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Dave Biering

Dave Biering


Recent posts by Dave Biering

3 min read

Thermoset vs Thermoplastic Materials: Bearings and Other Applications

By Dave Biering on June 30, 2020

Polyethylene Plastic Molecule - A Thermoplastic

Thermoset and Thermoplastic materials have similar names, but they have very different properties. In this post, we provide an overview of what makes these two categories different and why these differences matter for different applications.

What is the difference between thermoset and thermoplastic bearings?

The primary difference between these two bearing materials is that thermoset plastics retain their solid state indefinitely, and include just a few trade names. Thermoplastic bearing materials can be heated and reheated many times to form new shapes. Thermoplastics are the largest groups of plastics and include PVC, PEEK, polyethylene, nylon, acetal, and acrylic. Thermoplastics are particularly good for machining into custom fabricated components (explore The Essential Guide To Machining Plastics).

We explore the key differences in more detail below.

Thermoset v Thermoplastic | Remolding Properties

Thermoset: Synthetic materials that are not able to be reheated or remolded.

Thermoplastic: This is the largest group of plastics (polymers) and the group is also known as “thermosoftening” plastics given their ability to melt at high temperatures.

Thermoset v Thermoplastic | Heat Resistance

Thermoset: As it cures, the material increases in its ability to resist heat and succeed in high-heat applications (approaching 400°F or more).

Thermoplastic: Readily liquefies upon reaching melting points. The material also hardens and strengthens after cooling.

Thermoset v Thermoplastic | Chemical Characteristics

Thermoset: This category often incorporates fillers. When heated, the material’s molecules begin to crosslink, which helps to determine final strength and other characteristics. However, some of these materials also have a tendency to shatter under certain circumstances.

Thermoplastic: Provides good chemical resistance (will re-form without any chemical changes), but keep in mind that material properties will deteriorate if over-processed. Thermoplastics offer good impact-resistance as compared to thermoset plastics, and are also easily recycled.

Thermoset v Thermoplastic | Machining

Thermoset: Some of these materials are brittle and chip easily, making them hard to machine into custom parts. Other thermosets with fillers and fibers are easier to machine and produce very clean finished parts.

Thermoplastic: Are stronger and well-suited to machining techniques – as long as proper heat controls are followed. Get the Machining Slide Deck to review heating and cooling guidelines.

Examples of Thermoplastics and Thermosetting Plastics

Thermoset: Common formulas include Phenolic, Epoxy, PTFE, Ultracomp, CJ, Micartas, Melamine and some grades of imides.

Thermoplastic: This group includes both trade and generic names, representing Acetal, ABS, nylon, polyethelene, PET and PBT.

The different properties of thermoset plastics and thermoplastics have vital implications for your design, whether used as a bearing or in a different application. But this basic material difference is only one of many factors that need to be carefully considered. We always recommend approaching materials selection as a strategic engineering decision, not a box to be checked.

You can connect with our polymer experts here to discuss the right material for your design.

Custom Plastic Fabrication: Get the Guide!

Topics: Thermoplastic bearings
4 min read

Consultative Engineering for Optimal Material Selection

By Dave Biering on June 16, 2020

TriStar Engineering Consultants

In this blog post, we highlight TriStar’s application-focused approach to finding the right bearing materials for our client’s needs.

For a broader look at bearings, bearings failure, and bearings materials, take a look at our Bearings 101 page here. Or keep reading to learn why choosing the right bearing for an application can be a real engineering challenge. 

Careful Component Selection Can Solve Engineering Problems

For fundamental mechanical components like bearings, bushings, and wear pads, material selection matters. Options range from traditional greased metals to advanced, self-lubricating polymers.

Even within a broad material type like polymers, different materials (and material specifications) have very different performance characteristics. These attributes have important implications for the life and effectiveness of the bearing itself. But they can also have much broader effects on the performance of the equipment where they are employed. Excessive vibration, heat, or electrical conductivity can create real problems for the reliability of an entire complex machine.

