Tech Talk Blog

Q&A - Techtron PPS

What are some key attributes of Techtron? 

I recently had a call about our Techtron^® product, which is an excellent alternative to PEEK in lower temperatures. Techtron is a Polyphenylenesulfide (PPS) semi-crystalline material that excels in heavy-duty applications. It can also resist most solvents, strong acids, bases, and biological salts. We’ve installed it as a replacement for steel in different chemical pump applications.

Other key features of Techtron PPS:

• High-strength and hardness
• Excellent chemical, weather and radiation resistance
• Machines to tight tolerances
• Near-zero moisture absorption
• Excellent electrical characteristics

Consult our team to see if Techtron would be a good fit for your next application, or visit our Video Learning Center for more information. 

CJ Bearings Were Designed for Construction

I recently returned from visiting one of our new international distribution partners.   While there, I was asked about the history of our self-lubricating CJ bearings.  Did you know that CJ (or composite journal) bearings were originally designed to meet the needs of the construction industry? 

Construction equipment manufacturers discovered that although bronze and steel bearings had worked fine in the past, they also had many shortcomings. They required constant lubrication to remain effective in dirty, off-road environments, and that dirt and grease accumulated and formed a tacky compound that corroded the metal bearings. The manufacturers also tried rolling element bearings, but they were ineffective in the low-angle oscillations and lift-and-tilt requirements of heavy-duty construction equipment. CJ bearings have solved those challenges and many more.

Share your experience with CJ bearings, or consult our team to see if they would be a good fit for your next project.

Machining UHMW – Points to Consider

A customer recently asked us for tips on machining UHMW materials to better hold tolerances. UHMW is a very unstable material to machine, since it has roughly 12x the thermal expansion of steel. 

Some of the key factors that we like to review include the size and geometry of the part, the speeds and feeds of the machine, plus the types of coolants to use (and those to avoid). With the right technique in place, chipping, threading and other challenges can be avoided. 

We’ve created a video to provide even more machining tips. Or our in-house machining experts are always available to help you troubleshoot, and can point you to our “Machining Plastics" seminar.

Q&A: Cleaning Metal Parts Prior to Overmolding

Question:

We machine metal parts in-house and then overmold the parts with elastomer materials – usually liquid injection (LIM) silicone.  We frequently have adhesion problems between the metal part and the silicone.  Can you recommend a method of cleaning the metal to get better bonding?

Answer:

Getting good adhesion of overmolded materials to machined or molded parts – plastics as well as metals – is a problem a lot of folks have.  There are many very good products on the market, such as Alconox detergents, that are effective at removing most of the gross contamination from metal part after machining.  Although liquid industrial cleaners often do a good job, they can be expensive and they are not always user-friendly (such as keeping the solution hot, measuring ratios of water to cleaner, etc.).  In addition, although these cleaners are effective at removing gross contamination – and we often recommend that this is done - a small amount of residual contamination may remain on the cleaned part(s).  Depending on the level of adhesion required, even a trace amount of residual contamination may be enough to adversely impact uniform and effective adhesion.

A vacuum plasma treatmenton (post liquid cleaned) parts will assure you the very best possible adhesion of your overmolded material.  Plasma is extremely effective at removing all trace amounts of organic contamination as well as making the surface of the part(s) more hydrophilic.

Applications that benefit from plasma cleaning prior to overmolding include surgical device handles, aircraft and/or automotive components, consumer and sports equipment, and thousands of other types of overmolded devices.

Please contact your local TriStar sales engineer for details, or Ask the Surface Modification Experts for more information.

What are some advantages of using polymer materials for gears?

We’ve had great success installing polymer gears in everything from paper mills to copiers.  Polymer has clear advantages as a gear material; it helps to reduce noise and can significantly reduce weight, plus it can deliver cost savings over metal.  When using polymer in a gear design, there are some key considerations to remember such as thermal expansion and contraction, tensile and flex strength, moisture absorption and even chemical exposure. Other important design considerations are tooth profile, height and bending forces.

