Carbon Fiber Reinforced Polymers (CFRP): Material Properties & Tool Selection

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Carbon Fiber Reinforced Polymers (CFRP) is composed of carbon fibers, bound with resin, to create a groundbreaking material that has proven to have limitless application possibilities in a wide range of composite cutting industries. Due to its attractive properties of strength, durability, corrosion resistance, and its lightweight nature, there has been a rising utilization of carbon fiber in the aerospace and automotive industries. However, it does not come without its own set of challenges in comparison to typical metal machining.

cfrp material

CFRP Properties

CFRP has a high resistance to being deformed without permanent effects (elastic modulus), resistance to tension, low thermal conductivity, and low thermal expansion. While many of these properties are ideal for many applications, there are unique effects that must be considered when machining.

Abrasiveness

CFRP’s high elastic modulus makes it highly abrasive, causing challenges in tool wear and tool life that must be addressed. For example, while milling typical metals, clean chips are formed and ejected. But milling carbon fiber is like sanding, where material is removed in the form of dust particles.

Abrasion is a large issue in carbon fiber machining as it is responsible for poor tool life and dullness of the tool that can cause a part to be scrapped. As soon as a tool begins to dull, it will cause poor part finish and increase the chances of delamination and fraying.

Causes of Heat Generation

Typically, in metal machining, most of the heat is transferred into the chips with a fraction of the heat into the part and workpiece. Due to CFRP’s low thermal conductivity and no chips formed to dissipate the heat, most of the heat is transferred to the tool and part. This heat is unideal, as it will cause more tool wear and potentially cause damage, resulting in delamination.

For more information on composite delamination, read “Overcoming Composite Holemaking Challenges.”

Varying Properties

No composition of CFRP is made the same, meaning that operating parameters can vary. There is no one-solution-fits-all for every application, as it is often found to be less predictable than metals due to its varying properties. These varying components includes the fiber type, fiber density, resin type, layup orientations, thickness, matrix hardness, and heat sensitivity, which all must be taken into consideration.

Methods to Reduce CFRP Issues

Having high interval checks to monitor cutting and dimension quality to catch any errors before they may be irreversible is one way address CFRP machining issues. Another method to tackle CFRP would be through picking the right tool for the application.

Selecting a CFRP Tool

Tooling material type (substrate) and geometry both determine the quality of cutting the carbon fiber and durability of the tool.

Tooling Substrate/Coating

When selecting a tool to machine CFRP materials, it is essential to opt for a tool that is strong, sharp, and resistant to the abrasive properties that CFRP holds. Many machinists opt for solid carbide cutters with diamond coatings such as DLC, CVD, or PCD, as they provide the tooling with increased tool life and improved cutting action. These tools provide added hardness and abrasion resistance to combat the effects of machining CFRP.

Corehog end mill coating chrt
CoreHog’s Coating Chart

While PCD diamond tools are considerably higher in price than other diamond coated tooling options, they provide the longest tool life and performance against abrasion and tool wear. Often, they are more cost effective in the long run due to their longevity, when compared to cheaper options that only save money in the short term.

corehog square pcd end mill
CoreHog PCD Diamond End Mill – Square

 

Corehog ball nose PCD end mill
CoreHog PCD Diamond End Mill – Ball Nose

In comparison to the cost of the part to be machined, the tool may be a fraction of the cost, making it worth spending the extra money to prevent greater costs that come with scrapping the part. Composite cutting tool manufacturer, CoreHog, stocks an array of PCD Diamond End Mills in Square and Ball Nose profiles.

Tooling Geometry

The geometry of a tool also plays a vital role in its machining capabilities of CFRP. There are many different geometry solutions, depending on your application, with different flutes, angle of cut approach, and profile. Corehog’s selection of CFRP Router Bits offer a great solution to your various CFRP needs.

corehog cfrp router bit upcut burr style
CoreHog CFRP Router Bits – Burr Style – Upcut

corehog cfrp router bit end mill upcut
CoreHog CFRP Router Bits – End Mill Style – Upcut

corehog cfrp router bit drill point upcut
CoreHog CFRP Router Bits – Drill Point Style – Upcut

Understanding Machining Advisor Pro (MAP) 2.0

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Machining Advisor Pro (MAP) was first introduced to the CNC Machining Industry in 2018 as a tool to quickly, seamlessly, and accurately deliver recommended running parameters to machinists using Helical Solutions end mills. then, thousands of users have utilized this cutting-edge resource, every day. In August 2022, a new and improved version of MAP was launched, optimized for Harvey Tool’s 27,000+ miniature and specialty cutting tools.

