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Contouring Considerations

What is Contouring?

Contouring a part means creating a fine finish on an irregular or uneven surface. Dissimilar to finishing a flat or even part, cnc contouring involves the finishing of a rounded, curved, or otherwise uniquely shaped part.

CNC Contouring & 5-Axis Machining

5-axis machines are particularly suitable for contouring applications. Because contouring involves the finishing of an intricate or unique part, the multiple axes of movement in play with 5-axis Machining allow for the tool to access tough-to-reach areas, as well as follow intricate tool paths.

Recent  Advances

Advanced CAM software can now write the G-Code (the step-by-step program needed to create a finished part) for a machinists application, which has drastically simplified contouring applications. Simply, rather than spend several hours writing the code for an application, the software now handles this step. Despite these advances, most young machinists are still required to write their own G-Codes early on in their careers to gain valuable familiarity with the machines and their abilities. CAM software, for many, is a luxury earned with time.

Benefits of Advanced CAM Software

Increased Time Savings
Because contouring requires very specific tooling movements and rapidly changing cutting parameters, ridding machinists of the burden of writing their own complex code can save valuable prep time and reduce machining downtime.

Reduced Cycle Times
Generated G-Codes can cut several minutes off of a cycle time by removing redundancies within the application. Rather than contouring an area of the part that does not require it, or has been machined already, the CAM Software locates the very specific areas that require machining time and attention to maximize efficiency.

Improved Consistency
CAM Programs that are packaged with CAD Software such as SolidWorks are typically the best in terms of consistency and ability to handle complex designs. While the CAD Software helps a machinist generate the part, the CAM Program tells a machine how to make it.

Proper Tips

Utilize Proper Cut Depths

Prior to running a contouring operation, an initial roughing cut is taken to remove material in steps on the Z-axis so to leave a limited amount of material for the final contouring pass. In this step, it’s pivotal to leave the right amount of material for contouring — too much material for the contouring pass can result in poor surface finish or a damaged part or tool, while too little material can lead to prolonged cycle time, decreased productivity and a sub par end result.

CNC Contouring planes

The contouring application should remove from .010″ to 25% of the tool’s cutter diameter. During contouring, it’s possible for the feeds to decrease while speeds increases, leading to a much smoother finish. It is also important to keep in mind that throughout the finishing cut, the amount of engagement between the tool’s cutting edge and the part will vary regularly – even within a single pass.

Use Best Suited Tooling

Ideal tool selection for contouring operations begins by choosing the proper profile of the tool. A large radius or ball profile is very often used for this operation because it does not leave as much evidence of a tool path. Rather, they effectively smooth the material along the face of the part. Undercutting End Mills, also known as lollipop cutters, have spherical ball profiles that make them excellent choices for contouring applications. Harvey Tool’s 300° Reduced Shank Undercutting End Mill, for example, features a high flute count to benefit part finish for light cut depths, while maintaining the ability to reach tough areas of the front or back side of a part.

CNC Contouring ball end mill

Fact-Check G-Code

While advanced CAM Software will create the G-Code for an application, saving a machinist valuable time and money, accuracy of this code is still vitally important to the overall outcome of the final product. Machinists must look for issues such as wrong tool call out, rapids that come too close to the material, or even offsets that need correcting. Failure to look G-Code over prior to beginning machining can result in catastrophic machine failure and hundreds of thousands of dollars worth of damage.

Inserting an M01 – or a notation to the machine in the G-Code to stop and await machinist approval before moving on to the next step – can help a machinist to ensure that everything is approved with a next phase of an operation, or if any redundancy is set to occur, prior to continuation.

Contouring Summarized

CNC contouring is most often used in 5-axis machines as a finishing operation for uniquely shaped or intricate parts. After an initial roughing pass, the contouring operation – done most often with Undercutting End Mills or Ball End Mills, removes anywhere from .010″ to 25% of the cutter diameter in material from the part to ensure proper part specifications are met and a fine finish is achieved. During contouring, cut only at recommended depths, ensure that G-Code is correct, and use tooling best suited for this operation.

TL Technologies – Featured Customer

Featured Image Courtesy of TL Technologies

TL Technologies helps manufacturers reduce time to market and drive down per-piece cost with their unique “Intelligent Design and Planning” processes. Located in Lancaster, Pennsylvania, TL Technologies serves manufacturers throughout the mid-Atlantic from their centrally located, 10,000 sq. ft. facility. Their unique manufacturing processes and services quickly made them stand out in the industry since their inception in 2012.

Jonathon Thompson is the Vice President of Engineering at TL Technologies. Jonathon talked with us about their rigorous manufacturing and inspection processes, the advantage of using high-quality tooling, their unique on-site assembly services, and much more in this Featured Customer interview.

Tell us a bit about your shop, how you got started, and what sort of products you manufacture.

TL Technologies got started in January 2012. Our first customers were firearms and defense based. Since then we have diversified our business through growth within customers and word of mouth. We started with the intent to be precise and accurate in a lights-out or nearly automated fashion.

What sort of machines do you use in your shop?

We use an array of modern equipment. 4 axis Kitamura HX400G Horizontal Mills. Nakamura Tome 9 axis Turn Mill, Star 6 axis, and two 5 axis vertical Hurco Machines. All our machines are optioned out with Renishaw probing and all the bells and whistles required to handle high accuracy runs for 24 hours a day with no process issues. Most of the machines have glass scales and thermal packages.

kitamura cnc machine

Photo Courtesy of: TL Technologies

Which materials do you most often work with at your shop?

Mostly steels; the usual 4000 and 8000 series steels. Comparatively less 6061 and 7075 aluminum and other common stainless grades. We’ve been fortunate to have many of our materials within a reasonable range of Rockwell so that we may tool accordingly for most of the business.

How has your experience been with multi-axis machining?

Fantastic. Multi axis Machining has been excellent for us. It requires high-level understanding to fully maximize but the benefits are huge.