With so many nuances in polymer gear design, reach out to our engineering experts to find the exact material to fit your application.

Q&A: Dual Treatments On The Same Device

Question:

I have an application where I am looking at manipulating the location of a volume of fluid in a container under partial-pressure conditions. I would like to use surface tension to control the position of the liquid in the polypropylene container, which is similar to a PCR strip tube. Could the inside of the tube be modified selectively to impart different properties in separate areas – such as make the upper half hydrophobic, and the lower half hydrophobic?

Answer:

This is a tricky application: making the device hydrophobic in one area and hydrophilic in another. However, this can be easily accomplished by employing the use of a mask.  For example, to make the inside lower portion of the container hydrophilic (wettable), the entire device would first be treated with a hydrophilic process in a vacuum plasma system.  After the entire device (inside and out) was made hydrophilic, a mask would be placed inside the container to mask the portions that you would want to remain hydrophilic.  The devices would be treated again, this time with a hydrophobic process.  After the treatment is complete, the mask would be removed.  The end result is that the lower inside portion of the tube would be hydrophilic and the upper portion of the tube would be hydrophobic.

Q&A: Which material do you recommend for small construction equipment? Our cast nylon bearings are not lasting as long as we’d like.

This question was posed to us from a manufacturer of small excavators, the kind you often see in the consumer rental market.  Cast nylon is a good material for farming and construction, but with some drawbacks when it comes to moisture absorption and UV stability.  Depending on where you use them, nylon is good for cable sheaves, but for pivot points, we recommend these materials for top performance.

 

Q&A: Painting Plastic Parts

Question:

I am developing a few new plastic injection molded and thermo-formed parts that need to have capability of being painted. The preferred paint method is a wet paint process. What materials and/or processes would you recommend?

Answer:

Anyone who has tried painting plastic parts can attest to the difficulties associated with getting uniform paint coverage without fisheyes, beading, or delamination after drying. Painting (or printing on) plastics parts is easily achievable if the device(s) is treated with vacuum plasma. Our treatments are used to clean the parts of any organic contamination (such as mold-release, etc.) and to functionalize the surface of the polymer to enhance chemical bonding properties.  Whereas mechanical abrasion (sandpaper, grit blasting, etc.) may be used to roughen the surface of the part(s) to create mechanical bond-sites, plasma treatments are used to create chemical bond sites.  The result of the treatment is a uniform and wettable surface.  Although corona treatments are sometimes used to treat selective areas of the molded device prior to paining, only vacuum plasma offers the highest level of uniformity, repeatability, and long treatment lifetime.

Thanks for your question!  And feel free to contact us for any additional information.

TriSteel PE Metal-Backed Bearings

I recently had a call about our TriSteel line of bearings.  TriSteel PE bearings are specifically-designed for high-temperature and corrosive environments. Using a PEEK liner and stainless steel backing, this PE bearing can withstand temperatures up to 485°F in the most corrosive environments

Tri-Steel™ PE Series Bearings are ideal for application such as:

• Pump shaft bearings
• Valve stem bushings
• Oven bearings
• Tenter frame bushings
• Automotive applications

Want more details about TriSteel?  View our video.

 

Q&A: Plasma Treatments Versus Chemical Etch

Question:

Have you utilized plasma surface modification to etch or prepare fluoropolymer materials for rubber molding, etc.?

Answer:

Etching fluoropolymers via “wet” chemistry (Sodium Ammonia, Tetra-Etch, etc.) for the purpose of creating a bondable surface has been common for decades.  As with all types of surface preparation, there are good aspects as well as bad.  The benefit of wet-chemical etching is that you can treat large areas of material easily and it is very easy to visually confirm the degree of etching that has occurred due to the discoloration of the material caused by the treatment.

Treating fluoropolymer materials with vacuum plasma – for the same purpose – is achievable but there are limitations with respect to substrate size and configuration. 

Experience the TriStar Advantage to find a solution to your next bonding challenge.