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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!

5 Things to Know About Helical’s High Feed End Mills

Helical Solutions‘ High Feed End Mills provide many opportunities for machinists, and feature a special end profile to increase machining efficiencies. A High Feed End Mill is a High Efficiency Milling (HEM) style tool with specialized end geometry that utilizes chip thinning, allowing for drastically increased feed rates in certain applications. While standard end mills have square, corner radius, or ball profiles, this Helical tool has a specialized, very specific design that takes advantage of chip thinning, resulting in a tool that can be pushed harder than a traditional end mill.

Below are 5 things that all machinists should know about this exciting Helical Solutions product offering.

1. They excel in applications with light axial depths of cut

A High Feed End Mill is designed to take a large radial depth of cut (65% to 100% of the cutter diameter) with a small axial depth of cut (2.5% to 5% diameter) depending on the application. This makes High Feed End Mills perfect for face milling, roughing, slotting, deep pocketing, and 3D milling. Where HEM toolpaths involve light radial depths of cut and heavy axial depths of cut, High Feed End Mills utilize high radial depths of cut and smaller axial depths of cut.

2. This tool reduces radial cutting forces

The end profile of a High Feed End Mill is designed to direct cutting forces upward along the axis of the tool and into the spindle. This reduces radial cutting forces which cause deflection, allowing for longer reach tools while reducing chatter and other issues that may otherwise lead to tool failure. The reduction of radial cutting forces makes this tool excellent for use in machines with lower horsepower, and in thin wall machining applications.

3. High Feed End Mills are rigid tools

The design and short length of cut of High Feed End Mills work in tandem with the end geometry to produce a tool with a strong core, further limiting deflection and allowing for tools with greater reach lengths.

4. They can reduce cycle times

In high RDOC, low ADOC applications, High Feed End Mills can be pushed significantly faster than traditional end mills, saving time and money over the life of the tool.

5. High Feed End Mills are well suited for hard materials

The rigidity and strength of High Feed End Mills make them excellent in challenging to machine materials. Helical’s High Feed End Mills come coated with Tplus coating, which offers high hardness and extended tool life in high temp alloys and ferrous materials up to 45Rc.

In summary, High Feed End Mill tools with specialized end geometry that utilizes chip thinning and light axial depths of cut to allow for significantly increased feed rates in face milling, slotting, roughing, deep pocket milling, and 3D milling applications. The end profile of a High Feed End Mill applies cutting forces back up into the spindle, reducing radial forces that lead to deflection in long reach applications. Combining this end geometry with a stubby length of cut results in a tool that is incredibly rigid and well suited for harder, difficult to machine materials.

Benefits & Drawbacks of High and Low Helix Angles

While many factors impact the outcome of a machining operation, one often overlooked factor is the cutting tool’s helix angle. The Helix angle of a tool is measured by the angle formed between the centerline of the tool and a straight line tangent along the cutting edge.

A higher helix angle, usually 40° or more, will wrap around the tool “faster,” while a “slower” helix angle is usually less than 40°.

When choosing a tool for a machining operation, machinists often consider the material, the tooling dimensions and the flute count. The helix angle must also be considered to contribute to efficient chip evacuation, better part finish, prolonged tool life, and reduced cycle times.

Helix Angles Rule of Thumb

One general rule of thumb is that as the helix angle increases, the length of engagement along the cutting edge will decrease. That said,
there are many benefits and drawbacks to slow and high helix angles that can impact any machining operation.

Slow Helix Tool <40°

Benefits

  • Enhanced Strength – A larger core creates a strong tool that can resist deflection, or the force that will bend a tool under pressure.
  • Reduced Lifting – A slow helix will decrease a part from lifting off of the worktable in settings that are less secure.
  • Larger Chip Evacuation – The slow helix allows the tool to create a large chip, great for hogging out material.

Drawbacks

  • Rough Finish – A slow helix end mill takes a large chip, but can sometimes struggle to evacuate the chip. This inefficiency can result in a sub-par part finish.
  • Slower Feed Rate – The increased radial force of a slow helix end mill requires running the end mill at a slower feed rate.

