EPP’s Alex Curtiss featured in MDT Magazine

Alex Curtiss

Alex Curtiss President and CEO, Engineered Plastic Products Corporation

It is natural for a company that makes highly sensitive medical devices to turn to a trusted vendor to make its components. But if those components are made of plastic and that vendor is a metal machinist, that can be a huge mistake.

A company that specializes in only machined plastic parts not only brings expertise in dealing with plastics to the table, but can help avoid problems that might arise from contamination or simply not understanding the subtle differences between working with plastic, as opposed to metal parts.

Take the case of a medical analytics company that turned to a metal machinist to make a plastic component. The part had precisely made holes that needed to contain a small ball to measure gas levels. If working properly, the ball would float in the instrument. Unfortunately, even after passing initial inspections, these parts sometimes failed after two to three weeks in the field. The ball would no longer rise. The manufacturer thought it was a problem with static—a reasonable assumption, but one that proved wrong. The real problem became apparent after putting the piece under a microscope. There were tiny cracks inside the holes, not visible to the naked eye. The cracks were due to crazing, a degradation caused by cutting oils. That is not an uncommon problem when metal machining equipment is used to create plastic parts.

Components for medical diagnostic equipment
Components for medical diagnostic equipment

Metal parts, unlike plastic ones, typically require the use of oil-based cutting fluids. And no matter how conscientious the metal machinist is, it is nearly impossible to clean every bit of oil from a machine before using it to make a plastic part. Because of this, equipment used to manufacture metal parts, even if used for metal only, can occasionally contaminate plastic parts with those oil-based cutting fluids. Many plastics are highly sensitive to petroleum-based cutting fluids and will degrade if they come into contact with them. Also, many plastics are hydroscopic and will absorb the cutting oils. The result is a part that may pass initial inspections, but will degrade over time and fail in the field.

It is not just cleaning oils off a machine that is difficult for a metal machinist, but also clearing every tiny metal fragment that may remain on a machine used to make metal parts. If the plastic material being machined is soft, residual metal fragments can become embedded in the plastic machined parts. Again, the metal fragment may not cause a problem initially, but over time it can cause the plastic to degrade and stop performing properly.

Problems can also arise in something as simple as how a metal machinist holds a plastic part. With plastic machined parts, the plastic is usually held with vices. Machinists who don’t specialize in plastic have a tendency to hold the plastic the same way they do metal—but this can be too tight for a plastic. As a consequence, when a drill goes into the plastic, the material flexes a bit, which can put stresses on the part that might not surface until later. A plastics machining company would know that, and be able to prevent that from happening. It is a subtle difference in manufacturing, but one that can turn into a huge problem down the road.

Of course, a plastics expert should be more knowledgeable than a metal machinist about the variety of plastics materials available and what uses they’re best suited for. This level of knowledge is especially important in fields like medical device technology, where manufacturers often use plastics that are less common than those used for other purposes. A plastics expert can help designers and manufacturers sort through materials according to factors such as sensitivity to humidity, abrasion resistance and thermo-sensitivity.

A company that specializes in only machined plastic parts not only brings expertise in dealing with plastics to the table, but can help avoid problems that might arise from contamination or simply not understanding the subtle differences between working with plastic, as opposed to metal parts.
A company that specializes in only machined plastic parts not only brings expertise in dealing with plastics to the table, but can help avoid problems that might arise from contamination or simply not understanding the subtle differences between working with plastic, as opposed to metal parts.

Sourcing is another important consideration. A metal machinist will most likely get their plastics from a distributor whose materials may come from a variety of sources. They may be able to provide certification, for example, that all the materials they are using are nylon rods, but they may not know the source of those rods. A plastics specialist, on the other hand, should be able to tell you not only what mill the material came from, but also the lot number. If there is ever a problem, they can easily trace the material back to its original source. There is a level of accountability you may not get from a metal machinist.

Of course, not all plastic machining companies are alike. The best for your job is one that is familiar with each machining process you need for your medical device application, as well as with the specific plastic material you will be using. The company should have access to up-to-date information and be willing to share it through property charts or plastic material handbooks.  They also should be ISO Certified, use documented SPC (statistical process control) procedures and own the proper inspection equipment such as CMM (coordinate measuring machine) or video inspection systems. These certifications and systems will help ensure that you receive the highest quality medical device for the lowest cost, with the fewest possible errors the first time around.

The final consideration in this is cost. Surprisingly, using a plastics expert may actually save money.  Plastics machining companies deal with plastic parts all day long. Their expertise means they can often perform the job more efficiently than the typical metal machinist. But most important, the lower risk of contamination when dealing with a plastic machinist means that medical device parts not only have a higher chance of passing inspection, but a much lower chance of failing down the road. That is important in any industry, but even more so when someone’s health is on the line.

This article appeared in the March 2016 print edition of MDT.

