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Introduction to High Efficiency Milling

The following is just one of several blog posts relevant to High Efficiency Milling. To achieve a full understanding of this popular machining method, view any of the additional HEM posts below!

High Speed Machining vs. HEM I How to Combat Chip Thinning I Diving into Depth of Cut I How to Avoid 4 Major Types of Tool Wear I Intro to Trochoidal Milling


High Efficiency Milling (HEM) is a strategy that is rapidly gaining popularity in the metalworking industry. Most CAM packages now offer modules to generate HEM toolpaths, each with their own proprietary name. In these packages, HEM can also be known as Dynamic Milling or High Efficiency Machining, among others. HEM can result in profound shop efficiency, extended tool life, greater performance, and cost savings. High performance end mills designed to achieve higher speeds and feeds will help machinists to reap the full benefits of this popular machining method.

High Efficiency Milling Defined

HEM is a milling technique for roughing that utilizes a lower Radial Depth of Cut (RDOC) and a higher Axial Depth of Cut (ADOC). This spreads wear evenly across the cutting edge, dissipates heat, and reduces the chance of tool failure.

This strategy differs from traditional or conventional milling, which typically calls for a higher RDOC and lower ADOC. Traditional milling causes heat concentrations in one small portion of the cutting tool, expediting the tool wear process. Further, while Traditional Milling call for more axial passes, HEM toolpaths use more passes radially.

For more information on optimizing Depth of Cut in relation to HEM, see Diving into Depth of Cut: Peripheral, Slotting & HEM Approaches.

High Efficiency Milling

Built-In CAM Applications

Machining technology has been advancing with the development of faster, more powerful machines. In order to keep up, many CAM applications have developed built-in features for HEM toolpaths, including Trochoidal Milling, a method of machining used to create a slot wider than the cutting tool’s cutting diameter.

HEM is largely based on the theory surrounding Radial Chip Thinning, or the phenomenon that occurs with varying RDOC, and relates to the chip thickness and feed per tooth. HEM adjusts parameters to maintain a constant load on the tool through the entire roughing operation, resulting in more aggressive material removal rates (MRR). In this way, HEM differs from other high performance toolpaths, which involve different methods for achieving significant MRR.

Virtually any CNC machine can perform HEM – the key is a fast CNC controller. When converting from a regular program to HEM, about 20 lines of HEM code will be written for every line of regular code. A fast processor is needed to look ahead for the code, and keep up with the operation. In addition, advanced CAM software that intelligently manages tool load by adjusting the IPT and RDOC is also needed.

HEM Case Studies

The following example shows the result a machinist had when using a Helical Solutions HEV-5 tool to perform an HEM operation in 17-4PH stainless steel. While performing HEM, this ½” diameter, 5-flute end mill engaged the part just 12% radially, but 100% axially. This machinist was able to reduce tool wear and was able to complete 40 parts with a single tool, versus only 15 with a traditional roughing toolpath.

The effect of HEM on a roughing application can also be seen in the case study below. While machining 6061 aluminum with Helical’s H45AL-C-3, a 1/2″, 3-flute rougher, this machinist was able to finish a part in 3 minutes, versus 11 minutes with a traditional roughing toolpath. One tool was able to make 900 parts with HEM, a boost of more than 150% over the traditional method.

Importance of Tooling to HEM

Generally speaking, HEM is a matter of running the tool – not the tool itself. Virtually every tool can perform HEM, but using tooling built to withstand the rigors of HEM will result in greater success. While you can run a marathon in any type of shoes, you’d likely get the best results and performance from running shoes.

HEM is often regarded as a machining method for larger diameter tooling because of the aggressive MRR of the operation and the fragility of tooling under 1/8” in size. However, miniature tooling can be used to achieve HEM, too.

Using miniature tooling for HEM can create additional challenges that must be understood prior to beginning your operation.

Best Tools for HEM:

  • High flute count for increased MRR.
  • Large core diameter for added strength.
  • Tool coating optimized for the workpiece material for increased lubricity.
  • Variable Pitch/Variable Helix design for reduced harmonics.

Key Takeaways

HEM is a machining operation which continues to grow in popularity in shops worldwide. A milling technique for roughing that utilizes a lower RDOC and higher ADOC than traditional milling, HEM distributes wear evenly across the cutting edge of a tool, reducing heat concentrations and slowing the rate of tool wear. This is especially true in tooling best suited to promote the benefits of HEM.

Magnuson Superchargers – Featured Customer

Magnuson Superchargers is a manufacturer of aftermarket and OEM (Original Equipment Manufacturer) supercharger systems for the automotive industry, located in Ventura, California. Started by industry legend Jerry Magnuson, Magnuson Superchargers has quickly grown into one of the most respected brands in the automotive industry. Magnuson creates products for various brands, including GM, Mopar, Ford, AUDI, Mercedes-Benz, Lexus, Toyota, and Jeep. Magnuson Superchargers are most commonly found in “hot rods,” everyday vehicles, off-road vehicles, and vehicles purpose built for competitive racing, as they are used to significantly yet reliably increase horsepower.