High Helix Tool >40°

Benefits

  • Lower Radial Force – The tool will run quieter and smoother due to better shearing action, and allow for less deflection and more stability in thin wall applications.
  • Efficient Chip Evacuation – As the helix angle increases, the length of cutting edge engagement will decrease, and the axial force will increase. This lifts chips out and away, resulting in efficient chip evacuation.
  • Improved Part Finish – With lower radial forces, high helix tools are able to cut through material much more easily with a better shearing action, leaving an improved surface finish.

Drawbacks

  • Weaker Cutting Teeth – With a higher helix, the teeth of a tool will be thinner, and therefore thinner.
  • Deflection Risk – The smaller teeth of the high helix tool will increase the risk of deflection, or the force that will bend a tool under pressure. This limits how fast you can push high helix tools.
  • Increased Risk of Tool Failure – If deflection isn’t properly managed, this can result in a poor finish quality and tool failure.

Helix Angle: An Important Decision

In summary, a machinist must consider many factors when choosing tools for each application. Among the material, the finish requirements, and acceptable run times, a machinist must also consider the helix angle of each tool being used. A slow helix end mill will allow for larger chip formation, increased tool strength and reduce lifting forces. However, it may not leave an excellent finish. A high helix end mill will allow for efficient chip evacuation and excellent part finish, but may be subject to increased deflection, which can lead to tool breakage if not properly managed.

High Efficiency Milling for Titanium Made Easy With Helical’s New HVTI Cutter

Titanium is a notoriously difficult material to machine, especially in aggressive toolpaths, such as those associated with High Efficiency Milling (HEM). Helical Solutions’ new line of tooling, the HVTI-6 series of end mills, is optimized specifically for this purpose, and proven to provide 20% more tool life than a competitor’s similar tool.

At face level, these new Helical end mills feature corner radius geometry, 6 flutes, and are Aplus coated for optimal tool life and increased cutting performance. But there is much more to these end mills than the typical geometry of standard 6 flute tools. The HVTI-6 was designed with a combination of a unique rake, core, and edge design that give it a leg up over standard 6 flute tools for Titanium while cutting HEM toolpaths. Click here to watch the HVTI-6 in action!

End Mills for Titanium

The design of the HVTI-6 was the result of significant testing by the Harvey Performance Company Innovation and New Product Development teams. These teams spent many months testing tools, doing in-depth analysis on materials and tool geometry, and pushing these tools through dozens of hours in the cut at testing sites across the country.

The new HVTI-6 cutter experienced higher metal removal rates (MRR) and 20% longer tool life while performing HEM in Titanium when compared to a standard 6 flute tool offered by a Helical Solutions competitor. This type of tool life improvement will produce huge cost savings on tooling, as well as shortened cycle times and lower cost per part.

Helical HVTI Titanium

The Harvey Performance Innovation team targeted Titanium grade Ti6Al4V for their testing, which accounts for the vast majority of the Titanium being machined in North America. The test part was designed and programmed to allow for a more defined agility test of the tool, taking the tool into key geometry cutting exercises like tight corners, long straight line cuts, and rapid movement.

Many hours were spent with Lyndex-Nikken, manufacturers of high-quality rotary tables, tool holders, and machining accessories, at their Chicago headquarters. By working with the team at Lyndex-Nikken, the Harvey Performance Company team was able to test under optimal conditions with top-of-the-line tool holders, work holding, and machining centers. Lyndex was also available to provide their expert support on tool holding techniques and were an integral part of the testing process for these tools. Video of the impressive test cuts taken at the Lyndex facility can be seen below.

WATCH THE HVTI IN ACTION

In these tests, the HVTI was able to run HEM toolpaths at 400 SFM and 120 IPM in Ti6Al4V, which served as the baseline for most of the testing.