EPP’s Alex Curtiss featured in Sensors Magazine

Why Using A Plastics Machining Specialist For Instrumentation Equipment Is The Best Choice

January 29, 2016 By: Alex Curtiss, Engineered Plastic Products Corporation

 Alex Curtiss

Initial Gander

At first glance, it’s hard to see why it’s best to choose a plastics specialist to make a machined plastic part in your instrumentation product, rather than just having a metal machining company, maybe one you know and trust, do the work. A metal machining company may be able to make your plastic part. The part may look fine to the naked eye and it may also seem to work well when it’s put into a product and tested out. At first, it may even perform as it should—until something goes wrong and everyone is left scratching their heads looking for answers.

Here’s What Can Go Wrong

That’s exactly what happened to one company in Ohio who manufactures precision scientific instrumentation. A new $2 million dollar machine that they manufactured for one of their top customers was delivered and installed but soon developed an electrical problem and no one knew why. Finally, they took the whole machine apart and examined it piece by piece. Finally, in one of the plastic parts, they noticed a tiny sliver of metal embedded in the plastic.

That tiny spec was the culprit creating an electrical short circuit and that was the reason the machine had stopped working. The plastic part was machined by the company’s vendor that produces their metal components. That is one problem that can happen when a metal machining company produces plastic parts rather than an experienced plastics only specialist.

Why That Happened

This example is not a fluke. It is very difficult to adequately clean a machine that has been working on metals parts. The process can lead to contamination.

If the plastic material is soft, residual metal fragments can become embedded in the plastic machined parts. Depending on what the part is used for, the metal fragment may not cause a problem initially, but, over time, it can cause the plastic to degrade and eventually stop performing properly.

What Else Can Go Wrong

There’s another contamination risk with metal machining companies. Metal parts, unlike plastic ones, typically require the use of oil-based cutting fluids. Because of this, equipment used to manufacture metal parts, even if used for metal only occasionally, can contaminate plastic parts with those oil-based cutting fluids.

Many plastics are highly sensitive to petroleum-based cutting fluids and will degrade if they come into contact with them. Also, many plastics are hydroscopic and will absorb the cutting oils. Additionally, if these parts are being manufactured for FDA-approved uses or medical applications, they will not meet their standards.

Who Is Plastic-Materials Knowledgeable?

Generally there is not an abundance of knowledge about what plastic to use for different component applications. To say plastic is like saying vehicle. There are many types of vehicles from dump trucks to Ferraris. Both are vehicles but the quality and use is not the same. The same applies to plastic.

plastic partsPlastics specialists are knowledgeable of the variety of plastics and which are the best to use for a given application.

Metal shops are experts in metal and cannot be expected to have knowledge of the differences between the many types of plastics. Metal machining companies rarely have any in-depth knowledge of the performance characteristics of different plastics. On the other hand, a good plastic machining specialist know what plastics are best for each function and can produce the plastic part needed without risk of failure.

Ensure The Plastics Vendor Is The Correct One For The Project

Even if you do choose a plastics expert rather than a metal machining company, there are still some points to consider.

First, experience matters. Make sure the supplier you choose is familiar with each machining process you need for your application, as well as with the specific plastic material you will be using. Ask them to share information such as property charts or plastic material handbooks. Specialists in plastic machining should have a wealth of up-to-date information.

A company that specializes in only machined plastic parts not only brings expertise in dealing with plastics to the table, but can help avoid problems that might arise from contamination or simply not understanding the subtle differences between working with plastic, as opposed to metal parts.Machining metal versus plastic.

Second, check for certification. The plastic machining vendor who makes the fewest errors the first time around should give you the highest quality at the lowest cost. Plastic machining vendors can keep errors to a minimum if they are highly process driven The best ones are ISO Certified, use documented statistical process control (SPC) procedures, and own the proper inspection equipment such as coordinate measuring machine (CMM) or video inspection systems.

Remember, experience, more than anything else, will ensure a supplier can manufacture the most cost-effective part with the best quality.

About the Author

Alex Curtiss is President and CEO of Engineered Plastic Products Corporation (EPP) in Elk Grove Village, IL. The company has specialized in producing high-precision machined plastic parts for the aerospace, medical, instrumentation and water treatment industries since 1976 and has been ISO certified since 2002 and ISO compliant since 1994.

EPP’s Alex Curtiss is featured in Product Design and Development Magazine

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plastic parts

Many designers don’t realize there are  plastics machining specialists. That’s why they often turn to a metal machinist to make their plastic parts. But doing so can cause the best designs to go awry.

Many designers see no difference between a metal machinist and a plastic machinist making a plastic part. The truth is, both are capable and both can probably make the part to a designer’s specifications. Both parts may work the way they’re supposed to, at least at first. But the potential for something to go wrong when the part is made by a metal machinist can cost a company time and money. The problem can arise from anything from contamination to a simple lack of expertise of how metal and plastic differ.

Take, for example, an Ohio company that manufactures precision scientific instrumentation.

