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How to Select a Spindle

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

Why is Choosing the Right Spindle Important?

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

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

Types of CNC Spindles

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

CAT and BT Holders

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

HSK Holders

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

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

Torque vs. Horsepower

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

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

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

Torque-Horsepower Chart

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

Image Source: HAAS Machine Manual

Proper Spindle Size

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

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

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

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

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

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

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

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

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

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

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

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

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

Image courtesy of Okluma.

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

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

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

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

Tip 4: Effort Pays Off – Long Hours Result in Shop Growth

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

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

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

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

Image courtesy of Liberty Machine Inc.

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

 

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

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

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

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

Additional Thoughts Regarding Boosting Your Machining Career With Tooling:

Don’t Cheap Out

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

Consistency is Key

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

Superior Specialty Tools

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

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

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

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

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

Tip 7: Value Your Customers – Always Put Them First

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

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

Image courtesy of MedTorque.

Tip 8: Never Stop Learning – Ask Questions Whenever You Can

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

An Introduction to Reamers & CNC Reaming

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

Critical Reamer Geometries

reamers

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

The Functions of Miniature Reamers

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

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

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

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

Main Differences Between Engravers & Marking Cutters

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

Engravers & Marking Cutters Serve Different Purposes

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

engraver

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

engraver

These Tools Have Unique Geometry Features

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

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

engraver

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

Harvey Tool Product Offering

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

engraver

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

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

Marking Cutters & Engravers Summarized

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

Effective Ways To Reduce Heat Generation

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

Reduce Heat Generation with HEM Tool Paths

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

heat generation

Chip Thinning Awareness

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

heat generation

Consider Climb Milling

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

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

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

 

heat generation

Utilize Proper Coolant Methods

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

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

Importance of Controlling Heat Generation

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

5 Questions to Ask Before Selecting an End Mill

Few steps in the machining process are as important as selecting the best tooling option for your job. Complicating the process is the fact that each individual tool has its own unique geometries, each pivotal to the eventual outcome of your part. We recommend asking yourself 5 key questions before beginning the tool selection process. In doing so, you can ensure that you are doing your due diligence in selecting the best tool for your application. Taking the extra time to ensure that you’re selecting the optimal tool will reduce cycle time, increase tool life, and produce a higher quality product.

Question 1: What Material am I Cutting?

Knowing the material you are working with and its properties will help narrow down your end mill selection considerably. Each material has a distinct set of mechanical properties that give it unique characteristics when machining. For instance, plastic materials require a different machining strategy – and different tooling geometries – than steels do. Choosing a tool with geometries tailored towards those unique characteristics will help to improve tool performance and longevity.

Harvey Tool stocks a wide variety of High Performance Miniature End Mills. Its offering includes tooling optimized for hardened steels, exotic alloys, medium alloy steels, free machining steels, aluminum alloys, highly abrasive materials, plastics, and composites. If the tool you’re selecting will only be used in a single material type, opting for a material specific end mill is likely your best bet. These material specific tools provide tailored geometries and coatings best suited to your specific material’s characteristics. But if you’re aiming for machining flexibility across a wide array of materials, Harvey Tool’s miniature end mill section is a great place to start.

Helical Solutions also provides a diverse product offering tailored to specific materials, including Aluminum Alloys & Non-Ferrous Materials; and Steels, High-Temp Alloys, & Titanium. Each section includes a wide variety of flute counts – from 2 flute end mills to Multi-Flute Finishers, and with many different profiles, coating options, and geometries.

Question 2: Which Operations Will I Be Performing?

An application can require one or many operations. Common machining operations include:

  • Traditional Roughing
  • Slotting
  • Finishing
  • Contouring
  • Plunging
  • High Efficiency Milling

By understanding the operations(s) needed for a job, a machinist will have a better understanding of the tooling that will be needed. For instance, if the job includes traditional roughing and slotting, selecting a Helical Solutions Chipbreaker Rougher to hog out a greater deal of material would be a better choice than a Finisher with many flutes.

Question 3: How Many Flutes Do I Need?

One of the most significant considerations when selecting an end mill is determining proper flute count. Both the material and application play an important role in this decision.