On your website, you mention that TL Technologies has never delivered a rejected part. What sets your quality apart from the competition?

From day one and job one, we worked with the customer to understand exactly how they were measuring the parts, exactly with what tools, processes, and methods to identically duplicate the process in our shop. After replicating key processes we performed many correlation studies to ensure that our measurements were within single-digit microns of what our customers were seeing on their end during inspection. This methodology was scaled up into our overall quality program and allows us to greater understand and manufacture our goods. Our ISO process coupled with this method truly does prevent bad work from getting out. We have never had a case where a part did not function or perform due to our oversight or bad specs. There have been failures on the customer side of things due to engineering, bad prints, and tolerance stackups, but we have not supplied parts that were flat out incorrect.

TL Technologies

Photo Courtesy of: TL Technologies

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

Typically single or double-digit microns. .0002” to .003” total is common for a large percentage of specs. It is not unusual for +/-.0002” to run long-term over many fixture stations with no manual adjustment. Our machined products are from 1” to 8” cubed.

What are some of the coolest projects you have had come through the shop?

That’s a good question. TL Technologies sat on the United States Senate committee in 2013 for Small Business and Entrepreneurship. We were featured on the cover of New York Times business section in 2013 as well. Throughout our years we’ve been fortunate to meet many amazing people from high branches in the government, the US Military, top name manufacturers, lenders, and local municipalities. Some of the coolest contacts were folks that formerly operated with US Special Forces. Unfortunately, we cannot comment.

As for projects not covered by an NDA, one of my personal favorites was producing low impact physical therapy products for rehabilitating shoulders after surgery. Though simple in manufacturing, this project provided an array of fun challenges that required high performance tooling, 3D printing, and using our machines with custom cycles. This allowed us to use the equipment very unconventionally. In this way, we were able to provide a cost-effective product utilizing the maximum ability of our equipment with a very short lead-time and low up-front cost.

harvey tool catalog

Photo Courtesy of: TL Technologies

You also offer assembly services on-site, which is fairly unique in the industry. Can you talk a little bit more about this?

Sure. Both my business partner and I have tremendous experience with assemblies in both hands-on and directorial roles. Whether it was a high precision multi-axis mechanism that ended up being a custom machine, on and off-road vehicles, or even things like child safety seats, we have had our hands in a lot of things over the years. At TL Technologies we’ve provided assistance to machine tool builders, special tooling designers, consumer goods of various types, and most frequently to firearms builders. Mostly we drive out cost, but as we age we’ve been called upon to troubleshoot high-end assemblies where the issues were not immediately apparent. This led to us creating sub-assemblies and even semi-finished OEM products. This includes hand fitting and assembling collectible pistols and precision bolt action rifles. This is usually offered as a temporary solution or process engineering service to larger companies developing new goods or revamping existing ones, and is offered as part of our comprehensive knowledge to attract clients. It has been very successful.

You service a variety of industries, including defense, automotive, agricultural equipment, and consumer products. Do you have a personal favorite?

I’d have to say the products we make that almost every soldier carries and relies on are my favorite. We take great pride in knowing that these parts have not failed due to machining error since we took over the production years ago on the core components.

TL Technologies

Photo Courtesy of: TL Technologies

Why is American manufacturing important to you?

It’s everything. It’s the heart and soul of all products and by extension facilitates the means with which goods and services exist in our society. By bolstering the skills, knowledge, and experience, we can not only succeed economically but also further the craft and pride of making quality goods. We will always need to be able to make our own goods. The skill and craft to create is more than just economic. We absolutely must embrace and respect the skill and hard work it takes to create. We must pass that knowledge on for posterity so the next generation might find the satisfaction and pride of skilled work.

Why is high-quality tool performance important to you?

It’s everything. The old adage, “Garbage in, garbage out,” is accurate for us. 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.

Have Harvey Tools had an impact on your performance?

Oh man…frequently. Harvey Tools are a mainstay in our company. If I had to think of some key examples it would have to be your variety of Keyseat Cutters, 3 Flute Counterbores, Extended Reach Ball End Mills, and Miniature End Mills under .040”. The 270 degree Lollipop Cutters are excellent for deburring, and we also rely on the 140° spot drills, corner radius forming tools, and more. In short, not only are the tools good, but they provide exactly what we need and the specifications to handle major OEM jobs. We absolutely love metric and you’ve got that too. Your catalogs help us eliminate the need for customs. That is key to cost and lead time.

harvey tool end mills

Photo Courtesy of: TL Technologies

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

Embrace the old knowledge and techniques. The manual skills learned with files and hand ground tools translate critically into the concepts you will need to master if CNC becomes your career. Understand how and why materials cut or refuse to cut, what rake angle to use and when, and how to leverage machine physics to help you work smarter instead of harder. Don’t be afraid to jump down the rabbit hole of engineering concepts, materials, physics, elementary chemistry; these all help give you an edge. Machining is done best with comprehensive knowledge of the machines and machining environment. You never stop learning. All that said, keep a fresh perspective. Old knowledge can be great, but operationally each business will likely have its own methods and flow. Try to understand there is more to the overall business picture than you can often see.

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

Oh definitely! Buy our stuff!! Ha. We are a supplier of choice for OEM, and small batch bolt actions for rifles, pistol components, and pistol slides. We machine to spec and provide cost-competitive options as well as super-premium options.  We are working now to release our own line of aftermarket products in 2018, so keep an eye out for those!

TL Technologies

Photo Courtesy of: TL Technologies


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

The Advances of Multiaxis Machining

CNC Machine Growth

As the manufacturing industry has developed, so too have the capabilities of machining centers. CNC Machines are constantly being improved and optimized to better handle the requirements of new applications. Perhaps the most important way these machines have improved over time is in the multiple axes of direction they can move, as well as orientation. For instance, a traditional 3-axis machine allows for movement and cutting in three directions, while a 2.5-axis machine can move in three directions but only cut in two. The possible number of axes for a multiaxis machine varies from 4 to 9, depending on the situation. This is assuming that no additional sub-systems are installed to the setup that would provide additional movement. The configuration of a multiaxis machine is dependent on the customer’s operation and the machine manufacturer.

