A chamfer mill, or a chamfer cutter, is one of the most common tools used by machinists daily. When creating a part, machining operations can oftentimes leave a sharp edge on a workpiece. A chamfer mill eliminates sharp edges, leaving a sloped surface, or a chamfer, instead. In doing so, the part will be stronger and more aesthetically appealing to its eventual user.
This singular tool can provide many cost-saving benefits to machinists. Aside from the namesake operation it performs on a part, a chamfer mill can be used for several machining operations including beveling, deburring, countersinking, and spotting.
Chamfer Mill for Beveling
The terms “chamfer” and “bevel” are often used interchangeably. These two features, while similar, actually have two different definitions. While a chamfer impacts a portion of the side of a workpiece – specifically the edge of a part, a bevel angles the entire side of what was a squared-off part feature. Thus, the side of a part can feature two chamfers, or only one bevel (Figure 1).
A chamfer mill, however, can perform both operations. The two features are equivalent in both geometry, and how they are machined. A chamfer mill will create both part features in the exact same fashion; a bevel just may use a larger portion of the cutting surface, or may require multiple passes to create a large part feature.
Chamfer Mill for Deburring
Like many other versatile tools, a chamfer mill can be used to easily and swiftly deburr a part during the CNC machining process. In doing so, efficiency is maintained as manual deburring – a time exhaustive process – isn’t necessary.
A chamfer mill’s angled cutting surface, shown in the image below, makes it a great tool for deburring workpiece edges. Because a very small amount of the chamfer cutter’s cutting face will be used, a simple adjustment to running parameters will allow for simple deburring operations using a very light cut depth.
Did you know that Harvey Tool fully stocks Deburring Chamfer Cutters, that are specifically designed for deburring operations? This tool features an increased flute count, allowing for minimized cycle times.
Chamfer Mill for Spotting & Countersinking
Drilling precise, clean, and aesthetically appealing holes into a part is not a one-step process. In fact, some use up to four different tools to machine a perfect hole: spotting drill, drill, flat bottom counterbore, and countersink. However, a chamfer cutter is often used to perform two of these operations simultaneously.
By using a pointed chamfer cutter with a diameter larger than that of the hole being drilled, a machinist can spot and countersink the hole in one operation prior to its creation. Tipped-off Chamfer Cutters are unable to perform a spotting operation because they are non-center cutting. By spotting a hole, the drill has a clear starting point. This works to alleviate walking during the drilling process, which in turn drastically reduces the chance of misaligned holes. By countersinking a hole, the screw sits flush with the part, which is often a requirement for many parts in the aerospace industry.
One consideration to keep in mind is that a carbide spot drill should always have an angle larger than that of the drill following it. However, many countersinks have angles that are smaller than most drill points. This creates a dilemma in choosing a chamfer tool for both spotting and countersinking, as they can reduce the number of tools needed, but do not see the full benefit of a spot drill with a proper angle.
A chamfer mill, also known as a chamfer cutter, is a tool that can perform several machining operations including chamfering, beveling, deburring, spotting, and countersinking. Due to this versatility, chamfer mills are an essential part of every machinist’s arsenal. All that’s needed to run them is these various operations is a slight change to running parameters and depth of cut.
https://www.harveyperformance.com/wp-content/uploads/2017/08/Feature-Image-Uses-of-Chamfer-Mill-IMG.jpg5251400Harvey Performance Companyhttp://www.harveyperformance.com/wp-content/uploads/2018/08/Logo_HarveyPerformanceCompany-4.pngHarvey Performance Company2017-08-30 12:17:462021-11-19 08:47:04The Multiple Uses of a Chamfer Mill
Undercutting end mills, also known as lollipop cutters or spherical ball end mills, are a common choice for machining undercuts. An undercut is a common part feature characterized by one part of a workpiece “hanging” over another. Undercuts are typically difficult, or even impossible, to machine with a standard tool, especially on 3-axis machines. In many cases, a specialty tool is needed to tackle this feature. Although they are frequently associated with a singular use, undercutters are actually very versatile tools that are worth keeping on hand for a variety of operations.
Undercutting
Unsurprisingly, these tools are very well suited to undercutting operations. Creating an undercut on a part can be tricky and time consuming, especially when forced to rotate the workpiece. Fortunately, this can be greatly simplified with an undercutter.