The following article is intended to introduce MAP 2.0 features. For more in depth information about MAP, including how to get started using it, please visit the original “In the Loupe,” post Get to Know Machining Advisor Pro.

New Map 2.0 Features

Addition of all Harvey Tool Products

With the release of MAP 2.0, users now have access to expertly tailored speeds and feeds parameters and recommendations to meet the exact demands of cutting tool and machine setup for all Harvey Tool products. This means that more than 27,000 Harvey Tool products are available in MAP and users can find their Specialty Profile Cutting Tools, Miniature End Mills, and Holemaking and Threading products to confidently use MAP generated speeds and feeds. With the addition of new products, there is now a new variety of operations to choose from, specific to the product selected.

New Strategy Option for Operations

Before the MAP 2.0 update, there were only two drop down menus for operation: type and toolpath. With the new update, there is an additional third operation drop down menu titled “strategy.” This option allows for users to further refine their machining operation, but only for certain tools that require it. For example, when using a Double Angle Shank Cutter on MAP, users can choose from a list of toolpaths including deburring, chamfer, or v-groove.

Once selected, users will choose a strategy for the toolpath – single side or double side engagement. The use of this feature gives the user more flexibility in their operations and saves time by automating their operation calculations. This feature is available for a variety of different toolpaths within the application.

MAP Offline Mode

With the release of MAP 2.0, and the addition of over 27,000 Harvey tools, users now can work offline. The work offline feature is only available for the new Harvey Tools. To access this feature, users can select the “User Account” button in the top right and start the process to allow MAP to work offline. Activating the work offline mode will cache the Harvey Tool data and takes around 15-20 minutes to complete before allowing the user to work offline.

Having the ability to use MAP offline can be useful when users are unable to connect to the internet as you will still be able to access MAP on a desktop or mobile app, whenever and wherever you need it.

Reduce Tool Chatter by Avoiding these 5 Boring Bar Application Mistakes

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Boring bar applications are very popular in the lathe 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.

Boring Bar Application Mistake 1: 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. 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.

Image Source: Carbide inserts Wear Failure modes. | machining4.eu, 2022

Boring Bar Application Mistake 2: Utilizing Incorrect Speeds & Feeds

Like many applications, using improper 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. 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.

Boring Bar Application Mistake 3: 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.


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. 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.

Image Source: @abom79

Boring Bar Application Mistake 4: 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.

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.

Boring Bar Application Mistake 5: 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. 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 the chips to be cut again, 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.

Machining Nickel Alloys: Avoiding All-Too-Common Mishaps

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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.

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.

BUE 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.

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”.

4 Key Benefits of Combination Feed & HEM End Mills

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Designed to conquer machine limitations and other common machining issues, combination and multifunctional tooling are highly coveted by machinists. These tools often integrate multiple geometries and flute designs to tackle wider varieties of machining applications with the same tool. This means fewer tools and tool changes are needed within a job, reducing complexity and increasing shop flexibility.

Taking these Issues and limitations into consideration, Harvey Performance Company’s Engineering Team went to work to design a new series of end mills referred to as Helical Solutions’ Combination High Feed & HEM End mills. This product series offers a feature set that will solve the four common issues listed below along with a few other issues that machinists commonly experience in the spindle.

For most shops, machine limitations cause longer, costlier, and more complicated jobs. If you are reading this article, you may know exactly what we are talking about. Machinists have a job that needs to be completed and end up having to add another operation. They find themselves improvising on tooling to complete an operation. This is because their machine has a limited number of tool stations, less than adequate horsepower, or several other limitations. Many times, this will impact operations in a negative way by increasing overall cost or reducing the quality of parts. As the name suggests, Helical’s Combination Feed & HEM tooling has been designed to excel in both applications without requiring a tool change. The end profile is non-center cutting for high feed applications, while the offset chipbreaker OD geometry excels in high efficiency milling strategies.