Multiaxis Machining

With this continuous innovation has come the popularity of multiaxis machines – or CNC machines that can perform more than three axes of movement (greater than just the three linear axes X, Y, and Z). Additional axes usually include three rotary axes, as well as movement abilities of the table holding the part or spindle in place. Machines today can move up to 9 axes of direction.

https://www.instagram.com/p/BdssKBsg0Sa/

Multiaxis machines provide several major improvements over CNC machines that only support 3 axes of movement. These benefits include:

  • Increasing part accuracy/consistency by decreasing the number of manual adjustments that need to be made.
  • Reducing the amount of human labor needed as there are fewer manual operations to perform.
  • Improving surface finish as the tool can be moved tangentially across the part surface.
  • Allowing for highly complex parts to be made in a single setup, saving time and cost.

9-Axis Machine Centers

The basic 9-axis naming convention consists of three sets of three axes.

multiaxis machining

Set One

The first set is the X, Y, and Z linear axes, where the Z axis is in line with the machine’s spindle, and the X and Y axes are parallel to the surface of the table. This is based on a vertical machining center. For a horizontal machining center, the Z axis would be aligned with the spindle.

Set Two

The second set of axes is the A, B, and C rotary axes, which rotate around the X, Y, and Z axes, respectively. These axes allow for the spindle to be oriented at different angles and in different positions, which enables tools to create more features, thereby decreasing the number of tool changes and maximizing efficiency.

Set Three

The third set of axes is the U, V, and W axes, which are secondary linear axes that are parallel to the X, Y, and Z axes, respectively. While these axes are parallel to the X, Y, and Z axes, they are managed by separate commands. The U axis is common in a lathe machine. This axis allows the cutting tool to move perpendicular to the machine’s spindle, enabling the machined diameter to be adjusted during the machining process.

The Growing Industry of Multiaxis Machining

In summary, as the manufacturing industry has grown, so too have the abilities of CNC Machines. Today, tooling can move across nine different axes, allowing for the machining of more intricate, precise, and delicate parts. Additionally, this development has worked to improve shop efficiency by minimizing manual labor and creating a more perfect final product.

Aspex CNC – Featured Customer

Featured Image Courtesy of Aspex Cnc

Aspex CNC is a CNC machine shop based out of Poway, California. They offer prototype turning and milling, as well as production level machining. Their quick turnaround times and premium quality have garnered them some serious recognition in the manufacturing industry. Aspex CNC is just one of the four businesses that Gary Colle Jr. currently owns, but they are an essential part of his business ecosystem, creating parts for the other three product-based companies while also offering machining services to outside customers.

We talked to Gary about his unique experiences in the industry, his thoughts on 5 axis machining, his advice for trying High Efficiency Milling, and more!

Tell us a bit about how you got started in machining, your businesses, and how Aspex CNC was formed.

It is a bit of an interesting story. I got started in manufacturing because my father designed, developed, and manufactured one of the first lines of Wheelchair Accessible Vehicle lifts, which allow people in wheelchairs to easily get in and out of their vehicles. The company was called GoldenBoy Mobility and is still one of the four business I currently own and operate today.

At a young age, I was working in my father’s shop, answering phones and doing odd jobs as young as the age of 10. When I got to high school, I worked after school and during the summers in a more hands-on position, welding parts, cutting up cars, and helping on the shop floor. This really inspired my love for metalworking at a young age.

goldenboy mobility

Photo Courtesy of: Aspex CNC

My dad used to let me mess around in the shop at night, so I started welding my own parts and trying to learn as much as I could. One day, someone came in and asked if I could create a “tuna tower” (an accessory for wakeboarding/water skiing) for their boat. I relented at first, but eventually gave in and welded all the parts together for him. After I made that one, word got around that I could create these at night. I started to advertise a little bit locally, and people started ordering more and more. That summer, I ended up making 50 of these towers and got noticed by a couple of big distributors. Scaling up like that made it necessary to outsource some of our parts to local machine shops, which is where I discovered machining. I had very little prior knowledge of machining, but once I stepped into my first machine shop, I was blown away.

As that business grew even larger (now known as DBG Concepts), I needed more parts and needed them faster. We outgrew the local shops and purchased our first machine, a Fadal 4020 CNC Mill, from a local machine salesman, who also helped teach me the ropes. I learned a lot in those first 6 months about machining.

Business kept ramping up, and my father eventually retired and I took over GoldenBoy Mobility. With all the extra parts we needed, we kept machining things in-house, and buying more mills. Eventually, machining became an even larger part of the business than either DBG Concepts or GoldenBoy Mobility, so we formed Aspex CNC to move our machining out of the product line and more into prototype work and production machining for other business. We still machine most of the parts for DBG and GoldenBoy in-house, but we are doing much more for outside sources than we used to.

What sort of machines do you use in your shop?

Right now, we are a Haas-only shop. We currently have eight Haas machines in our shop. Our lineup consists of a couple of lathes (ST10 and ST30), a Super Mini Mill, and five CNC Mills (VF2SS, VF2SSYT, VF4SS, VF5SS, and UMC750SS), with another UMC750 on the way!

aspex cnc

Photo Courtesy of: Aspex CNC

Which materials do you most often work with in your shop?

We work with a lot of the common materials, 6061/7075 Aluminum, 1018/1045 Steel, 303/304/17-4ph Stainless, as well as plastics like Acetal, UHMW, HDPE, and PVC.

How has your experience been with 5 axis machining?

If you don’t keep up with technology, you won’t be able to keep up with business, so learning multi-axis machining was a no-brainer for us. We first started with a Haas HRT210 4th axis rotary, and began to play with that. Over the next two years, we learned everything we could about multi-axis machining and made the decision to upgrade to a 5 axis machine. We actually went to IMTS that year to talk to manufacturers and find the perfect machine for us and ended up sticking with Haas because of their support platform and educational resources.

