Tag Archive for: miniature tooling

Hybrid Machining – Featured Customer

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Featured Image Courtesy of Jeff Robinson, Hybrid Machining

Located in Holland, MI, Hybrid Machining uses machining skills combined with 3 different 3D printing technologies to manufacture complex projects. Hybrid Machining is a manufacturing company that can take the customer’s design from start to finish, allowing customers to dictate their path. Rather than focusing on a single product, Hybrid has listened to customer needs and presented solutions that, in many cases, customers didn’t know were possible. Jeff Robinson, the owner, took some time out of his day to answer some questions about Hybrid Machining.

How did you get into manufacturing?  

I started working in an architectural shop during my high school years.  I quickly realized that there was a more advanced part of the industry that I was missing out on. Therefore, I started researching CNC Routing.  I fell in love with the technology and have been studying it ever since. 

What sort of machines and materials do you use in your shop?

We currently run a Datron Neo, Fanuc Robodrill, and a CR Onsrud 5-axis Router. We work primarily with wood, plastic, and non-ferrous materials. We currently use Autodesk Fusion 360, FeatureCAM, Powermill, Vectric Aspire, and AlphaCAM for CAM.  For CAD, we run Fusion 360, Inventor, and Solidworks.

hybrid machining datron neo
Photo Courtesy of: Jeff Robinson, Hybrid Machining

When did you start using 3D printing and how has it benefitted you?

I have been 3D printing for just over a year.  It was the first technology that we initiated here at Hybrid Machining, and it has allowed us to provide the best solution to the customer no matter what the requirements are. By expanding into 3D printing, we can help the customer decide which technology will work the best for their part. Many times, we take the “Hybrid” approach and use both additive and subtractive technologies together.

How have you adapted during the Covid-19 outbreak and how has it changed your business?

We started by stopping normal production to form a non-profit called 3DC19 with other local, small business owners with the sole purpose of 3D printing and assembling plastic face shields.  Hybrid Machining became the distribution center for the efforts.  Collectively, we produced and donated 75K articles of PPE to local hospitals, nursing homes, doctor offices, and first responders.  You can learn more about the efforts at www.3DC19.com. We have also been machining a lot of acrylic face guards for customers so that we can help them to get their office staff back to work safely. 

fanuc robodrill machine
Photo Courtesy of: Jeff Robinson, Hybrid Machining

What sets Hybrid Machining apart from the rest of the manufacturing community? 

We have a serious passion for educating our youth and local businesses on the rapid changes currently happening in the manufacturing industry and preparing them for the impact that Industry 4.0 will have on our lives in the future.  We want to produce knowledgeable people just as much as we produce products, and we do this in our unique Learning Lab.  We team up with local schools, vocational schools, and community colleges to help them spread the word about manufacturing.  We also intend to do ‘Lunch and Learns’ with local businesses to help them understand what other manufacturing methods and advanced materials are available on the market today.

What is the coolest project you have had come through the shop?

Many years ago, at my previous shop, we worked on the presidential handrail that the last three presidents stood behind during the inauguration.

hybrid machining metal business card
Photo Courtesy of: Jeff Robinson, Hybrid Machining

Are you using HEM techniques to improve cycle times? 

Yes, we use a couple of the fastest and most nimble machines on the market: the Datron NEO and the Fanuc Robodrill.  We leverage the machine’s tools’ high accelerations and deceleration rates, along with HEM, to drastically reduce cycle times for our customers.  This allows us to be competitive against over-seas importers.

What do you have to lose other than cycle time? You purchased the entire tool, not just the tip, so use it!  You will be surprised how the different the machine will sound and you can get parts done faster with less tool wear.

Why is high quality tool performance important to you?

The tooling is super important to the success of a project because the tool is what is doing the work.  I like to tell people, “Why would you buy a high-end sports car with all bells and whistles and then put crappy tires on it?  All that power and handling is worthless unless you have good tires.”  The same goes for tooling.  You can have a half-million-dollar machine that is super-fast and accurate and yet still produce a terrible part with cheap tooling. 

When was a time that Harvey Tool, Helical Solutions, or Micro 100 saved the day?

Harvey Tool helped me get through some tough composite projects in the past.  Their technical support team was extremely knowledgeable on the subject matter and helped me pick the right tool and parameters to get the job done. 

machined metal part from hybrid machining
Photo Courtesy of: Jeff Robinson, Hybrid Machining

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

NEVER STOP LEARNING.  Things may be going great at first and you think you have it all figured out, but then a new technology comes and swipes you off your feet.  Spend your spare time studying industry trends, talking to other business leaders, new and old, and preparing for the future.

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

We are extremely thankful that Harvey Tool spends a lot of time developing ‘material-specific’ tooling.  We spend 90% of our time in that section of the catalog.  We recently tested out the new wood cutters and are extremely happy. We pushed these tools at speeds and feeds that are unbelievable.  We also use the Harvey Tool plastic cutters on a regular basis. 

Here at Hybrid Machining, we are blending the lines between routing and milling.  For many decades, the line had been fairly clear. There were certain types of jobs you ran on certain types of machines.  We are blurring those lines and are using the best tools for the jobs.  For instance, we use the 24K RPM spindle on the Robodrill to run it more like a router than a mill.  Therefore, we call it the “RoboRouter”.  We can produce wood and plastic parts at unbelievable speeds while achieving surface finishes that are off the charts.  This is not conventional practice, but the team at Hybrid Machining is willing to blaze the path forward for others to follow.