Material:

When working in Non-Ferrous Materials, the most common options are the 2 or 3-flute tools. Traditionally, the 2-flute option has been the desired choice because it allows for excellent chip clearance. However, the 3-flute option has proven success in finishing and High Efficiency Milling applications, because the higher flute count will have more contact points with the material.

Ferrous Materials can be machined using anywhere from 3 to 14-flutes, depending on the operation being performed.

Application:

Traditional Roughing: When roughing, a large amount of material must pass through the tool’s flute valleys en route to being evacuated. Because of this, a low number of flutes – and larger flute valleys – are recommend. Tools with 3, 4, or 5 flutes are commonly used for traditional roughing.

Slotting: A 4-flute option is the best choice, as the lower flute count results in larger flute valleys and more efficient chip evacuation.

Finishing: When finishing in a ferrous material, a high flute count is recommended for best results. Finishing End Mills include anywhere from 5-to-14 flutes. The proper tool depends on how much material remains to be removed from a part.

High Efficiency Milling: HEM is a style of roughing that can be very effective and result in significant time savings for machine shops. When machining an HEM toolpath, opt for 5 to 7-flutes.

end mill selection

Question 4: What Specific Tool Dimensions are Needed?

After specifying the material you are working in, the operation(s) that are going to be performed, and the number of flutes required, the next step is making sure that your end mill selection has the correct dimensions for the job. Examples of key considerations include cutter diameter, length of cut, reach, and profile.

Cutter Diameter

The cutter diameter is the dimension that will define the width of a slot, formed by the cutting edges of the tool as it rotates. Selecting a cutter diameter that is the wrong size – either too large or small – can lead to the job not being completed successfully or a final part not being to specifications.  For example, smaller cutter diameters offer more clearance within tight pockets, while larger tools provide increased rigidity in high volume jobs.

Length of Cut & Reach

The length of cut needed for any end mill should be dictated by the longest contact length during an operation. This should be only as long as needed, and no longer. Selecting the shortest tool possible will result in minimized overhang, a more rigid setup, and reduced chatter. As a rule of thumb, if an application calls for cutting at a depth greater than 5x the tool diameter, it may be optimal to explore necked reach options as a substitute to a long length of cut.

Tool Profile

The most common profile styles for end mills are square, corner radius, and ball. The square profile on an end mill has flutes with sharp corners that are squared off at 90°. A corner radius profile replaces the fragile sharp corner with a radius, adding strength and helping to prevent chipping while prolonging tool life. Finally, a ball profile features flutes with no flat bottom, and is rounded off at the end creating a “ball nose” at the tip of the tool. This is the strongest end mill style.  A fully rounded cutting edge has no corner, removing the mostly likely failure point from the tool, contrary to a sharp edge on a square profile end mill. An end mill profile is often chosen by part requirements, such as square corners within a pocket, requiring a square end mill.  When possible, opt for a tool with the largest corner radius allowable by your part requirements. We recommend a corner radii whenever your application allows for it. If square corners are absolutely required, consider roughing with a corner radius tool and finishing with the square profile tool.

Question 5: Should I use a Coated Tool?

When used in the correct application, a coated tool will help to boost performance by providing the following benefits:

  • More Aggressive Running Parameters
  • Prolonged Tool life
  • Improved Chip Evacuation

Harvey Tool and Helical Solutions offer many different coatings, each with their own set of benefits. Coatings for ferrous materials, such as AlTiN Nano or TPlus, typically have a high max working temperature, making them suitable for materials with a low thermal conductivity. Coatings for non-ferrous applications, such as TiB2 or ZPlus, have a low coefficient of friction, allowing for easier machining operations. Other coatings, such as Amorphous Diamond or CVD Diamond Coatings, are best used in abrasive materials because of their high hardness rating.

Ready to Decide on an End Mill

There are many factors that should be considered while looking for the optimal tooling for the job, but asking the aforementioned five key question during the process will help you to make the right decision. As always, The Harvey Performance Company Technical Service Department is always available to provide recommendations and walk you through the tool selection process, if need be.

Harvey Tool Technical Support: 800-645-5609

Helical Solutions Technical Support: 866-543-5422

Shining a Light on Diamond End Mills

Diamond tooling and diamond-coated end mills are a great option when machining highly abrasive materials, as the coating properties help to significantly increase tool life relative to uncoated carbide tools. Diamond tools and diamond-like coated tools are only recommended for non-ferrous applications, including highly abrasive materials ranging from graphite to green ceramics, as they have a tendency to break down in the presence of extreme heat.

