dial in their new tools for their specific material grade, depth of cut, and machine setup.  

The team saw immediate positive results and cost-savings on this job. They were able to increase their roughing toolpaths to 4,500 RPM and 157 IPM. The finishing path remained largely the same, but resulted in a much improved final part. In total, cycle time dropped from 15 minutes and 22 seconds per part to 12 minutes and 17 seconds per part, which was great, but the improvement in tool life was where Sosa was most impressed.

titanium end mills

With the new Helical end mill in the shop, Geospace was able to run both tools for 580 parts with very minimal wear on the tool. This was a nearly 1000% improvement in tool life for their roughing passes and a 483% improvement in tool life for the finishing operation. In total, one roughing tool was able to last more than 42 hours in the cut before needing to be replaced.

Eliminating the need for a tool change every 60 parts was also a significant time-saver. Constant tool changes were causing serious machine downtime, which was eliminated with the longer tool life experienced with the Helical end mills. What seems like a minor inconvenience will truly add up to dozens of hours in saved time over the course of a few months for Sosa’s team.

titanium machining tool wear
A Closeup of the 7 Flute Chipbreaker After 42 Hours In The Cut

Geospace was thrilled with the results they saw on this Titanium job, as they had never experienced long tool life in Titanium with any other competitor brand. Sosa and his team are excited to continue using Helical Solutions product across all of their other jobs going forward and to continue working with Kanigowski and the Helical tech team on dialing in tool selection and speeds and feeds on future projects.

Please see below for a head-to-head breakdown of the Helical end mills’ performance in terms of total costs and productivity gained versus that of the competitor. These numbers are measured per 1,000 parts, taking into account tooling costs, tool change time, labor costs, running parameters, and cycle times.


titanium machining cost savings

Chipbreaker Tooling: Not Just for Roughing

When many people think about solid carbide tools with chip breakers, they are usually tooling up for a roughing application. While the chip breaker tool is a great choice for such applications, it can be utilized in a number of other areas too. In this post, we’ll examine many other benefits of the chip breaker style of tooling.

High Efficiency Milling (HEM)

High Efficiency Milling (HEM) uses CAM software to program advanced toolpaths that reduce cutting forces. These tool paths employ smaller end mills with a higher number of flutes (for a stronger core) running at higher speeds and feeds. This strategy includes a light radial depth of cut (RDOC), high axial depth of cut (ADOC), and a controlled angle of engagement.

Helical’s chipbreaking tools include serrated indents along the edge of flute for the entire length of cut. Because HEM utilizes heavy axial depths of cuts, these tools are able to break long chips into smaller ones. In addition to improving chip control and reducing cutting resistance, chipbreaker tools also help in decreasing heat load within the chips. This delays tool wear along the cutting edge and improves cutting performance. 

Check out this testimony from a Helical Solutions customer:

“We were able to get going with the 7 flute tools with the chipbreaker. I have to say the difference was INCREDIBLE! We can now rough the entire part with one tool. Also, the operator doesn’t have to open the door to clear chips hardly at all. We were able to rough and finish a 4.15 dia. bore 2 inches deep through the part without having to clear chips at all. Before we had to clear the chips out at least 15-20 times. Many thanks for your support.”

Slotting

When slotting, a major concern is chip control. A large buildup of chips can cause the recutting of chips, which adds a lot of heat back into the tool. Chip buildup can also cause a heavy amount of chattering. Both of these conditions are detrimental to tool life. A chip breaking tool can help reduce chip build-up when slotting which will extend tool life. Remember when slotting that 4 flute tools should be utilized in steel. For aluminum and other non- ferrous materials, a 3 flute tool is best.

Trochoidal Slotting

Trochoidal slotting is a form of slotting that uses HEM techniques to form a slot. Trochoidal milling implements a series of circular cuts to create a slot wider than the cutting tool’s cutting diameter. Using the logic listed in the earlier paragraphs of this article, a chipbreaker should be used when performing this operation.

Advantages of Trochoidal Slotting:

Decreased cutting forces

Reduced heat

Greater machining accuracy

Improved tool life

Faster cycle times

One tool for multiple slot sizes

Finishing

A little known fact about Helical’s chipbreaker style tool is that the chip breakers are offset flute to flute, which allows for a quality finish on the walls of the part. When utilizing light depths of cuts, high-quality finishes can be achieved.