While the standard 6 flute tools offered by Helical will still perform to high standards in Titanium and other hard materials (steels, exotic metals, cast iron), the HVTI-6 is a specialized, material-specific tool designed specifically for HEM toolpaths in Titanium. Advanced speeds and feeds for these new tools are already available in Machining Advisor Pro, and the complete offering is now available in the Helical CAM tool libraries for easy programming.

To learn more about the HVTI 6 Flute End Mills for Titanium, please visit the Helical Solutions website. To learn more about HEM techniques, download the HEM Guidebook for a complete guide on this advanced toolpath.

Axis CNC Inc. – Featured Customer

Axis CNC Inc was founded in 2012 in Ware, Massachusetts, when Dan and Glenn Larzus, a father and son duo, decided to venture into the manufacturing industry. Axis CNC Inc has provided customers with the highest quality manufacturing, machining, and programming services since they’ve opened. They specialize in manufacturing medical equipment and have a passion for making snowmobile parts.

We sat down with Axis CNC Inc to discuss how they got started and what they have learned over there years in the manufacturing world. Watch our video below to see our full interview.

Show Us What You #MadeWithMicro100

Are you proud of the parts you #MadeWithMicro100? Show us with a video of the parts you are making, the Micro 100 Tool used, and the story behind how that part came to be, for a chance to win a $1,000 Amazon gift card grand prize!

With the recent addition of the Micro 100 brand to the Harvey Performance Company family, we want to know how you have been utilizing its expansive tooling offering. Has Micro 100’s Micro-Quik™ system helped you save time and money? Do you have a favorite tool that gets the job done for you every time? Has Micro 100 tooling saved you from a jam? We want to know! Send us a video on Instagram and show us what you #MadeWithMicro100!

How to Participate

Using #MadeWithMicro100 and @micro_100, tag your video of the Micro 100 tools machining your parts on Instagram or Facebook. Remember, don’t share anything that could get you in trouble! Proprietary parts and trade secrets should not be on display.

Official Contest Rules

Contest Dates:

  • The contest will run between December 5, 2019 to January 17, 2020. Submit as many entries as you’d like! Entries that are submitted before or after the contest period will not be considered for the top prizes (But we’d still like to see them!)

The Important Stuff:

  1. Take a video of your Micro 100 tool in action, clear and visible.
  2. Share your video on social media using #MadeWithMicro100 and tagging @Micro_100.
  3. Detail the story behind the project (tool number(s), operation, running parameters, etc.)

Prizes

All submissions will be considered for the $1,000 Amazon gift card grand prize. Of these entries, the most impressive (10) will be put up to popular vote. All entries put up to vote will be featured on our new customer testimonial page on our website with their name, social media account, and video displayed for everybody to see.

We’ll pick our favorites, but the final say is up to you. Public voting will begin on January 21, 2020, and a winner will be announced on January 28, 2020.

The top five entries will be sent Micro 100’s Micro-Quik™ tool change system with a few of our quick change tools. The top three entries will be offered a spot as a “Featured Customer” on our “In The Loupe” blog!

The Fine Print:

  • Please ensure that you have permission from both your employer and customer to post a video.
  • All entries must be the original work of the person identified in the entry.
  • No purchase necessary to enter or win. A purchase will not increase your chances of winning.
  • On January 28, 2020, the top 5 winners will be announced to the public. The Top 5 selected winners will receive a prize. The odds of being selected depend on the number of entries received. If a potential winner cannot be contacted within five (5) days after the date of first attempt, an alternative winner may be selected.
  • The potential winners will be notified via social media. Each potential winner must complete a release form granting Micro 100 full permission to publish the winner’s submitted video. If a potential winner cannot be contacted, or fails to submit the release form, the potential winner forfeits prize. Potential winners must continue to comply with all terms and conditions of these official contest rules, and winning is contingent upon fulfilling all requirements.
  • Participation in the contest constitutes entrants’ full and unconditional agreement to and acceptance of these official rules and decisions. Winning a prize is contingent upon being compliant with these official rules and fulfilling all other requirements.
  • The Micro 100 Video Contest is open to residents in US and Canada who are at least 18 years old at the time of entry.