5 axis can be hard, but there are a lot of tools out there (HSM Works from Autodesk being one) that can help you learn. It does require a little more upfront work and discipline, but it eliminates a lot of setup time, creates new opportunities for our shop, and has been really good for us from a business standpoint. A big part of our business is machining one-off parts, so the 5 axis machine allows for a faster turnaround time for those odd shapes and sizes we come across.

5 axis machining

Photo Courtesy of: Aspex CNC

You are very active on social media promoting your business. How has the online machinist community helped your business?

Honestly, even though it can become a bit of a distraction at times, using social media to share our work and partner up with companies like Harvey Tool and Helical has been a lot of fun. We are still young in the social media space, so we haven’t seen a massive impact yet, but the best is yet to come. We have received a few bites here and there which has led to work, but as with everything, it takes some time. We expect a lot of growth this year as we work on more really neat projects and continue to get our name out there. As we grow, the opportunities are going to come.

aspex cnc

Photo Courtesy of: Aspex CNC

What are some of the coolest projects you have ever worked on?

Unfortunately, we can’t talk about most of the work we do, due to customer confidentiality, but we did just do a project for the State of California building a training vehicle for their driver’s education program. We designed and built a dual steering system that gave the driver’s trainer a second steering wheel on the passenger side of the car to be used during training. Another job we just finished up was some parts for the new Raiders football stadium in Las Vegas. They contacted us in a pinch and needed them in two days, and we made it happen. It is pretty cool to know you played a part in a huge project like that.

Aspex CNC also does a lot of work with racing/off-road vehicle companies, often machining parts for the chassis and suspension components. We have worked on projects for companies like Scarbo Performance, ID Designs, TSCO Racing and a whole list of others.

You can only use one machine for the rest of your life. Do you go with a CNC Milling machine or the Lathe?

I would hate to have to choose between them, but it is 100% the CNC Mill. I love ripping around with end mills and working with the 5 axis machines. It is mind blowing what these things are capable of.

Why is manufacturing products in America important to you?

Growing up in the industry which I did while working under my father (building wheelchair accessible vehicles), we had a lot of customers who were veterans coming back from Vietnam or Desert Storm who had been injured overseas and needed extra accommodations, which we could provide for them. The veterans I have worked with made me so patriotic with their stories and courage. We also get to work on a lot of projects with the US Department of Veteran’s Affairs, which is putting money back into the American economy by supporting companies like ours and contracting us to make these vehicles. It only makes sense that we employ more people here and avoid sending things overseas to support those who have supported us.

aspex cnc

Photo Courtesy of: Aspex CNC

Do you utilize High Efficiency Milling (HEM) techniques in your shop? What advice do you have for those who are getting started with HEM?

Absolutely, all the time!

The biggest thing is listening to your tool manufacturer for recommendations and then cut those in half to start. From there, work your way up until you are comfortable. Just because the tool can handle it doesn’t necessarily mean your machine, work holding and or set up can, so I would advise people to walk before you run when it comes to HEM.

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

Be conservative and establish good habits from the start. You can get more aggressive as your career starts to take off, but don’t run out and try to run the biggest and baddest machines on day one and try to cut corners. You need to learn what is behind machining; you can get easily lost in all the technology that is available, but you need to understand the core science behind it first. Take it slow, because if you go too fast, you might miss something important along the way.

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

The best thing is building relationships with companies like Haas, Harvey Tool, and Helical. Not only do they provide great service and support for you, but it quickly becomes a mutually beneficial relationship. As we give feedback to the tool and machine manufacturers, and even our metal supplier, it helps them improve their products, which in turn allows our shop to increase our production and efficiency.

Also, having a good team with good people makes all the difference. No matter how many machines you have and how automated you get, you still need good people on your side. I would put my guys up against any other machine shop out there in terms of skill, and it is a big part of what has made our business so successful.

aspex cnc

Photo Courtesy of: Aspex CNC


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

Optimizing Material Removal Rates

 What is the Material Removal Rate?

Material Removal Rate (MRR), otherwise known as Metal Removal Rate, is the measurement for how much material is removed from a part in a given period of time. Every shop aims to create more parts in a shorter period of time, or to maximize money made while also minimizing money spent. One of the first places these machinists turn is to MRR, which encompasses Radial Depth of Cut (RDOC), Axial Depth of Cut (ADOC), and Inches Per Minute (IPM). If you’re aiming to boost your shop’s efficiency, increasing your MRR even minimally can result in big gains.

Click Here to Download the High Efficiency Milling (HEM) Guidebook

Calculating MRR

The calculation for Material Removal Rate is RDOC x ADOC x Feed Rate. As an example, if your RDOC is .500″, your ADOC is .100″ and your Feed Rate is 41.5 inches per minute, you’d calculate MRR the following way:

MRR = .500″ x .100″ x 41.5 in/min = 2.08 cubic inches per minute.

Optimizing Efficiency

A machinists’ depth of cut strategy is directly related to the Material Removal Rate. Using the proper RDOC and ADOC combination can boost MRR rates, shaving minutes off of cycle times and opening the door for greater production. Utilizing the right approach for your tool can also result in prolonged tool life, minimizing the rate of normal tool wear. Combining the ideal feed rate with your ADOC and RDOC to run at your tool’s “sweet spot” can pay immediate and long term dividends for machine shops.

The following chart illustrates how a 1/2″, 5-flute tool will perform in Steel when varying ADOC and RDOC parameters are used. You can see that by varying the ADOC and RDOC, a higher feed rate is achievable, and thus, a higher MRR. In this case, pairing a high ADOC, low RDOC approach with an increased feed rate was most beneficial. This method has become known as High Efficiency Milling.

