3 Tips for Avoiding Misaligned Holes


One of the most common issues machinists face during a drilling operation is hole misalignment. Hole alignment is an essential step in any assembly or while mating cylindrical parts. When holes are properly aligned, the mating parts fit easily in each other. When one of the pieces to the puzzle is inaccurate, however, machinists run into issues and parts can be scrapped. The two types of common misalignment woes are Angular Misalignment and Offset Misalignment.

Angular Misalignment

Angular misalignment is the difference in slope of the centerlines of the holes. When the centerlines are not parallel, a shaft will not be able to fit through the hole properly.

Offset Misalignment

Offset misalignment is the distance between the centerlines of the hole. This is the position of the hole from its true position or mating part. Many CAD software programs will help to identify if holes are misaligned, but proper technique is still paramount to creating perfect holes.

1.    Utilize a Spotting Drill

Using a spotting drill is a common way to eliminate the chance of the drill walking when it makes contact with the material. A spotting drill is designed to mark a precise location for a drill to follow, minimizing the drill’s ability to walk from a specific area.

Valor Holemaking High Performance Spotting Drill

Although using a spotting drill would require an additional tool change during a job, the time spent in a tool change is far less than the time required to redo a project due to a misaligned hole. A misaligned hole can result in scrapping the entire part, costing time and money.

Do you know how to choose the perfect spot drill angle? Learn how in this in-depth guide so you can eliminate the chance of drill walking and ensure a more accurate final product.

2.    Be Mindful of Web Thickness

A machinist should also consider the web thickness of the drill when experiencing hole misalignment. A drill’s web is the first part of the drill to make contact with the workpiece material.

Essentially, the web thickness is the same as the core diameter of an end mill. A larger core will provide a more rigid drill and a larger web. A larger web, however, can increase the risk of walking, and may contribute to hole misalignment. To overcome this machining dilemma, machinists will oftentimes choose to use a drill that has a thinned web.

Web Thinning

Also known as a split point drill, web thinning is a drill with a thinned web at the point, which helps to decrease thrust force and increase point accuracy. There are many different thinning methods, but the result allows a drill to have a thinner web at the point while having the benefit of a standard web through­out the rest of the drill body.

A thinner web will:

  1. Be less susceptible to walking
  2. Need less cutting resistance
  3. Create less cutting force

3.    Select a Material Specific Drill

Choosing a material specific drill is one of the easiest ways to avoid hole misalignment. A material specific drill design has geometries that will mitigate the specific challenges that each unique material presents. Further, material specific drills fea­ture tool coatings that are proven to succeed in the specific material a machinist is working in.

Valor Holemaking High Performance Drills for Steels and High Performance Drills for Aluminum

Helical Solutions Teams up With Mastercam to Test Different Levels of Continuous Time In Cut (CTIC)

Don Grandt, Harvey Performance Company National Application Engineer, met up with Jesse Trinque at the Mastercam Manufacturing Lab to demo some Helical Solutions End Mills and discuss Continuous Time In Cut (CTIC).

Continuous Time in Cut (CTIC) is the amount of time that a tool is engaged with a material. When an end mill is in a cut for too long, the friction can build and surface foot can be sacrificed, greatly affecting the performance and wear of a tool.

Check out this video to watch Jesse and Don test out how different levels of CTIC directly affect tool life and performance. This series of tests, which were facilitated by Mastercam, were conducted in Okuma’s GENOS M560-V, and utilized tool paths from Mastercam. For tooling, a standard ½” Helical Solutions HEV-6, a 6 flute, variable pitch end mill with a .03” corner radius, was used to machine 17-4 stainless steel.

All tests used the same cutting parameters, setup, material, and tool, with altered CTIC.

Take a Deeper Dive Into CTIC

Tune into this episode of In The Loupe TV to learn how you can manipulate Continuous Time In Cut (CTIC) and surface foot to reduce heat in your machining applications.

Carbon Fiber Reinforced Polymers (CFRP): Running Parameters, Tool Life, & Safety Tips


Carbon Fiber Reinforced Polymers (CFRP) is a collection of carbon fibers that, when bound together via resin, creates a material with a wide range of application possibilities. It’s strong, durable, and resistant to corrosion, making it an advantageous material for use in several advanced industries, including the aerospace and automotive industries. Despite its unique abilities, however, machining CFRP is not without its set of challenges, all of which machinists must be cognizant of to achieve desired results. Once CFRP is properly understood and the right cutting tool is selected for the job, the next step is to properly set running parameters for your application.

Square piece of cfrp laminate carbon fiber material

Running Parameters

Comparison of Metal Machining vs Composite Machining

When machining CFRP, the suggested running parameters are to have a high RPM with low feed rates. Feed rates will need to be adjusted to account for heat minimization, while RPMs may need to be dialed back to prevent excessive fraying, tearing, or splitting of fibers when cutting.

In metal machining, the tool cuts away at material, forming chips. This is possible due to the formation of the metal having natural fracture and stress lines that can be wedged by the cutting tool to create a chip. Unlike metals, machining carbon fiber does not peel away material but rather fracture and break the fibers and resin.

Milling vs Drilling Carbon Fiber

Composite holemaking or drilling is found to be more challenging than milling carbon fiber. It generates more dust due to the drilling speed. Using specific tooling for composites will be crucial in effective drilling. When machining holes, the carbon fiber will relax, creating undersized holes which requires extensive adjustments that are best automated for efficiency.

For help mitigating the challenges of composite holemaking, read Overcoming Composite Holemaking Challenges and browse CoreHog’s offering of drills, specially engineered to mitigate all-too-common holemaking headaches. To achieve better finish and avoid delamination, it is recommended to utilize conventional milling over climb milling within composites contrary to what is recommended in metal machining.

Combination of corehog specific cfrp drills including helical step, dagger, 8 facet, and tapered drill reamer

Within the aerospace industry, drilling is the most common application in machining. Like milling, performing operations such as pecking may be preferred even with increased cycle time if it reduces any chances of error that result in scrapping of the part.

Running Parallel to Grain of Fibers

While every part is different, there is a method for reducing fraying, chipping, or delamination by cutting parallel to the fiber direction when possible. This can be like cutting along the grain of wood instead of cutting perpendicular or at an angle to the grain.

Coolant Applications

The use of coolant when machining CFRP can either benefit or negatively affect the part depending on the application. The preferred coolant of choice for machining carbon fiber is typically using water or a water-soluble coolant. This is due to composites having a porous surface that could allow contaminates to enter the part itself. By using water, it prevents any issues after machining where adhesives or paint may need to be applied to the part that otherwise would not have adhered properly with contaminates present.

cnc machine looking through glass window focusing on a tool in the cut with external coolant spraying the workpiece

High Scrapping Costs

Many composite parts are unique in shape and size with custom molded designs that create a large initial cost prior to the machining stage. After the part is molded near to its shape, machining is often used to finish the part or drill holes where needed to finalize the part.