To check out more about Hybrid Machining go to their website or follow them on social media!

Schon DSGN – Featured Customer

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Featured Image Courtesy of Ian Schon, Schon DSGN

In 2012, engineer Ian Schon wanted to put his skill for design to the test. He decided to challenge himself by designing a normal, everyday item: a pen. His goal was to take the pen from the design concept to manufacturing it within his own shop. Ian designed his pen how he thought a pen should be: durable, reliable, compact, leak-proof, and easy to use. Most of all, though, he wanted the pen to be of a superior quality, not something easily lost or thrown away.

With the design concept in place, Ian started his work on engineering and manufacturing his new pen. He made many prototypes, and with each discovered new features and additions to better his design. Today, Ian manufacturers his pens through local fabrications in Massachusetts, using local supplies. He makes them from 6061 Aluminum, unique in that it molds to its users’ hand, over time. His pens are designed to outlast its user and be passed on through generations.

Ian was kind enough to take time out of his busy schedule to answer some questions about his manufacturing success.

Schon DSGN silver wrist watch with black band
Photo Courtesy of: Ian Schon, Schon DSGN

What sets Schon DSGN apart from competition?

I think I have a unique approach to designing and manufacturing. I design things that I like, and make them the way that I want to.  I don’t rush things out the door. I’m not thinking about scale, growth, making a big shop, etc. I just want to live a simple life where I make cool objects, sell them, and have enough time in the week to sneak out into the woods and ride my bike. This ethos takes the pressure off a lot, and that makes the workflow freer without as much stress as I had in my past career as a product development engineer.

This workflow isn’t for everyone. it’s not a winning combo for massive business success, per se, and if you audited me you would tell me I’m holding back by not scaling and hiring, but I like it. I see myself as a hybrid between artist and entrepreneur. I love doing things start to finish, blank paper to finished part on the machine. Owning that entire workflow allows for harmony of engineering, machining, tooling, finishing, R+D, marketing, etc. Further, it ensures that I don’t miss critical inflection points in the process that are ripe for process evolution and innovation, resulting in a better product in the end.

I’m sure the way I do things will change over time, but for now I’m still figuring things out and since I work largely alone (I have one amazing helper right now assisting with assembly, finishing, and shipping) I have lots of flexibility to change things and not get stuck in my ways.

Also, by working alone, I control the music. Key!

schon dsgn turning metal on lathe
Photo Courtesy of: Ian Schon, Schon DSGN

Where did your passion for pens come from?

My friend Mike had a cool pen he got from a local shop and I was like “man I like that,” so I made one with some “improvements.” At the time, in my mind, they were improvements, but I have learned now that they were preferences, really. I made a crappy pen on a lathe at the MIT MITERS shop back in 2010, and that summer I bought a Clausing lathe on craigslist for $300 and some tooling and started figuring it all out. I made a bunch of pens, wrote with them, kept evolving them, and eventually people asked me to make pens for them.  I didn’t really intend to start a business or anything, I just wanted to make cool stuff and use it. Bottle openers, knives, bike frames, etc. I made lots of stuff. Pens just stuck with me and I kept pushing on it as a project for my design portfolio. Eventually it became something bigger. Turns out my pen preferences were shared with other people.

Schon dsgn gold and copper metal pens
Photo Courtesy of: Ian Schon, Schon DSGN

What is the most difficult product you have had to make and why?

Making watch cases – wow. What an awful part to try and make on a desktop Taig 3 axis mill and a Hardinge lathe in my apartment! I started working on machining watch cases in 2012, and I finished my first one in my apartment in 2015 (to be fair, I was working on lots of other stuff during that time! But yeah, years…). What a journey. Taught me a lot. Biting off more than you can chew is a great way to learn something. 

What is the most interesting product you’ve made?

When I worked at Essential Design in Boston I worked on the front end of a Mass Spectrometer. The requirements on the device were wild. We had high voltage, chemical resistance, crazy tolerances, mechanism design, machining, injection molding – truly a little bit of everything! It was a fun challenge that I was fortunate to be a part of. Biomolecule nanoscale analysis device. Try saying that ten times fast.

I have something fountain pen related in the works now that I find more interesting, and very, very complex, but it’s under wraps a bit longer. Stay tuned. 

Schon dsgn gold and copper metal pens
Photo Courtesy of: Ian Schon, Schon DSGN

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

I have made watches for some incredible customers, but I unfortunately cannot talk about who they are. Most of my watch work outside of my own parts is also under NDA which is a bummer, but hey it was great work regardless.

Same thing with the pens. I know that some of my pen are in the touring cases of a few musicians, one of which is in the rock and roll hall of fame. But I have to keep it tight!

Before leaving to work for myself, I was part of a design team at IDEO in Cambridge that designed the new Simplisafe Home Security System. As an engineer and designer, I got listed on the patents. That wasn’t machining and was more design and engineering of injection molded plastic assemblies,  but it was still cool, though! Cutting my teeth in the design industry before machining helps me a lot with the creative process in the workshop. Lots of overlap.

What capabilities does your shop have?

I utilize Citizen L series sliding headstock machines to run my company. These are Swiss Machines (though made in Japan) with twin spindles and have live tooling for milling operations. I got into this type of machining after getting advice from friends in the industry and subcontracting my work to shops with these style of machines for 7 years.