How This Tool Addresses Machine Limitations

A common issue present in a fair number of shops is a limited number of tool stations available. The Combination Feed & HEM products afford the ability to do multiple roughing and finishing operations with one tool, using only one tool position. This eliminates the need to try to blend tools or control multiple offsets in your machining operation.

A second machine limitation that may affect your tool choice is you machine horsepower. The high feed end geometry and the chipbreaker OD geometry are both designed to reduce the amount of power required. This opens up new opportunities within light duty and low horsepower machines, offering more flexibility to your shop.

Cut Down Part Cycle Times

In a shop, long cycle times negatively impact productivity and machine availability. As the manufacturing industry becomes more competitive and as jobs become more demanding, the need for reducing cycle times becomes even more important.

The Combination Feed & HEM End Mills allow the use of both High Feed and High Efficiency milling strategies that provide high metal removal rates in your operations.  Increased material removal rates lead directly to reduced cycle times, plus the versatility of these tools helps to avoid time-consuming tool changes.

Click Here to Watch Helical’s Combination Feed & HEM Mill Be Pushed to the Limits

Limiting Complexity and Increasing Ease of Use

With today’s machined parts growing in complexity, programming can become cumbersome with multiple machining strategies and many tools required.  Finding ways to reduce the complexity of programming can help an entire job run smoother through your shop.

These Combination Feed & HEM End Mills provide an increased ease of use. This gives you the ability to conquer multiple operations with one tool. This eliminates the need to program and set-up multiple tools, boosting productivity

Cutting Down on Costs

Another common issue is the cost of purchasing tooling. The Combination Feed & HEM End Mills offer a feature set that allows the consolidation of tooling and operations. Reducing the number of different tools needed for your application can reduce the overall cost of your operations substantially.

Feed/HEM Product Capabilities and Application Areas

Helical’s Combination Feed & HEM End mills are designed to tackle a broad range of demanding operations in a wide variety of steel types. As these products were engineered to solve machine limitation issues, the end geometry excels across a variety of operations. These include High-Feed milling operations, machining bores, closed or open pockets, internal or external contours, etc. The peripheral geometry was engineered with flexibility in mind. This allows the use of an HEM (High Efficiency Machining) toolpath to achieve high metal removal rates while maintaining great chip control as well as most traditional roughing and finishing strategies.

Helical Solutions Combination Feed & HEM End Mill

The versatility of these tools can be easily illustrated with a long list of applications:

  1. High efficiency milling
  2. High feed slotting
  3. High feed roughing
  4. Milling in open and closed pockets
  5. Internal and external profiling
  6. Helical ramping and interpolation
  7. Rough and finish profile milling
  8. Offset plunge milling in slots and deep pockets
  9. Traditional roughing operations
  10. Contouring and profiling operations

Commonly, machinists would need a range of specialty tooling to complete different aspects of a job. This requires long cycle times, and higher costs when all the necessary tools are considered. As most shops suffer from a limited number of available tool stations, combination mills aid in alleviating this pressure. These tools are designed to excel and conquer.

Conquer Machine Limitations and Shop Issues

Helical’s Combination Feed & HEM End Mills were designed with versatility in mind. The major benefit of these tools is addressing machine limitations and the common issues presented above. These tools will provide you with a feature set that will allow you to combine operations, reduce cycle times, reduce cost, reduce scrap, and expand your machines capabilities. Let Helical impress you with the Combination Feed & HEM line of end mills.

How to Adjust Running Parameters for Miniature Tooling

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High precision machining is a subset of subtractive manufacturing that has grown in popularity over the years, especially as industries like medical, dental, mold tool and die, and semi-conductor manufacturing grow. Some jobs can call for extremely small diameters (down to even .001”) and ultra-precise tolerancing. With tooling this miniature, machinists must utilize different machining practices than they otherwise would, as common issues that would arise with larger end mills are magnified within miniature tooling applications.  Speeds and feeds become critical to ensure your tool survives the job.