Importance of Considering Machining Challenges to Avoid Scrapping

Having a set process that is consistent and reliable is important in helping to prevent scrapping. Eliminating human error with machines that can monitor the entire process while automating tool changes when tools are worn, avoids issues before they can happen. A key factor is ensuring the setup is correct, having the right tooling, tool path, and coolant option to perform the operation effectively and accurately. With some parts serving critical functions and with a high cost, there is no exception for poor finish or incorrect cuts emphasizing the importance of having a procedure that gets the job done the right way.

Composite Cutting Tool Life Management

Wear Rate & its Effects 

Due to carbon fiber’s abrasion on the cutting tools, a rapid decrease in cutting quality will occur as soon as the tool begins to dull. Fibers will be grabbed instead of fractured, causing fraying and damage to the part. Therefore, tool life should be vigilantly monitored to replace the tool before reaching the point of dullness.

Developing a Process for Success

Unlike metal machining where tools may be utilized until they show signs of wear, this method would be unideal for CFRP as the highly expensive part could be ruined or damaged causing scrapping costs and time. It is good practice to take preventative measures by taking note of typical wear of your tools and using that information to set tool changes before it dulls. Noting tool changes and having high interval checks on cutting and dimension quality will aid in avoiding poor finish or scrapping. Some machines are equipped with tool life management systems which will greatly reduce the chances of having to scrap a part because of tool dullness.

Safety Practices When Machining CFRP

Being that chips are not formed when machining CFRP, and instead, the material is fractured, it creates dust that can spread throughout the air and other surfaces. Not only does this cause hazardous conditions for anyone nearby who may inhale the dust, but the dust is also conductive, which can ruin electronics. To avoid these issues, two different extraction methods can be used depending on the needs of the application.

Wet vs Dry Extraction

The two options for dust extraction are using coolant (wet) or vacuuming (dry). Choosing between the two is dependent on the application, but mostly dictated by the size of the application. Smaller scale machining can be contained through vacuuming, but larger applications would require coolant as vacuuming a large area may be challenging. If a lot of heat will be generated, then it is necessary to have a water-soluble coolant. This would also benefit the use of diamond tooling as they will wear faster at lower temperatures in comparison to carbide tooling. Another would be the dust collection would remain contained with the liquid preventing any airborne exposure.

Disposal Considerations

One benefit of vacuuming over coolant is the disposal process. After machining, the coolant/dust mix would require post-treatment to remove excess water before being transferred to a landfill. This would incur additional costs to the process which may cause some to lean towards vacuuming if heat is not an issue.

Conclusion

With CFRP’s wide range of uses and desirable mechanical properties for its applications, comes the effect of its challenges in machining and high cost of scrapping. Refining this process will be essential for the growing demand of carbon fiber machining in the near future. For more information on CFRP, specifically related to material properties and tool selection, read In the Loupe’s complementary post “Carbon Fiber Reinforced Polymers (CFRP): Material Properties & Tool Selection”.

The Benefits of CoreHog’s Assembly Style Tooling in Composites


Harvey Performance Company brand CoreHog, which focuses on the manufacturing of the world’s most advanced composite and honeycomb core cutting tools, fully stocks an array of “Assembly Style Cutting Tools,” which allow a machinist to build the perfect solution for their specific application’s needs. In doing so, a cutting tool can be optimized for specific materials, densities, and manufacturing styles to increase efficiency, decrease costs, and provide unbelievable machining flexibility.

Corehog tooling for machining composites

How Does Assembly Style Tooling Work?

CoreHog’s Assembly Style Tooling works by taking multiple pieces and tool components, and assembling them together to create one finished cutting tool. The concept of assembling a completed tool allows machinists greater flexibility in choosing cutting edges that are best suited for their application or material type. Further, this type of tooling is often utilized by machinists because it’s often a less expensive alternative to solid round, non-assembled tooling, as a machinist would only need to replace the cutting end components when they begin to dull, and not the arbors or shank pieces.

CoreHog’s offering of Assembly Style Tooling includes Small Size, Medium Size, and Large Size Finishing Core Tools, as well as Valve Stem Cutters and Rebating Cutters. The way in which each system is built varies by tool type.

Finishing Core Tools

Small Finishing Core Tools

Optimized to machine small, closed features in composites, such as pockets, joggles, and closed walls, Small Size Finishing Tools are engineered for the superior finishing of honeycomb core materials. This configuration includes a Small Coreslicer with three different edge options: Smooth, Sawtooth, or Staggered Tooth, and an optional Small CoreHogger. The right edge style for the Coreslicer depends largely on the material you’re working in. While a Smooth edge style works well in lighter density honeycomb core materials such as Kevlar®, Nomex®, and Aluminum, Sawtooth and Staggered Tooth options work best for honeycomb core materials with densities of 6 pounds or higher, such as aluminum core, Kevlar®, or Nomex®.


Key Benefits: Eliminating the risk of material wrapping around the spindle by disintegrating them as they approach the face of the slicer.

Browse Small Finishing Core Tools

Medium Finishing Core Tools

Designed for finishing honeycomb core materials, this assembly style CNC tooling is engineered for shaping smaller complex surfaces, bevels, and external radii. For this configuration, a Medium CoreHogger and a Medium Coreslicer must be utilized and fastened with a screw. Similar to the Small Finishing Core Tool options, this assembly can be used with a Smooth, Sawtooth, or Staggered Tooth Coreslicer edge.

Key Benefits: This Medium Size Finishing Tool offering includes both carbide and high speed steel options. The carbide version is uncoated, whereas the high speed steel version is TiCN coated for extended tool life and improved wear resistance.

Browse Medium Finishing Core Tools

Large Finishing Core Tools

Designed to vastly reduce cycle times while finishing honeycomb core materials, this assembly style tooling removes large volumes of material quickly, while providing excellent surface finish and keeping tool pressure and heat low.


Large Finishing Core Tools require a slightly more complex configuration. This type of modular tool features an Arbor, which includes a washer and screw; Large CoreHogger; and Large Coreslicer. For this assembly, four types of Coreslicer edge options are available: Smooth, Sawtooth, Staggered Tooth, or Wavy. Wavy style options are best utilized in heavier density types of Kevlar®, Nomex®, and Aluminum Core, and are engineered to be useful when machining parts that contain bond lines.

Key Benefits: The Arbors in this configuration are heat treated and finish ground for extremely tight tolerances in runout, concentricity, and perpendicularity. With tighter tolerances, harmonics are minimized while longer tool life and better part finish are observed.