Beyond the Swiss Machines, I have a new Precision Matthews Manual Mill, a Southbend Model A, a Hardinge Cataract Lathe, and a bunch of smaller Derbyshire lathes and mills. Most of these are for maintenance related tasks – quick mods and fixtures and my watchmaking/R&D stuff. I also have a Bantam Tools Desktop CNC machine on the way, a nice machine for quick milled fixtures in aluminum and nonferrous materials. I tested this machine during their development phases and was really impressed.

What CAM/CAD software are you using?

I use Fusion 360 for quick milled stuff, but most of my parts are programmed by hand since the lathe programming for Swiss work can be done without much CAM. I’m sure I could be doing things better on the programming side, but hey, every day I learn something new. Who knows what I’ll be doing a year or two from now?

schon dsgn turning wrist watch on lathe
Photo Courtesy of: Ian Schon, Schon DSGN

What is your favorite material to work with and why?

Brass and Copper. The chips aren’t stringy, it’s easy to cut quickly and the parts have this nice hefty feel to them. Since I make pens, the weight is a big piece of the feeling of a pen. The only downside is I’m constantly figuring out ways to not dent the parts as they are coming off the machines! My brass parts are like tiny brass mallets and they LOVE to get dinged up in the ejection cycles. I ended up making custom parts catchers and modifying the chutes on the machines to navigate this. I might have some conveyors in my future….yeah. Too many projects!

schon dsgn disassembled wrist watch
Photo Courtesy of: Ian Schon, Schon DSGN

Why is high quality tool performance important to you?

It’s not just important, it’s SUPER important. As a solo machinist running my own machines, being able to call a tooling company and get answers on how I should run a tool, adjust its RPM, feed, DOC, or cutting strategy to get a better result is invaluable. I find that as much as I’m paying for tool performance, I’m also paying for expertise, wisdom and answers. Knowing everything is cool and all (and I know some of you out there know everything under the sun), but since I don’t know everything, it’s so nice to be able to pick up a phone and have someone in my corner. These tech support people are so crucial. Being humble and letting support guide me through my tooling challenges has helped me grow a lot. It’s like having a staff of experienced machinists working at my company, for free! Can’t beat that. Micro 100 and Helical have helped me tons with their great support.

schon dsgn multicolored fountain pens
Photo Courtesy of: Ian Schon, Schon DSGN

When was a time that Harvey, Helical or Micro product really came through and helped your business?

The Helical team (shout out to Dalton) helped me nail some machining on some very wild faceted pens I was working on this month. When I switched to Helical, my finishes got crazy good. I just listened to recommendations, bought a bunch of stuff, and kept trying what Dalton told me to. Eventually, that led to a good recipe and manageable tool wear. It was great!

I also like how representatives from the Harvey/Helical/Micro family often cross reference each other and help me find the right solution, regardless of which company I’m getting it from. Nice system.

The quiet hero in my shop is my Micro 100 quick change system. It just works great. Fast to swap tools, easy to setup, cannot argue with it! Too good. 

Schon DSGN silver wrist watch with black band
Photo Courtesy of: Ian Schon, Schon DSGN

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

Find a mentor who supports you and challenges you. Find a good tooling company, or good tooling companies, and make good relationships with their tech support so you can get answers. Make good relationships with service technicians who can help you fix your machines. Be a good person. Don’t let yourself become a hot head under the pressure of this industry (since it can be hard at times!), cooler heads prevail, always. Be open to seeing things from other viewpoints (in life and in machining), don’t be afraid to flip a part around and start over from square one.

To learn more about Ian and Schon DSGN, follow them @schon_dsgn and @the_schon on Instagram and check out his website. And, to learn more about how Ian got his start in the manufacturing industry, check out this video.

Successful Slotting With Miniature Cutting Tools

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Whether your tool is a 1” diameter powerhouse rougher or a .032” precision end mill, slotting is one of the hardest operations on the tool. During slotting operations, a lot of force and pressure is placed on the entire cutting edge of the tool. This results in slower speeds and feeds and increased tool wear, making it one of the nastier processes even for the best cutting tools.

With miniature tooling (for the purposes of this blog, under 1/8” diameter) the game changes. The way we approach miniature tooling is completely different as it relates to slotting. In these instances, it is vitally important to select the correct tool for these operations. A few of the suggestions may surprise you if you are used to working with larger tooling, but rest assured, these are tried and tested recommendations which will dramatically increase your success rate in miniature slotting applications.

Use as Many Flutes as Possible

When running traditional slotting toolpaths, the biggest concern with the cutting tool is getting the best chip evacuation by using the proper flute count. Traditionally speaking, you want to use the fewest amount of flutes possible. In Aluminum/Non-Ferrous jobs, this is typically no more than 2/3 flutes, and in Steel/Ferrous applications, 4 flutes is recommended. The lower flute count leaves room for the chips to evacuate so you are not re-cutting chips and clogging the flutes on your tool in deep slots.

Achieve Increased Efficiency With Miniature Tooling – Utilize Harvey Tool’s Speeds & Feeds Charts Today

When slotting with miniature tools, the biggest concerns are with tool rigidity, deflection, and core strength. With micro-slotting we are not “slotting”, but rather we are “making a slot”. In traditional slotting, we may drive a ½” tool down 2xD into the part to make a full slot, and the tool can handle it! But this technique simply isn’t possible with a smaller tool.

graphic showing difference between core sizes on 3 flute and 5 flute slotting tools

For example, let’s take a .015” end mill. If we are making a slot that is .015” deep with that tool, we are likely going to take a .001” to .002” axial depth per pass. In this case, chips are no longer your problem since it is not a traditional slotting toolpath. Rigidity and core strength are now key, which means we need to add as many flutes as possible! Even in materials like Aluminum, 4 or 5 flutes will be a much better option at smaller diameters than traditional 2/3 flute tools. By choosing a tool with a higher flute count, some end users have seen their tool life increase upwards of 50 to 100 times over tools with lower flute counts and less rigidity and strength.