Hardenability of Steel

Many types of steel have a beneficial response to a method of heat treatment known as quenching. One of the most important criteria in the selection process of a workpiece material is hardenability. Hardenability describes how deep a metal can be hardened upon quenching from high temperature, and can also be referred to as the depth of hardening.

Steel At Microscopic Scale:

The first level of classification of steels at a microscopic level is their crystal structure, the way in which atoms are arranged in space. Body-Centered Cubic (BCC) and Face Centered Cubic (FCC) configurations are examples of metallic crystal structures. Examples of BCC and FCC crystal structures can be seen below in Figure 1. Keep in mind that the images in Figure 1 are meant to display atomic position and that the distance between the atoms is exaggerated.

Figure 1: Example of a BCC crystal structure (left) and FCC crystal structure (right)

The next level of classification is a phase. A phase is a uniform portion of a material that has the same physical and chemical properties. Steel has 3 different phases:

  1. Austenite: Face-Centered cubic iron; also iron and steel alloys that have the FCC crystal structure.
  2. Ferrite: Body-centered cubic iron and steel alloys that have a BCC crystal structure.
  3. Cementite: Iron carbide (Fe3C)

The final level of classification discussed in this article is the microstructure. The three phases seen above can be combined to form different microstructures of steel. Examples of these microstructures and their general mechanical properties are shown below:

  • Martensite: the hardest and strongest microstructure, yet the most brittle
  • Pearlite: Hard, strong, and ductile but not particularly tough
  • Bainite: has desirable strength-ductility combination, harder than pearlite but not as hard as martensite

Hardening at Microscopic Scale:

The hardenability of steel is a function of the carbon content of the material, other alloying elements, and the grain size of the austenite. Austenite is a gamma phase iron and at high temperatures its atomic structure undergoes a transition from a BCC configuration to an FCC configuration.

High hardenability refers to the ability of the alloy to produce a high martensite percentage throughout the body of the material upon quenching. Hardened steels are created by rapidly quenching the material from a high temperature. This involves a rapid transition from a state of 100% austenite to a high percentage of martensite. If the steel is more than 0.15% carbon, the martensite becomes a highly strained body-centered cubic form and is supersaturated with carbon. The carbon effectively shuts down most slip planes within the microstructure, creating a very hard and brittle material. If the quenching rate is not fast enough, carbon will diffuse out of the austenitic phase. The steel then becomes pearlite, bainite, or if kept hot long enough, ferrite. None of the microstructures just stated have the same strength as martensite after tempering and are generally seen as unfavorable for most applications.

The successful heat treatment of a steel depends on three factors:

  1. The size and shape of the specimen
  2. The composition of the steel
  3. The method of quenching

1. The size and shape of the specimen

During the quenching process, heat must be transferred to the surface of the specimen before it can be dissipated into the quenching medium. Consequently, the rate at which the interior of the specimen cools is dependent on its surface area to volume ratio. The larger the ratio, the more rapid the specimen will cool and therefore the deeper the hardening effect. For example, a 3-inch cylindrical bar with a 1-inch diameter will have a higher hardenability than a 3-inch bar with a 1.5-inch diameter. Because of this effect, parts with more corners and edges are more amendable to hardening by quenching than regular and rounded shapes. Figure 2 is a sample time-temperature transformation (TTT) diagram of the cooling curves of an oil-quenched 95 mm bar. The surface will transform into 100% martensite while the core will contain some bainite and thus have a lower hardness.

Figure 2: Sample time temperature transformation (TTT) diagram also known as an isothermal transformation diagram

2.  The composition of the steel

It’s important to remember that different alloys of steel contain different elemental compositions. The ratio of these elements relative to the amount of iron within the steel yield a wide variety of mechanical properties. Increasing the carbon content makes steel harder and stronger but less ductile. The predominant alloying element of stainless steels in chromium, which gives the metal its strong resistance to corrosion. Since humans have been tinkering with the composition of steel for over a millennium, the number of combinations is endless.

Because there are so many combinations that yield so many different mechanical properties, standardized tests are used to help categorize different types of steel. A common test for hardenability is the Jominy Test, shown in Figure 3 below. During this test a standard block of material is heated until it is 100% austenite. The block is then quickly moved to an apparatus where it is water quenched. The surface, or the area in contact with the water, is immediately cooled and the rate of cooling drops as a function of distance from the surface. A flat is then ground onto the block along the length of the sample. The hardness at various points is measured along this flat. This data is then plotted in a hardenability chart with hardness as the y-axis and distance as the x-axis.