Browse Large Finishing Core Tools

Valve Stem Cutters


Different from CoreHog’s Finishing Core Tools, Valve Stem Cutters are assembly tooling engineered for machining honeycomb core materials and finishing thin features, such as bevels and knife edge parts. To build a Valve Stem Cutter, utilize an Arbor, a Valve Stem Slicer, and a screw to fasten the two together. Similar to Small and Medium Finishing Core Tools, the Valve Stem Slicer can feature a Smooth, Sawtooth, or Staggered Tooth edge profile.

Key Benefits: The Stem design of CoreHog’s Valve Stem Arbors is optimized for free flowing applications, eliminating grabbing when machining Honeycomb Core Materials.

Browse Valve Stem Cutters

Rebating Cutters


Machinists may opt to use a Modular Rebating Tool if they are aiming to reduce setup, minimize cost per cutter, and obtain flexibility with varying sandwich panel configurations. For this configuration, an Arbor connects to a Core Insert, Skin Insert, and is fastened with a screw. Here, the Arbor, which features a .500” shank diameter and a 3” overall length, can be paired with multiple sizes of Core Inserts. As of September 2022, CoreHog’s offering of Core Inserts range in diameter from .875” to 1”, with a length of cut spanning from .160” to .312”. All Inserts feature TiAlN coating, which provides high hardness and high temperature resistance. Finally, the Skin Insert features a ½” diameter, and provides a machinist with the option of DLC or CVD Coating. While DLC coating provides optimal performance, true crystalline CVD diamond coating works to significantly extend tool life.

Key Benefits: The complex geometry of Sandwich Panel Cutters – Arbors helps to reduce tearing, flagging, and fuzz, while providing a rebated area to allow for edge filling or fasteners, later on.

Browse Rebating Cutters

For more information on CoreHog’s Assembly Style Tooling, visit its website at corehog.com.

Reduce Tool Chatter by Avoiding these 5 Boring Bar Application Mistakes

Boring bar applications are very popular in the lathe and CNC machining industry, as they provide a shop with extreme diversity and accuracy. Running a boring bar properly, however, is essential to ensuring you’re maximizing shop efficiency and achieving outstanding part finish. There are many mistakes that can be made when running boring bars and many that cause excessive machining vibrations or chatter that must be avoided. Learn the five mistakes that could be causing tool chatter in your boring applications and how you can stop chatter once and for all.

Lathe Boring Bar Application Mistakes

Using a Dull Cutter

Boring with a worn-out tool significantly increases cutting forces generated by the cut, leading to chatter. The more a tool is run, the more chance it has for galling, or in other words, built-up edge (BUE), making it imperative to inspect your boring bar before each application. BUE occurs when material is welded onto the cutting tool due to high friction and heat generation during a CNC machining operation. This condition is not desirable because it leads to poor tool life and increased vibrations due to an uneven cutting edge. Stocking your tool crib with great quality boring bars can help reduce BUE by providing a sharp, long lasting cutting edge, catered for your exact application. Learn other ways to reduce BUE in your turning applications, today.

Shows zoomed in effects of built-up edge and wear failure on carbide boring bar
Image Source: Carbide inserts Wear Failure modes. | machining4.eu, 2022

Utilizing Incorrect Speeds & Feeds

Like many applications, using improper turning speeds & feeds can lead to poor performance. In boring applications, using too high of a chip load can cause deflection, greatly increasing the chances of tool failure. Using too low of a chip load doesn’t allow the tool to cut enough, which causes the tool to bounce off the material, leading to increased tool wear and poor part finish. Discovering the right balance for using chip load is crucial in order to produce a more efficient cut.

lathe turning speeds and feeds

When running a boring bar, it is imperative to use the speeds & feeds recommended for the tool being used. Micro 100 provides downloadable and printer-friendly Speeds & Feeds for all Standard and Quick Change Micro-Quik turning tools.

Lacking Workpiece Support

A main cause of chatter in boring applications is lack of support on the workpiece. If a workpiece is not properly supported when entering a boring application, the tool will begin to chatter. Not only is it essential to confirm the proper workholding device is being used, but it’s also important to ensure that your setup is as rigid as possible. Learn more about workholding styles and considerations to make sure you’re supporting your workpiece properly in your next boring application.

Uneven Tool Holding

Similarly, tool holding also plays a vital role in the performance of a boring bar application. It is important to select a tool holder that accommodates the tooling being used and is as rigid as possible. Using an improper method of tool holding can lead to tool runout, which occurs when the tool or holder deviates too far off its axis.

Micro-Quik tool holder with a tool inserted and pointing towards workpiece
Image Source: @abom79

Many machinists opt for tools that promote machining efficiency by boosting the speed at which tool changes occur. For example cutting tool manufacturer Micro 100 offers Micro-Quik Holders, which offer unmatched rigidity, axial and radial repeatability, tip-to-tip consistency, and part-to-part accuracy in tool changes totaling fewer than 30 seconds.

Drilling an Improper Starter Hole

Before starting a boring application, drilling the proper hole is vital to ensuring that the boring bar has sufficient contact with the workpiece to properly stabilize the cut. If a hole is too large, the boring bar could deflect off of the workpiece. If the hole is too small, there will not be enough clearance for the tool, increasing chances of tool wear and possibly tool failure. When selecting a drill to prepare the workpiece for your boring applications, there are two dimensions that should be considered: the Head Width and the Minimum Bore Diameter.

Boring bar with line drawing showing where different dimensions are located on the tool

The Head Width, or “H” value on the above line drawing, is the actual width of the boring tool. The Minimum Bore Diameter is a calculated dimension slightly larger in size compared to the head with that is associated with the smallest drill size that should be used to start a boring application. It is recommended to opt for a drill that is the same or slightly larger than the Minimum Bore Diameter of the boring bar being used, to ensure there is proper clearance for the cutting edge.

Utilizing an Inefficient Coolant Strategy

If coolant isn’t aimed properly on the workpiece or if improper coolant is being used, tool life and quality part finish can be significantly reduced. Additionally, if coolant lines are aimed directly at the bore, the pressure of the coolant holds the chips in the bore, causing them to evacuate improperly. This then causes chip recutting, leading to chatter and finish problems. Opting for a Plumbed and Ported Tool Holder can mitigate this problem, ensuring chips are being properly evacuated out of the cut.

coolant being sprayed onto a part during a cnc machining operation

Machinists generally utilize Flood or High Pressure coolant methods for chip removal. Flood coolant uses low pressure to create lubricity and aid in chip evacuation. On the other hand, high pressure coolant delivers instant cooling of a part and quickly shoots chips away to prevent recutting.