Understanding the Properties of Diamond Coatings

To ensure proper diamond tooling selection, it’s critical to understand the unique properties and makeup of the coatings, as there are often several diamond coating variations to choose from. Harvey Tool, for example, stocks Amorphous Diamond, CVD Diamond, and PCD Diamond End Mills for customers looking to achieve significantly greater tool life when working in non-ferrous applications.

Diamond, the hardest known material on earth, obtains its strength from the structure of carbon molecules. Graphite, a relatively brittle material, can have the same chemical formula as diamond, but is a completely different material; while Graphite has a sp2 bonded hexagonal structure, diamond has a sp3 bonded cubic structure. The cubic structure is harder than the hexagonal structure as more single bonds can be formed to interweave the carbon into a stronger network of molecules.

diamond tool coatings

Amorphous Diamond Coating

Amorphous Diamond is transferred onto carbide tools through a process called physical vapor deposition (PVD). This process spreads a mono-layer of DLC coating about 0.5 – 2.5 microns thick onto any given tool by evaporating a source material and allowing it to condense onto that tool over the course of a few hours.

amorphous diamond coating

Chemical Vapor Deposition (CVD)

Chemical Vapor Deposition (CVD) is a coating process used to grow multiple layers of polycrystalline diamond onto carbide tooling. This procedure takes much longer than the standard PVD coating method. During the coating process, hydrogen molecules are dissociated from the carbon molecules deposited onto the tool, leaving a diamond matrix under the right temperature and pressure conditions. Under the wrong conditions, the tool may be simply coated in graphite. 6% cobalt carbide blanks allow for the best adhesion of diamond and a substrate. CVD diamond coated end mills have a typical thickness of coating that is between 8 and 10 microns thick.

CVD Diamond Coating

Polycrystalline Diamond (PCD)

Polycrystalline Diamond (PCD) is a synthetic diamond, meaning it is grown in a lab and contains mostly cubic structures. Diamond hardness ranges from about 80 GPa up to about 98 GPa. PCD end mills have the same diamond structure as CVD diamond tools but the binding technique is different. The diamond starts in a powdery form that is sintered onto a carbide plate using cobalt as a solvent metal substrate. This is done at an extreme temperature and pressure as the cobalt infiltrates the powder, causing the grains to grow together. This effectively creates a thick diamond wafer, between 010” and .030” in width, with a carbide base. This carbide base is then brazed onto the head an end mill and sharpened.

PCD Diamond CoatingHow Diamond Coatings Differ

Coating Hardness & Thickness

Polycrystalline tools (CVD or sintered) have a much higher hardness, thickness, and max working temperature than Amorphous Diamond oated tools. As mentioned previously, a PCD tool consists of a diamond wafer brazed to a carbide body while a CVD tool is a carbide end mill with a relatively thick layer of polycrystalline diamond grown into it. This grown layer causes the CVD tools to have a rounded cutting edge compared to PCD and Amorphous Diamond coated tools. PCD tools have the thickest diamond layer that is ground to a sharp edge for maximum performance and tool life. The difference between PCD tools and CVD coated tools lies in the thickness of this coat and the sharpness of the cutting edge. Amorphous Diamond tools maintain a sharper edge than CVD coated tools because of their thin coating.

Flute Styles

Harvey Tool’s line of PCD end mills are all straight fluted, CVD coated tools are all helically fluted, and Amorphous Diamond tools are offered in a variety of options. The contrast between straight fluted and helically fluted can be seen in the images below, PCD (top) and CVD (bottom). Electrical discharge machining, grinding or erosion are used cut the PCD wafer to the specifications. The size of this wafer limits the range of diameters that can be achieved during manufacturing. In most situations a helically fluted tool would be preferred over a straight fluted tool but with true diamond tooling that is not the case. The materials that PCD tools and CVD coated tools are typically used to cut produce a powdery chip that does not require the same evacuation that a metallic or plastic chip necessitates.