All too often, however, we see bearings treated like a commodity-part. In this situation, material selection is often based on a broad, pre-existing preference for one material over another. In our experience, this approach comes with real risks. Employing an improper bearing in a design heightens the risk of acute failure. But simply using a sub-optimal bearing may result in chronic problems that affect reliability, maintenance costs, and performance for years without going recognized.

To be clear, there are certainly low-performance, cost-sensitive applications where the priority is simply to find the cheapest possible material. But a wide variety of applications call for materials that are carefully selected to reflect specific operational concerns.

There is no “perfect” bearing material: there’s only the right bearing for the task (and budget) at hand. This reality calls for real engineering expertise to identify the demands of a particular application and match the right material to the application.

TriStar’s Approach: Consultative Engineering to Find the Right Bearing for Every Application

TriStar works with our clients to understand precisely how and where a bearing is going to be used. Our engineers and sales representatives take time to study the applications where our bearings will be expected to perform. In some cases, TriStar team members will spend weeks on-site to learn more about the operating conditions where a bearing or other component will be expected to thrive.

That’s the only way to select materials that are not only fit-for-purpose but capable of solving problems our clients didn’t know they had. For some great examples of this approach in action, see our case study library here.

In some cases, a very subtle problem can result in serious implications for a broader design. Even utilizing a bearing that is over-specified for an application can result in a problem: the bearing may not deform to the intended geometry under operating stress. Within the same factory, and even within the same machine, different bearings may be subjected to very different environmental stresses.

The right materials selection offers a viable solution for many common engineering problems that bearings are called to solve. But to find the right solution, real expertise helps match the chosen material and shape to the precise operating conditions it will be confronting.

The operating concerns listed below illustrate how careful bearing selection is simply good business. A bearing that is marginally cheaper may end up costing far more if it requires frequent replacement or constant re-lubrication.

Example Operating Concerns for Bushing, Bearings, and Wear Pads

  • Corrosion: Applications everywhere from manufacturing to underwater introduce corrosion concerns. Even the cleaning chemicals used in food processing plants will destroy the wrong material.
  • Dusty and Dirty Environments: Particular matter risks being attracted to traditional grease lubricants almost like a magnet. Once inside the bearing, abrasive contaminants will negatively affect performance and service life.
  • Lubrication: inadequate lubrication is the number one cause of bearing failure. The viability and cost-effectiveness of regular lubrication need to be carefully considered when selecting a bearing. Self-lubricating characteristics, for example, are a must in hard-to-reach locations.
  • Weight: a lighter bearing capable of handling the same load can offer vital performance advantages for the entire design. For instance, plastic polymer bearings are up to 5x lighter than steel.
  • Noise/Vibration: high-levels of bearing vibration is a common operating condition, yet it’s still one of the most common causes of failure for metal bearings. Reducing metal-on-metal contact can help dramatically reduce vibration and noise. This reduction is not only good for the life of bearings but the entire mechanical design.
  • Temperature: it’s best to avoid broad generalizations about material temperature tolerances. While every polymer has some theoretical melting point, the right plastics can succeed at relatively high operating temperatures. However, material deformation needs to be carefully considered, as a material can begin losing crucial structural integrity long before its actual melting point.

These concerns are just a few examples, and every different material and application will vary across each of these categories.

At TriStar, we take pride not only in our advanced, high-performance materials but our years of hard-won knowledge on how bearings can be best applied in a huge range of applications.

Our experience allows us to offer our clients a true end-to-end partnership, from solution engineering to final production to support.

Tstar-Advantage-2020

From choosing the right polymer to conducting surface treatments to ensure the right adhesion and bonding properties, we treat bearing selection as a real engineering problem that is best addressed with genuine expertise. Our enhanced materials division even adapts our materials to specialized applications such as filtering membranes.

We work closely with clients to understand both functional and financial needs, identifying the material that will ultimately provide the best possible ROI.