Miniature Tooling over dictionary

Where Breakage Occurs with Miniature Tooling

When breakage happens with miniature tooling, it’s important to determine where on the tool the breakage is occurring. Breakage points are sometimes quite difficult to see with such small tooling. Finding the location, when possible, helps to diagnose the issue. For example, if the breakage occurs along the length of cut, there could be chip packing. If chip packing is the issue, it’s helpful to decrease the feed rate and lower the depth of cut per pass. If the tool breaks on the transition angle toward the shank, this could be due to a few things. The first instinct should be to check the runout of the tool. Runout should be measured at less than .0001”. In this case, check tool set up to ensure that the tool is stable within the tool holder. Another issue could be excess pressure on the tool caused by high pressure coolant or even deflection. Deflection occurs when the cutting pressure causes the tool to bend slightly – in this case, the tool will break at its weakest point. To minimize the opportunity for deflection, ensure the tool is the largest diameter and shortest length of cut possible for the job.

Miniature tooling on dime

Tips for Avoiding Future Breakage

There are a few different points of interest to focus on to prevent tool breakage.

The Right Tool

 Determining the correct end mill is the necessary first step toward preventing breakage. Choosing a material specific end mill is preferred, especially with the more difficult to machine materials. Harvey Tool’s material specific tools have different geometries and coatings for different materials. For example, our aluminum specific end mills have a variable helix of approximately 42 ° whereas the high temperature alloy specific end mills we offer have a variable helix of about 34°. A tool with an odd number of flutes or a variable helix or pitch also helps to avoid chatter that could lead to breakage in the machining process. Approaches also change depending on the application. With slotting for example, rigidity is critical for success, therefore a tool with the most flutes possible is recommended.

Tool Set Up

The smaller the tool, the more fragile it is. Therefore, proper handling before and during set up is critical. It is key to keep tooling in the original packaging if it is not in the machine and covering the tip when positioning the tool in the tool holder. Determining coolant for miniature tooling is also critical to ensure that high pressure from the coolant doesn’t cause damage of the tool. High pressure coolant directly to the tool almost always causes some form of breakage. For this reason, high pressure coolant is not recommended on the smaller end of the miniature tooling spectrum. In this case, flood coolant is the recommended approach.

Miniature Tooling Running Parameters

Running speed of an end mill is determined based on the tool diameter, so the smaller the tool, the faster the RPM. To ensure best tool life, it is crucial to run the smaller end mills at the recommended parameters.

Harvey Tool speeds and feeds charts list recommendations for SFM, chip load and depth of cut based on the cutting material, tool diameter and cutting application. To calculate speeds and feeds using Harvey Tool speeds and feeds charts, follow the following formulas and our recommended parameters:

Note*: There are often limitations with the machines used for these tools. One of the most asked questions about our speeds and feeds for miniature end mills is how to adjust for this quick speed. We recommend setting the RPM at something the machine can handle (or the fastest the customer feels comfortable with) and keep the feed rates and depth of cut the same.

Choosing depth of cut parameters for miniature tooling is extremely important based on the application. For example, finishing parameters often have a much higher speed and feed rate than slotting or roughing parameters but the depth of cut passes are much smaller. This enables the tool to run such high parameters without breakage as there is less contact with the workpiece.

zoomed in miniature tooling

Using miniature tooling can be a little bit intimidating if you’ve never used it before. Issues that arise with larger end mills tend to be amplified with smaller tools. It is very important to have the right end mill for the application. Speeds, feeds, and depth of cut are also essential in proper cutting. With smaller tooling comes higher speeds. Always follow manufacturer recommended speeds and feeds, lowering the speed when necessary to accommodate machine capabilities. Lastly, if breakage does occur, be sure to find where the break is to help diagnose the issue.

PVD Coating vs. CVD: Two Common Coating Application Methods

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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.

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)

PVD coating vs CVD Coated Tool
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

Titan USA Carbide Drills: Jobber, Stub, & Straight Flutes

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When navigating Titan USA’s offering of carbide drills, it is imperative to understand the key differences among the three carbide drill styles: Jobber Length, Stub Length, and Straight Flute Drills. The right drill for your application depends on, among other factors, the material you are working in, the job requirements, and the required accuracy.

PRO TIP:

Chip evacuation can be an obstacle for hole making. Pecking cycles can be used to aid in chip removal. Peck cycles are when the drill is brought in and out of the hole location, increasing depth each time until the desired depth is reached. However, pecking cycles should only be used when necessary; this process increases cycle time and subjects the tool to added wear from the repeated engaging and disengaging.

