Tag Archive for: Plastic Cutting

How Material Specific Tooling Pays Off

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A machinist is faced with many questions while selecting the proper tool for their job. One key decision that must be made is whether a material specific tool is appropriate and necessary for the application that’s going to be performed – whether the benefits of using this type of tool outweigh the higher price tag than that of a tool designed for use in a variety of materials. There are four main categories to consider when deciding whether a material specific tool is your best bet: internal tool geometry, coatings, material removal rates (MRR), and cost.

When to Utilize Material Specific Tooling

Are you a machinist in a shop that deals primarily with one type of material? Or, do you generally change materials frequently throughout the day? Further, how many parts do you make at a time? These are questions you must ask yourself prior to making a tooling decision.

Material Specific Tooling is best utilized where several parts are being machined of the same material. For instance, if your shop is machining 1,000 plastic parts, it would be in your best interest to opt for a tool designed for this material as your tooling would not only last longer but perform better. If machining flexibility is paramount for your shop, if you’re only machining a few parts, or if part finish is not of high importance, a regular end mill may suffice.

Pros and Cons of Material Specific Tooling

There are pros and cons to purchasing a Material Specific Tool.

Pros:

  • Tool geometry designed for the material you’re working in to achieve the best results.
  • Coating optimized for the material you’re cutting.
  • More aggressive speeds and feeds, and boosted MRR as a result.
  • Increased tool life.

Cons:

  • Higher upfront cost, though long term savings are possible if used in proper situations.
  • Less opportunity for flexibility. While most end mills may be suitable for use in many jobs and many machines, Material Specific End Mills are engineered for use in specific materials

Special Benefits of Material Specific Tooling

A Unique Internal Tool Geometry

Many manufacturers supply tooling designed for use in specific material buckets. For instance, Harvey Tool has distinct catalog sections for material specific tooling for Hardened Steels, Exotic Alloys, Medium Alloy Steels, Free Machining Steels, Aluminum Alloys, Plastics, Diamond Tooling for Non-Ferrous Materials, and Composites. The special geometry of tools found in these sections is optimized to allow the tool to perform optimally in its select material group.

For instance, a machinist may be faced with a dilemma while preparing to machine a plastic part. While an end mill found in Harvey Tool’s Miniature End Mill section could certainly machine this material, Harvey Tool’s end mill offering designed to machine plastics feature a high rake, high relief design. This is ideal for plastics because you want to effectively cut and form chips while the strength of the tool is less of a concern. The high rake and high relief creates a sharp cutting edge that would quickly break down in metals. However, in plastics, this effectively shears the material and transfers the heat into the chip to produce a great finish in your part.

material specific tooling

Harvey Performance Company, LLC.

Specific Coatings & Substrates for Optimal Performance

One key benefit of opting for a material specific tool is the ability to utilize the best coating option available for that material. Tool coatings serve many functions, including improved lubricity, increased tool life, and a higher-quality part finish. In addition, coated tools can typically be run around 10% faster than uncoated tools.

While many manufacturers will specially coat a standard end mill at your request, this takes added time and cost. In its Material Specific catalog sections, Harvey Tool offers coated tools stocked and ready to ship. For instance, their Hardened Steels and Exotic Alloys categories utilize AlTiN Nano coating. This is a unique nanocomposite coating that has a max working temperature of 2,100° F and shows improved performance in materials such as Hardened Steels, Titantium Alloys, and Inconel, among others.

Increased Material Removal Rates

Because Material Specific Tooling features optimal tool geometry for a job, running parameters are generally able to be more aggressive. Any machinist knows that Material Removal Rates (MRR), is the metric that’s most closely related to shop efficiency, as the more material removed from a part in a given period of time, the faster parts are made and the higher the shop output.

The following example compares running parameters of end mills from Harvey Tool’s Miniature End Mill and Material Specific End Mill Sections. You can notice that while key geometries between the two tools are identical, and are in use in the same material with the same operation, the chip load (+25%), linear feed rate (+33%), and depth of cut (+43%) are boosted. This allows for more material to be removed in a shorter period of time.

Miniature End Mill

Part Number: 836408

Description: 3 Flute 1/8 inch diameter 3x LOC Square Stub & Standard

Material: 6061 Aluminum

Application: Slotting

Speed: 10,000 RPM

Chip Load: .00124 IPT

Linear Feed: 37.2 IPM

DOC: .04375

Material Specific End Mill

Part Number: 942308

Description: 3 Flute 1/8 inch diameter 3x LOC Square Variable Helix for Aluminum Alloys

Material: 6061 Aluminum

Application: Slotting

Speed: 10,000 RPM

Chip Load: .00165 IPT

Linear Feed: 49.5 IPM

DOC: .0625

Harvey Performance Company, LLC.

Extensive Cost Savings

The following chart displays a cost analysis breakdown between a tool found in the Miniature End Mill section, item 993893-C3; and a tool found in the Material Specific End Mill section, item 933293-C6. When compared for the machining of 1,000 parts, the overall savings is nearly $2,500.

material specific tooling benefit chart

Material Specific Tooling Summarized

In conclusion, Material Specific End Mills have many benefits, but are best utilized in certain situations. While the initial cost of these tools are higher, they can work to save your shop time and money in the long run by lasting longer and producing more parts over a given period of time.

Selecting the Right Plastic Cutting End Mill

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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.

plastic cutter selection

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.

plastic cutter selection

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.

Shop Harvey Tool Plastic Cutting End Mills Today

Flute Count Case Study

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.

plastic cutter selection

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.

plastic cutter selection