For a detailed look at some of our materials and their specific properties, we recommend our materials database here. If you’d like to reach out to our team to discuss finding the right solution for your application, just click the button below. 

DO YOU HAVE A QUESTION FOR OUR EXPERTS?

Bearing Selection: Get the Ultimate Plastic Bearing Design

2 min read

TriStar’s Engineering Partnership with Clients of All Sizes

By Dave Biering on June 9, 2020

TriStar’s Engineering Partnership with Clients of All Sizes

The market for bearings and similar components like bushing and shock absorbers is multi-faceted.

On one hand, a variety of non-specialized, high-volume applications demand extremely cheap solutions. These components can be as simple as furniture drawers slides. In this context, bearings are often treated like a commodity: cheap, plentiful, and interchangeable.

For manufacturers that focus on this bulk production bearings market, volume matters. For the largest bearings manufacturers, the ideal client will purchase huge quantities, even millions, of bearings per year. But while this style of production makes sense in support of some applications, we find that it hasn’t always served TriStar’s customers well.

Smaller manufacturers and high-tech firms with specialized, high-performance bearings needs often don’t receive adequate attention from bulk manufacturers chasing accounts at some of the biggest companies on earth. Yet smaller companies, often in the sub-contractor role, are often doing the heavy-lifting when it comes to design and component selection.

Bearings are expected to thrive in a huge variety of specialized conditions that are anything but interchangeable. And they have vital implications for a design’s performance, reliability, service life, and maintenance needs. Businesses of different sizes and industries feature crucial applications where bearings aren’t a commodity, but a vital, precisely engineered component.

TriStar takes pride in bringing our full engineering expertise to bear on each and every client account. 

A Prototype to Production Partnership for Customers of All Sizes

TriStar retains the ability to engage with each client’s application as a real engineering challenge. We’re not just selling bearings, but using bearings to solve problems our clients didn’t know they had. We work directly with client engineers to understand specifically how our products will be used, where they’ll be expected to thrive, and how they can help promote superior performance and reliability. From extensive consulting on material selection to 24/7 support, we center our service model on customer success from prototyping to production.

Our business is built on finding the right bearing for every possible client application, and you’ll never struggle with a service issue or order too small to get our attention. From working with niche agriculture equipment manufacturers to developing specialized membranes for medical applications, we’re always working to find new problems to solve with our materials. Which is why you’ll find our products everywhere from underwater to high-altitude. We’re still finding exciting new applications for our low-friction, self-lubricating materials every day.

If you’re interested in learning more about taking advantage of our advanced, customizable materials (and working with a bearing provider that always picks up the phone) you can get in touch with our experts using the button below.

CONTACT THE TRISTAR TEAM

Topics: TriStar Engineering bearing engineering
4 min read

Why Material Selection Matters for Bearings and Beyond

By Dave Biering on June 2, 2020

Why Material Selection Matters for Bearings and Beyond

Bearings and similar components often have serious implications for the performance and reliability of the design where they are employed. But in many cases, bearing selection is conducted based only on a vague, abstract preference for one material over the other.

In TriStar’s experience working with applications ranging from advanced military to food processing, taking the time to carefully match component materials to specific application demands can pay real dividends.

In this blog post, we take a look at why careful materials selection can offer serious value across a wide variety of use cases. If you’re looking for an overview of bearings, what they’re made of, and why they matter, please see our Bearings 101 page here.

Bearing Materials Selection: An Engineering Priority

Generalities about bearings materials can be limiting (and even dangerous). Sometimes, an organization will stick with a particular bearing type because it has “always worked for them.” But new applications put new environmental stresses on bearings.

Anything ranging from a dusty desert (where particulates can rapidly stick to lubricated metal bearings) to a corrosive cleaning chemical (like those used in food processing plants) can cause an otherwise reliable material to fail.