Jobber Length Drills

A carbide Jobber Length Drill is the standard general-purpose drill within Titan USA’s offering. It has a long flute length and an included angle of 118o. These drills are great for general purpose drilling where the tolerances are not as tight as the Stub Drill or Straight Flute Drill. Due to the length of these drills, however, they will be more affected by any lack of rigidity in the set up and can have higher runout, or straying from a desired location, during the drilling operation.

PRO TIP:

To achieve high accuracy and great finish, consider utilizing a Reamer. Reamers are designed to remove a finite amount of material but bring a hole to a very specific size. To do this, first drill 90% – 94% of the desired hole diameter with a Jobber Drill. After 90% – 94% of the material is removed, go in for a finishing pass with a Reamer. Reaming tools are highly accurate and leave a beautiful finish.

Stub Length Drills

Titan USA carbide Stub Length Drills have a shorter flute length, wider included point angle, and a significant drop in helix angle, when compared to Jobber Length Drills. The shorter length and wider tip create for a more rigid tool and, in turn, more accurate holes. The stub drill is the best option when drilling with tight tolerances on shallower holes.

Straight Flute Drills

Carbide Straight Flute Drills have the smallest core of the three drill types mentioned within this post. Titan USA offers Straight Flute Drills with 2 flutes and a 140o included angle. These drills are designed for hole making in materials that create short chips. Materials in which the Straight Flute Drill typically performs best include cast aluminums and cast irons, as well as copper. In addition, this type of drill can work very well in high hardness materials, but the core diameter should first be adjusted to accommodate the increased hardness. For these difficult to machine materials, casting the part with a core hole and then opening it up with the Straight Flute is a great option. This removes some of the stress caused by chip removal and allows for the drill to do what it does best.

Chip removal can be more difficult in this style of carbide drill because the chips are not guided along a helix. With helix flutes, the motion of chip removal is mostly continuous from their initiation point, through the flute valleys, and finally out of the flute valleys. The helix creates a wedge which helps push the chips along, but the straight flute does not have that. It interrupts that natural turning motion created by the drill face which can affect chip evacuation. Due to the interruption in motion this type of drill is better suited for applications involving chips of smaller size.

PRO TIP:

Helix drills create multiple different forces on the part, which can create micro imperfections. The Straight Flute Drills do not create those forces, so the finish is much more consistent down to the micro level. The margins of the Straight Flute Drill also burnish the inside of the hole as they spin, which improves the finish as well. When comparing the Straight Flute Drill to a helix drill, the length of the overall contact point is much shorter in the Straight Flute Drill, and has less heat generation. The decreased heat will also reduce the probability of work hardening.

Selecting Your Perfect Titan USA Carbide Drill

Selecting the correct carbide drill for your application is a crucial step in hole making. The Jobber Drill is a great general-purpose drill and should be utilized in applications requiring long reach. The Stub Drill increases the rigidity with its shorter length of flute, allowing it to drill with higher accuracy. Applications which involve tight tolerances and more shallow holes can be done with the Stub Drill for high-quality results. Lastly, for difficult to machine and hard materials, the Straight Flute Drill is the perfect solution. When the core diameter and chip evacuation is properly addressed, the Straight Flute Drill produces beautifully consistent surface finish and extremely tight tolerances. Similarly, Titan USA offers its carbide drills in both an uncoated option, and AlTiN coating. Traditionally, uncoated tools are general purpose workhorses in a wide variety of materials both ferrous and non-ferrous. AlTiN or Aluminum Titanium Nitride is an enhanced coating specifically made for ferrous materials that extends tool life and performance across a wide range of steels and their alloys.

For more information on Titan USA Drills, and to view its full selection, click here.

Understanding Key Qualities in Micro 100’s Offering of Micro-Quik Quick Change Tool Holders

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Did you know that, along with supplying the machining industry with premier turning tools, Micro 100 also fully stocks tool holders for its proprietary Micro-Quik Quick Change Tool Holder System? In fact, Micro 100’s Spring 2021 Product Catalog introduced new “headless” style tool holders, which are revolutionizing the machine setup process for turning operations.