Use the Strongest Corner Possible When Slotting

Outside of making sure you have a strong core on your miniature tools while making a slot, you also need to take a hard look at your corner strength. Putting a corner radius on your tooling is a great step and does improve the corner strength of the tool considerably over a square profile tool. However, if we want the strongest tip geometry, using a ball nose end mill should also be considered.

A ball nose end mill will give you the strongest possible tip of the three most common profiles. The end geometry on the ball nose can almost work as a high feed end mill, allowing for faster feed rates on the light axial passes that are required for micro-slotting. The lead angle on the ball nose also allows for axial chip thinning, which will give you better tool life and allow you to decrease your cycle times.

.078" harvey tool ball nose end mill for slotting
A .078″ ball nose end mill was used for this miniature slotting operation

Finding the Right Tool for Miniature Slotting Operations

Precision and accuracy are paramount when it comes to miniature tooling, regardless of whether you are slotting, roughing, or even simply looking to make a hole in a part. With the guidelines above, it is also important to have a variety of tooling options available to cater to your specific slotting needs. Harvey Tool offers 5 flute end mills down to .015” in diameter, which are a great option for a stronger tool with a high flute count for slotting operations.

miniature .010" harvey tool end mill
Harvey Tool offers many miniature end mill options, like the .010″ long reach end mill above.

If you are looking to upgrade your corner strength, Harvey Tool also offers a wide selection of miniature end mills in corner radius and ball nose profiles, with dozens of reach, length of cut, and flute count options. Speeds and feeds information for all of these tools is also available, making your programming of these difficult toolpaths just a little bit easier.

speeds and feeds chart ad

Achieving Slotting Success: Summary

To wrap things up, there are three major items to focus on when it comes to miniature slotting: flute count, corner strength, and the depth of your axial passes.

It is vital to ensure you are using a corner radius or ball nose tool and putting as many flutes as you can on your tool when possible. This keeps the tool rigid and avoids deflection while providing superior core strength.

For your axial passes, take light passes with multiple stepdowns. Working your tool almost as a high feed end mill will make for a successful slotting operation, even at the most minuscule diameters.

How to Optimize Results While Machining With Miniature End Mills

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 The machining industry generally considers micromachining and 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 micromachining. If you are using these tools in a repetitive application, then optimization of this process is key.

Size Comparison for Harvey Tool’s #13901 Square Miniature End Mill

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.

chart comparing tool diameter for runout in micromachining with miniature end mills
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.

chart of edge radius in relation to chip thickness for micromachining
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 in Conventional vs. Micromachining Applications

Tool deflection has a much greater impact on the formation of chips and accuracy of the operation in micromachining 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).

burr formation mechanism using a miniature end mill
Figure 2: Burr formation mechanism using a miniature end mill 

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.

Micromachining 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 End Mill

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 miniature end mills 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 in Micromachining Applications

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 With Miniature End Mills

Try to minimize runout and deflection as much as possible when micromachining with miniature end mills. 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 micromachining 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.
variable pitch versus non-variable pitch
Figure 3: Variable pitch tool (yellow) vs. a non-variable pitch tool (black)

New Dublin Ship Fittings – Featured Customer

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Featured Image Courtesy of Lucas Gilbert, New Dublin Ship Fittings

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.

New Dublin Ship Fittings shop

Photo Courtesy of: New Dublin Ship Fittings

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.

cnc machined boat parts

Photo Courtesy of: New Dublin Ship Fittings

What projects have you worked on at New Dublin Ship Fittings 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.

cnc milled boat cleat

Photo Courtesy of: New Dublin Ship Fittings

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.

cnc machined rigging

Photo Courtesy of: New Dublin Ship Fittings

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!

How to Select a Spindle

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When trying to develop efficient processes, many machinists and programmers turn to tool selection first. It is true that tooling can often make a big difference in machining time, and speeds and feeds, but did you know that your machine’s spindle can have an equally impactful effect? The legs of any CNC machine, spindles are comprised of a motor, a taper for holding tools, and a shaft that will hold all of the components together. Often powered by electricity, spindles rotate on an axis which receives its input from the machine’s CNC controller.

Why is Choosing the Right Spindle Important?

Choosing the right spindle to machine your workpiece with is of very high importance to a successful production run. As tooling options continue to grow, it is important to know what tooling your spindle can utilize. Large diameter tools such as large end mills or face mills typically require slower spindle speeds and take deeper cuts to remove vast amounts of material. These applications require supreme machine rigidity and require a spindle with high torque.

Contrastingly, smaller diameter tools will need a higher-speed spindle. Faster speeds and feeds deliver better surface finishes and are used in a variety of applications. A good rule of thumb is that an end mill that is a half inch or smaller will run well with lower torque.

Types of CNC Spindles

After finding out what you should look for in a spindle, it is time to learn about your different options. Spindles typically vary by the type, style of the taper, or its size. The taper is the conical portion of the tool holder that fits inside of the opening of the spindle. Every spindle is designed to mate with a certain taper style and size.

properly selecting a spindle

CAT and BT Holders

This is the most widely utilized holder for milling in the United States. Referred to as “V-flange holders,” both of these styles need a retention knob or pull stud to be secured within the machine spindle. The BT (metric style) is popular overseas.