Meanwhile, misconceptions about material limitations can prevent an organization from taking advantage of the best materials available. Sometimes, for example, we run into a vague belief that plastics can only be used in low-load, load temperature applications. But this couldn’t be further from the truth: as you can see in our materials database, polymers can thrive when faced with a wide variety of loads, temperatures, and environmental risks. With this knowledge in hand, engineers can take advantage of self-lubricating polymers in a huge range of applications.

Priorities for Effective Bearing Selection

  • Careful material selection: performance characteristics can vary widely within a broad material category like polymers. It’s important to resist broad generalizations and look at specific data points on material properties. In many cases, materials can even be customized specifically to your application. Materials like TriSteel take advantage of the desired properties of multiple materials at once, another great reason to resist generalization about materials.
  • Application-specific engineering: there is no “best” bearing material. Rather than relying on a wholesale preference for one material over the other, it’s important to consider the performance requirements and operating environments of each application. Different components within the same design can even call for very different materials. TriStar works hand-in-hand with client engineers to find the best solution for each application.
  • Consideration of full TCO: finding the right bearing is about more than just preventing catastrophic failures. It’s important to consider how material selection will affect broader operational concerns like maintenance schedules. Or to consider the costs of dealing with massive amounts of grease often required by traditional metal bearings. With one client, for instance, we were able to save over $300,000 per year in downtime losses and reduced maintenance expenses, just by changing a simple material.

Materials Matter: Advantages of TriStar’s Advanced Materials for Bearings

  • Self-lubricating design means lower lubrication costs, less maintenance, and cleaner operation.
  • Vibration and impact resistance is vital for service life. Transferring less vibration throughout the machine can be beneficial for the service life of other components as well, while also reducing noise from metal on metal contact.
  • Superior strength and wear resistance. They also wear and age more predictably and gradually, reducing the risk of a sudden, catastrophic failure that can damage far more than the bearing.
  • Low friction coefficients help improve performance and increase component life.
  • Corrosion resistance maximizes service life while enabling production in conditions that are acidic, wet, or full of abrasive particulate matter.
  • Polymers offer minimal moisture absorption. This trait helps reduce bearing expansion, even in wet environments.
  • These materials are capable of handling high loads yet are lightweight, with a compact strength-to-weight ratio for good durability and flexible design options
  • Our materials are approved for regulation-intensive applications like food processing and pharmaceuticals, giving manufacturers a path to speedy, simplified regulatory compliance.

Using The Right Materials to Build the Best Product

The advantages of effective bearing material selection can go beyond obvious failure modes of the bearing itself. These critical components can play a huge role in how much heat, vibration, and even electricity are transferred throughout the broader design where they are incorporated.

Within a complex machine, issues like excessive vibration can have detrimental effects on the reliability of a design even when the bearing is still operating properly. This can result in sub-optimal performance (or excessive failure) that is very hard to pin down. TriStar often finds bearing replacement options that solve chronic reliability issues within a mechanical design.

If you’re interested in chatting with the TriStar team about finding the perfect material to tackle your engineering challenge (or just building a longer-lasting product) you can reach out using the button below.

DO YOU HAVE A QUESTION FOR OUR EXPERTS?

Bearings 101: What They Are, How They Fail, and Why They Matter

Topics: Material Selection featured
2 min read

How Much Grease Do Bronze Bushings Really Need?

By Dave Biering on May 19, 2020

Bronze Bushing Grease Example

For traditional bushing materials like bronze, lubrication is simply a requirement of the material. Lubrication requirements mean not only more maintenance but more muck. While precise needs will vary by application, it’s important to understand that we’re not talking about “little drops” of grease. In this post, we wanted to provide a concrete example of just how much grease a bronze bushing can require when employed in a high-performance application.

test

How much grease do bronze bushings need?

Unlike self-lubricating polymer options, bronze bushings require abundant amounts of lubricating grease to keep industrial equipment running. But have you ever wondered just how much grease they need? We did, so we asked a client to show us the sludge that was left behind after a routine cleaning. Since a picture is worth a thousand words, today we want to share this incredible image. Even our experienced engineers were amazed at the amount of greasy sludge that was removed!