This “In the Loupe” guide is designed to provide you with insight for navigating Micro 100’s offering, and to help you select the optimal holder style for your operation.

Understanding Micro 100’s Micro-Quik

Micro 100’s Micro-Quik is unlike any other tool change system you may have seen from other tool manufacturers because of its incredible axial and radial repeatability and its ease of use. This foolproof system delivers impressive repeatability, tip-to-tip consistency, and part-to-part accuracy, all the while resulting in tool changes that are 90 % faster than conventional methods.

In all, a tool change that would regularly take more than 5 minutes is accomplished in fewer than 30 seconds.

Micro 100 Quick Change Tool Holder Selection

Straight Style, Headless Tool Holders

When using a straight style tool holder, you will enjoy significantly enhanced versatility during the machine set up process. These holders are engineered specifically for use in any Swiss, standard lathe, or multi-function lathe, and allow for adjustable holder depth in a tooling block. Radial coolant access ports provide easier access to coolant and the ability to utilize coolant through functionality in tooling blocks that share a static and live tool function, and cannot be plumbed through the back of the holder. Further, their headless design allows for installation through the backside of the tooling block in machines where the work envelope is limited, allowing for a simplified installation process.

Created by Harvey Performance Company Application Engineers, the following videos outline the simple process for inserting each style of Micro 100 Straight Tool Holder into a tooling block.

Micro 100 Straight Holder, Plumbed Style (QTS / QTSL)

In the video, you’ll notice that the first step is to place your Micro-Quik tool in this quick change holder, and align it with the locating pin. Then, tighten the locating and locking screw into the whistle notch. This forces the tool against the locking pin, and allows for repeatable accuracy, every time. From there, the quick change tool holder can be installed as a unit into a tooling block. When desired tool position is achieved, set screws can be tightened to lock the holder in place.

Micro 100 Straight Holder, Plumbed & Ported Style (QTSP / QTSPL)

This unique Micro 100 quick change tool holder style is plumbed and ported, allowing for enhanced versatility and coolant delivery efficiency. The setup process using this style of holder is also simple. First, place your Micro 100 quick change tool into the holder, and align it with the locating pin. From there, tighten the locating and locking screw into the whistle notch, forcing the tool against the locating pin and allowing for repeatable accuracy, every time. When plumbed coolant is being used, remove the plumbed plug in the back of the holder, and connect the appropriate coolant adapter and line. Then, the holder can be installed as a unit into the tooling block and locked into place with set screws.

When using ported coolant, make sure that the coolant plug in the back of the holder is tightly installed. Then, be sure to only use one of the radial ports. Simply plug the two that aren’t in use. Install the provided porting adapter to allow for coolant access. Porting options allow for coolant capabilities in machine areas where coolant is not easily accessible.

Headed Tool Holders

headed quick change tool holder

Micro 100’s original quick change tool holder for its Micro-Quik system, this style of tool holder for lathe applications features a unique “3 point” locking and locating system to ensure repeatability. When conducting a tool change with this tool holder style, you must follow a simple, 3-step process:

  1. Loosen the tool holder’s set screw
  2. Remove the used tool from the holder
  3. Insert the new tool and retighten the set screw

These headed holders are plumbed through the back of the holder for NPT coolant connection and are available in standard length and long length styles.

Try Micro 100’s “Headless” Tool Holders for Incredible Flexibility

Double-Ended Modular Tool Holder System

double ended quick change tool holder

For twin spindle and Y-axis tooling block locations, Micro 100 fully stocks a double-ended modular system. Similar to its single-ended counterparts, this modular is headless, meaning it enhances machine access during the tool block installation process, and the holder depth can be adjusted while in the block. Because this system is double-ended, however, there is obviously no plumbed coolant option through the end of the tool. Instead, coolant is delivered via an external coolant port, the adapter for which is included in the purchase of the modular system. Right hand and left hand tool holders are designed so the set screws are facing the operator for easy access. Both right and left hand styles are designed for right hand turning.

Enjoy Quick Change Tool Holding Confidence & Ease of Use

When opting for a quick change system, machinists long for simplicity, versatility, and consistency. Though many manufacturers have a system of their own, Micro 100’s Micro-Quik sets itself apart with axial and radial repeatability, and tip-to-tip consistency. Further, Micro 100 fully stocks several quick change tool holder options, allowing a machinist to select the style that best fits their application.