Axial Depth of CutRadial Depth of CutFeed RateMaterial Removal Rate
 .125″ .200″19.5 IPM .488 in.³/min.
.250″.150″26.2 IPM.983 in.³/min.
.500″.100″41.5 IPM2.08 in.³/min.
.750″.050″89.2 IPM3.35 in.³/min.
1.00″.025″193 IPM4.83 in.³/min.

High Efficiency Milling

High Efficiency Milling (HEM) is a milling technique for roughing that utilizes a lower RDOC and a higher ADOC strategy. This spreads wear evenly across the cutting edge, dissipates heat, and reduces the chance of tool failure. This results in a greater ability to increase your MRR, while maintaining and even prolonging tool life versus traditional machining methods.

High Efficiency Milling Material Removal Rate

Obviously, with higher MRR’s, chip evacuation becomes vitally important as more chips are evacuated in a shorter period of time. Utilizing a tool best suited for the operation – in terms of quality and flute count – will help to alleviate the additional workload. Additionally, a tool coating optimized for your workpiece material can significantly help with chip packing. Further, compressed air or coolant can help to properly remove chips from the tool and workpiece.

In conclusion, optimizing workplace efficiency is vital to sustained success and continued growth in every business. This is especially true in machine shops, as even a very minor adjustment in operating processes can result in a massive boost in company revenue. Proper machining methods will boost MRR, minimize cycle times, prolong tool life, and maximize shop output.

What You Need to Know About Coolant for CNC Machining

Coolant in purpose is widely understood – it’s used to temper high temperatures common during machining, and aid in chip evacuation. However, there are several types and styles, each with its own benefits and drawbacks. Knowing which cnc coolant – or if any – is appropriate for your job can help to boost your shop’s profitability, capability, and overall machining performance.

Coolant or Lubricant Purpose

Coolant and lubricant are terms used interchangeably, though not all coolants are lubricants. Compressed air, for example, has no lubricating purpose but works only as a cooling option. Direct coolants – those which make physical contact with a part – can be compressed air, water, oil, synthetics, or semi-synthetics. When directed to the cutting action of a tool, these can help to fend off high temperatures that could lead to melting, warping, discoloration, or tool failure. Additionally, coolant can help evacuate chips from a part, preventing chip recutting and aiding in part finish.

Coolant can be expensive, however, and wasteful if not necessary. Understanding the amount of coolant needed for your job can help your shop’s efficiency.

Click Here to Shop Harvey Tool’s Fully Stocked Offering of Deep Hole Coolant Through Drills

Types of Coolant Delivery

CNC coolant is delivered in several different forms – both in properties and pressure. The most common forms include air, mist, flood coolant, high pressure, and Minimum Quantity Lubricant (MQL). Choosing the wrong pressure can lead to part or tool damage, whereas choosing the wrong amount can lead to exhausted shop resources.

Air: Cools and clears chips, but has no lubricity purpose. Air coolant does not cool as efficiently as water or oil-based coolants. For more sensitive materials, air coolant is often preferred over types that come in direct contact with the part. This is true with many plastics, where thermal shock – or rapid expansion and contraction of a part – can occur if direct coolant is applied.

Mist: This type of low pressure coolant is sufficient for instances where chip evacuation and heat are not major concerns. Because the pressure applied is not great in a mist, the part and tool do not undergo additional stresses.

Flood: This low pressure method creates lubricity and flushes chips from a part to avoid chip recutting, a common and tool damaging occurrence.

High Pressure: Similar to flood coolant, but delivered in greater than 1,000 psi. This is a great option for chip removal and evacuation, as it blasts the chips away from the part. While this method will effectively cool a part immediately, the pressure can be high enough to break miniature diameter tooling. This method is used often in deep pocket or drilling operations, and can be delivered via coolant through tooling, or coolant grooves built into the tool itself. Harvey Tool offers Coolant Through Drills and Coolant Through Threadmills.

Minimum Quantity Lubricant (MQL): Every machine shop focuses on how to gain a competitive advantage – to spend less, make more, and boost shop efficiency. That’s why many shops are opting for MQL, along with its obvious environmental benefits. Using only the necessary amount of coolant will dramatically reduce costs and wasted material. This type of lubricant is applied as an aerosol, or an extremely fine mist, to provide just enough coolant to perform a given operation effectively.

To see all of these coolant styles in action, check out the video below from our partners at CimQuest.

In Conclusion

CNC coolant is all-too-often overlooked as a major component of a machining operation. The type of coolant or lubricant, and the pressure at which it’s applied, is vital to both machining success and optimum shop efficiency. Coolant can be applied as compressed air, mist, in a flooding property, or as high pressure. Certain machines also are MQL able, meaning they can effectively restrict the amount of coolant being applied to the very amount necessary to avoid being wasteful.

Anderson Prototypes – Featured Customer

Featured Image Courtesy of Anderson Prototypes

Anderson Prototypes is a custom machine shop in Port Moody, British Columbia. Working with everything from Titanium to Bamboo, they create mechanical mechanisms and working prototypes of new technology. By applying 25 years of experience with manual and CNC machinery, they craft amazing parts, some even bordering on impossible. The team at Anderson Prototypes works in a variety of industries, ranging from large-scale prototype work to small batch production, machine repair, and even movie and TV props.

Jim Anderson, a 30 year veteran of the manufacturing industry, is the Founder and Owner of Anderson Prototypes. We caught up with Jim and talked to him about some of the “impossible” projects his team likes to take, his experiences in the film industry, and his advice for the aspiring machinist.

Tell us a bit about your shop, how you got started, and what sort of products you manufacture.

I started in machining in 1985, as a full-time student in a machining class at a local community college. I spent years working in jobbing shops, plastic mold injection shops, and specialized start-up companies, scratch building a range of things from high-speed water “pouch” filling machines to hydrogen fuel-cells. Today I work with a wide range of clients including 3 submarine companies, a military contractor, companies that use custom built or modified ROVs and drones, food packaging companies, production companies needing film and TV props, and more.