PCD Diamond end mill

PCD Ball End Mill

CVD Diamond end mill

CVD Ball End Mill

Proper Uses

CVD tools are ideally suited for abrasive material not requiring a sharp cutting edge – typically materials that produce a powdery chip such as composites and graphite. Amorphous Diamond tools have a broad range of non-ferrous applications spanning from carbon fiber to precious metals but ceramics are typically outside their range as they can be too abrasive and wear away the coating. PCD tools overlap their CVD and DLC coated counterparts as they can be used for any non-ferrous abrasive material.

Cut to the Point

Harvey Tool carries physical vapor deposition diamond-like carbon coated tools, chemical vapor deposition diamond tools and polycrystalline diamond tools. PCD tools are composed of the thickest diamond wafer brazed onto a carbide shank and are ground to a sharp edge. CVD coated tools have the diamond grown into a carbide end mill. Amorphous Diamond coated tools have the DLC coated onto them through the PVD process. For more information on the diamond coating best suited for your operation, contact a Harvey Tool Tech Team Member for immediate help.

Tool Deflection & Its Remedies

Every machinist must be aware of tool deflection, as too much deflection can lead to catastrophic failure in the tool or workpiece. Deflection is the displacement of an object under a load causing curvature and/or fracture.

For Example: When looking at a diving board at rest without the pressure of a person’s weight upon it, the board is straight. But as the diver progresses down further to the end of the board, it bends further. Deflection in tooling can be thought of in a similar way.

Deflection Can Result In:

  • Shortened tool life and/or tool breakage
  • Subpar surface finish
  • Part dimensional inaccuracies

Tool Deflection Remedies

Minimize Overhang

Overhang refers to the distance a tool is sticking out of the tool holder. Simply, as overhang increases, the tool’s likelihood of deflection increases. The larger distance a tool hangs out of the holder, the less shank there is to grip, and depending on the shank length, this could lead to harmonics in the tool that can cause fracture. Simply put, For optimal working conditions, minimize overhang by chucking the tool as much as possible.

extended reach tool

Image Source: @NuevaPrecision

Long Flute vs. Long Reach

Another way to minimize deflection is having a full grasp on the differences between a long flute and a long reach tool. The reason for such a difference in rigidity between the two is the core diameter of the tool. The more material, the more rigid the tool; the shorter the length of flute, the more rigid the tool and the longer the tool life. While each tooling option has its benefits and necessary uses, using the right option for an operation is important.

The below charts illustrate the relationship between force on the tip and length of flute showing how much the tool will deflect if only the tip is engaged while cutting. One of the key ways to get the longest life out of your tool is by increasing rigidity by selecting the smallest reach and length of cut on the largest diameter tool.

tool deflection

 

tool deflection

 

When to Opt for a Long Reach Tool

Reached tools are typically used to remove material where there is a gap that the shank would not fit in, but a noncutting extension of the cutter diameter would. This length of reach behind the cutting edge is also slightly reduced from the cutter diameter to prevent heeling (rubbing of noncutting surface against the part). Reached tools are one of the best tools to add to a tool crib because of their versatility and tool life.

 

When to Opt for a Long Flute Tool

Long Flute tools have longer lengths of cut and are typically used for either maintaining a seamless wall on the side of a part, or within a slot for finishing applications. The core diameter is the same size throughout the cutting length, leading to more potential for deflection within a part. This possibly can lead to a tapered edge if too little of the cutting edge is engaged with a high feed rate. When cutting in deep slots, these tools are very effective. When using HEM, they are also very beneficial due to their chip evacuation capabilities that reached tools do not have.

 

Deflection & Tool Core Strength

Diameter is an important factor when calculating deflection. Machinists oftentimes use the cutter diameter in the calculation of long flute tools, when in actuality the core diameter (shown below) is the necessary dimension. This is because the fluted portion of a tool has an absence of material in the flute valleys. For a reached tool, the core diameter would be used in the calculation until its reached portion, at which point it transitions to the neck diameter. When changing these values, it can lower deflection to a point where it is not noticeable for the reached tool but could affect critical dimensions in a long flute tool.

Deflection Summarized

Tool deflection can cause damage to your tool and scrap your part if not properly accounted for prior to beginning a job. Be sure to minimize the distance from the tool holder to the tip of the tool to keep deflection to a minimum. For more information on ways to reduce tool deflection in your machining, view Diving into Depth of Cut.