Figure 3: Diagram of a Jominy end quench specimen mounted during quenching (left) and post hardness testing (right)

Hardenability curves are constructed from the results of Jominy Tests. Examples of a few steel alloy curves are shown in Figure 4. With a diminishing cooling rate (steeper drop in hardness over a short distance), more time is allowed for carbon diffusion and the formation of a greater proportion of softer pearlite. This means less martensite and a lower hardenability. A material that retains higher hardness values over relatively long distances is considered highly hardenable. Also, the greater the difference in hardness between the two ends, the lower the hardenability. It is typical of hardenability curves that as the distance from the quenched end increases, the cooling rate decreases. 1040 steel initially has the same hardness as both 4140 and 4340 but cools extremely quickly over the length of the sample. 4140 and 4340 steel cool at a more gradual rate and therefore have a higher hardenability. 4340 has a less extreme rate of coolness relative to 4140 and thus has the highest hardenability of the trio.

Figure 4: Hardenability charts for 4140, 1040 and 4340 steels

Hardenability curves are dependent on carbon content. A greater percentage of carbon present in steel will increase its hardness. It should be noted that all three alloys in Figure 4 contain the same amount of carbon (0.40% C).  Carbon is not the only alloying element that can have an effect on hardenability. The disparity in hardenability behavior between these three steels can be explained in terms of their alloying elements. Table 1 below shows a comparison of the alloying content in each of the steels. 1040 is a plain carbon steel and therefore has the lowest hardenability as there are no other elements besides iron to block the carbon atoms from escaping the matrix. The nickel added to 4340 allows for a slightly greater amount of martensite to form compared to 4140, giving it the highest hardenability of these three alloys. Most metallic alloying elements slow down the formation of pearlite, ferrite and bainite, therefore they increase a steel’s hardenability.

Table 1: Shows the alloying contents of 4340, 4140, and 1040 steel

Type of Steel: Nickel (wt %): Molybdenum (wt %): Chromium (wt %):
4340 1.85% 0.25% 0.80%
4140 0.00% 0.20% 1.00%
1040 0.00% 0.00% 0.00%

There can be a variation in hardenability within one material group. During the industrial production of steel, there are always slight unavoidable variations in the elemental composition and average grain size from one batch to another. Most of the time a material’s hardenability is represented by maximum and minimum curves set as limits.

Hardenability also increases with increasing austenitic grain size. A grain is an individual crystal in a polycrystalline metal. Think of a stained glass window (like the one seen below), the colored glass would be the grains while the soldering material holding it altogether would be the grain boundaries. Austenite, ferrite, and cementite are all different types of grains that make up the different microstructures of steel. It is at the grain boundaries that the pearlite and bainite will form. This is detrimental to the hardening process as martensite is the desired microstructure, the other types get in the way of its growth. Martensite forms from the rapid cooling of austenite grains and its transformation process is still not well understood. With increasing grain size, there are more austenite grains and fewer grain boundaries. Therefore, there are fewer opportunities for microstructures like pearlite and bainite to form and more opportunities for martensite to form.

Figure 5: The colorful glass pieces represent grains of austenite which transforms into the desirable martensite upon quenching. The black portions in between the color portions represent grain boundaries. Sites where pearlite or bainite will form upon quenching.

3. The method of quenching

As previously stated, the type of quench affects the cooling rate. Using oil, water, aqueous polymer quenchants, or air will yield a different hardness through the interior of the workpiece. This also shifts the hardenability curves. Water produces the most severe quench followed by oil and then air. Aqueous polymer quenchants provide quenching rates between those of water and oil and can be tailored to specific applications by changing the polymer concentration and temperature. The degree of agitation also affects the rate of heat removal. The faster the quenching medium moves across the specimen, the greater the quenching effectiveness. Oil quenches are generally used when a water quench may be too severe for a type of steel as it may crack or warp upon treatment.