Spot Drilling: The First Step to Precision Drilling

Drilling an ultra-precise hole can be tough. Material behavior, surface irregularities, and drill point geometry can all be factors leading to inaccurate holes. A Spot Drill, if used properly, will eliminate the chance of drill walking and will help to ensure a more accurate final product.

Choosing a Spot Drill

Ideally, the center of a carbide drill should always be the first point to contact your part. Therefore, a spotting drill should have a slightly larger point angle than that of your drill. Common drill point angles range from 118° to 140° and larger. Shallower drill angles are better suited to harder materials like steels due to increased engagement on the cutting edges. Aluminums can also benefit from these shallower angles through increased drill life. While these drills wear less and more evenly, they are more prone to walking, therefore creating a need for a proper high performance spot drill in a shallow angle to best match the chosen drill.

Five Valor holemaking high performance spot drills displayed on top of a workpiece with a purple product packaging container in front

If a spotting drill with a smaller point angle than your drill is used, your drill may be damaged due to shock loading when the outer portion of its cutting surface contacts the workpiece before the center. Using a drill angle equal to the drill angle is also an acceptable situation. Figure 1 illustrates the desired effect. On the left, a drill is entering a previously drilled spot with a slightly larger angle than its point. On the right, a drill is approaching an area with an angle that is far too small for its point.

Proper Spot Angle Diagram

Marking Your Spot

A Spotting Drill’s purpose is to create a small divot to correctly locate the center of a drill when initiating a plunge. However, some machinists choose to use these tools for a different reason – using it to chamfer the top of drilled holes. By leaving a chamfer, screw heads sit flush with the part once inserted.

Spot Drill

What Happens if I Use a Spot Drill with an Improper Angle?

Using a larger angle drill will allow the drill to find the correct location by guiding the tip of the drill to the center. If the outer diameter of a carbide drill were to contact the workpiece first, the tool could chip. This would damage the workpiece and result in a defective tool. If the two flutes of the drill were slightly different from one another, one could come into contact before the other. This could lead to an inaccurate hole, and even counteract the purpose of spot drilling in the first place.

Avoiding CNC Drill Walking With a Spotting Drill

Few CNC machining applications demand precision like drilling. The diameter hole size, hole depth, part location, and finish are all important and provide little recourse if not up to specifications. That said, accuracy is paramount – and nothing leads to inaccurate final parts faster than drill walking, or the inadvertent straying from a drill’s intended location during the machining process. So how does drill walking occur, and how can one prevent it?

To understand drill walking, think about the act of striking a nail with a hammer, into a piece of wood. Firm contact to a sharp nail into an appropriate wood surface can result in an accurate, straight impact. But if other variables come into play – an uneven surface, a dull nail, an improper impact – that nail could enter a material at an angle, at an inaccurate location, or not at all. With CNC Drilling, the drill is obviously a critical element to a successful operation – a sharp, unworn cutting tool – when used properly, will go a long way toward an efficient and accurate final part.

To mitigate any variables working against you, such as an uneven part surface or a slightly used drill, a simple way to avoid “walking” is to utilize a Spotting Drill. This tool is engineered to leave a divot on the face of the part for a drill to engage during the holemaking process, keeping it properly aligned to avoid a drill from slipping off course.

When Won’t a Spot Drill Work for My Application?

When drilling into an extremely irregular surface, such as the side of a cylinder or an inclined plane, this tool may not be sufficient to keep holes in the correct position. For these applications, flat bottom versions or Flat Bottom Counterbores may be needed to creating accurate features.

Harvey tool spot drill zoomed in on the tip of the drill
Harvey Tool Spot Drill

Machining Nickel Alloys: Avoiding All-Too-Common Mishaps


Nickel-based alloys are growing in popularity across many industries such as aerospace, automotive, and energy generation due to their unique and valuable mechanical and chemical properties. Nickel alloys exhibit high yield and tensile strengths at low weights and have high corrosion resistance in acidic and high temperature environments. Because of these advantageous properties, nickel alloys have increasingly become popular in machine shops.

Unfortunately, nickel alloys have a reputation for creating issues at the spindle. These metals present themselves to be problematic as they easily work harden. Further, nickel alloys generate high temperatures during machining, and have gummy chips that can weld onto cutting tools, creating built-up edge (BUE). Fortunately, with the correct approach, one can be successful in cutting nickel alloys.

Work Hardening

Across machine shops, nickel alloys are notorious for being difficult to machine. This reputation stems, largely, from work hardening, or a metal’s microhardness increasing due to the addition of heat. According to the Nickel Development Institute, this heat is generated through friction and plastic deformation of the metal. As the metal is cut, the friction between the cutting tool and workpiece generates heat which is concentrated around the cutting area.

Simultaneously, the metal is being physically worked. This means that as it is being machined, it is experiencing plastic deformation, which is a physical property that measures how much a material can be deformed to the point that it cannot return to its original shape.

This physical working of a nickel alloy increases its hardness faster than it does most other metals. The combination of high heat generation and physical work quickly increases the alloy’s hardness, causing tools to dull quickly and fail. This may result in scrapped parts and broken tools.

8 flute HVNI End Mill for Machining Nickel Alloys
Shown above is Helical Solutions’ End Mill for Nickel Alloys. This tool, engineered to excel in Inconel 718 and other nickel-based superalloys, is fully stocked in 6 and 8 flute styles.

Tool Adhesion

As nickel alloys are being machined and heat is generated, chips tend to become stringy and weld themselves to a tool’s cutting edge. This phenomenon, built up edge or BUE, rounds the cutting edge of the tool, resulting in poor cuts and increased friction, thus further contributing to work hardening. An example of BUE is seen in the image below.

Zoomed in display of built-up edge on End Mill Flutes
On the above tool, chips from the workpiece (Inconel 718) have welded onto the cutting edge, severely decreasing the tool’s effectiveness. Image Source: International Journal of Extreme Manufacturing

Built-up edge also speeds up tool wear, as the rotational forces involved in the cut increase. Now that the cutting edge is rounded from welded chips, a blunt tool is being forced into the workpiece.

With a blunt edge, the cutting motion changes from a shearing action to plowing. In other words, instead of cutting through the metal, the tool is pushing the material, resulting in poor cuts and increased friction.

Excessive Heat Generation

With poor cutting, internal heat of the tool rises, which can cause thermal cracking, defined by cracks that form perpendicular to the cutting edge. The fractures within the tool are created by extreme internal tool temperature fluctuations.

As a cutting tool rapidly overheats while cutting nickel alloys, cracks may form which can lead to catastrophic tool failure. With high temperatures, galling may also occur, which is characterized by pieces of the tool flaking off due to the same adhesion that causes BUE. As the tool is being welded to the workpiece and the machine continues to rotate it, pieces of the tool may start to break off resulting in tool failure.