The Magnuson Superchargers team of technicians combine modern and time-tested prototyping and fabrication techniques to construct each component to exact specifications and the highest quality. Magnuson has a complete machine shop in house for fabrication of new prototype system components. This allows them to operate efficiently with short runs and high volume production.

magnuson superchargers

Hubert Gromek, Magnuson Superchargers’ Machine Shop Manager, is a 15-year veteran of the industry. We spoke with Hubert about his experiences building a career in the manufacturing industry, his advice for young machinists, and the way he and his team use both Harvey Tool and Helical Solutions tools in their machine shop every day.


Tell us a little bit about yourself.

I started with Magnuson Superchargers 15-plus years ago as a young kid who didn’t know anything about machining at all. Being a major car guy and drag racer, working for a company that makes superchargers was a perfect fit for me.  I started by deburring and washing parts and worked my way up to operating our Fadal Vertical Mills.

From there I started to get the concept of what it actually takes to machine things and started learning how to do all the setups; I even started making my own fixtures here and there. After a couple of years of being the setup guy for our shop, I started looking into the programming aspect of the job and that really grabbed my interest right away. It’s one thing to run and set up machines with other people’s programs and instruction, but it’s a whole new world when you have to do the entire job from scratch on your own.

magnuson superchargers

After a couple of years of being the Lead Setup Programmer here at our shop, I was given the opportunity to be the Machine Shop Manager. I was very honored that the owner of such a big and great company thought I had what it takes to run the whole shop. Let me tell you, when you are responsible for everything that goes on in a machine shop, it really opens your eyes to how much every little thing matters. The one thing I learned very quickly is how important it is to have the right team in your shop to support you and reach the goals that are set. It doesn’t matter how great a manager or programmer you are, if you don’t have the right team of machinists in your shop, you are setting yourself up for failure. After many years of trying, I think I have finally found that team that I’ve been looking for.

What made you get into machining?

It was when I first saw a raw piece of material (billet aluminum) become a billet bracket for a hot rod my boss was working on. I thought that was the coolest thing ever. You start with nothing and the finished product was a work of art to me. I knew right then that I wanted to do that someday.

What is your greatest challenge as a machinist?

This is a two-part answer. First, it is finding the right core team that you can trust and not have to worry about what they are doing. My current team is comprised of experienced and disciplined machinists and they know what needs to get done. I don’t have to watch over them, I just try to guide them and teach them everything that I have learned over the years.

The second part has always been fixture design. I am always learning how to make better, more user-friendly fixtures to help speed up production but still maintain very high part quality.

magnuson superchargers

What is your favorite part of this profession?

I really love the fact that I learn something new every day. It doesn’t matter how much you think you know, there is always a job that will test your ability as a machinist.

What made you decide to use Harvey Tool and Helical products?

Actually I have a great local tool supplier that I deal with all the time. His name is Mike Baldino over at PM Industrial, and he is the one who first introduced me to both of these products. We make tiny Dovetail O-Ring grooves in a lot of our parts and I couldn’t find a tool that would do the job like I wanted it to. Mike recommended the Harvey Tool .135″ Dovetail Cutter and I haven’t used anything else since. As for the Helical End Mills, since 98% of our jobs are in aluminum, Mike also recommended I try these new (at the time) Zplus coated Helical End Mills. Just like the Harvey Tool Dovetail Cutter, I haven’t used anything else since I found out how amazing these cutters worked for us.

magnuson superchargers

Why is high quality tool performance important to your team at Magnuson Superchargers?

We work with a lot of castings here at Magnuson Superchargers, and even though they are aluminum, they can be very abrasive. Because of this, tool life and part finishes are very important to us. The Helical End Mills hold up very well to cast and billet materials and the Harvey Tool Dovetail Cutters are the only thing that works for us.

Tell us about your favorite projects that Harvey Tool or Helical Solutions tools helped you create.

We make most of our casting tooling in-house, which includes master patterns and core boxes, usually in 6061 Billet Aluminum. The Helical Zplus coated End Mills are amazing for doing these jobs. Using the dynamic toolpaths and utilizing the entire flute length is great. As for the Harvey Tool Dovetail Cutters, I haven’t used anything that works better than these. Every project has become easier with the use of both Harvey Tool and Helical Solutions tools.

magnuson superchargers

A 2016 Chevrolet Camaro loaded with the TVS2300 supercharger at the track.

One of our most exciting projects is our new TVS2300 supercharger that we built for our 2016 Chevrolet Camaro. We took a completely stock engine and transmission, and with just our supercharger and a couple of modifications it was able to run a 9 second 1/4 mile drag race. This was very impressive and has made a huge impact in the automotive industry. We are very excited about this kit and the potential it has in the market.

We have also been working on the biggest supercharger that our company has ever made, the new TVS2650. We are very proud of the all the R&D work that has gone into this kit and we are seeing some incredible horsepower numbers from these units. We displayed this at last year’s Specialty Equipment Market Association (SEMA) show in Las Vegas. We are still in the prototype stages of this project but will have production units coming very soon.

magnuson superchargers

A prototype of the new TVS2650 supercharger, the largest ever built by Magnuson.

Would you recommend that young people take the #PlungeIntoMachining and start a career as a machinist?