What made you get into machining?

I have always been an actively creative person, and I enjoyed wood and machine shop in high school. I found a creative outlet for my talents to build and fix things inside the machine shop environment. I continue to study machines and items, to understand how they were made, and how it could be made better or simplified.

anderson prototypes

Photo Courtesy of: Anderson Prototypes

What is your favorite part of this profession?

I always enjoy creating something for a client that they have been dreaming of, sometimes for years. They come to me with a sketch on a napkin or a verbal idea, and I turn that dream into reality. When they come to pick it up and see it for the first time, the emotions are tremendous!

What sort of machines do you use in your shop?

I have 2 Tormach 1100 CNC mills, one 4 axis and the other 3 axis, a Sherline 2000, 4 axis CNC mill, a Frankenstein CNC lathe with a 8 station tool changer for small work, a Milltronics ML-17 CNC lathe, a Colchester Student Engine Lathe, and a smaller manual milling machine. I also have drill presses, tapping heads and tons of specialized fixturing and work holding devices, as well as a 60 ton hydraulic press and the specialized equipment that comes with it.

micro machining

Photo Courtesy of: Anderson Prototypes

Which materials do you work with in your shop?

Just about everything. Lots of plastics, PEEK, Delrin and Acrylic, aluminum, steels, stainless steels, carbon fiber, different woods, laminates, and more.

What sets Anderson Prototypes apart from the competition?

We often take on jobs that other shops won’t, due to our team’s large vision. We stand behind every piece we make and have zero returned items to date. Embodying both old-school traditions and cutting-edge technology, Anderson Prototypes believes that “Impossible is just an Opinion”. We work with a project from the very beginning to the time it is up and running at the client’s facility. We work with building very small detailed machines to unique and weird items that someone dreamed up and could not find anyone able to make. We also love to give back to the community. We have sponsored local high school and university students in competitions, and we have played a part in the Maker Community since Day One. We also made and donated a doggy wheelchair to a dog in need (YouTube), and we sponsor a local softball league.

How did you get into the entertainment/prop business?

Vancouver has a huge movie industry, and there are many people in my network that work in the industry. The need for various props, new equipment, and repairs can go up and down as movies are being filmed. The first job I did (I think), was for a movie called Space Buddies, the 4th or 5th entry in the Air Bud movie series. I made the Doggles (dog goggles), that the dog is wearing on the DVD cover. Most movies require a Non-Disclosure Agreements before any work is done, so I can’t talk about much, but I have made my impact on the screen, behind the scenes, and even live on stage. I also did a major prop for an Australian TV show that was apparently popular down under, so you never know where this work will take you!

micro machined

Photo Courtesy of: Anderson Prototypes

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

I have met many directors and producers of large budget films and TV shows. Unfortunately, because of the Non-Disclosure Agreements, I cannot mention any names.

Why is high-quality tool performance important to you?

I buy all my tooling from North America. I am lucky enough to have a solid carbide tooling manufacturer 5 miles from my shop, so I get quality endmills, made to order. When I need something specialized, Harvey is the only company I go to. When a tool does more than I expect, I make more money and have less stress. I count on that and become a return customer. For example, I used a .018″ Miniature End Mill (#73018-C3) on some acrylic parts I was making. There were 40 parts in total, all around the size of a stamp, with lots of tiny details, high tolerances, and very small features. I had the machine running at 15,500 RPM for 3 weeks, and I only broke one tool in that entire run. What a great tool!

What is your favorite process to work on as a machinist?

I really enjoy making something I have never worked on before, that new challenge. Often it seems that I am designing new items now more than ever. I have to do things that are not being done commercially and I stand behind it. So I might run the manual lathe, the CNC mill and then the CNC lathe on one part. I enjoy the variety.

anderson prototypes

Photo Courtesy of: Anderson Prototypes

Why is manufacturing your products in North America important to you?

American and Canadian-made products are very important to me. I purchase North American-made products like steel and aluminum, and bearings and fasteners all of kinds. I also access services locally, such as laser cutting, anodizing and powder coating, to support these local businesses. I feel its very important to the customer making the purchase that these are products my neighbors are helping to build.

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

Take the time to take an accredited machine shop training course, like I did. It will give you all the groundwork to understand the real world of machining. I know a few fellas with small CNCs that can’t make a living because they don’t understand the depth of set-ups or work holding, for example, because they never learned from an expert. They can’t make parts fast enough, they charge 1/2 of what I do, and it takes then 3 times as long, so they simply can’t compete with me. Just be aware that it doesn’t happen overnight; I was a Journeyman Machinist for over 30 years, and still ask for help from my mentors occasionally. Oh, and find yourself a quality machine. Find a good used HAAS, or OKK, or something made in the US, UK or Europe. Your clients will respect you more and it will work longer and more accurately.

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

I am grateful for the education I have received from the many journeyman machinists, engineers, mechanics, electricians, pilots, sea captains and more who I have worked beside in my years. I am happy to share and offer problem-solving, sometimes for free, other times at consultation rates. When a young eager person asks me a question, I do the best I can to answer it in a way that benefits them long term. Sometimes they don’t like the answer, but I tell them to come back in 6 months and tell me how it went. That’s when the rubber hits the road.

anderson prototypes

Photo Courtesy of: Anderson Prototypes


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Photos courtesy of Anderson Prototypes.

Optimize Roughing With Chipbreaker Tooling

Chipbreaker End Mills feature unique notch profiles, creating a serrated cutting edge. These dividers break otherwise long, stringy chips into small, easily-managed swarf that can be cleanly evacuated from the part. But why is a chipbreaker necessary for some jobs, and not others? How does the geometry of this unique tool impact its proper running parameters? In this post, we’ll answer these questions and others to discover the very real benefits of this unique cutting geometry.

