Schon DSGN – Featured Customer

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.

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!

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.

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. 

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?

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!

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.

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. 

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.

Rennscot LLC – Featured Customer

David Bamforth is the founder and CEO of Rennscot LLC, a manufacturing company based out of Woburn, Massachusetts, which was created to meet product design demands of both individual and commercial clients. From idea to prototype, and eventually to final product, Rennscot LLC prides itself on its ability to make part ideas come to life. David took some time to talk with us about Rennscot LLC, his company’s machining capabilities, and much more.

What capabilities does your shop have?

We are mostly a mill shop with two verticals and one 5-axis machine. We also have a small bar fed lathe, a larger sub-spindle live-tooling lathe, and some design tools like a Faro Design Scan Arm. We work predominantly with aluminum, but sometimes see brass, stainless, titanium, and steel alloy jobs come through. We use Fusion 360 for everything and currently all 4 of our machines are Haas.

What sets Rennscot LLC apart from the competition?

We are a bit different from most shops because, in addition to machining services, we also offer design services. A lot of our jobs are won because we are a one-stop-shop from idea to producing the final product. Recently we have been making a lot of parts for vehicle restoration. Typically, we are just handed a part and asked to reproduce it.

David, what is your favorite part of your job?

Problem solving and learning new skills. We are a pretty young team and love being challenged by new projects. We also pride ourselves on being pretty innovative with our machining strategies to help reduce lead times and cost for our customers.

Where did your passion for automobiles come from?

Like many, I have always been passionate about cars. I have some great memories of going to car shows with my dad and watching any TV show with a car in it as a kid. Nowadays, I spend my personal time taking our shop development car, a Porsche Cayman, to the track.

What is the coolest product you have made?

We have had some pretty unusual characters bring us some really cool projects. Currently, we are working with a guy from Connecticut on laser scanning a model Mercedes C10 Le Mans car that we will CAD model, so a full-sized car body can be reproduced. It’s a really interesting project, trying to take a 1:43 car and blow it up to full size. Eventually, we will help design and manufacture many of the machined components on this car. Also, we once made a custom billet alternator mount in just 5 days for a 996 Porsche GT3 with a Chevy LS engine in it. We really enjoyed being part of that project and the V8 sounded amazing on track!

What is the most difficult product you have made?

We once worked on an enclosure for a handheld x-ray machine. The part was only about 1”x 1.25” x4” and only had .040” walls all around. The main pocket was machined with our go-to Helical ¼” reduced shank end mill. It also had #0-80 taps all along the top edge of the enclosure, making for a few broken taps! It was a pain to get dialed in but once the process was proved out it was really rewarding to get consistent good parts off the will.

Why is high quality tool performance important to you?

Once we started using high quality end mills, we immediately saw an improvement in tool life and surface finish. We also really enjoy using tools that are backed by a company that puts out so much information and resources to help its customers out.

When was a time that Harvey Tool or Helical products really came through and helped your business?

We have had several moments when we hit a wall while building a process for a new part, and Helical’s phone support helped us find the perfect tool for the process. The combination of great phone support, having such a vast array of product offerings, and all of the tools always being in stock has helped my business tremendously.

Are you guys using High Efficiency Milling (HEM) techniques to improve cycle times?

Always! All our mills are spec’ed with HSM and 12k RPM spindles, and we take full advantage of this with chip breaking roughers. Honestly, we are so young that we have only ever used HEM techniques, so I’m honestly just confused by companies that don’t use it. Not using HEM is like not driving a car on the highway because it’s too fast.

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

Machining is probably the most in demand and most satisfying industries that someone can get into now-a-days. There are a lot of companies that are in demand for green machinists who are just eager to learn. I would recommend putting together and sending out a resume to local shops that shows that you have the ability to take on projects and complete them.

If anyone is interested in learning more about what we do our manufacturing website, rennscotmfg.com is a great resource. Also, check us our on Instagram at @rennscot.

Successful Slotting With Miniature Cutting Tools

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.

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.

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

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.

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. If you need even smaller tooling, there are 4 flute options available down to .005” in diameter.

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.

Conclusion

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

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

Key Cutting Differences between Conventional and Miniature End Mills

Runout

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

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

Chip Thickness

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

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

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

Tool Deflection

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

Workpiece Homogeny

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

Surface Finish

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

Tool Path Best Practices for Miniature End Mills

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

Ramping Into a Part

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

Machining in Circular Paths

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

Slotting with a Miniature Tool

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

Slowing Down Your Feed Around Corners

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

Climb Milling vs. Conventional Milling

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

Combined Roughing and Finishing Operations

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

Helpful Tips for Achieving Successful Micromachining Operations

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

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