Selecting the Right Harvey Tool Miniature Drill

Among Harvey Tool’s expansive holemaking solutions product offering are several different types of miniature tooling options and their complements. Options range from Miniature Spotting Drills to Miniature High Performance Drills – Deep Hole – Coolant Through. But which tools are appropriate for the hole you aim to leave in your part? Which tool might your current carousel be missing, leaving efficiency and performance behind? Understanding how to properly fill your tool repertoire for your desired holemaking result is the first step toward achieving success.

Pre-Drilling Considerations

Miniature Spotting Drills

Depending on the depth of your desired machined hole and its tolerance mandates, as well as the surface of the machine you will be drilling, opting first for a Miniature Spotting Drill might be beneficial. This tool pinpoints the exact location of a hole to prevent common deep-hole drilling mishaps such as walking, or straying from a desired path. It can also help to promote accuracy in instances where there is an uneven part surface for first contact. Some machinists even use Spotting Drills to leave a chamfer on the top of a pre-drilled hole. For extremely irregular surfaces, however, such as the side of a cylinder or an inclined plane, a Flat Bottom Drill or Flat Bottom Counterbore may be needed to lessen these irregularities prior to the drilling process.

spotting drill

Tech Tip: When spotting a hole, the spot angle should be equal to or wider than the angle of your chosen miniature drill. Simply, the miniature drill tip should contact the part before its flute face does.

spotting drill correct angle

Selecting the Right Miniature Drill

Harvey Tool stocks several different types of miniature drills, but which option is right for you, and how does each drill differ in geometry?

Miniature Drills

Harvey Tool Miniature Drills are popular for machinists seeking flexibility and versatility with their holemaking operation. Because this line of tooling is offered uncoated in sizes as small as .002” in diameter, machinists no longer need to compromise on precision to reach very micro sizes. Also, this line of tooling is designed for use in several different materials where specificity is not required.

miniature drill

Miniature High Performance Drills – Deep Hole – Coolant Through

For situations in which chip evacuation may be difficult due to the drill depth, Harvey Tool’s Deep Hole – Coolant Through Miniature Drills might be your best option. The coolant delivery from the drill tip will help to flush chips from within a hole, and prevent heeling on the hole’s sides, even at depths up to 20 multiples of the drill diameter.

miniature drill coolant through

Miniature High Performance Drills – Flat Bottom

Choose Miniature High Performance Flat Bottom Drills when drilling on inclined and rounded surfaces, or when aiming to leave a flat bottom on your hole. Also, when drilling intersecting holes, half holes, shoulders, or thin plates, its flat bottom tool geometry helps to promote accuracy and a clean finish.

flat bottom drill

Miniature High Performance Drills – Aluminum Alloys

The line of High Performance Drills for Aluminum Alloys feature TiB2 coating, which has an extremely low affinity to Aluminum and thus will fend off built-up edge. Its special 3 flute design allows for maximum chip flow, hole accuracy, finish, and elevated speeds and feeds parameters in this easy-to-machine material.

drill for aluminum

 

Miniature High Performance Drills – Hardened Steels

Miniature High Performance Drills – Hardened Steels features a specialized flute shape for improved chip evacuation and maximum rigidity. Additionally, each drill is coated in AlTiN Nano coating for hardness, and heat resistance in materials 48 Rc to 68 Rc.

drill for hardened steel

Miniature High Performance Drills – Prehardened Steels

As temperatures rise during machining, the AlTiN coating featured on Harvey Tool’s Miniature High Performance Drills – Prehardened Steels creates an aluminum oxide layer which helps to reduce thermal conductivity of the tool and helps to promote heat transfer to the chip, as well as improve lubricity and heat resistance in ferrous materials.

drill for prehardened steel

Post-Drilling Considerations

Miniature Reamers

For many operations, drilling the actual hole is only the beginning of the job. Some parts may require an ultra-tight tolerance, for which a Miniature Reamer (tolerances of +.0000″/-.0002″ for uncoated and +.0002″/-.0000″ for AlTiN Coated) can be used to bring a hole to size. miniature reamer

Tech Tip: In order to maintain appropriate stock removal amounts based on the reamer size, a hole should be pre-drilled at a diameter that is 90-94 percent of the finished reamed hole diameter.