Overcoming Nickel Alloy Difficulties

Temperature Control and Coolant Usage

The first step to effectively machine nickel alloys is to keep temperatures manageable as the workpiece is cut. Using high pressure coolant is mandatory. Coolant pressure should be 1000 psi or greater. This high pressure concentrating on the cutting zone of the workpiece will dissipate heat within both the cutting tool and workpiece. By doing so, the chances of work hardening lessen.

High pressure coolant will also aid in clearing out chips from the cutting area. Those hot gummy chips are responsible for BUE. Removing them as quickly as possible reduces the risk of BUE forming on the cutting edge. Additionally, chip removal is important to avoid chip recutting.

Chips absorb much of the heat and often work harden themselves. Recutting these hardened chips will dull the cutting edge resulting in poor cuts and decrease tool life. In general, water-based cutting fluids are preferable as they have higher heat removal rates and have a lower viscosity, which is needed for high metal removal operations.

Using the Proper Techniques

To also assist with heat removal, utilize climb milling techniques, where possible. When climb milling, the chip thickness is at its maximum at the beginning of the cut and tapers off until the cut is complete. Due to this, less heat is generated, as the cutting tool does not rub on the workpiece. Most of the heat from the cut is transferred into the chip.

Selecting the Proper Tooling and Coating

The next step is selecting the right end mill. Your end mill of choice should have a proper tool coating, such as Helical’s Tplus coating. Tool coatings are specifically engineered to improve tool performance by reducing friction, increasing tool microhardness, and extending tool life.

Next is selecting flute count. Tools used for nickel alloys need to be rigid to withstand the cutting forces present when machining high hardness alloys. Therefore, higher flute counts are necessary. If using traditional roughing toolpaths, your end mill should have at least 6 flutes. With 6 flutes, there is sufficient flute valley depth to allow for chip evacuation, while having a larger core diameter keeps the tool strong and rigid.

For finishing operations and instances of implementing high efficiency milling, higher flute counts should be considered. A tool used this way should have 8 flutes to provide excellent surface finish.

Helical’s End Mills for Nickel Alloys

CNC tooling manufacturer Helical Solutions’ End Mills for Nickel Alloys product offering, its HVNI tool family, specializes in machining nickel alloys as it exhibits these key tool features.

Four Helical Solutions End Mills for Nickel Alloys positioned over a Helical product container
The tools shown above are Helical Solutions’ End Mills for Nickel Alloys. These tools are coated in Tplus for high hardness, resulting in improved tool life and increased strength,

With its Tplus coating and variable pitch to minimize chatter, these solid carbide end mills are engineered to perform in all grades of nickel alloys. Coupled with their geometry to maximize cutting performance, Helical’s End Mills for Nickel Alloys utilize faster speeds and feeds, which are readily available on the Helical Solutions website and Machining Advisor Pro.

For more information about the chemical make-up, uses, and categorization of nickel alloys, read “In the Loupe’s” post “Understanding Nickel Alloys: Popularity, Chemical Composition, & Classification”.

PVD Coating vs. CVD: Two Common Coating Application Methods

Most tool manufacturers offer tool coatings, made up of a layer of metal compounds adhered to the surface of the tool to enhance its performance. The most common methods for adding coatings to a tool are Physical Vapor Deposition (PVD coating) and Chemical Vapor Deposition (CVD coating). This article will take a deep dive into PVD vs CVD to identify their unique and shared characteristics.

Physical Vapor Deposition (PVD) Coatings

The PVD coating method is a process in which metals go through a cycle of vaporization and condensation to be transferred from their original solid state to the tool. The metal compounds that make up the coatings are often referred to as the “metal material” in this process. The metal material starts as a solid wafer and is vaporized into a plasma, which can then be put onto the tools in the chamber. In this process, the tools are referred to as the “substrate.”

There are two different ways in which PVD coatings can be performed: arc ion plating and sputtering.

Arc Ion Plating & Sputtering

Key Differences

The main difference between arc ion plating and sputtering is that arc ion plating uses high electrical currents to vaporize the metallic material, and the metal ions are steered onto the tool for coating. Sputtering, in contrast, uses the properties of magnetic fields to direct reactive gasses to collide with a target made up of metallic material. During these collisions, metallic surface ions fall from the target and land on the substrate, slowly bombarding it until it is sufficiently coated. Both arc ion plating and sputtering are high temperature, ultrahigh vacuum processes. The term “vacuum” refers to any pressure below atmospheric pressure at sea level.

Three Harvey tool AlTiN coated end mills
Above is an example of a Harvey Tool AlTiN Coated tool, which is applied using a PVD process.

Application Processes of Arc Ion Plating & Sputtering

Arc Ion Plating

  1. The internal pressure within the reaction chamber is dropped to form a vacuum to around 1 Pa (0.0000145 psi). Creating a vacuum is crucial as it removes any moisture and impurities, on or surrounding the tools.
  2. The chamber is heated to temperatures ranging from 150 – 750°C (302 – 1382°F). The temperature of the chamber is dependent on the coating that is being applied to create an ideal chemical reaction and adhesion between the plasma and substrate. A high current of around 100 A is applied to the metallic material causing an explosive reaction.
  3. The high current positively ionizes the metal and vaporizes it into a dense plasma.
  4. The substrate is negatively charged to attract the positive metal ions.
  5. The ions collide into tools with force and are deposited, forming a film that builds up in thickness to create the desired coating.

Sputtering

  1. The internal pressure within the reaction chamber is dropped to form a vacuum to around 1 Pa (0.0000145 psi) to remove any moisture and impurities on or surrounding the tools.
  2. An inert gas is pumped into the chamber to create a low pressure atmosphere. Inert gases are specifically used, as it is non-reactive with the metal elements and ensures that impurities are not mixed in with the tool coatings.
  3. The gas used is dependent on the atomic weight of the metal material; a heavier gas is commonly used with heavier metals.
  4. The chamber is heated to temperatures anywhere from 150 – 750°C (302 – 1382°F) depending on the coating that is being applied.
  5. The tools are placed between the metallic materials (called the “target” in sputtering) and an electromagnet, so that when turned on, a magnetic field runs along and around the tools.
  6. A high voltage is then applied along the magnetic field ionizing the argon atoms.
  7. Voltage ranges from 3-5 kV, and if using AC, with a frequency of around 14 MHz.
  8. The target is negatively charged attracting the positively charged Argon gas.
  9. The inert gas collides with the target ejecting metallic compounds onto the substrate to create a coating.