Figure 6: Metalworker quenching casts in an oil bath

Machining Hardened Steels:

The type of cutter that should be chosen for processing tools chosen for machining a workpiece after hardening depends on a few different variables. Not counting the geometric requirements specific to the application, two of the most important variables are the material hardness and its hardenability. Some relatively high-stress applications require a minimum of 80% martensite to be produced throughout the interior of the workpiece. Usually, moderately stressed parts only require about 50% martensite throughout the workpiece. When machining a quenched metal with very low hardenability a standard coated solid carbide tool may work without a problem. This is because the hardest portion of the workpiece is limited to its surface. When machining a steel with a high hardenability it is recommended that you use a cutter with specialized geometry that is for that specific application. High hardenability will result in a workpiece that is hard throughout its entire volume. Harvey Tool has a number of different cutters for hardened steel throughout the catalog, including drills, end mills, keyseat cutters, and engravers.

Summary:

Hardenability is a measure of the depth to which a ferrous alloy may be hardened by the formation of martensite throughout its entire volume, surface to core. It is an important material property you must consider when choosing a steel as well as cutting tools for a particular application. The hardening of any steel depends on the size and shape of the part, the molecular composition of the steel, and the type of quenching method used.

Save Time With Quick Change Tooling

Making a manual tool change on any CNC machine is never a timely or rewarding process. Typically, a tool change in a standard holder can take up to 5 minutes. Add that up a few times, and suddenly you have added significant minutes to your production time.

As CNC machine tool and cutting tool technology has advanced, there are more multi-functional tools available to help you avoid tool changes. However, sometimes it just isn’t feasible, and multiple tool changes are needed. Luckily, Micro 100 has developed a revolutionary new method to speed up tool changes significantly.

What is the Micro-Quik™ Tooling System?

Developed in Micro 100’s world-class grinding facility in Meridian, Idaho, the Micro 100 Micro-Quik™ tooling system is held to the same standards and tight tolerances as all of the Micro 100 carbide tooling.

The quick change tooling system allows for highly repeatable tool changes that save countless hours without sacrificing performance. This system combines a unique tool holder with a unique tool design to deliver highly repeatable and accurate results.

Each quick change tool holder features a locating/locking set screw to secure the tool and a locating pin which helps align the tool for repeatability. Removing a tool is as simple as loosening the set screw and inserting its replacement.

During tool changes, the precision ground bevel on the rear of the tool aligns with a locating pin inside the tool holder. The distance from this locational point to the tip of the tool is highly controlled under tight tolerances, meaning that the Micro-Quik™ tooling system ensures a very high degree of tool length and centerline repeatability. The “L4” dimension on all of our quick change tools, as seen in the image above, remains consistent across the entire product line. Check out the video below for a demonstration of the Micro 100 Micro-Quik™ system in action!

Quick Change Tooling Benefits

The most obvious benefit to using Micro 100’s Micro-Quik™ system is the time savings that come with easier tool changes. By using the quick change holders in combination with quick change tooling, it is easy to reduce tool changes from 5 minutes to under 30 seconds, resulting in a 90% decrease in time spent swapping out tools. This is a significant benefit to the system, but there are benefits once the tool is in the machine as well.

As mentioned above, the distance from the locational point on each tool shank to the tip of the tool is highly controlled, meaning that regardless of which type of tool you insert into the holder, your stick out will remain the same. This allows you to have confidence in the tooling and does not require additional touch offs, which is another major time saver.

By removing additional touch-offs and tool changes from your workflow, you also reduce the chances for human or machine error. Improper touch-offs or tool change errors can cause costly machine crashes and result in serious repairs and downtime. With the Micro 100 Micro-Quik™ system, initial setups become much easier, allowing you to hit the cycle start button with total confidence for each run.

By making a few simple changes to your tool holding configurations and adopting the Micro-Quik™ system, your shop can save thousands in time saved, with less machine downtime and increased part production. To learn more about the Micro 100 Micro-Quik™ cutting tools and tool holders, please visit (URL here to quick change page).

KAD Models – Featured Customer

Established in 2012, KAD Models is a small, yet steadily growing prototype machine shop, which originated in the San Francisco Bay Area and has since opened its second location in Vermont. They have been a regional leader in the advanced manufacturing space for many years, and operate in close connection with other machine shops and related businesses like turning facilities, anodizers, welders, and more. KAD Models staff is comprised of diverse occupational backgrounds (e.g. mechanic, industrial engineer, blacksmith, etc.). Further, they have invested into their local community college and technical training programs to support an expanding talent pipeline for advanced manufacturing.

Brian Kippen is the owner & founder of KAD Models & Prototypes, Inc. Before launching KAD with model maker John Dove, Brian worked as the Director of Operations at A&J Product Solutions and a machinist at Performance Structures. Brian is drawn to the challenge of making design concepts into reality, and motivated by the ever-changing landscape of machining. Brian took time to speak with us about KAD Models, his experiences, machining techniques, and so much more.

