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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.

Plastic Machining and Plastic Prototypes With Engineering Assistance From Experts-The Solution

Machining Plastic is the perfect solution for many varied component needs in numerous critical industries however, most engineers may not have the necessary knowledge.

Many of the brightest, most talented engineers do not have the knowledge required in order to know what material is best for a component or plastic prototype need. Simply the reason being that until recently, plastic machining was not taught in engineering schools. Currently the presence of plastic machining courses is limited to only a small number of schools. In order to select the proper material, contact a plastic machining expert for design application assistance.

Design considerations when machining plastic are unique to plastic.  One with experience machining metal for example, would not be aware of these specifications.  When ordering plastic machined components or plastic prototypes, the following considerations are evaluated:

  • Thermosensitivity
  • Sensitivity to humidity and hygroscopic absorption
  • Sensitivity to chemicals and oils
  • Notch sensitive corners and square ID’s
  • Tolerances
  • High loads
  • High impact
  • Fatigue loading or cycle loading
  • Temperature
  • Electrical considerations
  • Wear resistance or abrasion resistance
  • Dimensional shape retention
  • Regulatory requirements (such as FDA or UL)
  • Appearance
  • Optical requirements
  • Whether or not part is for outdoor use

A plastic machining expert has the knowledge and expertise to help you select the best material for plastic machined parts and plastic prototypes according to the necessary specifications and considerations.

At EPP Corporation we provide design application, engineering, and purchasing assistant to all customers for both plastic machining production and fast plastic prototypes.

We also have an online plastic design as a free, excellent resource that compares different materials based on above criteria, as well as comparing the plastic materials side by side

To download our FREE Plastic Properties Handbook and Design Guide CLICK HERE

Plastic Machining:Eliminate High Administrative Costs Through Supply Chain Management

A plastic machining vendor with a proven supply chain system can save company the time and money associated with the constant placing of reoccurring orders. Certain plastic machined parts will be required on a repetitive basis, and why not focus on innovation instead?

The typical practice in ordering plastic machined parts is as follows:

The first cost associated with this practice is the cost of soliciting the quote and the analysis of the information. The admin time to issue the quote, phone, fax or email the plastic machined part request and collect the numbers can range from $15-50 per part depending on the company’s overhead which can result in a total cost of $45-150 to solicit three bids. The cost is multiplied by the number of times per year, which can be 2-3 times. That is $135-450 annual cost per part before an order is placed.

Instead when all reoccurring plastic machined component orders are placed at once using EPP’s proven supply chain management system, these additional costs are not necessary.  Place an order once per year on reoccurring plastic machined part needs, and save the time, as of course time is money.  Base your orders on previous historical custom plastic machined part usage, and if increases or decreases to plastic machined component needs do occur, give us at least 90 days in order to adjust the quantities to meet your changed quantity requirements.

In order to drive business, the focus needs to be on new product development, and going to market fast with the new products.  The focus can then be shifted to ordering plastic prototypes of components for new projects.  As time is of the essence in beating the competition, EPP offers its solution for fast plastic prototypes.  Have plastic prototypes machined in, and delivered in under a week.

For more details on how to save on plastic machining through our supply chain management system Click Here

For more details about or fast plastic prototype solution Click Here