Key PVD Coating Differences, Summarized

Arc ion plating and sputtering are both effective methods of applying a PVD coating. So why use one over the other? Arc ion plating has a significantly higher ionization rate than sputtering, allowing for much faster deposition rates, shortening coating times. In turn, since sputtering is a slower process, it allows for more control when applying multi-metal compositions and ensuring that the stoichiometry of the coating is even throughout the tool. Finally, during the PVD coating process, micro-droplets are formed as the vaporized metals condense and solidify onto the tools. As these droplets impact the newly applied coating, they can cause defects and craters, producing residual stress points. In order to achieve a perfect coating, droplet size must be minimized. Arc ion plating produces droplets up to 3µm (micrometers) in diameter, while sputtering has droplets with diameters up to 0.3µm. With droplets up to ten times smaller, sputtering produces much smoother and defect-free surfaces which have been proven to slow corrosion rates.

Chemical Vapor Deposition (CVD)

Harvey tool CVD ball end mill held in person's hand
Above is an example of a Harvey Tool CVD Ball End Mill.


Unlike PVD coating operations, which use high electrical charges and atomic collisions to deposit coatings onto a tool, the CVD method utilizes the chemical properties of the metals to transfer metallic compounds onto the tool. The following steps are required to carry out the CVD operation:

  1. Much like the PVD method, the first step is creating an ultrahigh vacuum within the reaction chamber of around 1 Pa (0.0000145 psi) to eliminate all moisture and impurities.
  2. The internal temperature of the chamber is increased between 600 – 1000°C (1112 – 2012°F).
  3. The temperatures required in the CVD process are significantly higher than PVD coating because this method requires a chemical reaction to occur between gases flowed into the chamber and the substrate. High temperatures are required to initiate and maintain these reactions.
  4. Once the substrate is heated to its desired temperature, the metals intended to be coated onto the tools, which are already in their vapor state, are chemically bonded with a reactive gas (typically chlorine), and flowed into the chamber.
  5. The metallic materials being bonded to a gas keeps it in a gaseous state while it is being transported through the chamber and around the tools.
  6. Hydrogen gas is then pumped into the chamber and mixes with the chlorine and metals.
  7. When this mixture meets the heated substrate, the thermal energy creates a reaction where hydrogen and chlorine bond and leave the metallic materials behind on the tools.
  8. In the chamber, there is an exit vent where the waste gas (H2Cl) is removed.

PVD Coating & CVD Coating, Summarized

Tool coatings are utilized by machinists every day to accomplish prolonged tool life, a more efficient machining operation, and an overall higher quality final part. Most manufacturers use two different types of application techniques, PVD coating and CVD coating. Stay on “In the Loupe” to learn more about tool coatings by reading the following blog posts: Overview of Harvey Tool Coatings: Maximizing Performance and 3 Ways Tool Coatings Increase Tool Life.

Citation:
[1] Ucun, İ., Aslantas, K., & Bedir, F. (2013). An experimental investigation of the effect of coating material on tool wear in micro milling of Inconel 718 super alloy. Wear, 300(1-2), 8–19. https://doi.org/10.1016/j.wear.2013.01.103

3 Ways Tool Coatings Increase Tool Life

Cutting tools are commonly found with an ultra-thin molecular compound coating applied to its cutting surfaces. These coatings are engineered to combat against forces that wear down your cutting tools and lead to catastrophic tool failure. Not only are coatings created for cutting specific materials, but they also limit heat and friction and enhance the performance of your tool. When selecting a coated tool, the machinist must consider how the material and desired cutting operations may break down the cutting edges of the tool, to determine which coating will best serve their needs. Before those decisions can be made, one must understand how coatings increase a tool’s cutting abilities. The following is an in-depth look into the benefits provided by tool coatings and how they work to improve tool life and performance.

What Is a Coating?

Tool coatings consist of organic and inorganic compounds which are applied and adhered onto the substrate using Physical Vapor Deposition (PVD) or Chemical Vapor Deposition (CVD). Compounds are deposited onto the tools in layers until a desired thickness is achieved.

Coated cutting tools provide three main functions:

  1. Provide a thermal barrier between the tool and workpiece
  2. Improve tool lubricity
  3. Increase tool wear resistance

With the proper utilization of these three features, cutting tools can be pushed much harder, run with faster cycle times, and last longer.

1.      Provide a Thermal Barrier Between the Tool and Workpiece

Heat mitigation is essential in machining, as excessive tool and workpiece heating during cutting operations can be detrimental. As the carbide tool’s temperature rapidly increases, its hardness decreases, resulting in greater wear and burn out. Thermal conductivity is a material property used to measure a material’s ability to retain or transfer heat energy. For example, tungsten carbide has a thermal conductivity of 88 W/m.K at 20°C. This means at room temperature, 20°C (68°F), an uncoated carbide tool can conduct 88 Watts of thermal energy per meter with a temperature gradient measured in Kelvin. The materials used in tool coatings do not conduct heat as well with thermal conductivity rates as low as 4.5 W/m.K. This means that a coating with a thermal conductivity of 4.5 W/m.K, the coating would transfer 19.56 times less heat than tungsten carbide.

An experiment showcasing the thermal abilities of coatings is shown below. Both an AlTiN Nano coated tool and uncoated tool were turning 4340 steel at a speed of 155 m/min (508.5 ft/min) and 200 m/min (656.17 ft/min), at a feed rate on 0.5 mm/rev (0.019 in/rev) and a depth of cut of 3.5 mm (0.138 in) [1]. No coolant was used.

uncoated tool thermal gradient

Figure 1: Thermal gradient of the cutting tip of the uncoated tool [1].

tool coatings thermal gradient

Figure 2: The above images, found in a study titled “Experimental Study and Modeling of Steady State Temperature Distributions in Coated Cemented Carbide Tools in Turning,” written by Amol Thakare and Anders Nordgren, showcase the effects of cutting tool speed and tool deformation on temperature distributions in unworn (left) and worn (right) tool.

Comparing the two tools, it is clear that the coated tool absorbs far less heat than the tool without a coating. With lower thermal conductivity rates, tool coatings create a thermal barrier between the carbide and workpiece. This greatly decreases the internal temperature of the carbide as the heat generated during the cutting operations is redirected into the chips and workpiece. With lower temperatures, faster cutting speeds can be attained. Looking at the thermal gradients above, the uncoated tool running at 155 m/min and the coated tool running at 200 m/min roughly have the same surface temperature. This means the coated tool can run 22.5% faster than its uncoated counterpart.