Can you give us a little background on how KAD Models was started?

I worked for a few years repairing automobiles, then following high school, I attended college for about three weeks. After some strong encouragement from my mom, I moved out west. I joined the Marines, broke both of my feet, and was honorably discharged. Then, I got my broken foot in the door at a machine shop and knew what I wanted to be when I grew up. After years of working as a machinist, I went into business with one of my previous employers. After a year and a half, the partnership degraded and I made the decision to buy out my partner.

It’s been really gratifying to see the business grow and get to know different types of customers as the shop’s reputation spreads. One of the reasons I wanted to start my own shop is that I really wanted to see the industry evolve in a new way, to better meet people’s needs. It’s been really great to see that decision and the investments I’ve made in building KAD pay off.

We produce approximately $1.5M of parts for 100+ distinct clients each year.  Since its founding in 2012, KAD has continued on a steady path of growth, adding staff, equipment, and clients without marketing or advertising. We build a broad range of products such as automotive drive axles, silicone cardiovascular valves, and fully functional consumer product models. Due to the nature of prototyping, no component is outside of the realm of possibility. 

What machines are currently in your shop?

We use Haas CNC machines. At our West coast facility, we have six machines, five vertical 4 AXIS machining centers with capacities up to 26” Y AND 50” X and one 5 AXIS universal machining center. At our East coast facility, we currently have two new CNC ONE 3 AXIS and one 5 AXIS universal machining center paired with a Trinity Automation AX5 robotic cell. I decided to get a 5 axis milling machine earlier last year because I felt we should invest before the absolute necessity arose. I’m excited about the creative options it opened up and it’s been fun to put it to good use. We are currently using both Fusion 360 and Surfcam software.

What sets KAD Models apart from the competition?

Our quick turnaround time of 3-5 days with our ability to tackle very complex parts sets KAD apart from a majority of manufacturers.

I also think our willingness to really dig in with the client and get to know what they need and why. We have a really creative team here at KAD and thrive at not only building complex parts, but helping industrial designers and engineers think through manufacturing, design, and usage requirements to build the simplest, most effective product we can. I’ve created prototypes before, just from a conversation with someone – not even a CAD drawing. It’s these types of interesting challenges that made me want to be a machinist in the first place and that keeps me engaged and excited day-to-day.

KAD Models is an innovative company. Can you speak about what innovations KAD makes?

Well, KAD works with some of the most innovative companies out there, across all kinds of industries: medical devices, aerospace, automotive, and consumer electronics. We help people at the forefront of innovation bring their ideas to life, so I’d say innovation is basically our bread and butter. As far as our innovations in process, as I said before, KAD has a really creative team. Since we are well known for prototyping and since prototype manufacturing need not follow all the common work holding rules, we break them on a daily basis.

What is your favorite part of your job?

I love the challenge of taking on seemingly impossible ideas and turning them into tangible things. I’m really satisfied when I can come home after a long day and have held the things I’ve made in my hands. I’m also really proud to be a business owner. It’s incredibly rewarding to see a team you’ve taught and grown to take on and be inspired by the same types of problems as you. It’s been really cool to see what we’ve been able to accomplish for our clients. My personal passion remains automotive.  KAD has reverse-engineered many no longer available automobile components and designed parts that upgrade vintage Datsuns.

Why is high-quality tooling important to you?

In prototyping, you often get one chance in order to make deadlines. High quality and high-performance tools allow you to get this done without question. Given 95% of our tooling is either Helical or Harvey, I would say that high-quality tooling helps us out on a daily basis. We also use High Efficiency Milling (HEM) techniques, which Helical is optimized for. We find with long cutters and with deep pockets, HEM is almost a must.  Often though, on shallow areas, it’s overkill.  As with salt, there can be too much. 

If you could give one piece of advice to a new machinist what would it be?

Fail fast and fail often. Then learn from your mistakes. 

I think the biggest thing is getting to know other machinists, learning other methods, and being open to alternative ideas. It’s important to keep your mind open because there’s always more than one way to machine something. One of the things I’ve found most rewarding about running my own shop is getting to set the tone of how we work with other shops and adjacent industries. I’m really passionate about the manufacturing community as a whole and I’m glad blogs like this exist to help draw connections amongst us.