How Chipbreaker Tooling Works

As a tool rotates and its cutting edge impacts a workpiece, material is sheared off from a part, creating chips. When that cutting process is interrupted, as is the case with breaks in the cutting portion of the tool, chips become smaller in length and are thus easier to evacuate. Because the chipbreakers are offset flute-to-flute, a proper, flat surface finish is achieved as each flute cleans up any excess material left behind from previously passed flutes.

Benefits of Chipbreaker Tooling

Machining Efficiency

When chips are removed from the part, they begin to pile in the machine. For extensive operations, where a great deal of material is hogged out, chip accumulation can very rapidly get in the way of the spindle or part. With larger chips, accumulation occurs much faster, leaving machinists to stop their machine regularly to remove the waste. As any machinist knows, a stopped machine equates to lost money.

metal chips in cnc mill form chipbreaking

Prolonged Tool Life

Inefficient chip evacuation can lead to chip recutting, or when the the tool impacts and cuts chips left behind during the machining process. This adds stresses on the tool and accelerates rate of wear on the cutting edge. Chipbreaker tooling creates small chips that are easily evacuated from a part, thus minimizing the risk of recutting.

Accelerated Running Parameters

A Harvey Performance Company Application Engineer recently observed the power of a chipbreaker tool firsthand while visiting a customer’s shop in Minnesota. The customer was roughing a great amount of 4340 Steel. Running at the parameters below, the tool was able to run uninterrupted for two hours!

Helical Part No.33737
Material4340 Steel
ADOC2.545″
RDOC.125″
Speed2,800 RPM
Feed78 IPM
Material Removal Rate24.8 Cubic In/Min

 

Chipbreaker Product Offering

Chipbreaker geometry is well suited for materials that leave a long chip. Materials that produce a powdery chip, such as graphite, should not be machined with a chipbreaker tool, as chip evacuation would not be a concern. Helical Solutions’ line of chipbreaker tooling includes a 3-flute option for aluminum and non-ferrous materials, and its reduced neck counterpart. Additionally, Helical offers a 4-flute rougher with chipbreaker geometry for high-temp alloys and titanium. Harvey Tool’s expansive product offering includes a composite cutting end mill with chipbreaker geometry.

In Summary

Chipbreaker geometry, or grooves within the cutting face of the tool, break down chips into small, manageable pieces during the machining process. This geometry can boost shop efficiency by minimizing machine downtime to clear large chips from the machining center, improve tool life by minimizing cutting forces exerted on the tool during machining, and allow for more accelerated running parameters.

Speeds and Feeds 101

Understanding Speeds and Feed Rates

NOTE: This article covers speeds and feed rates for milling tools, as opposed to turning tools.

Before using a cutting tool, it is necessary to understand tool cutting speeds and feed rates, more often referred to as “speeds and feeds.” Speeds and feeds are the cutting variables used in every milling operation and vary for each tool based on cutter diameter, operation, material, etc. Understanding the right speeds and feeds for your tool and operation before you start machining is critical.

It is first necessary to define each of these factors. Cutting speed, also referred to as surface speed, is the difference in speed between the tool and the workpiece, expressed in units of distance over time known as SFM (surface feet per minute). SFM is based on the various properties of the given material. Speed, referred to as Rotations Per Minute (RPM) is based off of the SFM and the cutting tool’s diameter.

HEM Guidebook Ad

While speeds and feeds are common terms used in the programming of the cutter, the ideal running parameters are also influenced by other variables. The speed of the cutter is used in the calculation of the cutter’s feed rate, measured in Inches Per Minute (IPM). The other part of the equation is the chip load. It is important to note that chip load per tooth and chip load per tool are different:

speeds and feeds formula
  • Chip load per tooth is the appropriate amount of material that one cutting edge of the tool should remove in a single revolution. This is measured in Inches Per Tooth (IPT).
  • Chip load per tool is the appropriate amount of material removed by all cutting edges on a tool in a single revolution. This is measured in Inches Per Revolution (IPR).

A chip load that is too large can pack up chips in the cutter, causing poor chip evacuation and eventual breakage. A chip load that is too small can cause rubbing, chatter, deflection, and a poor overall cutting action.

speeds and feeds formula

Material Removal Rate

Material Removal Rate (MRR), while not part of the cutting tool’s program, is a helpful way to calculate a tool’s efficiency. MRR takes into account two very important running parameters: Axial Depth of Cut (ADOC), or the distance a tool engages a workpiece along its centerline, and Radial Depth of Cut (RDOC), or the distance a tool is stepping over into a workpiece.

The tool’s depth of cuts and the rate at which it is cutting can be used to calculate how many cubic inches per minute (in3/min) are being removed from a workpiece. This equation is extremely useful for comparing cutting tools and examining how cycle times can be improved.

speeds and feeds

Speeds and Feeds In Practice

While many of the cutting parameters are set by the tool and workpiece material, the depths of cut taken also affect the feed rate of the tool. The depths of cuts are dictated by the operation being performed – this is often broken down into slotting, roughing, and finishing, though there are many other more specific types of operations.

Many tooling manufacturers provide useful speeds and feeds charts calculated specifically for their products. For example, Harvey Tool provides the following chart for a 1/8” diameter end mill, tool #50308. A customer can find the SFM for the material on the left, in this case 304 stainless steel. The chip load (per tooth) can be found by intersecting the tool diameter on the top with the material and operations (based on axial and radial depth of cut), highlighted in the image below.

hardness chart

The following table calculates the speeds and feeds for this tool and material for each operation, based on the chart above:

speeds and feeds

Other Important Considerations

Each operation recommends a unique chip load per the depths of cut. This results in various feed rates depending on the operation. Since the SFM is based on the material, it remains constant for each operation.

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Spindle Speed Cap

As shown above, the cutter speed (RPM) is defined by the SFM (based on material) and the cutter diameter. With miniature tooling and/or certain materials the speed calculation sometimes yields an unrealistic spindle speed. For example, a .047” cutter in 6061 aluminum (SFM 1,000) would return a speed of ~81,000 RPM. Since this speed is only attainable with high speed air spindles, the full SFM of 1,000 may not be achievable. In a case like this, it is recommended that the tool is run at the machine’s max speed (that the machinist is comfortable with) and that the appropriate chip load for the diameter is maintained. This produces optimal parameters based on the machine’s top speed.