An entire barrel (nearly 42 gallons/159 liters) of grease. Nearly 400 pounds worth!

That’s the amount of excess lubricant our partner removed from just one machine during routine maintenance of their bronze bushings. In this case, our client had two full-time workers assigned to degreasing their manufacturing and packaging lines. Because bearings that are left with excess grease are prone to seizure which can lead to a halt in production.

Do bronze bushings need grease? Always?

Bronze bearings need some sort of lubricant to reduce friction in virtually every application. While oil is sometimes used, most applications call for grease. Either way, this substance not only requires regular maintenance and cleaning but can be a magnet for contaminants like dust and particulate matter, negatively affecting machine lifespan. While some bronze bearings are impregnated with oil to generate some “self-lubricating” properties, these designs don’t change the need for cleaning. With these drawbacks in mind, more and more businesses are using alternative materials.

What to use instead of bronze bearings with grease?

Advanced materials like Rulon and other polymers and composites offer a powerful alternative bronze bushings/bearings. The right material choice will depend on your application, but these materials have self-lubricating properties that prevent the need for traditional lubricants like grease (you can read about how self-lubricating bearings work here).

Once our client replaced the high-maintenance bronze with no-maintenance plastic bearings, they realized immediate production gains. They were able to reassign the maintenance crew to other areas of the line, and experienced far fewer work stoppages. Ultimately, our partner estimates they will recover over 2,000 hours a year in lost labor. And their plant will provide a greener footprint.

Is it any surprise that they decided to say goodbye to bronze bushings forever and switch to greaseless plastic composites? Want to learn how you can end bearing lubrication? And save a barrel in maintenance costs? Ask the plastic composite bearing experts ― we can help!

To learn more about the different kinds of bearings, bearing failure, and more check out our Bearings 101 feature article.

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Topics: bronze bushings
2 min read

What is the shelf life of PTFE and Rulon® Materials?

By Dave Biering on May 8, 2020

WWhat is the shelf life of PTFE and Rulon Materials?

This was an excellent question from a customer wondering how long they could store non-etched Rulon materials.

Rulon and PTFE Shelf Life: Key Factors

When handled and stored properly, Rulon has an unlimited shelf life. But when the material is etched, the answer is not quite as simple.

When stored in normal warehouse conditions, all PTFE and Rulon materials have an unlimited shelf life. In fact, a common industry joke is that, at 85 years and counting, PTFE has “not been around long enough” to determine how long it will last! 

But etched-PTFE and Rulon are a different story. The etching process involves reducing the surface lubricity of the polymer in order to bond it to another material. For best results, etched materials must be stored in a black, UV-blocking bag or else the etch will degrade at about six months. The UV bag also protects Rulon materials from damaging ozone and heat exposure, which is common to a warehouse environment. With this protection, etched materials can last a year.

Rulon/Ptfe Degradation: How Can I Tell If My Material Is Degrading?

To determine if your PTFE/Rulon material has degraded, we recommend two methods:

  • Look at the color ― if it has faded to a light brown/tan or has a marbled look, it is no longer a viable manufacturing material.
  • Try a droplet test – add a drop of water and if it rolls around in a ball the material is now hydrophobic and the etch has been lost. If it disperses, than the etch is still hydrophilic and the material is good to go!

Still not sure about the shelf-life of your stored Rulon materials? Need a second opinion? Just connect with the official Rulon experts!

Rulon and PTFE have key advantages over traditional materials in a broad array of applications like bearings. You can learn about these advantages (like self-lubrication and friction coefficients) on our Bearings 101 page.

CONTACT THE TRISTAR TEAM

Topics: Rulon Materials
2 min read

How it Works: Conveyor Roller Bearing

By Dave Biering on April 7, 2020

How it Works: Plastic Conveyor Roller Bearing

From food packaging and processing to general material handling, the conveyor roller bearing is an underrated superstar of the manufacturing floor. You might even consider it the heart of the whole conveyor assembly. But how does this essential bearing assembly work?