Exactly what tool to use depends on the geometry of the feature and the part. These tools are available with a range of wrap angles like 220°, 270°, and 300°. Greater wrap angles are the result of a thinner neck and create a more spherical cutting end. This style offers more clearance at the cost of rigidity. Likewise, undercutting end mills with lower wrap angles sacrifice clearance for greater rigidity.
Deburring & Edgebreaking
Since undercuts have a wrap angle that is greater than 180°, they are very well-suited to deburring or edgebreaking anywhere on your workpiece, including the underside. Deburring your parts by hand can be inefficient for your shop – using an undercutting end mill instead will save you time and money. Edgebreaking operations are often a critical final step to create a part that looks and feels like a finished product and that is safe to handle.
All undercutting end mills can be used to deburr and edgebreak, which makes them a useful tool to have on hand in any shop. Some manufacturers also offer specialized deburring tools that are designed with a right and left hand flute orientation, giving them “teeth” that make them particularly useful for deburring complex shapes. Using a deburring tool in a 5-axis machine often makes it possible to deburr or edgebreak an entire workpiece in one shot.
Slotting
Most machinists might not think of undercutting end mills for slotting, but they are fully capable of this operation. An equivalent slot can be machined with a regular ball end mill, but doing so might not be feasible due to clearance issues – an undercutter has a reduced neck, unlike a standard ball end mill. Additionally, using an undercutter to slot can save time switching to an equivalent ball end mill.
Since only 180° of the cutting end can be used to slot, undercutting end mills with lower wrap angles and thicker necks are best suited to slotting. However, high helix undercutting tools may be ideal if improved finish and increased chip removal are important to the operation.
Contouring & Profiling
With their wrap angle and increased clearance, undercutting end mills are very useful for both simple and complicated contouring and profiling operations. Their versatility means that it is sometimes possible to accomplish the entire operation with a single tool, rather than several, especially when 5-axis milling.
Reduced shank tools offer the most versatility in complex contouring and profiling operations. The ability to chuck these tools at any depth means that they are capable of maximum clearance.
Choosing An Undercutting End Mill
While most undercutting end mills are conceptually similar, there are a few key differences that must be considered when picking the right tool for your job. Harvey Tool offers the following styles as stock standard tools.
https://www.harveyperformance.com/wp-content/uploads/2017/08/Feature-Image-Undercutting-IMG.jpg5251400Harvey Performance Companyhttp://www.harveyperformance.com/wp-content/uploads/2018/08/Logo_HarveyPerformanceCompany-4.pngHarvey Performance Company2017-08-16 16:00:002022-09-08 10:21:09Undercutting End Mills: Well-Rounded Tools That Offer Maximum Versatility
Ball nose end mills are ideal for machining 3-dimensional contour shapes typically found in the mold and die industry, the manufacturing of turbine blades, and fulfilling general part radius requirements. To properly employ a ball nose end mill (with no tilt angle) and gain the optimal tool life and part finish, follow the 2-step process below (see Figure 1).
Step One: Calculate Your Effective Cutting Diameter
A ball nose end mill’s Effective Cutting Diameter (Deff) differs from its actual cutting diameter when utilizing an Axial Depth of Cut (ADOC) that is less than the full radius of the ball. Calculating the effective cutting diameter can be done using the chart below that represents some common tool diameters and ADOC combinations or by using the traditional calculation (see Figure 2).
Step Two: Calculate Your Compensated Speed
Given the new effective cutting diameter a “Compensated Speed” will need to be calculated. If you are using less than the cutter diameter, then its likely your RPM’s will need to be adjusted upward (see Figure 3).
KEY ADOC = Axial Depth of Cut D = Cutting Diameter Deff = Effective Cutting Diameter R = Tool Radius (Dia./2) RDOC = Radial Depth of Cut SFM = Surface Feet per Minute Sc = Compensated Speed
Ball Nose Milling With a Tilt Angle
If possible, it is highly recommended to use ball nose end mills on an incline (ß) to avoid a “0” SFM condition at the center of the tool, thus increasing tool life and part finish (Figure 4). For ball nose optimization (and in addition to tilting the tool), it is highly recommended to feed the tool in the direction of the incline and utilize a climb milling technique.