HSK Holders

This type of holder is a German standard known as “hollow shank taper.” The tapered portion of the holder is much shorter than its counterparts. It also engages the spindle in a different way and does not require a pull stud or retention knob. The HSK holder is utilized to create repeatability and longer tool life – particularly in High Efficiency Milling (HEM) applications.

All of these holders have benefits and limitations including price, accuracy, and availability. The proper selection will depend largely on your application requirements.

Torque vs. Horsepower

Torque is defined as force perpendicular to the axis of rotation across a distance. It is important to have high torque capabilities when using an end mill larger than ½ inch, or when machining a difficult material such as Inconel. Torque will help put power behind the cutting action of the tool.

Horsepower refers to the amount of work being done. Horsepower is important for smaller diameter end mills and easy-to-machine materials like aluminum.

You can think of torque as a tractor: It can’t go very fast, but there is a lot of power behind it. Think of horsepower as a racecar: It can go very fast but cannot pull or push.

Torque-Horsepower Chart

Every machine and spindle should come with a torque horsepower chart. These charts will help you understand how to maximize your spindle for torque or horsepower, depending on what you need:

Haas spindle horsepower and torque chart
Image Source: HAAS Machine Manual

Proper Spindle Size

The size of the spindle and shank taper corresponds to the weight and length of the tools being used, as well as the material you are planning to machine. CAT40 is the most commonly used spindle in the United States. These spindles are great for utilizing tools that have a ½ inch diameter end mill or smaller in any material. If you are considering using a 1 inch end mill in a material like Inconel or Titanium, a CAT50 would be a more appropriate choice. The higher the taper angle is, the more torque the spindle is capable of.

While choosing the correct tool for your application is important, choosing a tool your spindle can utilize is paramount to machining success. Knowing the amount of torque required will help machinists save a lot of headaches.

How to Advance Your Machining Career: 8 Tips From Machining Pros

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Since we began shining a light on Harvey Performance Company brand customers via “In the Loupe’s,” Featured Customer posts, more than 20 machinists have been asked to share insight relevant to how they’ve achieved success in advancing their machining career. Each Featured Customer post includes interesting and useful information on a variety of machining-related subjects, including prototyping ideas, expanding a business, getting into machining, advantages and disadvantages of utilizing different milling machine types, and more. This post compiles 8 useful tips from our Featured Customers on ways to advance your machining career.

Tip 1: Be Persistent – Getting Your Foot in the Door is Half the Battle

With machining technology advancing at the amazing rate that it is, there is no better time to become a machinist. It is a trade that is constantly improving, and offers so many opportunities for young people. Eddie Casanueva of Nueva Precision first got into machining when he was in college, taking a job at an on-campus research center for manufacturing systems to support himself.

“The research center had all the workings of a machine shop,” Eddie said. “There were CNC mills, lathes, injection molding machines, and more. It just looked awesome. I managed to get hired for a job at minimum wage sweeping the shop floor and helping out where I could.

As a curious student, I would ask a million questions… John – an expert machinist – took me under his wing and taught me lots of stuff about machining. I started buying tools and building out my toolbox with him for a while, absorbing everything that I could.”

One of the best things about becoming a machinist is that there is a fairly low entry barrier. Many machinists start working right out of high school, with 12-18 months of on-the-job training or a one to two year apprenticeship. Nearly 70% of the machinist workforce is over the age of 45. The Bureau of Labor Statistics is predicting a 10% increase in the machinist workforce with opportunities for 29,000 additional skilled machinists by 2024, so it is certainly a great time to get your foot in the door.

Tip 2: Keep an Open Mind – If You Can Think of It, You Can Machine It

Being open-minded is crucial to becoming the best machinist you can be. By keeping an open mind, Oklahoma City-based company Okluma’s owner Jeff Sapp has quickly earned a reputation for his product as one of the best built and most reliable flashlights on the market today. Jeff’s idea for Okluma came to him while riding his motorcycle across the country.

“I had purchased what I thought was a nice flashlight for $50 to carry with me on the trip. However, two days in to the trip the flashlight broke. Of course, it was dark and I was in the middle of nowhere trying to work on my bike. I’m happy to pay for good tools, but that wasn’t what happened. Not only was there no warranty for replacement, there was no way to fix it. It was just made to be thrown away. That whole attitude makes me angry. When I got home, I decided I was going to put my new skills to work and design and build my own flashlight, with the goal of never running into an issue like I had on my trip ever again. I started by making one for myself, then four, then twenty. That was four years ago. Now I have my own business with one employee and two dogs, and we stay very busy.”

An awesome side benefit to working as a machinist is that you have all the resources to create anything you can dream of, like Jeff did with Okluma.

machining career

Image courtesy of Okluma.

Tip 3: Be Patient – Take Time to Ensure Your Job is Setup Correctly before Beginning

The setup process is a huge part of machining, but is often overlooked. Alex Madsen, co- owner of M5 Micro in Minnesota, has been working in manufacturing for more than 11 years. Alex is also a part owner of World Fabrication, and owns his own job shop called Madsen Machine and Design. Alex has spent countless hours perfecting his setup to improve his part times.

“It is certainly challenging to use little tools, but the key is to not get discouraged. You should plan on lots of trial and error; breaking tools is just a part of the game. You may buy ten end mills and break six, but once you dial one in it will last the rest of the job.