What is a Conveyor Roller Bearing?

A conveyor roller bearing is a specialized bearing which presses into the ends of a conveyor belt roller, allowing the rollers to rotate smoothly. Typically, this conveying belt moves materials along a manufacturing or food processing production line. In this context, smooth operation allows for optimal performance and component lifespan.

As the name suggests, conveyor roller bearings have a cylindrical shape and are designed to carry heavy loads, since the weight is evenly distributed over a large surface area. Also referred to as cylinder rollers, this bearing type can easily handle radial (but not thrust) loads. For a good fit, we always recommend choosing a conveyor roller bearing with the largest diameter at the shortest length in order to minimize roller deflection. For tight spots, needle bearings (a close cousin to roller bearings), offer a very small diameter design envelope.

Steel Conveyor Bearings vs Plastic Conveyor Bearings

Plastic roller bearings offer significant advantages over metal; they are lightweight, require no manual lubrication (for a look at just how much lubrication can build up in a traditional metal bearing, check out our post here) and do not rust or corrode after sanitation baths.

And since they require less energy to turn, they can help you reduce energy costs. Roller bearings excel in virtually any manufacturing environment from cold rooms (explore how Ultracomp plastic bearings increased production for an ice cream manufacturer), to tough, heavy-vibration manufacturing areas.

Ultracomp bearings are available in tube and sheet stock, or can be fabricated to your exact specifications (fill out an engineering worksheet for a custom quote).

See how plastic conveyor roller bearings work in our video:

This crucial bearing application is one of many where material selection has serious implications for performance, lifespan, maintenance needs, and more. For a broader look at bearings and the materials used to make them, we recommend our Bearings 101 page here.

Need more info? Connect with the Conveyor Roller Bearing experts!

Topics: conveyor roller bearing
1 min read

Rulon 641: Performance from Food Processing to Medical Equipment Manufacturing

By Dave Biering on July 16, 2019

Rulon 641: Performance from Food Processing to Medical Equipment Manufacturing

The food and medical manufacturing industries share many commonalities; most notably, they operate in environments with strict regulations for quality, safety and sanitation.  Processing equipment must be of the highest quality and offer contamination resistance.  Rulon® 641 is the only FDA-cleared material for use in food processing that also has USP Class VI approval for medical applications.

Two demanding manufacturing environments, one common material ― Rulon 641.  See our Rulon Comparison Chart to explore the advantages.

Temperature tolerance for food processing

A major food processor approached us seeking a replacement for their virgin-PTFE seals located on the miniature cryogenic valves of the fast-freeze systems. The equipment is used to flash-freeze fruits and other foodstuffs. The PTFE seals were failing from exposure to the cryogenic temperatures and required frequent and expensive change out. Rulon 641 offered our partner a material with superior temperature stability and a longer lifespan for significant savings. Rulon 641 is non-abrasive for use against the systems’ stainless mating hardware, and has maintained good sealability under difficult conditions. 

Superior sterilization for medical manufacturing

We’ve also partnered with the manufacturers of surgical laser devices to replace failing PTFE valves seats with Rulon 641.  Rulon excels in the rotary and oscillating movements required of this application and has a very low coefficient of friction and a superior wear factor.   The material can be lapped using standard procedures to produce extremely good surface finishes in precision valve seats.  And the material’s white, stain-resistant color indicates a sanitary compound for medical environments.  Rulon 641 has USP Class VI approval, and easily tolerates all standard CIP procedures required of both the food and medical industries.

Is Rulon 641 the right material for your application?  Contact our Engineering Experts for a consultation. Or read our free Rulon White Paper to learn about the advantages of Rulon’s processing controls.