One of their top customers took delivery of a new $2 million machine they manufactured. At first, it ran fine, but it soon developed an electrical problem. The company ended up taking the entire machine apart and examining it bit by bit before they finally figured out the cause of the short circuit—a tiny sliver of metal embedded in the plastic. This is the kind of contamination that can occur when plastic parts are manufactured by a metal machining company rather than a plastics-only specialist.

Even if you’re not producing $2 million machines, mistakes like this can still produce million dollar headaches. That’s because it’s difficult to clean machines used to make metal parts. A machine may look clean to the naked eye, but if there is as much as just one tiny metal fragment on a machine, it can become embedded in a soft plastic machined part. While the part may seem fine at first, over time, that metal fragment can cause the part to degrade and stop working properly.

A company that specializes in only machined plastic parts not only brings expertise in dealing with plastics to the table, but can help avoid problems that might arise from contamination or simply not understanding the subtle differences between working with plastic, as opposed to metal parts.

Another pitfall

The difference between how metal and plastic parts are made can also lead to contamination with metal machining companies. Unlike plastic parts, metal parts typically require the use of oil-based cutting fluids. What’s necessary for metal, though, can wreak havoc on plastic. Many plastics are highly sensitive to petroleum-based cutting fluids and will degrade if they come in contact with them. In addition, many plastics are hydroscopic and will absorb cutting oils. When this kind of contamination occurs with parts being manufactured for FDA-approved uses or medical applications, they will not meet their standards.

Why knowledge matters

Plastics and metal machinists also differ in experience. A plastic machining expert has knowledge about the different types of plastic and how those plastics perform that a metal expert can’t be expected to know. All plastics are not alike. Dealing with a plastics expert can help you choose the type that’s right for your job.

There are also differences in the properties of metal and plastic that necessitates differences in design. For example, a metal machinist may not be aware that there is a difference between the amount of stress a metal part can handle versus a plastic part. A valve screwed on with the right torque for metal might be too much for plastic, leading to cracks. Designs, too, might have to differ when working with plastics as opposed to metal. Those sharp corners that work fine in a metal design can cause stress that lead to cracks in a plastic part. A plastics specialist should know this and suggest slightly rounding those corners—saving you precious time caused by design errors.

Choosing the right plastics vendor

If you do decide to choose a plastics specialist, keep these points in mind:

  • Experience. Make sure the plastics machining expert you choose has experience with the type of machining process your product requires as well as the material you will be using.
  • Information. Specialists in plastic machining should have up-to-date information and be willing to share it with you. Ask to see materials such as property charts or plastic material handbooks.
  • Certification. Plastic machining vendors can keep errors to a minimum if they are highly process driven. The best ones are ISO Certified, use documented SPC (statistical process control) procedures, and own the proper inspection equipment such as CMM (coordinate measuring machine) or video inspection systems.

In the long run, working with an experienced plastics machining expert from the start could save money. It may be easier to farm out parts to that same machinist who is making metal components, but doing so could increase the risk of the parts failing within months of reaching the customer’s hands. Using a plastic machining specialist could be the difference between a machine that breaks down after a month on the job, and one that keeps humming along.

 

Plastic Machining: Custom Plastic Manifolds

Plastic manifolds have many advantages over metal. Plastic manifolds can offer far more complex fluid paths and produce clean, easy to inspect fluid paths. Plastic manifolds are lighter and more compact. EPP’s manifold experts deliver quality custom plastic manifold fast and to your specifications. We can even provide Fluonic Engineering Design services to turn your current “spaghetti-like” tubing mess into a custom plastic manifold. Contact us for your Custom Plastic Manifold needs! Let EPP Corp be your Custom Plastic Manifold resource.

Low-Temp Interfusion Bonding

Low-Temp Interfusion Bonding is a proprietary technique that produces superior bonding joints. Other plastic manufacturers use either diffusion bonding or cement type gluing that leaves machine marks within the fluid channels. Diffusion boding creates heat and can distort the internal features. The Low-Temp Interfusion Bonding technique eliminates any distortion, thus allowing us to hold much tighter tolerances. This process also creates fully polished channels without the cement marks that can impede the overall fluonics.

Plastic Materials

Custom Plastic Manifolds can be produced from a wide range of plastic materials including:

Custom Plastic ManifoldsCustom Plastic Manifold Custom Plastic ManifoldCustom Plastic Manifold

Plastic Machining: Plastic Prototypes

EPP Corporation is pleased to announce short-run, quick-turn Custom Plastic Prototypes with delivery in one week or less.  Let EPP assist you in new product development through our fast turnaround on fully functional plastic prototypes.

· Plastic prototypes in one week or less

· Fully Functional

· Plastic prototypes with the highest quality on tolerances up to +/- .001″

· Both simple & complex 3D parts are welcome

· Free application engineering available

Let the plastic machining specialists at EPP Corporation be your source for all plastic prototypes.  Fast plastic prototypes in one week or less