To properly employ a ball nose end mill with a tool angle and gain the most optimal tool life and part finish, follow the 2-step process below.
Step One: Calculate Your Effective Cutting Diameter
The chart below that represents some common effective cutting diameters and ADOCs at a 15º tilt angle. Otherwise, the traditional calculation below may be used (see Figure 5).
Step Two: Calculate Your Compensated Speed
Given the new effective cutting diameter a compensated speed will need to be calculated. If you are using less than the cutter diameter, then its likely your RPM’s will need to be adjusted upward (see Figure 6).
A Double Angle Shank Cutter is often referred to as the “Swiss Army Knife of Machining” due to its extreme versatility. This singular tool can be used for chamfering, back chamfering, V-groove milling, deburring, and countersinking. Below, we’ll learn the nuances of each operation, and why a Double Angle Shank Cutter might is an excellent tool to have on hand in any machine shop.
Thread Milling
Both in purpose and look, a Double Angle Shank Cutter is very similar to that of a single-form thread mill. Single-form thread mills are more versatile than multi-form thread mills, as they are not locked into a fixed pitch. Double Angle Shank Cutters that have a 60° angle can create internal and external 60° Unified National (UN) and metric threads. Double Angle Shank Cutters with a 55° angle can be used to thread 55° British Standard Pipe Threads (BSPT). To determine the thread sizes that various Double Angle Shank Cutters can produce, it’s helpful to consult thread fit charts, which pair appropriate cutter diameters to the thread size needed.
Chamfering
Depending on the requirements of your chamfering operation, and the angle of the chamfer you’re creating on your part, a Double Angle Shank Cutter might be appropriate. The angle of the top or bottom of the cutting face of the tool (called out below in as a B1 dimension), will determine the angle of your part’s chamfer. The area marked in red in Figures 2 and 3 below indicate the cutting portion for your chamfering and back chamfering (leaving a chamfer on the bottom of a part) operation.
For more information on the angles of Double Angle Shank Cutters, view Harvey Tool’s helpful guide: “Angles Untangled.”
Back Chamfering
Consider a through-hole that has a burr or tear-out caused from drilling the back of a workpiece. Reorienting the workpiece and relocating the hole is time-consuming, and it may be difficult to accurately finish the hole. In a case like this, back chamfering the burred hole without changing the setup is a preferred method. Put simply, the ability to accurately chamfer not only the top – but also the bottom of a part without needing to refasten the workpiece in your machine will save valuable time and money.
For best results when chamfering with Double Angle Shank Cutters, use a stepping over technique with diminishing passes as the radial engagement increases. This strategy helps to manage the amount of contact along the angle and can significantly avoid tool deflection.
Machining V-Grooves
A Double Angle Shank Cutter is commonly applied for machining V-groove profiles because of its cutting head, which is perpendicular to the tool centerline. This provides effective cutting action, even at a low spindle speed. A low tip speed can lead to issues with other tools, such as Chamfer Cutters, where the pointed profile is on-center of the tool.
Deburring
The task of hand-deburring parts can be tiresome for you, and cost inefficient for your shop. It can also lead to inaccuracies in parts that require precise dimensions. Double Angle Shank Cutters can be used to debur a part right in your CNC machine. By doing so, the process of finishing a part is made simple, fast, and accurate. Of course, ensuring proper clearance prior to machining the bottom of a machined hole is pivotal.
Other useful and versatile tools to have on-hand for quick CNC deburring include deburring end mills, back deburring mills, undercutting end mills, and chamfer cutters.
Countersinking
Countersinking a part is done so a screw, nail, or bolt is able to sit flush with the part surface. Using specialty profile tooling can help enlarge the rim of a drilled hole and bevel the sides for a screw to sit accurately. A Double Angle Shank Cutter can also perform this operation by using the bottom portion of its cutting face.
Because of its ability to perform six different operations, Double Angle Shank Cutters are an ideal tool to keep in your tool carousel. In a bind, these tool forms can mill threads, chamfer, back chamfer, machine v-grooves, deburr in your CNC machine, and countersink. This versatility makes it a machining favorite and can offer shops boosted productivity by eliminating the need to flip parts, deburr by hand, or carry multiple tool forms.