Also, don’t be afraid to challenge the status quo. I love working with new machinists because they bring different ideas to the table. That’s really important for innovation and to keep us all moving forward.

Feel free to check them out at www.kadmodels.com or on Instagram @kadmodels or stop by their west coast shop in California or new east coast location in Vermont.

Grappling with Graphite: A Machining Guide

Despite being a softer material, graphite is actually one of the most difficult materials to machine. There are many considerations machinists need to make in terms of tooling, coolant use, and personal safety when it comes to machining graphite parts. This “In The Loupe” post will examine graphite’s material properties, the key machining techniques to consider, and tips for properly selecting cutting tools to achieve success in this tricky material.

What is Graphite?

While graphite is an allotrope of carbon, the two terms are not simply interchangeable. Carbon is an element that can form into several different allotropes including graphite, diamond, and fullerite. Graphite happens to be the most stable form of carbon, and is the most common, as carbon naturally occurs as graphite under standard conditions.

Graphite is most recognized for its superior conductivity and resistance to high heat and corrosion. This makes it a common material in high heat, high-pressure situations in the aerospace, electrode, nuclear, energy, and military industries.

graphite cnc material

Even though graphite can handle intense high-pressure situations with ease, it is actually a very soft, abrasive, and brittle material. This can cause serious challenges when machining, as graphite can eat up cutting tools, and severely minimize a tool’s usable life. However, with the proper tooling and techniques, there are ways to optimize graphite machining to be more cost-effective than the competition.

Graphite Machining Techniques

Since graphite is such a soft and brittle material, special consideration needs to be made when machining to avoid chipping it. To get a good cut, it is recommended that you take light chip loads and use lower feed rates in graphite. If you were to take a heavy cut at a fast feed rate, you would start chipping the graphite and could cause it to fracture completely. To give a comparison point, chip loads for graphite are similar to those for Aluminum materials, but with less than half the feed rate.

To give you an idea of speeds and feeds for graphite, here is an example using a 1/4″ Harvey Tool CVD Diamond Coated, 4 flute Square End Mill. If that tool was running at a standard RPM of 12,000 at 780 SFM, the recommended chip load would be .00292 for a feed rate of 140 IPM.

graphite electrode machining

In terms of machine setup, the one major tip to remember is to always avoid using coolant. Graphite is a fairly porous material, and so it can absorb coolant and act as a “coolant sponge,” which will cause problems with finished parts. Inside the machine and on the tooling, the coolant can actually react with the graphite dust and create an abrasive slurry, which will cause problems while machining. A vacuum system is recommended for clearing material while machining graphite. Otherwise, coated tools should be able to run dry.

Another thing to note when machining graphite is that because graphite does not produce chips, but rather a cloud of very abrasive dust, it can be harmful to operators and machines without proper care. Operators should be wearing a protective mask to avoid inhaling the graphite dust. Proper ventilation and maintaining air quality in the shop is also key for the protection of machinists when working in graphite.

Since the graphite dust is also extremely conductive, it can easily damage non-protective circuits inside your CNC machine, which can cause major electrical issues. While coolant is not recommended, a vacuum system can help to remove the dust, keeping it from accumulating too much inside the machine and preventing serious problems.

Cutting Tools for Graphite Machining

As previously mentioned, graphite is a notorious cutting tool-killer due to its extremely abrasive nature. Even the highest quality carbide end mills, if left uncoated, will wear quickly on most graphite jobs. This extreme wear may force a tool change during an operation, which could lead to an imperfection in the part when trying to restart the operation where the worn tool left off.

graphite cutting tools

When selecting a cutting tool for graphite machining, the coating and cutting edge is the most important consideration. Flute count, helix angles, and other key features of the tool geometry ultimately come second to the coating when purchasing tooling for graphite.

For graphite machining, a CVD (Chemical Vapor Deposition) diamond coating is recommended whenever possible to maximize tool life and tool performance. These coatings are grown directly into the carbide end mill, improving the hardness and leaving the tool with a coating layer that is 5 times thicker than a PVD Diamond Coating. While not the sharpest edge, the CVD diamond coating provides much longer tool life than other diamond coatings due to the thicker diamond layer.