You should also make sure to put extra time and effort into understanding your machine when working on micromachining jobs. You need to know where there is any backlash or issues with the machine because with a tiny tool, even an extra .0003” cut can mean the end of your tool. When a difference of one tenth can make or break your job, you need to take your time and be extra careful with your machine, tool inspection, and programming before you hit run.”

Tip 4: Effort Pays Off In Your Machining Career – Long Hours Result in Shop Growth

Success isn’t earned overnight. That is especially true in the machining world. Becoming a good machinist takes a great deal of sacrifice, says Josh from Fleet Machine Co. in Gloucester, MA.

“Opening your own shop involves more than learning how to program and machine. You also need to be willing to sacrifice some of your free time by working long hours to build your business from the ground up. Being a great machinist is important, but you also need to understand the basics of business, and you need to be able to sell your service and maintain a certain level of quality to keep your customers coming back.”

Working hard is a common theme we hear from our featured customers. Brothers Geordan and Nace Roberts of Master Machine Manufacturing have similar advice.

“We often need to work odd hours of the day to maintain the business, but we do it in a way that makes sure we have our family time. There are many times where we will go home, have dinner and hang out with the family, and wait until they are all sleeping to go back to work until two or three a.m. We will get back home later that morning to sleep a little and have breakfast with the family and send them on their way before heading back into the shop.” Starting and growing a business takes time. Every machinist starts from the beginning and through hard work and determination, grows their business.

Liberty Machine cnc mill

Image courtesy of Liberty Machine Inc.

Tip 5: Utilize Tooling from Quality Manufacturers – All Tooling Isn’t Created Equal

When it comes down to it, tooling is singlehandedly the biggest choice you will make in your machining career. Grant Hughson, manufacturing engineer at Weiss Watch Company who works as a manufacturing instructor in his spare time, reflected on the importance of tooling.

“Tool to tool accuracy and performance is vital in this business, especially with our extremely tight tolerances. High quality tools make sure that we get the same performance time after time without needing to scrap parts. This saves us valuable time and money.”

While opting for cheaper tooling can appear to be beneficial when just starting out, before long, machinists are losing time and money because of unpredictability. Jonathan from TL Technologies echoed this point, saying:

“We feel that if we invested so much in these high-end machining centers, it would be criminal to put insufficient tooling and holders into them. We found that by selecting the proper tool with the appropriate sciences behind it we have been able to create products with a cost per cut that is not only competitive, but required to stay current. By keeping the quality as high as possible on the part making side of things, we’ve insured as much ease and reliability into our downstream process as we could. Quality tooling also provides predictability and added safety into the workflow. High-quality carbide tooling is the lifeblood of the business.”

Additional Thoughts Regarding Boosting Your Machining Career With Tooling:

Don’t Cheap Out

  • “The additional cost is always worth the payoff in the end knowing that you have a tool that will produce quality parts and shave valuable minutes off your cycle times. The slightly higher cost of the Harvey/Helical product is small change compared to the long term cost savings associated with their performance” – Seth, Liberty Machine

Consistency is Key

  • “We know the performance we are going to get from the tools is consistent, and we can always rely on getting immaculate finishes. While using the Harvey Tool and Helical product, we can confidently walk away from the machine and come back to a quality finished part every time.” – Bennett, RIT Baja SAE

Superior Specialty Tools

  • “One of the greatest things that I’ve experienced over the past year and a half is flexibility. We’ve asked for some specific tools to be made typically, the lead times that we found were beyond what we needed. We went through the Helical specials division and had them built within a couple of weeks. That was a game changer for us.” – Tom, John Force Racing

“Having high quality tooling like Helical is essential. Helical tools help us maintain a much higher machining efficiency because of the outstanding tool life, while also achieving more aggressive run times. In addition, we are able to consistently keep high tolerances, resulting in a better final product.” – Cameron, Koenig Knives

Tip 6: Get With the Times – Join the Social Media Community

Social media is a valuable tool for machinists. With ever-increasing popularity in networks such as Facebook, LinkedIn, Twitter, and Instagram, there will always be an audience to showcase new and unique products to. We asked a few of our featured customers how they incorporated social media into their machining career and the benefits that come along with it.

“A lot of our sales come through Instagram or Facebook, so I would recommend those platforms to anyone who is trying to start a business,” Jeff from Okluma said. “We have also had a lot of success collaborating with others in the community. Typically it is something we couldn’t do ourselves, or they couldn’t do themselves, so we share the labor and collaborate on some really cool items.”

Tip 7: Value Your Customers – Always Put Them First

“In the Loupe’s” featured customers repeatedly emphasized the importance of putting customers first. It’s a simple concept to master, and pays off immensely as you advance in your machining career. Repeat customers tell you that you are doing something right, said Brian Ross, owner of Form Factory.

“We have kept our customers happy and consistently deliver parts on time, so we get a lot of repeat business. Word definitely gets around on how you treat people so we try to treat everyone with respect and honesty which is key to running a good business.” Jeff from Okluma takes great pride in his customer service, saying “we only sell direct to consumers through our website so we can control our lifetime warranty. It has worked really well for us so far, so we have no plans to change that right now. I care more about our customers than any retailer is able to.”

man examining machined part for machining career

Image courtesy of MedTorque.