For more on Harvey Tool Double Angle Shank Cutters, Click Here.
In today’s manufacturing industry, the reach necessary for many complex parts is pushing the boundaries of plausibility. Deep cavities and complex side milling operations are typical to the mold, tool, and die industry but are also quite common in many machining applications requiring angled walls. Fortunately, many long reach applications include angled walls extending into deep pockets and mold cavities. These slight angles afford machinists the opportunity to gain the necessary strength of tapered reach tool designs.
Increased Tool Performance & Productivity
The benefits of tapered end mills become clear when considering the increase in cross-sectional area compared to tools with straight reaches. Generally speaking, the larger a tool’s diameter is, the stronger it will be. A tool with a tapered neck will offer an increasing cross section, resulting in less tool deflection and increased strength over straight reach options.
When considering an end mill with a straight reach versus the same end mill with a slightly tapered reach, there are clear gains in tool performance and productivity. With just a 3° angle per side, feed rates may be increased by an average of 10% over a straight neck. In long-run jobs, or long run-time operations, this can offer a significant reduction in production time and cost. The same 3° angle also affords a tool as much as 60% less deflection than a straight neck tool (Figure 1). A taper as small as half a degree also provides a 10% decrease in deflection even for shorter reaches. This reduction in deflection results in less chatter, better finish, and ultimately a higher quality product.
Tapered End Mills vs. Straight End Mills
Tapered Reach
Compared with straight reach end mills, tapered reach end mills have the following pros and cons:
• Reduced clearance • Not plausible for use in certain situations
Tapered Length of Cut
End mills with a tapered length of cut experience the following pros and cons when compared with end mills with a straight length of cut:
Pros:
• Easier to create flat tapered walls on 3-axis machines • Avoid witness marks caused by multiple passes with other tools • Better, more consistent finish
Cons:
• “Single-use” tools, suited only to specific wall angles • Inconsistent cutting diameter can complicate optimizing speeds and feeds
Despite the potential significant benefits of even a slight taper, it is important to note that tapered end mills are not a plausible choice for every job. Depending on the wall angle of your part, a tapered end mill can interfere with the work piece in situations where a straight tool would not. In Figure 2 below, the top two images show the ideal use of a tapered tool, while the bottom two images show when using a tapered end mill is implausible and a straight tool is necessary. Where clearances allow, an end mill with the largest possible tapered reach should be chosen for optimal tool performance.
Even a slight taper offers an increase in tool performance over the same tool with a straight neck. With added strength and reduced deflection, the benefits of a tapered end mill can be significant, and extend to a much broader range of industries and applications beyond just mold tool and die.
Tapered Reach Tooling Interference Charts
Where clearances allow, an end mill with the largest possible tapered reach angle should be chosen to allow for optimal tool performance. Refer to Harvey Tool’s interference charts for our Square and Ball clearance cutters to ensure that you pick the ideal tapered end mill based on the parameters of your operation.
https://www.harveyperformance.com/wp-content/uploads/2017/05/Feature-Image-Tapered-End-Mills-IMG.jpg5251400Tom Pylehttp://www.harveyperformance.com/wp-content/uploads/2018/08/Logo_HarveyPerformanceCompany-4.pngTom Pyle2017-05-30 16:00:562022-04-20 16:50:52Increase Productivity With Tapered End Mills
While they are specialty tools, dovetail style cutters have a broad range of applications. Dovetails are typically used to cut O-ring grooves in fluid and pressure devices, industrial slides and detailed undercutting work. Dovetail cutters have a trapezoidal shape—like the shape of a dove’s tail. General purpose dovetails are used to undercut or deburr features in a workpiece. O-ring dovetail cutters are held to specific standards to cut a groove that is wider at the bottom than the top. This trapezoidal groove shape is designed to hold the O-ring and keep it from being displaced.
The dovetail cutter’s design makes it fragile, finicky, and highly susceptible to failure. In calculating job specifications, machinists frequently treat dovetail cutters as larger than they really are because of their design, leading to unnecessary tool breakage. They mistake the tool’s larger end diameter as the critical dimension when in fact the smaller neck diameter is more important in making machining calculations.