Even though initial tooling costs may be higher with CVD coated tools versus uncoated tools, since CVD coated tools see considerably longer tool life than uncoated tools, this makes the cost per part shrink significantly. In difficult, abrasive materials like graphite, the uncoated carbide tool will last a short time before the abrasiveness of the graphite completely wears down the cutting edge. Having a CVD coated tool will give you a leg up over the competition, keep your machine running with less downtime for tool changes, and ultimately deliver substantial cost savings.

end mills for graphite
CVD Diamond Coated End Mill from Harvey Tool

Overall, graphite can be a difficult material to machine, but with the right cutting tools and proper speeds and feeds you will be making quality parts in no time. Harvey Tool offers a wide selection of CVD coated end mills in various diameters, reaches, and lengths of cut to ensure you have what you need for any job that comes your way.

New Dublin Ship Fittings – Featured Customer

New Dublin Ship Fittings was established in 2017 by Lucas Gilbert, and is located on the scenic south shore of Nova Scotia, Canada.  Lucas began his career with a formal education in machining and mechanical engineering. In the early 2000’s, Lucas got into the traditional shipbuilding industry made famous in the region he grew up in, Lunenburg County, Nova Scotia. It is then when Lucas identified the need for quality marine hardware and began making fittings in his free time. After some time, Lucas was able to start New Dublin Ship Fittings and pursue his lifelong dream of opening a machine shop and producing custom yacht hardware.

Lucas was our grand prize winner in the #MadeWithMicro100 Video Contest! He received the $1,000 Amazon gift card, a Micro-Quik™ Quick Change System with some tooling, and a chance to be In the Loupe’s Featured Customer for February. Lucas was able to take some time out of his busy schedule to discuss his shop, how he got started in machining, and the unique products he manufactures.

How did you start New Dublin Ship Fittings?

I went to school for machine shop and then mechanical engineering, only to end up working as a boat builder for 15 years. It was during my time as a boat builder that I started making hardware in my free time for projects we were working on. Eventually, that grew into full-time work. Right now, we manufacture custom silicon bronze and stainless fittings only. Eventually, we will move into a bronze hardware product line.

Where did your passion for marine hardware come from?

I’ve always loved metalworking. I grew up playing in my father’s knife shop, so when I got into wooden boats, it was only a matter of time before I started making small bits of hardware. Before hardware, I would play around making woodworking tools such as chisels, hand planes, spokeshaves, etc.

What can be found in your shop?

The shop has a 13”x 30” and 16”x 60” manual lathe, a Bridgeport Milling Machine, Burgmaster Turret Drill Press, Gang Drill, Bandsaw, 30-ton hydraulic press, #2 Hossfeld Bender, GTAW, and GMAW Welding Machines, as well as a full foundry set up with 90 pounds of bronze pour capacity. We generally only work in 655 silicon bronze and 316 stainless steel.

What projects have you worked on that stand out to you?

I’ve been lucky to work on several amazing projects over the years. Two that stand out are a 48’ Motorsailer Ketch built by Tern Boatworks, as well as the 63’ Fusion Schooner Farfarer, built by Covey Island Boatworks. Both boats we built most of the bronze deck hardware for.

I’ve made many interesting fittings over the years. I prefer to work with bronze, so I generally have the most fun working on those. I’m generally the most interested when the part is very
challenging to make and custom work parts are often very challenging. I’m asked to build or machine a component that was originally built in a factory and is difficult to reproduce with limited machinery and tooling, but I enjoy figuring out how to make it work.

Why is high-quality tooling important to you?

When I first started I would buy cheaper tooling to “get by” but the longer I did it, the more I realized that cheaper tooling doesn’t pay off. If you want to do quality work in a timely fashion, you need to invest in good tooling.

What Micro 100 Tools are you currently using?

Currently, we just have the Micro 100 brazed on tooling but we have been trying to move more into inserts so we are going to try out Micro’s indexable tooling line. After receiving the Micro-Quik™ Quick Change System, we are looking forward to trying out more of what (Micro 100) has to offer. This new system should help us reduce tool change time, saving us some money in the long run.

What makes New Dublin Ship Fittings stand out from the competition?

I think the real value I can offer boat builders and owners over a standard job shop is my experience with building boats. I understand how the fitting will be used and can offer suggestions as to how to improve the design.

If you could give one piece of advice to a new machinist what would it be?

The advice I would give to new machinists is to start slow and learn the machines and techniques before you try to make parts quickly. There is a lot of pressure in shops to make parts as fast as possible, but you’ll never be as fast as you can be if you don’t learn the processes properly first. Also, learn to sharpen drill bits well!