How Boring Bar Geometries Impact Cutting Operations

Boring is a turning operation that allows a machinist to make a pre-existing hole bigger through multiple iterations of internal boring. It has a number of advantages over traditional drilling methods:

  • The ability to cost-effectively produce a hole outside standard drill sizes
  • The creation of more precise holes, and therefore tighter tolerances
  • A greater finish quality
  • The opportunity to create multiple dimensions within the bore itself

 

Solid carbide boring bars, such as those offered by Micro 100,  have a few standard dimensions that give the tool basic functionality in removing material from an internal bore. These include:

Minimum Bore Diameter (D1): The minimum diameter of a hole for the cutting end of the tool to completely fit inside without making contact at opposing sides

Maximum Bore Depth (L2): Maximum depth that the tool can reach inside a hole without contact from the shank portion

Shank Diameter (D2): Diameter of the portion of the tool in contact with the tool holder

Overall Length (L1): Total length of the tool

Centerline Offset (F): The distance between a tool’s tip and the shank’s centerline axis

Tool Selection

In order to minimize tool deflection and therefore risk of tool failure, it is important to choose a tool with a max bore depth that is only slightly larger than the length it is intended to cut. It is also beneficial to maximize the boring bar and shank diameter as this will increase the rigidity of the tool. This must be balanced with leaving enough room for chips to evacuate. This balance ultimately comes down to the material being bored. A harder material with a lower feed rate and depths of cut may not need as much space for chips to evacuate, but may require a larger and more rigid tool. Conversely, a softer material with more aggressive running parameters will need more room for chip evacuation, but may not require as rigid of a tool.

Geometries

In addition, they have a number of different geometric features in order to adequately handle the three types of forces acting upon the tool during this machining process. During a standard boring operation, the greatest of these forces is tangential, followed by feed (sometimes called axial), and finally radial. Tangential force acts perpendicular to the rake surface and pushes the tool away from the centerline. Feed force does not cause deflection, but pushes back on the tool and acts parallel to the centerline. Radial force pushes the tool towards the center of the bore.

 

Defining the Geometric Features of Boring Bars:

Nose Radius: the roundness of a tool’s cutting point

Side Clearance (Radial Clearance): The angle measuring the tilt of the nose relative to the axis parallel to the centerline of the tool

End Clearance (Axial Clearance): The angle measuring the tilt of the end face relative to the axis running perpendicular to the centerline of the tool

Side Rake Angle: The angle measuring the sideways tilt of the side face of the tool

Back Rake Angle: The angle measuring the degree to which the back face is tilted in relation to the centerline of the workpiece

Side Relief Angle: The angle measuring how far the bottom face is tilted away from the workpiece

End Relief Angle: The angle measuring the tilt of the end face relative to the line running perpendicular to the center axis of the tool

Effects of Geometric Features on Cutting Operations:

Nose Radius: A large nose radius makes more contact with the workpiece, extending the life of the tool and the cutting edge as well as leaving a better finish. However, too large of a radius will lead to chatter as the tool is more exposed to tangential and radial cutting forces.

Another way this feature affects the cutting action is in determining how much of the cutting edge is struck by tangential force. The magnitude of this effect is largely dependent on the feed and depth of cut. Different combinations of depth of cuts and nose angles will result in either shorter or longer lengths of the cutting edge being exposed to the tangential force. The overall effect being the degree of edge wear. If only a small portion of the cutting edge is exposed to a large force it would be worn down faster than if a longer portion of the edge is succumb to the same force. This phenomenon also occurs with the increase and decrease of the end cutting edge angle.

End Cutting Edge Angle: The main purpose of the end cutting angle is for clearance when cutting in the positive Z direction (moving into the hole). This clearance allows the nose radius to be the main point of contact between the tool and the workpiece. Increasing the end cutting edge angle in the positive direction decreases the strength of the tip, but also decreases feed force. This is another situation where balance of tip strength and cutting force reduction must be found. It is also important to note that the angle may need to be changed depending on the type of boring one is performing.