As the tools are downsized for micro-applications, their unique shape requires special considerations. When machinists understand the true size of the tool, however, they can minimize breakage and optimize cycle time.
Miniature Matters – Micro Dovetailing
As the trend towards miniaturization continues, more dovetailing applications arise along with the need for applying the proper technique when dovetailing microscale parts and features. However, there are several common misunderstandings about the proper use of dovetails, which can lead to increased tool breakage and less-than-optimal cycle times.
There are seven common mistakes made when dovetailing and several strategies for avoiding them:
1. Not Taking Advantage of Drop Holes
Many O-ring applications allow for a drop hole to insert the cutter into the groove. Take advantage of a drop hole if the part design allows it, as it will permit usage of the largest, most rigid tool possible, minimizing the chance of breakage (Figure 1).
Figure 1. These pictured tools are designed to mill a groove for a Parker Hannifin O-ring groove No. AS568A-102 (left). These O-rings have cross sections of 0.103″. There is a large variation in the tools’ neck diameters. The tool at right, with a neck diameter of 0.024″, is for applications without a drop hole, while the other tool, with a neck diameter of 0.088″, is for drop-hole applications. The drop-hole allowance allows application of the more rigid tool.
2. Misunderstanding a Dovetail’s True Neck Diameter.
The dovetail’s profile includes a small neck diameter behind a larger end-cutting diameter. In addition, the flute runs through the neck, further reducing the tool’s core diameter. (In the example shown in Figure 2, this factor produces a core diameter of just 0.014″.) The net result is that an otherwise larger tool becomes more of a microtool. The torque generated by the larger diameter is, in effect, multiplied as it moves to the narrower neck diameter. You must remember that excess stress may be placed on the tool, leading to breakage. Furthermore, as the included angle of a dovetail increases, the neck diameter and core diameter are further reduced. O-ring dovetail cutters have an included angle of 48°. Another common included angle for general purpose dovetails is 90°. Figure 3 illustrates how two 0.100″-dia. dovetail tools have different neck diameters of 0.070″ vs. 0.034″ and different included angles of 48° vs. 90°.
Figure 2. The dovetail tool pictured is the nondrop-hole example from Figure 1. The cross section illustrates the relationship between the end diameter of the tool (0.083″) and the significantly smaller core diameter (0.014″). Understanding this relationship and the effect of torque on a small core diameter is critical to developing appropriate dovetailing operating parameters.
Figure 3: These dovetail tools have the same end diameter but different neck diameters (0.070″ vs. 0.034″) and different included angles (48° vs. 90°).
3. Calculating Speeds and Feeds from the Wrong Diameter.
Machinists frequently use the wrong tool diameter to calculate feed rates for dovetail cutters, increasing breakage. In micromachining applications where the margin for error is significantly reduced, calculating the feed on the wrong diameter can cause instantaneous tool failure. Due to the angular slope of a dovetail cutter’s profile, the tool has a variable diameter. While the larger end diameter is used for speed calculations, the smaller neck diameter should be used for feed calculations. This yields a smaller chip load per tooth. For example, a 0.083″-dia. tool cutting aluminum might have a chip load of approximately 0.00065 IPT, while a 0.024″-dia. mill cutting the same material might have a 0.0002-ipt chip load. This means the smaller tool has a chip load three times smaller than the larger tool, which requires a significantly different feed calculation.
4. Errors in Considering Depth of Cut.
In micromachining applications, machinists must choose a depth of cut (DOC) that does not exceed the limits of the fragile tool. Typically, a square end mill roughs a slot and the dovetail cutter then removes the remaining triangular-shaped portion. As the dovetail is stepped over with each subsequent radial cut, the cutter’s engagement increases with each pass. A standard end mill allows for multiple passes by varying the axial DOC. However, a dovetail cutter has a fixed axial DOC, which allows changes to be made only to the radial DOC. Therefore, the size of each successive step-over must decrease to maintain a more consistent tool load and avoid tool breakage (Figure 4).
Figure 4: In microdovetailing operations, increased contact requires diminishing stepover to maintain constant tool load.