Micro100 also manufactures and stocks a wide variety of boring tools for the Micro-Quik. Click here to learn more.

For more information on selecting the appropriate quick change tool holder for your job, view our selection chart or call an experienced Micro 100 technical engineer at 800-421-8065.

quick change tool holder selection chart for Micro100

8 Unique Facts About Thread Forming Taps

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Unlike most CNC cutting tools, Thread Forming Taps, otherwise known as Form Taps, Forming Taps, or Roll Taps, work by molding the workpiece rather than cutting it. Because of this, Form Taps do not contain any flutes, as there is no cutting action taking place, nor are there any chips to evacuate. Below are 8 unique facts of Thread Forming Taps (and some may surprise you).

1. Chips Aren’t Formed

When using a Form Tap, chips are not formed, nor is any part material evacuated (Yes, you read that right). With thread forming, the tool is void of any flutes, as chip evacuation is not a concern. Form Taps quite literally mold the workpiece, rather than cut it, to produce threads. Material is displaced within a hole to make way for the threads being formed.

Increase Your Tapping Efficiency 20x With Titan USA’s Thread Form Taps

2. Cutting Oils Allow for Reduced Friction & Heat Generation

Did you know that Thread Forming Taps require good lubrication? But why is that the case if chips are not being evacuated, and how does lubrication enter the part with such a limited area between the tool and the perimeter of the hole being threaded? Despite the fact that chips aren’t being formed or evacuated, cutting oils aid the Form Tap as it interacts with the part material, and reduces friction and heat generation. Lube vent grooves are narrow channels engineered into the side of Forming Taps that are designed to provide just enough room for lubricant to make its way into – and out of – a part.

titan thread forming tool

Not all materials are well suited for Thread Forming Taps. In fact, attempting to use a tap in the wrong material can result in significant part and tool damage. The best materials for this unique type of operation include aluminum, brass, copper, 300 stainless steel, and leaded steel. In other words, any material that leaves a stringy chip is a good candidate for cold forming threads. Materials that leave a powdery chip, such as cast iron, are likely too brittle, resulting in ineffective, porous threads.

4. Threads Produced Are Stronger Than Conventional Tapping Threads

Thread forming produces much stronger threads than conventional tapping methods, due to the displacements of the grain of the metal in the workpiece. Further, cutting taps produce chips, which may interfere with the tapping process.

5. Chip Evacuation is Never a Concern With Thread Forming

In conventional tapping applications, as with most machining applications, chip evacuation is a concern. This is especially true in blind holes, or holes with a bottom, as chips created at the very bottom of the hole oftentimes have a long distance to travel before being efficiently evacuated. With form taps, however, chip removal is never a concern.

6. Form Taps Offer Extended Tool Life

Thread Forming Taps are incredibly efficient, as their tool life is substantial (Up to 20x longer than cutting taps), as they have no cutting edges to dull. Further, Thread Forms can be run at faster speeds (Up to 2x faster than Cutting Taps).

Pro Tip: To prolong tool life even further, opt for a coated tool. Titan USA Form Taps, for example, are fully stocked in both uncoated and TiN coated styles.

titan thread forming tools

7. A Simple Formula Will Help You Find the Right Drill Size

When selecting a Tap, you must be familiar with the following formula, which will help a machinist determine the proper drill size needed for creating the starter hole, before a Thread Forming Tap is used to finish the application:

Drill Size = Major Diameter – [(0.0068 x desired % of thread) / Threads Per Inch]
Drill Size (mm) = Major Diameter – [(0.0068 x desired % of thread x pitch (mm)]

8. Thread Forming Taps Need a Larger Hole Size

  1. Thread Form Taps require a larger pre-tap hole size than a cutting tap. This is because these tools impact the sides of the hole consistently during the thread forming process. If the pre-tap hole size is too small, the tool would have to work too hard to perform its job, resulting in excessive tool wear, torque, and possible breakage.

As an example, a ¼-20 cut tap requires a #7 drill size for the starter hole, whereas a ¼-20 roll tap requires a #1 drill size for 65% thread.