Tip 8: Never Stop Learning – Ask Questions Whenever You Can as Your Machining Career Advances

Hopefully some of these tips from our featured customers stuck with you in exploring a machining career. To leave you with a quote from of Seth Madore, owner of Liberty Machine, “Don’t stop learning. Keep your ears open and your mouth shut,” “That old guy in the shop has likely forgotten more than you will ever learn. The amount of tools in your Kennedy box doesn’t mean you’re a good machinist. Some of the best toolmakers I knew had small boxes with only the common tools. Learn how to excel with limited resources. Ask questions, and own up to your mistakes.”

An Introduction to Reamers & CNC Reaming

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Most machinists are familiar with CNC drilling, but did you know that the common practice for holemaking is to always use a reamer? When done correctly, reaming can be a fast and highly accurate operation that results in precision holes.

Critical Reamer Geometries

reamers
Harvey Tool Miniature Reamer

By examining a Harvey Tool Miniature Reamer and its critical dimensions, we can better understand the functionality of this useful tool. In the above image of a straight flute reamer, D1 references the reamer diameter, the specific size intended for your hole; and D2 points to the shank diameter. At Harvey Tool, reamer shanks are oversized to help maintain tool strength, stiffness, and accuracy. Shanks also have an h6 tolerance, which is crucial for high precision tool holders, such as heat shrink collets. Other critical dimensions of a reamer include its overall length (L1), margin length (L2), overall reach (L3), and chamfer length (L4).

Harvey Tool also offers Miniature Reamers – Right Hand Spiral. This tool is designed to leave a superior part finish and help with chip evacuation in blind hole applications.

miniature reamer

The Functions of Miniature Reamers

Reamers Provide Precision – As mentioned earlier, reamers are great for machining precision hole diameters. To use a reamer properly, you must first have a pre-drilled hole that’s between 90% and 94% of the final hole diameter. For example, if you need a finished a hole of .220″, your predrilled hole should be somewhere between .1980″ and .2068″. This allows the tool to take enough material off to leave a great finish, but does not overwork it, potentially causing damage. The tolerance for uncoated reamers is +.0000″/-.0002″, while the tolerance for AlTiN coating is +.0002″/-.0000″. These tolerances provide you the peace of mind of knowing that your hole will meet exact specifications.

Achieve a Quality CNC Finish – When a high surface finish is required of a hole, reamers should always be used to reach the desired tolerance. Both the pre-drilled hole and the tool’s margin help to keep the reamer centered while cutting, leading to a better finish.

miniature reamer and end mill

Minimize Machining Production Runs – For machine shops, consistency is a priority. This is especially true in production runs. The last thing a machinist wants to see is an oversized hole on a part they have already preformed many operations on. Remember, reamers have the benefit of offering consistent hole size, preventing an out of tolerance finish. These consistent holes lead to valuable time savings and reduced scrap costs.

CNC Machining Exotic Alloys: When machining Inconel, titanium, and other high-cost materials, reaming your hole is important to ensure that the desired finish specification is met. With reamers, a machinists can better predict tool life, leading to a better finished product and less scrap ratios. It is important to note that Harvey Tool reamers are offered AlTiN coated and fully stocked in every .0005” increment from .0080” to .0640”.

Main Differences Between Engravers & Marking Cutters

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While similar on the surface, Half-round Engraving Cutters and Marking Cutters are actually very different. Both tools are unique in the geometries they possess, the benefits they offer, and the specific purposes they’re used for. Below are the key differences that all machinists must know, as the engraving on a part is often a critical step in the machining process.

Engravers & Marking Cutters Serve Different Purposes

All Marking Cutters are Engraving Cutters, but not all Engraving Cutters are Marking Cutters. This is because Marking Cutters are a “type” of engraving tool. By virtue of their sturdier geometry, these tools are suited for applications requiring repetition such as the engraving of serial numbers onto parts. Harvey Tool has been able to customize specific tool geometries for ferrous and non-ferrous applications, offering Marking Cutters for material specific purposes.

engraver

Engraving Cutters, on the other hand, are meant for finer detailed applications that require intricate designs such as engraving a wedding band or a complex brand design.

engraver

These Tools Have Unique Geometry Features

Historically, Engraving Cutters have been made as a half round style tool. This tool allows for a true point, which is better for fine detail, but can easily break if not run correctly. Because of this, these tools have performed well in softer materials such as aluminum and wood, especially for jobs that require an artistic engraving with fine detail.

Marking cutters are not as widely seen throughout the industry, however. These tools hold up in harder-to-machine materials exceedingly well. Marking Cutters are a form of Engraving Cutter that contain 2 flutes and a web at the tip, meaning that the tool has a stronger tip and is less susceptible to breakage.

tip details of an engraver versus marking cutter

While these tools do not contain a true point (due to their web), they do feature shear flutes for better cutting action and the ability to evacuate chips easier when compared to a half-round engraver.

Harvey Tool Product Offering

Harvey Tool offers a wide variety of both Engraving Cutters and Marking Cutters. Choose from a selection of pointed, double-ended, tip radius, and tipped-off Engraving Cutter styles in 15 included angles ranging from 10° to 120°.

types of cnc engraver tips

Marking Cutters are fully stocked in tip radius or tipped-off options, and are designed specifically for either ferrous or non-ferrous materials. They are are offered in included angles from 20° to 120°.

While Engraving Cutters are offered uncoated or in AlTiN, AlTiN Nano, or Amorphous Diamond coatings, Marking Cutters are fully stocked in uncoated, AlTiN, or TiB2 coated styles.