5. Failing to Climb Mill.
Although conventional milling has the benefit of gradually loading the tool, in low-chip load applications (as dictated by a dovetail cutter’s small neck diameter) the tool has a tendency to rub or push the workpiece as it enters the cut, creating chatter, deflection and premature cutting edge failure. The dovetail has a long cutting surface and tooth pressure becomes increasingly critical with each pass. Due to the low chip loads encountered in micromachining, this approach is even more critical to avoid rubbing. Although climb milling loads the tool faster than conventional milling, it allows the tool to cut more freely, providing less deflection, finer finish and longer cutting-edge life. As a result, climb milling is recommended when dovetailing.
6. Improper Chip Flushing.
Because dovetail cuts are typically made in a semi-enclosed profile, it is critical to flush chips from the cavity. In micro-dovetailing applications, chip packing and recutting due to poorly evacuated chips from a semi-enclosed profile will dull the cutter and lead to premature tool failure. In addition to cooling and lubricating, a high-pressure coolant effectively evacuates chips. However, excessive coolant pressure placed directly on the tool can cause tool vibration and deflection and even break a microtool before it touches the workpiece. Take care to provide adequate pressure to remove chips without putting undue pressure on the tool itself. Specific coolant pressure settings will depend upon the size of the groove, the tool size and the workpiece material. Also, a coolant nozzle on either side of the cutter cleans out the groove ahead of and behind the cutter. An air blast or vacuum hose could also effectively remove chips.
7. Giving the Job Away.
As discussed in item number 3, lower chip loads result in significantly lower material-removal rates, which ultimately increase cycle time. In the previous example, the chip load was three times smaller, which would increase cycle time by the same amount. Cycle time must be factored into your quote to ensure a profitable margin on the job. In addition to the important micro-dovetailing considerations discussed here, don’t forget to apply the basics critical to all tools. These include keeping runout low, using tools with application-specific coatings and ensuring setups are rigid. All of these considerations become more important in micro-applications because as tools get smaller, they become increasingly fragile, decreasing the margin of error. Understanding a dovetail cutter’s profile and calculating job specifications accordingly is critical to a successful operation. Doing so will help you reach your ultimate goal: bidding the job properly and optimizing cycle time without unnecessary breakage.
This article was written by Peter P. Jenkins of Harvey Tool Company, and it originally appeared in MicroManufacturing Magazine.
Harvey Tool’sMiniature High Performance Composite Drills are specifically designed with point geometry optimized for the unique properties of composite materials. OurDouble Anglestyle is engineered to overcome common problems in layered composites and ourBrad Pointstyle is built to avoid the issues frequently experienced in fibrous composites.
Common Composite Problems
Drilling in composite materials is a unique challenge. There are a wide variety of regularly machined composites, each requiring different considerations and approaches. Overcome common composite holemaking problems by identifying and selecting the right tool for your job.
Defining Delamination
Delamination occurs when high drilling forces cause laminated layers to separate, yielding less structurally-sound parts. The more blunt a drill point is, the more force it will take to move through a part, increasing the chance of delamination.
Identifying Delamination
The separation of layers may be difficult to identify through visible scrutiny. Closely inspecting and testing the hole quality is ideal when looking for delamination.
Uncut fibers are largely caused by dull tooling. If a drill’s cutting edge is not sharp enough, fibers will remain uncut, frayed, or splintered, potentially ruining the part. –
Identifying Uncut Fibers
Uncut fibers should be easily noticed: look for splintered or frayed fibers around the edges of your hole.
Rather than leaving uncut fibers hanging on to a workpiece, dull tools can also grab fibers and tear them out of the material altogether. This can leave voids in your material and cause damage to even greater areas of the workpiece.
Identifying Tear-Out
Tear-out can be more difficult to spot than uncut fibers. However, it is often seen as an area of material completely removed around the edge of a hole.
Harvey Tool’s new Composite Drills are engineered with point geometry optimized for fibrous and layered composite materials. Each design is specifically built to overcome common composite drilling challenges and achieve excellent results.
Double Angle Composite Drills
Avoid Delamination and Push-Out
Harvey Tool’sDouble Angle Composite Drillshelp combat delamination and push-out in layered composite materials with specialized point geometry. The primary 130° point angle allows the drill to efficiently engage laminated composites without lifting the top layer of material. The shallower secondary 60° point angle reduces the amount of force required to move the drill through the material, further reducing the probability of delamination. The higher shear angle also aids in reducing push-out at the back of the workpiece by more gradually breaking through the part.