2. Coatings Increase Tool Lubricity

Another key to limiting heat generation and keeping cutting smooth and chatter-free is to decrease the amount of friction between the cutting tool and workpiece. Frictional force is the resistance to motion, and in the case of cutting tools, the force opposing the lateral and radial movements of the tools as it cuts through the workpiece. This opposing force is determined by the coefficient of friction, often denoted as the Greek letter Mu (μ). The friction coefficient is the ratio between the force required to move one surface across another, divided by the pressure between the two surfaces. Minimizing μ is how coatings decrease the overall frictional forces involved in cutting operations because the force of friction is directly proportional to μ.

An example to show how much a coating can reduce the coefficient friction during cutting operations, over an uncoated carbide tool, is shown in the study performed by the University of Technology of Malaysia. In this experiment, 1040 carbon steel was turned at 60 mm/min (2.36 in/min), a depth of cut of 1 mm (0.04 in), a feed rate of 0.06 mm/rev (0.0024 in/rev), and a repeated length of cut of 100 mm (3.937 in) until the tool cut a total length of 1000 m (3280.84 ft) [2]. The coated tool had a TiCN coating, a coating similar to the more popular AlTiN coating. Below are the results:

Figure 3: The above image, found in “Friction and Wear Characteristics of WC and TiCN-coated Insert in Turning Carbon Steel Workpiece,” displays the friction coefficient of the TiCN coated tool and uncoated tungsten carbide tool.

As seen in figure 3, the TiCN coated tool had a much lower coefficient of friction than the uncoated tool. This lower coefficient decreases the frictional forces experienced during cutting operations, reducing heat generation, giving a better part finish, and extending tool life.

Selecting a coated tool with high lubricity would also be ideal for cutting materials with low melting temperatures, as well as materials that generate a tremendous amount of heat during machining, such as high hardness alloys. In materials with low melting points (such as aluminum or other non-ferrous metals), high friction can cause heat generation and sticking of chips. These chips can then cause chip packing in flute valleys and galling on the cutting edge. This galling is called built up edge (BUE) which creates a thicker edge and can break down the tool. With lower friction coefficients, it is more difficult for chips to stick to the tool and for BUE to occur. When cutting materials that would generate high temperatures (such as stainless steels and aerospace alloys), keeping frictional forces at a minimum, will reduce heat generation, and result in smoother cutting, preserving the tool’s cutting edges.

3.      Tool Coatings Increase Tool Wear Resistance

Adding a coating with a high microhardness rating increases a cutting tool’s ability to resist wear and avoid permanent deformations. In the cutting industry, cutting tool grades for tungsten carbide range from grades C1 to C14, depending on what the cutting operation the tool will be performing. Between grades C1 to C14, tungsten carbide has a Vickers Hardness (HV) ranging from 760 HV to 1740 HV. Tool coatings have higher microhardness ratings than tungsten carbide. Adding a coating can increase a tool’s hardness anywhere from 2213 HV using a TiN coating, to 9993 HV with the CVD diamond coating. While a TiN coating would not be chosen solely for its hardness, it shows that even the coating with the lowest hardness is still harder than bare tungsten carbide. By making the cutting tool significantly harder, the ratio of workpiece hardness to tool hardness increases. Increasing the tool’s hardness will allow it to shear off chips and remove material with greater ease, especially against high abrasive materials, while the tool maintains its structural integrity against the extreme forces experienced during cutting operations.

The benefits of increasing tool hardness with its improved performance are demonstrated in an experiment done by Afyon Kocatepe University. In this experiment, a 2 flute micro end mill with a cutting diameter of 4 mm was slotting into Inconel 718 at 20,000 rpm, with a feed rate of 5 micrometers per flute, a depth of cut of 0.2 mm and a length of cut of 120 mm [3]. This cut was performed using both an uncoated and AlTiN coated (3620 HV hardness) carbide end mill with no coolant. Below are optical comparator images of the two tools showing their wear and deformations.

Figure 4: The image above from “An Experimental Investigation of the Effect of Coating Material on Tool Wear in Micro Milling of Inconel 718 Super Alloy,” showcases an uncoated cutting tool.

Figure 5: The image aboves from “An Experimental Investigation of the Effect of Coating Material on Tool Wear in Micro Milling of Inconel 718 Super Alloy,” showcases the difference a coating can make on a cutting tool. Figure 4 displays an uncoated cutting tool, and figure 5 displays a cutting tool with AlTiN PVD coating.

Looking at the two tools, it is evident that the uncoated tool experienced significant flank and crater wear, which resulted in the flaking of its cutting edges. As this tool performed its cuts, flank wear occurred first. This wear happened directly at the cutting edge as the abrasive Inconel alloy began to breakdown the tool. As the flank wear increased past the cutting edge and into the rake face of the tool, crater wear formed. Crater wear is characterized by its depth into the tool. As chips slid across the rake face and increased this crater, pieces of the carbide tool began to flake off, forming a new, weaker cutting edge. This new edge is blunt and will not be capable for cutting the workpiece properly, and will continue to break apart until catastrophic tool failure occurs.

Flank and crater wear are two types of mechanical tool decay that are a direct result of the abrasiveness of the workpiece material. Increasing the microhardness of the cutting tool can combat against these abrasive modes of tool wear. This is proven in figure 5, as the AlTiN PVD coated end mill held up much better in comparison to the uncoated tool as it experienced minimal flank wear. As the coated tool performed its cuts, the only detectable wear was a microfracture along one of its cutting edges, and peeling of the AlTiN coating. The protection provided by the coating against abrasive wear is evident in this example, and with this protection, tool life is significantly increased.

The Benefit of Tool Coatings During Machining

Combining the three main advantages of a tool coating, thermal resistance, increased lubricity, and higher microhardness, not only does the tool perform better, but it lasts longer. Minimizing thermal and abrasive tool wear can substantially prolong tool life.

Citations

      [1] Thakare, Amol, and Anders Nordgren. “Experimental Study and Modeling of Steady State Temperature Distributions in Coated Cemented Carbide Tools in Turning.” Procedia CIRP, vol. 31, 2015, pp. 234–239., doi:10.1016/j.procir.2015.03.024.

      [2] Talib, R.J., et al. “Friction and Wear Characteristics of Wc and Ticn-Coated Insert in Turning Carbon Steel Workpiece.” Procedia Engineering, vol. 68, 2013, pp. 716–722., doi:10.1016/j.proeng.2013.12.244.

[3] Ucun, İ., Aslantas, K., & Bedir, F. (2013). An experimental investigation of the effect of coating material on tool wear in micro milling of Inconel 718 super alloy. Wear300(1-2), 8–19. https://doi.org/10.1016/j.wear.2013.01.103

Harvey Tool Coatings: Maximizing Tool Performance

Proper tool coating plays a large role during the selection of a CNC cutting tool. At Harvey Tool, coatings are optimized for specific materials and alloys to ensure the highest tooling performance, possible. Each coating offers a unique benefit for the cutting tool: increased strength, enhanced lubricity, heat resistance, and wear mitigation, just to name a few.  

