We’ve got an exciting new addition to our plastic fabrication shop – a new coordinate measuring machine! Today I want to share some of the benefits of this new equipment, and explore how it can help you realize your product design dream.

Our new Coordinate Measuring Machine is now a key feature of our testing and inspection lab. It measures the geometrical characteristics of a component, and shows the collected data in a mathematical form using X, Y, and Z axes. The measurements are obtained via a probe that is attached to the third moving axis of the machine. The CMM allows for incredible accuracy and precision to within a micrometer.

What is the importance of a CMM in plastic fabrication?

Essentially, our goal of acquiring this machine is to enhance our quality commitment. We look to the CMM to test if engineered parts are up to the rigorous specifications of an application design. And beyond accuracy and product integrity, the machine also helps to ensure that a manufacturing process is repeatable. This CMM model is designed for large assemblies and will help us to increase throughput.

The CMM machine is just one piece of our custom plastic fabrication machine shop, which boasts: 

CNC Swiss Screw Machines

• High-speed turning
• Bar capacity up to 1.25”
• Continuous bar feeding
• 6-axis control system
• Secondary milling and drilling

CNC Milling

• Up to 36” x 81” travel
• Rapid tool change
• Close tolerance
• Prototype/production
• CAD/CAM

CNC Turning

• Live mill head attachments
• Bar capacity up to 2.75”
• Secondary milling & drilling
• Chucking capacity up to 21”

Consider TriStar’s plastic fabrication; we can guarantee your parts will meet design specs and that they are fully inspected and certified. 

We can also help you save on component costs by suggesting alternate materials, or providing machining tips to help you manage your own fabrication. Get your copy of the Plastic Fabrication White Paper for exclusive machining tips! Let us help!

Have you ever fabricated plastic components? 

For many traditional machine shops, metal is an easy and familiar material to work with, but plastic fabrication presents a whole new set of challenges. Metal is a solid material and predictable to machine, while plastics are a hybrid of different materials, and change shape as they are machined. Simply stated, the basic principles of machining metals do not apply when machining plastics. And any mistake in plastic fabrication can also result in expensive scrap loss. 

How can you master the art of plastic fabrication? We have 4 must-follow rules to success.

Metals are generally easy to machine; they don’t creep or change shape as you fabricate. Plastic materials are prone to substantial creep and can easily melt and chip during machining. Yet with the right tools and techniques, plastic fabrication can be achieved by following these four golden rules: 

1) Choose materials wisely

Plastics are high-performance and an excellent replacement for bronze, stainless steel and cast iron. They excel in high-temperature and extreme working environments. But choosing the right material is critical, since some high-performance formulas are substantially more expensive than metal. For instance, Polybenzimidazole (PBI-Celazole) is 25x the price of cold-rolled steel, and 15x more costly than Type 303 stainless steel.

When choosing plastics, remember that the materials you choose are an investment in performance. Choosing a higher-quality (more expensive) material will yield a higher-quality part. And higher-quality parts can save you from field failures or costly recalls down the line. Find the right bearing material from the materials database. 

2) Limit heat

Heat buildup is the number one cause of failure in plastic fabrication. In fact, the very act of machining generates friction ― or heat. Without the right machine speeds/feeds and coolants, plastic cutting tools can actually become plastic melting tools. Heat also presents dimensional challenges, which makes it more difficult to hold tolerances. Special attention must be paid to limit heat. 

3) Determine the best fabrication technique

Which machining technique is best for you material? Sawing? Milling? Drilling? Threading or tapping? Often, the right technique comes down to the category of plastic you are working with; either thermoset plastic or thermo plastics. Thermoset plastics retain their solid state indefinitely, while thermoplastics can be melted more than once to form new shapes. Thermoplastics are best suited to machining. 

4) Beware of burrs 

Burrs are a common machining hazard and can ruin surface finishes. They usually occur when a machining tool reaches a travel end without additional support. Techniques to avoid burring can take more time, but the time saved in deburring may pay for the longer machining cycle. Avoiding burrs can help you reduce the costs and obtain an optimal finish.

Is in-house plastic fabrication the right choice for your material application? Or would you be better outsourcing this service? Get our copy of our Plastics Machining Guide to help you decide. Or just connect with the Plastic Fabrication Experts to answer your questions! 

Plastic fabrication is completely unlike metal fabrication; a fact that we covered indepth in our recent Machining Plastics technical white paper. After all, plastics melt and chip as you machine them, plus they can expand 5x or more beyond their original shape. Machining requires skill, experience and proper tooling in order to achieve the best value for your material investment. 

Given all the variables, when does it make sense to consider moving your plastic fabrication from in-house to outsourced? What criteria should you consider when making this important decision?

We’ve prepared 4 top signs to help you review. 

Consider outsourcing your plastic fabrication when:

1. You’re not certain if the material is genuine

How do you know if the material that you have paid for is indeed the genuine material (counterfeiting is a widespread problem, a topic we covered in this paper). Consider outsourcing with a reputable bearing supplier who will review relative costs, and is also an authorized dealer of the material you are interested in. Unfortunately, counterfeit materials are fairly common in the plastics industry, so learn how to recognize genuine and avoid counterfeit!

2. Heat levels are a mystery

Plastics melt! And any type of machining generates friction, thus heat. In essence, your cutting tool can quickly become a “melting tool” if you’re not careful. If you’re uncomfortable with the connections between heat and cutting speeds, tool selection, coolants and tolerances, it might be worth outsourcing your project.

3. Best practices for drilling, turning, threading and tapping are unknown

Which technique will provide an optimal component without stressing and distorting the material? Look for a machine shop that has an extensive inventory of equipment and a quick delivery. CNC turning, Swiss screw machines, and milling equipment are all key equipment for precision engineering – look for a fabricator who has them!

4. Your component requires secondary processing

Do you need to paint your component once it’s machined? Or adhere it to another piece? You may be interested in Surface Modification, a series of techniques that help to improve the application of secondary processes including paints and other coatings. This is a select service that is not readily available in the market.

Reach out to the plastic machining experts with your questions!

When it comes to plastic fabrication, there is not one simple, one-size-fits-all solution to creating your ideal custom part. Plastics machining offers many advantages (as we covered in our new technical paper), yet injection molding also has offers unique benefits.

So how do you decide between these two plastic fabrication techniques? Ultimately, your decision should come down to answering a couple of basic questions that will help you make the most of your material investment. Consider the following:

Plastic Fabrication Considerations:

• What is the production quantity? 
  With injection molding, tooling can be expensive, so you need to be certain that the expensive tooling justifies the cost of the machined part. As a rule of thumb, we recommend injection molding for quantities over 5,000 pieces, and machining for anything under..
• Are tolerances matched to the material? 
  Some materials cannot hold tolerances, which can impact their compatibility with injection molding. Read all about material selection and plastic machining in our new white paper: Machining Plastics: The Essential Guide to Materials, Tools & Techniques. 
• How complex is the geometry? 
  If the part geometry very complex, you have many more fabrication options with machining vs. molding.
• What is the stress on the material? 
  You need to determine if there are fillers in the resin you are using, since this will directly impact stress. 
• What are the surface finish requirements? 
  This is particularly important in medical applications, where a proper finish is critical to the surface ID of the part. 

For a quick video review of this topic, check out the video (below). Of course, our Plastic Bearing Engineering Experts are always available to answer your questions too!