I personally would recommend a career in machining to anyone who has an interest in how things are made. I believe it is a great career choice. There are always going to be parts that have to get made somehow, so there is no shortage of open jobs available in the industry. I have a 4 year old son and as soon as he is old enough, I will teach him everything I know about this profession. If he chooses not to go that route, that is completely okay, but at least he will know what it takes to make something from scratch.

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

Learn the basics. Start with a manual mill or lathe and get some experience with how it feels to cut something. Lots of people start on a CNC as an operator and call themselves “machinists.” It took me 5 years before my boss officially called me a machinist! Trust me, it feels really good when your boss hands you a print or CAD model and says “make this,” and you come back with a perfect part that you were able to make yourself.

magnuson superchargers

The Magnuson Superchargers machine shop team. From left: John, Jesus, Jun, Miguel, Jesse, Kenton, and Armando.

Would you like to be considered for a future “Featured Customer” blog? Click here to submit your information.

Photos courtesy of Magnuson Superchargers

KeyBar – Featured Customer

KeyBar® is a manufacturing company based in Savannah, Georgia that prides itself on American-made products. Mike Taylor, the CEO, Owner, and Founder of KeyBar®, first got the idea for this company while working as the chief engineer at an upscale hotel in Savannah, Georgia. As a part of this position, he carried around countless keys attached to his belt. One day he realized that there must be an easier way to carry his keys, so that they made less noise and were easier to access. Mike used a multi-tool daily, and it occurred to him that he could apply the same concept to keys to create the KeyBar®, a patented key organizer that promises to “Stop the Noise”® of jangling keys, kill the clutter of a handful of keys, and make the key ring obsolete.

In 2014, Mike and his wife, Jessica, left their full-time jobs to take a chance on their new business, and it paid off. Mike, now 34, has built a thriving online store, retailers all over the country are carrying KeyBars, and they have an entire team of employees working at their Savannah, Georgia machine shop; quite the achievement for a young entrepreneur.

KeyBar® also offers other products, including the newly released Quick-Draw, which is a revolver-inspired, rotating desktop pen holder that recently raised over $25,000 in a Kickstarter campaign.

keybar

KeyBars are made of many different materials, ranging from aluminum and copper to brass, titanium, and carbon fiber, and end mills from Harvey Tool and Helical Solutions play a crucial part in the creation of each one.

We spoke with Mike for this Featured Customer profile, and talked about his experiences starting his own shop and the way Harvey Tool and Helical products have impacted his shop’s overall performance.

What made you get into machining?

We actually started manufacturing KeyBars by outsourcing our parts to some of my machinist friends. After watching several YouTube videos, I decided that machining our own parts in-house was something I wanted to achieve. I am new to machining, so every day is a challenge. I am truly learning as I go, but I learn more every single day in the shop and every day is a huge payoff.

Would you recommend a career as a machinist to young people trying to find a career path?

Absolutely! In this day and age of smart phones and computers, young people would be great in CNC machining and manufacturing.

How did you first hear about the Harvey Tool & Helical brands?

I first heard about both Harvey Tool and Helical from your Instagram pages. KeyBar® really took off when I started posting the finished product on Instagram, so I have always been an active user and firm believer in the power of social media.

keybar

What made you decide to go with these brands for your cutting tool needs?

I was told that Harvey made the best tool for cutting carbon fiber, which we do a lot of while manufacturing KeyBars, so it was a no-brainer.

How easy was the purchase process?

With only a quick email or phone call, I usually have my tools within 1-2 days, which is important for us to keep up our production and never lose a single second of time in the shop waiting for a tool.

Did you receive any help from our customer service teams? How was that experience?

It was great. I needed some initial speeds and feeds for all my composites, and in just a few minutes they had me all squared away. Time is money, and the customer service team saved me lots of time when we first started working with composite materials.

Tell us about your favorite product that Harvey Tool or Helical products helped to create.

We are currently producing a run of custom KeyBars with inlays. The Harvey end mills for composite materials allowed us to achieve a perfect fit and made the project a success.

keybar

What is your favorite operation to work on with Helical end mills?

I really like working on 1/4″ roughing passes with a Helical chipbreaker.

What was your first impression of these brands’ tools?

“Damn! That worked pretty good!”

You use a lot of Harvey Tool miniature drills in your work. Why is high quality drill performance important to you?

We drill a lot of holes, and every second counts in production. Most importantly, being able to depend on a tool and get consistent results is worth more than anything else.

How have the Harvey Tool and Helical products impacted your overall performance?

I never have to worry about getting a less than superior finish on our composite products. Harvey Tool products do an excellent job with composite materials– like I said, this is a huge part of our manufacturing process and so it is very important to our performance.

If you were stranded on a desert island with only one Harvey Performance tool, which would it be, and why?

I would choose the Harvey Tool 933316-C6 (1/4″ Corner Radius End Mill for Hardened Steels up to 55 Rc) because you never know what you are going to run in to, and there isn’t much that a 1/4″ end mill can’t do!

keybar

Would you like to be considered for a future “Featured Customer” blog? Click here to submit your information.

Photos courtesy of KeyBar