Side Rake Angle: The nose angle is one geometric dimension that determines how much of the cutting edge is hit by tangential force but the side rake angle determines how much that force is redistributed into radial force. A positive rake angle means a lower tangential cutting force as allows for a greater amount of shearing action. However, this angle cannot be too great as it compromises cutting edge integrity by leaving less material for the nose angle and side relief angle.

Back Rake Angle: Sometimes called the top rake angle, the back rake angle for solid carbide boring bars is ground to help control the flow of chips cut on the end portion of the tool. This feature cannot have too sharp of a positive angle as it decreases the tools strength.

Side and End Relief Angles: Like the end cutting edge angle, the main purpose of the side and end relief angles are to provide clearance so that the tools non-cutting portion doesn’t rub against the workpiece. If the angles are too small then there is a risk of abrasion between the tool and the workpiece. This friction leads to increased tool wear, vibration and poor surface finish. The angle measurements will generally be between 0° and 20°.

Boring Bar Geometries Summarized

Boring bars have a few overall dimensions that allow for the boring of a hole without running the tool holder into the workpiece, or breaking the tool instantly upon contact. Solid carbide boring bars have a variety of angles that are combined differently to distribute the 3 types of cutting forces in order to take full advantage of the tool. Maximizing tool performance requires the combination of choosing the right tool along with the appropriate feed rate, depth of cut and RPM. These factors are dependent on the size of the hole, amount of material that needs to be removed, and mechanical properties of the workpiece.

 

The Geometries and Purposes of a Slitting Saw

When a machinist needs to cut material significantly deeper than wide, a Slitting Saw is an ideal choice to get the job done. A Slitting Saw is unique due to its composition and rigidity, which allows it to hold up in a variety of both straightforward and tricky to machine materials.

What is a Slitting Saw?

A Slitting Saw is a flat (with or without a dish), circular-shaped saw that has a hole in the middle and teeth on the outer diameter. Used in conjunction with an arbor, a Slitting Saw is intended for machining purposes that require a large amount of material to be removed within a small diameter, such as slotting or cutoff applications.

Other names for Slitting Saws include (but are not limited to) Slitting Cutters, Slotting Cutters, Jewelers Saws, and Slitting Knives. Both Jewelers Saws and Slitting Knives are particular types of Slitting Saws. Jewelers Saws have a high tooth count enabling them to cut tiny, precise features, and Slitting Knives are Slitting Saws with no teeth at all. On Jewelers Saws, the tooth counts are generally much higher than other types of saws in order to make the cuts as accurate as possible.

Key Terminology

Why Use a Slitting Saw?

These saws are designed for cutting into both ferrous and non-ferrous materials, and by utilizing their unique shape and geometries, they can cut thin slot type features on parts more efficiently than any other machining tool.

Common Applications:

  1. Separating Two Pieces of Material
    1. If an application calls for cutting a piece of material, such as a rod, in half, then a slitting saw will work well to cut the pieces apart while increasing efficiency.
  2. Undercutting Applications
    1. Saws can perform undercutting applications if mounted correctly, which can eliminate the need to remount the workpiece completely.
  3. Slotting into Material
    1. Capable of creating thin slots with a significant depth of cut, Slitting Saws can be just the right tool for the job!

When Not to Use a Slitting Saw

While it may look similar to a stainless steel circular saw blade from a hardware store, a Slitting Saw should never be used with construction tools such as a table or circular saw.  Brittle saw blades such as slitting saws will shatter when used on manual machines, and can cause injury when not used on the proper set up.

In Conclusion

Slitting Saws can be beneficial to a wide variety of machining processes, and it is vital to understand their geometries and purpose before attempting to utilize them in the shop. They are a great tool to have in the shop and can assist with getting jobs done as quickly and efficiently as possible.