Effective Cutter Diameter

On angled tools the cutter diameter changes along the LOC. For example, Helical tool #07001, a flat-ended chamfer cutter with helical flutes, has a tip diameter of .060” and a major/shank diameter of .250”. In a scenario where it was being used to create a 60° edge break, the actual cutting action would happen somewhere between the tip and major/shank diameters. To compensate, the equation below can be used to find the average diameter along the chamfer.

cutter diameter calculation

Using this calculation, the effective cutter diameter is .155”, which would be used for all Speeds and Feeds calculations.

Non-linear Path

Feed rates assume a linear motion. However, there are cases in which the path takes an arc, such as in a pocket corner or a circular interpolation. Just as increasing the DOC increases the angle of engagement on a tool, so does taking a nonlinear path. For an internal corner, more of the tool is engaged and, for an external corner, less is engaged. The feed rate must be appropriately compensated for the added or lessened engagement on the tool.

non-linear path

This adjustment is even more important for circular interpolation. Take, for example, a threading application involving a cutter making a circular motion about a pre-drilled hole or boss. For internal adjustment, the feed rate must be lowered to account for the additional engagement. For external adjustment, the feed rate must be increased due to less tool engagement.

adjusted internal feed

Take this example, in which a Harvey Tool threadmill #70094, with a .370” cutter diameter, is machining a 9/16-18 internal thread in 17-4 stainless steel. The calculated speed is 2,064 RPM and the linear feed is 8.3 IPM. The thread diameter of a 9/16 thread is .562”, which is used for the inner and outer diameter in both adjustments. After plugging these values into the equations below, the adjusted internal feed becomes 2.8 IMP, while the external feed becomes 13.8 IPM.

adjusted external feed

Click here for the full example.

Conclusion

These calculations are useful guidelines for running a cutting tool optimally in various applications and materials. However, the tool manufacturer’s recommended parameters are the best place to start for initial numbers. After that, it is up to the machinist’s eyes, ears, and experience to help determine the best running parameters, which will vary by set-up, tool, machine, and material.

Click the following links for more information about running parameters for Harvey Tool and Helical products.

Why Flute Count Matters

One of the most important considerations when choosing an end mill is determining which flute count is best for the job at hand. Both material and application play an important role in this critical part of the tool selection process. Understanding the effects of flute count on other tool properties, and how a tool will behave in different situations is an essential consideration in the tool selection process.

Machining Advisor Pro (MAP) Takes Flute Count Into Consideration When Helping You Dial In Running Parameters.

Click Here to Get Started.

Tool Geometry Basics

Generally, tools with more flutes have a larger core and smaller flute valleys than tools with fewer flutes.  More flutes with a larger core can provide both benefits and restrictions depending on the application.  Simply put, a larger core is directly proportional to tool strength; the larger the core, the stronger a tool will be.  In turn, a larger core also reduces the flute depth of a tool, restricting the amount of space for chips to exist.  This can cause issues with chip packing in applications requiring heavy material removal.  However, these considerations only lead us part way when making a decision on which tool to use, and when.

flute count core

Material Considerations

Traditionally, end mills came in either a 2 flute or 4 flute option.  The widely accepted rule of thumb was to use 2 flutes for machining aluminum and non-ferrous materials, and 4 flutes for machining steel and harder alloys.  As aluminum and non-ferrous alloys are typically much softer than steels, a tool’s strength is less of a concern, a tool can be fed faster, and larger material removal rates (MRR) is facilitated by the large flute valleys of 2 flute tools.  Ferrous materials are typically much harder, and require the strength of a larger core.  Feed rates are slower, resulting in smaller chips, and allowing for the smaller flute valleys of a larger core tool.  This also allows for more flutes to fit on the tool, which in turn increases productivity.

end mill flute count

Recently, with more advanced machines and toolpaths, higher flute count tools have become the norm in manufacturing.  Non-ferrous tooling has become largely centered on 3 flute tools, allowing greater productivity while still allowing proper chip evacuation.  Ferrous tooling has taken a step further and progressed not only to 5 and 6 flutes, but up to 7 flutes and more in some cases.  With a wider range of hardness, sometimes at the very top of the Rockwell hardness scale, many more flutes have allowed longer tool life, less tool wear, stronger tools, and less deflection.  All of this results in more specialized tools for more specific materials.  The end result is higher MRR and increased productivity.

Running Parameters

Just as material considerations will have an impact on the tool you choose, operation type and depth of cut requirements may also have a big impact on the ideal number of flutes for your application.  In roughing applications, lower flute counts may be desirable to evacuate large amounts of chips faster with larger flute valleys.  That said, there is a balance to find, as modern toolpaths such as High Efficiency Milling (HEM) can achieve extreme MRR with a very small step over, and a higher number of flutes.  In a more traditional sense, higher flute counts are great for finishing operations where very small amounts of material are being removed, and greater finish can be achieved with more flutes, not worrying as much about chip evacuation.

flute count

Flute count plays a big role in speeds and feeds calculation as well.  One common rule of thumb is “more flutes, more feed,” but this can be a very detrimental misconception.  Although true in some cases, this is not an infinitely scalable principle.  As stated previously, increasing the number of flutes on a tool limits the size that the flute valleys can be.  While adding a 5th flute to a 4 flute tool theoretically gives you 25% more material removal per revolution with an appropriately increased feed rate, feeding the tool that much faster may overload the tool.  The 25% increase in material removal is more likely closer to 10-15%, given the tool is exactly the same in all other specifications.  Higher flute count tools may require speeds and feeds to be backed off so much in some cases, that a lower flute count may be even more efficient.  Finding the right balance is key in modern milling practices.