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How to Extend the Life of Your End Mill

Breaking and damaging an end mill is oftentimes an avoidable mistake that can be extremely costly for a machine shop. To save time, money, and your end mill it is important to learn some simple tips and tricks to extend your tool’s life.

Properly Prepare Before the Tool Selection Process

The first step of any machining job is selecting the correct end mill for your material and application. However, this doesn’t mean that there should not be an adequate amount of legwork done beforehand to ensure the right decision on a tool is being made. Harvey Tool and Helical Solutions have thousands of different tools for different operations – a vast selection which, if unprepared – can easily result in selecting a tool that’s not the best for your job. To start your preparation, answer the 5 Questions to Ask Before Selecting an End Mill to help you quickly narrow down your selection and better understand the perfect tool you require.

Understand Your Tooling Requirements

It’s important to understand not only what your tool needs, but also general best practices to avoid common machining mishaps. For instance, it is important to use a tool with a length of cut only as long as needed, as the longer a tools length of cut is, the greater the chance of deflection or tool bending, which can decrease its effective life.

tool life

Another factor to consider is the coating composition on a tool. Harvey Tool and Helical Solutions offer many varieties of coatings for different materials. Some coatings increase lubricity, slowing tool wear, while others increase the hardness and abrasion resistance of the tool. Not all coatings increase your tool’s life in every material, however. Be wary of coatings that don’t perform well in your part’s material – such as the use of AlTiN coating in Aluminum (Both coating and material are aluminum-based and have a high affinity for each other, which can cause built-up edge and result in chip evacuation problems).

Consider Variable Helix & Pitch Geometry

A feature on many of our high performance end mills is variable helix or variable pitch geometry, which have differently-spaced flutes. As the tool cuts, there are different time intervals between the cutting edges contacting the workpiece, rather than simultaneously on each rotation. The varying time intervals minimizes chatter by reducing harmonics, increasing tool life and producing better results.

Ensure an Effective Tool Holding Strategy

Another factor in prolonging tool life is proper tool holding. A poor tool holding strategy can cause runout, pullout, and scrapped parts. Generally, the most secure connection has more points of contact between the tool holder and tool shank. Hydraulic and Shrink Fit Tool Holders provide increased performance over other tightening methods.

tool life

Helical also offers shank modifications to all stocked standards and special quotes, such as the ToughGRIP Shank, which provides added friction between the holder and the shank of the tool for a more secure grip; and the Haimer Safe-Lock™, which has grooves on the shank of the tool to help lock it into place in a tool holder.

tool life

Trust Your Running Parameters, and their Source

After selecting the correct end mill for your job, the next step is to run the tool at the proper speeds and feeds.

Run at the Correct Speed

Understanding the ideal speed to run your machine is key to prolonging tool life. If you run your tool too fast, it can cause suboptimal chip size, ineffective chip evacuation, or even total tool failure. Adversely, running your tool too slowly can result in deflection, bad finish, or decreased metal removal rates.

Push at the Best Feed Rate

Another critical parameter of speeds and feeds is finding the best possible feed rate for your job, for sake of both tool life and achieving maximum shop efficiency. Pushing your tool too aggressively can result in breakage, but being too conservative can lead to recutting chips and excess heat generation, accelerating tool wear.

Use Parameters from Your Tooling Manufacturer

A manufacturer’s speeds and feeds calculations take into account every tool dimension, even those not called out in a catalog and readily available to machinists. Because of this, it’s best to rely on running parameters from tooling manufacturers. Harvey Tool offers speeds and feeds charts for every one of its more than 21,000 tools featured in its catalog, helping machinists to confidently run their tool the first time.

Harvey Performance Company offers the Machining Advisor Pro application, a free, cutting-edge resource that generates custom running parameters for optimized machining with all of Helical’s products.

tool life

Opt for the Right Milling Strategy: Climb vs Conventional

There are two ways to cut material when milling: Climb Milling and Conventional Milling. In conventional milling, the cutter rotates against the feed. In this method, chips will start at theoretical zero and increase in size. Conventional milling is usually recommended for tools with higher toughness, or for breaking through case hardened materials.

In Climb Milling, the cutter rotates with the feed. Here, the chips start at maximum width and decrease, causing the heat generated to transfer into the chip instead of being left in the tool or work piece. Climb milling also produces a cleaner shear plane, causing less rubbing, decreasing heat, and improving tool life. When climb milling, chips will be removed behind the cutter, reducing your chances of recutting.

Utilize High Efficiency Milling

High Efficiency Milling (HEM), is a roughing technique that uses the theory of chip thinning by applying a smaller radial depth of cut (RDOC) and a larger axial depth of cut (ADOC). The parameters for HEM are similar to that of finishing, but with increased speeds and feeds, allowing for higher material removal rates (MRR). HEM utilizes the full length of cut instead of just a portion of the cutter, allowing heat to be distributed across the cutting edge, maximizing tool life and productivity. This reduces the possibility of accelerated tool wear and breakage.

Decide On Coolant Usage & Delivery

Coolant can be an extremely effective way to protect your tool from premature wear and possible tool breakage. There are many different types of coolant and methods of delivery to your tool. Coolant can come in the form of compressed air, water-based, straight oil-based, soluble oil-based, synthetic or semi-synthetic. It can be delivered as mist, flood, high pressure or minimum quantity lubricant.

Appropriate coolant type and delivery vary depending on your application and tool. For example, using a high pressure coolant with miniature tooling can lead to tool breakage due to the fragile nature of extremely small tools. In applications of materials that are soft and gummy, flood coolant washes away the long stringy chips to help avoid recutting and built-up edge, preventing extra tool wear.

Extend Your Tool’s Life

The ability to maximize tool life saves you time, money and headaches. To get the best possible outcome from your tool, you first need to be sure you’re using the best tool for your job. Once you find your tool, ensure that your speeds and feeds are accurate and are from your tooling manufacturer. Nobody knows the tools better than they do. Finally, think about how to run your tool: the rotation of your cutter, whether utilizing an HEM approach is best, and how to introduce coolant to your job.

 

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, contouring involves the finishing of a rounded, curved, or otherwise uniquely shaped part.

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 Contouring 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

1. 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.

2. 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.

3. 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.

Contouring 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.

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.

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

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

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

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

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

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

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

 

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


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