In Benefits of Tool Coatings, the method of applying coatings to tools is examined. In this post, we’ll take a closer look at each Harvey Tool coating to examine its key properties, and to help you decide if it might add a boost to your next CNC application.

Harvey Tool offers a wide range of tool coating options for both ferrous and exotic materials, as well as non-ferrous and non-metallic materials. In the Harvey Tool catalog, coatings are often denoted in a -C# at the end of the product part number.

Harvey Tool Coating Gallery

Harvey Tool Coatings for Ferrous and Exotic Materials

TiN

TiN, or Titanium Nitride (-C1), is a mono-layer coating meant for general purpose machining in ferrous materials. TiN improves wear resistance over uncoated tools and aids in decreasing built-up edge during machining. This coating, however, is not recommended for applications that generate extreme heat as its max working temperature is 1,000 °F. TiN is also not as hard as AlTiN and AlTiN Nano, meaning its less durable and may have a shorter tool life.

Harvey Tool 46062 Tin Tool Coating

Harvey Tool 46062-C1

AlTiN

AlTiN, or Aluminum Titanium Nitride (-C3), is a common choice for machinists aiming to boost their tool performance in ferrous materials. This coating has a high working temperature of 1,400 °F, and features increased hardness. AlTiN excels in not only dry machining, due to its increased lubricity, but also in machining titanium alloys, Inconel, stainless alloys, and cast iron. To aid in its high heat threshold, the aluminum in this coating coverts to aluminum oxide at high temperatures which helps insulate the tool and transfer its heat into the formed chips.

altin tool coating 823816-C3

Harvey Tool 823816-C3

AlTiN Nano

AlTiN Nano or Aluminum Titanium Nitride Nano (-C6) is Harvey Tool’s premium coating for ferrous applications. This coating improves upon AlTiN by adding silicon to further increase the max working temperature to 2,100 °F while also increasing its hardness for increased tool life during demanding applications. Due to its penchant for demanding applications, AlTiN is recommended for hardened steels, hardened stainless, tool steels, titanium alloys, and aerospace materials. These applications often create high levels of heat that AlTiN Nano was designed to combat.

altin nano tool coating

Harvey Tool 843508-C6

harvey tool coating zoomed in

Tool Coatings for Non-Ferrous and Non-Metallic Materials

TiB2

TiB2, or Titanium Diboride (-C8), is Harvey Tool’s “bread and butter” coating for non-abrasive aluminum alloys and magnesium alloys, as it has an extremely low affinity to aluminum as compared to other coatings. Aluminum creates lower working temperatures than ferrous materials, so this coating has a max working temperature of of a suitable 900 °F. TiB2 prevents built-up edge and chip packing, further extending its impressive tool life. TiB2 is not recommended for abrasive materials as the carbide is slightly weakened during the coating process. These materials can cause micro fractures that may damage the tool at high RPMs.

TiB2 can be found on a wide variety of Harvey Tool 2 and 3 flute tools as the premium option for high performance in aluminum alloys.

tib2 tool coating

Harvey Tool 820654-C8

ZrN

ZrN, or Zirconium Nitride (-C7), is a general-purpose coating for a wide variety of non-ferrous materials, including abrasive aluminum alloys. This tool coating is a lower cost alternative to diamond coatings, while still boasting impressive performance through its high hardness levels and overall abrasion resistance. ZrN has a max working temperature of 1,110 °F with strong lubricity in abrasive alloys. This coating is best suited for abrasives, such as brass, bronze, and copper, as well as abrasive aluminum alloys that should not be used with TiB2.

zrn tool coating

Harvey Tool 27912-C7

CVD Diamond Tool Coatings

CVD Diamond, or Crystalline CVD Diamond, is a process where the coating is grown directly onto the carbide end mill. This process dramatically improves hardness over other coatings, improving tool life and abrasion resistance while also allowing for higher feed rates. The trade-off for increased wear resistance is a slight rounding of the cutting edge due to the coating application. Due to its increased wear resistance, CVD is best suited for highly abrasive materials such as graphite, composites, green carbide, and green ceramics. Similarly, these tool coatings have a max working temperature of 1,100 °F, meaning they are not well suited for ferrous applications.

Harvey Tool’s CVD Diamond Coating Options:

diamond tool coatings
Amorphous, CVD 4 μm, CVD 9 μm, PCD Diamond

CVD Diamond (4 μm)

The 4 μm is thinner than the 9 μm allowing for a sharper cutting edge, which in effect leaves a smoother finish.

CVD Diamond 9 μm)

The 9 μm CVD tool coating offers improved wear resistance over the 4 μm CVD and Amorphous coatings due to its increased coating thickness.

Amorphous Diamond

Amorphous Diamond (-C4) is a PVD diamond coating which creates an exceptionally sharp edge as compared to CVD. This coating aids in performance and finish in abrasive non-ferrous applications, as it allows for greatly improved abrasion resistance during machining, while still maintaining a sharp cutting edge necessary for certain abrasives. Due to the thinness of the coating, edge rounding is prevented in relation to CVD diamond tooling. Amorphous Diamond is best suited for use in abrasive plastics, graphite, and carbon fiber, as well as aluminum and aluminum alloys with high silica content, due to their abrasiveness. The max working temp is only 750 °F, so it is not suited for use in ferrous machining applications.

Harvey Tool 809362-C4

PCD Diamond

PCD Diamond, or Polycrystalline Diamond, is a tool coating that is brazed onto the carbide body. In comparison to the other diamond coatings, PCD does not face the same challenges of other coatings as it pertains to rounded cutting edges, as these edges are ground sharp. PCD has the edge benefits of Amorphous Diamond with the abrasion resistance of CVD Diamond. PCD is the thickest diamond layer offered by Harvey Tool, and excels due to its incredible hardness and abrasion resistance. This tool is best suited for all forms of abrasive, non-ferrous materials including abrasive plastics, graphite, carbon fiber, and composites. Similar to the other non-ferrous tool coatings, PCD is not suited for ferrous applications due to its working temperature of 1,100 °F.

pcd diamond

Harvey Tool 12120

Tool Coating Summary

When deciding on a coating for your application there are many factors to be considered. Different coatings often cross several applications with performance trade-offs between all of them. Harvey Tool offers a “Material Specific Selection” that allows users to choose tooling based upon what materials they are working with. Further, Harvey Tool’s technical team is always a phone call away to help in finding the right tool for your specific applications at 1-800-645-5609. Also, you can contact Harvey Tool via e-mail.