Flat Bottom Counterbores

Other operations may require a hole with a flat bottom to allow for a superior connection with another part. Flat Bottom Counterbores leave a flat profile and straighten misaligned holes. For more information on why to use a Flat Bottom Counterbore, read 10 Reasons to Use Flat Bottom Tools.

flat bottom counterbores

Key Next Steps

Now that you’re familiar with miniature drills and complementary holemaking tooling, you must now learn key ways to go about the job. Understanding the importance of pecking cycles, and using the correct approach, is vital for both the life of your tool and the end result on your part. Read this post’s complement “Choosing the Right Pecking Cycle Approach,” for more information on the approach that’s best for your application.

5 Ways Your Shop is Inefficient

5 Ways Your Shop is Inefficient

In today’s ultracompetitive industry, every machine shop seeks even the slightest edge to gain an advantage on their competition and boost their bottom line. However, what many machinists don’t know is that improving their shop’s efficiency might be easier than they thought. The following five ways your shop is inefficient will provide a clear starting point of where to look for machinists desperate to earn a competitive edge.

1. Premature Tool Decay / Tool Failure

If you’re finding that your tools are failing or breaking at an unacceptable rate, don’t mistake it for commonplace. It doesn’t have to be. Prolonging the life of your tooling starts with finding not just the right tool, but the best one; as well as running it in a way to get its optimal performance. Many machinists mistake premature tool failure with running parameters that were too aggressive. In fact, not pushing the tool to its full potential can actually cause it to decay at an accelerated rate in certain situations.

Tool failure can occur in many different ways: Abrasive Wear, Chipping, Thermal Cracking or Tool Fracture, just to name a few. Understanding each type and its causes can help you to quickly boost your shop’s efficiency by minimizing downtime and saving on replacement tool costs.

tool wear

An example of a tool with excessive wear

For more information on tool wear, view Avoiding 4 Major Types of Tool Wear.

2. Subpar Part Finish

Your shop spends money to employ machinists, run machines, and buy cutting tools. Get your money’s worth, lead the industry, and ensure that you’re providing your customers with the highest quality product. Not only will this help to keep your buyer-seller relationship strong, but it will allow you the flexibility to increase your prices in the future, and will attract prospective customers.

Many factors influence part finish, including the material and its hardness, the speeds and feeds you’re running your tool at, tool deflection, and the tool-to-workpiece orientation.

For more information on ways to improve your part finish, view our Part Finish Reference Guide.

3. Inefficient Coolant Usage

One often forgotten expense of a machine shop is coolant – and it can be pricey. A 55-gallon drum of coolant can run more than $1,500. What’s worse is that coolant is often applied in excess of what’s required for the job. In fact, some machines even feature a Minimum Quantity Lubricant (MQL) functionality, which applies coolant as an extremely fine mist or aerosol, providing just enough coolant to perform a given operation effectively. While drowning a workpiece in coolant, known as a “Flood Coolant,” is sometimes needed, it is oftentimes utilized on jobs that would suffice with much less.

For more information about coolants and which method of application might be best for your job, view What You Need to Know About Coolant for CNC Machining.

4. Not Taking Advantage of Tool Versatility

Did you know that several CNC cutting tools can perform multiple operations? For example, a Chamfer Mill can chamfer, bevel, deburr, and countersink. Some Chamfer Mills can even be used as a Spotting Drill. Of course, the complexity of the job will dictate your ability to reap the benefits of a tool’s versatility. For instance, a Spotting Drill is obviously the best option for spotting a hole. If performing a simple operation, though, don’t go out of your way to buy additional tooling when what’s already in your carousel can handle it.

chamfer mills

To learn more about versatile tools that can perform multiple applications, check out Multi-Functional Tools Every Shop Should Have.

5. High Machine Downtime

What use is a machine that’s not running? Minimizing machine downtime is a key way to ensure that your shop is reaching its efficiency pinnacle. This can be accomplished a variety of ways, including keeping like-parts together. This allows for a simple swap-in, swap-out of material to be machined by the same cutting tool. This saves valuable time swapping out tooling, and lets your machine to do its job for more time per workday. Production planning is a key factor to running an efficient machine shop.