Add Fine Details to Your Parts With Harvey Tool’s Expansive Selection of Marking Cutters

Marking Cutters & Engravers Summarized

While both Engraving Cutters and Marking Cutters can accomplish similar tasks, each tool has its own advantages and purpose. Selecting the correct tool is based largely on preference and applicability to the job at hand. Factors that could impact your selection would be final Depth of Cut, Width of Cut, the angle needing to be achieved, and the desired detail of the engraving.

Effective Ways to Reduce Heat Generation

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Any cutting tool application will generate heat, but knowing how to counteract it will improve the life of your tool. Heat can be good and doesn’t need to totally be avoided, but controlling heat will help prolong your tool life. Sometimes, an overheating tool or workpiece is easy to spot due to smoke or deformation. Other times, the signs are not as obvious. Taking every precaution possible to redirect heat will prolong your tool’s usable life, avoid scrapped parts, and will result in significant cost savings.

Reduce Heat Generation with HEM Tool Paths

High Efficiency Milling (HEM), is one way a machinist should explore to manage heat generation during machining. HEM is a roughing technique that uses the theory of chip thinning by applying a smaller radial depth of cut (RDOC) and a larger axial depth of cut (ADOC). HEM uses RDOC and ADOC similar to finishing operations but increases speeds and feeds, resulting in greater material removal rates (MRR). This technique is usually used for removing large amounts of material in roughing and pocketing applications. HEM utilizes the full length of cut and more effectively uses the full potential of the tool, optimizing tool life and productivity. You will need to take more radial passes on your workpiece, but using HEM will evenly spread heat across the whole cutting edge of your tool, instead of building heat along one small portion, reducing the possibility of tool failure and breakage.

heat generation in HEM

Chip Thinning Awareness

Chip thinning occurs when tool paths include varying radial depths of cut, and relates to chip thickness and feed per tooth. HEM is based off of the principal of chip thinning. However, if not properly executed, chip thinning can cause a lot of heat generation. When performing HEM, you effectively reduce your stepover and increase your speeds and feeds to run your machine at high rates. But if your machine isn’t capable of running high enough speeds and feeds, or you do not adjust accordingly to your reduced stepover, trouble will occur in the form of rubbing between the material and tool. Rubbing creates friction and mass amounts of heat which can cause your material to deform and your tool to overheat. Chip thinning can be good when used correctly in HEM, but if you fall below the line of reduced stepover without higher speeds and feeds, you will cause rubbing and tool failure. Because of this, it’s always important to be aware of your chips during machining.

heat generation in HEM

Consider Climb Milling

There are two ways to cut materials when milling: conventional milling and climb milling. The difference between the two is the relationship of the rotation of the cutter to the direction of feed. In climb milling, the cutter rotates with the feed, as opposed to conventional milling where the cutter rotates against the feed.

When conventional milling, chips start at theoretical zero and increase in size, causing rubbing and potentially work hardening. For this reason, it’s usually recommended for tools with higher toughness or for breaking through case hardened materials.

In climb milling, the chip starts at maximum width and decreases, causing the heat generated to transfer into the chip instead of the tool or workpiece. When going from max width to theoretical zero, heat will be transferred to the chip and pushed away from the workpiece, reducing the possibility of damage to the workpiece. Climb milling also produces a cleaner shear plane which will cause less tool rubbing, decreasing heat and improving tool life. When climb milling, chips are removed behind the cutter, reducing your chances of re-cutting. climb milling effectively reduces heat generated to the tool and workpiece by transferring heat into the chip, reducing rubbing and by reducing your chances of re-cutting chips.

heat generation

Utilize Proper Coolant Methods

If used properly, coolant can be an extremely effective way to keep your tool from excessive heat generation. There are many different types of coolant and different ways coolant can be delivered to your tool. Coolant can be compressed air, water-based, straight oil-based, soluble oil-based, synthetic or semi-synthetic. It can be delivered as mist, flood, high pressure or minimum quantity lubricant.

Different applications and tools require different types and delivery of coolant, as using the wrong delivery or type could lead to part or tool damage. For instance, using high pressure coolant with miniature tooling could lead to tool breakage. In materials where chip evacuation is a major pain point such as aluminum, coolant is often used to flush chips away from the workpiece, rather than for heat moderation. When cutting material that produces long, stringy chips without coolant, you run the risk of creating built-up edge from the chips evacuating improperly. Using coolant will allow those chips to slide out of your toolpath easily, avoiding the chance of re-cutting and causing tool failure. In materials like titanium that don’t transfer heat well, proper coolant usage can prevent the material from overheating. With certain materials, however, thermal shock becomes an issue. This is when coolant is delivered to a very hot material and decreases its temperature rapidly, impacting the material’s properties. Coolant can be expensive and wasteful if not necessary for the application, so it’s important to always make sure you know the proper ways to use coolant before starting a job.

Importance of Controlling Heat Generation

Heat can be a tool’s worst nightmare if you do not know how to control it. High efficiency milling will distribute heat throughout the whole tool instead of one small portion, making it less likely for your tool to overheat and fail. By keeping RDOC constant throughout your toolpath, you will decrease the chances of rubbing, a common cause of heat generation. Climb milling is the most effective way to transfer heat into the chip, as it will reduce rubbing and lessen the chance of re-chipping. This will effectively prolong tool life. Coolant is another method for keeping temperatures moderated, but should be used with caution as the type of coolant delivery and certain material properties can impact its effectiveness.