Brad Point Composite Drills
Avoid Uncut Fibers and Tear Out
Harvey Tool’sBrad Point Composite Drillsare designed specifically for superior performance in fibrous materials. The trident-like brad point ensures that holes in fiber filled and reinforced materials come out clear and free of fraying. The outer points accurately score the outer diameter of drilled holes, eliminating uncut fibers, tear-out, and splintering.
Many challenges can arise when machining different types of plastics. In the ever changing plastics industry, considerations for workholding, the melting point of your material, and any burrs that may potentially be created on the piece need to be examined prior to selecting a tool. Choosing the correct tool for your job and material is pivotal to avoid wasting time and money. Harvey Tool offers One, Two, and Three Flute Plastic Cutting End Mills with Upcut and Downcut Geometries. The following guide is intended to aid in the tool selection process to avoid common plastic cutting mistakes.
Choose Workholding Method
When it comes to workholding, not all plastic parts can be secured by clamps or vices. Depending on the material’s properties, these workholding options may damage or deform the part. To circumnavigate this, vacuum tables or other weaker holding forces, such as double sided tape, are frequently used. Since these workholdings do not secure the part as tightly, lifting can become a problem if the wrong tool is used.
Downcut Plastic Cutting End Mills — tools with a left hand spiral, right hand cut — have downward axial forces that push chips down, preventing lifting and delamination. If an Upcut Plastic Cutting End Mill is required, then a tool with minimal upward forces should be chosen. The slower the cutter’s helix, the less upward forces it will generate on the workpiece.
Determine Heat Tolerance
The amount of heat generated should always be considered prior to any machining processes, but this is especially the case while working in plastics. While machining plastics, heat must be removed from the contact area between the tool and the workpiece quickly and efficiently to avoid melting and chip welding.
If your plastic has a low melting point, a Single Flute Plastic Cutting End Mill is a good option. This tool has a larger flute valley than its two flute counterpart which allows for bigger chips. With a larger chip, more heat can be transferred away from the material without it melting.
For plastics with a higher heat tolerance, a Two or Three Flute Plastic Cutting End Mill can be utilized. Because it has more cutting edges and allows for higher removal rates, its tool life is extended.
Consider Finish Quality & Deburring
The polymer arrangement in plastics can cause many burrs if the proper tool is not selected. Parts that require hand-deburring offline after the machining process can drain shop resources. A sharp cutting edge is needed to ensure that the plastic is sheared cleanly, reducing the occurrence of burrs.Three Flute Plastic Cutting End Mills can reduce or eliminate the need to hand-deburr a part. These tools employ an improved cutting action and rigidity due to the higher flute count. Their specialized end geometry reduces the circular end marks that are left behind from traditional metal cutting end mills, leaving a cleaner finish with minimal burrs.
2 FLUTE PLASTIC CUTTER: A facing operation was performed in acrylic with a standard 2 Flute Plastic Cutting End Mill. The high rake, high relief design of the 2 flute tool increased chip removal rate, but also left distinct swirling patterns on the top of the workpiece.
3 FLUTE PLASTIC FINISHER: A facing operation was performed on a separate acrylic piece with a specialized 3 Flute Plastic Finisher End Mill. The specialized cutting end left minimal swirling marks and resulted in a smoother finish.
Identifying the potential problems of cutting a specific plastic is an important first step when choosing an appropriate plastic cutter. Deciding on the right tool can mean the difference between an excellent final product and a scrapped job. Harvey Tool’s team of technical engineers is available to help answer any questions you might have about selecting the appropriate Plastic Cutting End Mill.
https://www.harveyperformance.com/wp-content/uploads/2017/04/Feature-Image-Plastic-Cutter-Selection-IMG.jpg5251400Harvey Performance Companyhttp://www.harveyperformance.com/wp-content/uploads/2018/08/Logo_HarveyPerformanceCompany-4.pngHarvey Performance Company2017-04-07 08:31:562023-09-21 13:29:01Selecting the Right Plastic Cutting End Mill
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