Rulon - Quality Assurance Begins With Precision Processing

Topics: Food Rulon Medical
2 min read

National Robotics Week is Here – Explore the Plastic Bearings Factor

By Dave Biering on April 9, 2019

National Robotics Week is Here – Learn How Plastic Bearings Fit In

This year National Robotics Week falls on April 6-14 and there are a wide range of activities and events intended to inspire students in STEM-related fields and to educate audiences of all ages about the cultural and economic impact of robotics – today and into the future.

One thing you may not be aware of is the importance of plastic bearings to the success of many innovative robotic applications. From precision surgical robot arms to pipeline oil-leak sniffing subseas, plastic bearings are a key component driving innovation in this field.

Plastic Bearings Replace Rolling Elements and the Benefits are Clear

Plastic bearings are greaseless, durable and nearly maintenance-free. Compared to metal bearings they can be easily custom fabricated to precise specifications at a significantly lower cost than metal bearings. It’s no wonder that the robotics industry has been so eager to embrace this technology.

Plastic Bearings in Robotics – Some Specific Examples

There are many uses for plastic bearings in robotic applications; here are just a few interesting examples:

  • Swimming Pool Cleaning Robots – Swimming pools are harsh environments and pool chemicals, algae, and UV exposure can quickly weaken metal bearings. Rulon W2 flanged bearings in the wheels of robotic pool vacuums offer clear benefits over metal. The tribological properties of Rulon W2 actually improve when wet and they do not absorb water at all, which keeps them dimensionally stable.
  • Picking and Packing Robots on Food Assembly Lines – TriStar’s FCJ composite bearings excel in the pivot points of robotic arms. They are increasingly used to replace bronze bearings, which corrode and seize in the sub-zero and high-moisture environments encountered in food processing. FCJ bearings offer the same strength-to-weight ratio as powdered steel, but in a lighter, flexible design that can help boost production.
  • Surgical Spherical Robots – Surgical spherical robots require bearing materials that are rigid enough to exert a good level of force, yet also remain flexible enough to deliver precise control. In addition, any components specified must be FDA compatible to meet clean room standards. Rulon 641 meets these requirements. They are self-lubricating to eliminate the risk of oil contamination and give surgical arms excellent rotary and oscillating movements for incredibly precise cutting and placement.
  • Military Remote Tracked Vehicles – Remote tracked vehicles play a key role in protecting soldiers by allowing them to investigate and detonate IEDs from a safe distance. Our CJ Bearings proved to be more reliable than bronze bushings in early tracked vehicle designs. More recently, our Ultracomp bearings have been specified for sophisticated lifting arms and rotating grips due to their tight tolerances and ability to function at the lowest possible friction levels.

These are just a few of the many robotics applications for plastic bearings. Why not grab a copy of our free Robotics White Paper for a deep dive on the subject with many additional examples?

For more on National Robotics Week check out the official website or explore the ongoing conversation using the #RoboWeek hashtag on Twitter. If you have a robotics application you’d like us to take a look at, don’t hesitate to reach out to our engineering team!

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Topics: Robotics
2 min read

Q&A – Do You Have Any Tips for Annealing Cast Acrylic?

By Dave Biering on August 15, 2018

Do You Have Any Tips for Annealing Cast Acrylic?

We recently had a customer ask us for some tips on annealing cast acrylic. There are definitely some potential pitfalls when working with acrylic in both sheet and finished part form, but following the guidelines outlined below should yield excellent results.

First… What is Annealing?

Annealing is the process of relieving stresses in molded or formed plastics by heating to a predetermined temperature, maintaining this temperature for a set period, and slowly cooling the parts. Sometimes, formed parts are placed in jigs to prevent distortion as internal stresses are relieved during annealing.

Tips for Annealing Acrylic Sheet

To anneal cast acrylic sheet, heat it to 180°F (80°C), just below the deflection temperature, and cool slowly. Heat one hour per millimeter of thickness – for thin sheet, at least two hours total.

Cooling times are generally shorter than heating times – see the chart below. For sheet thickness above 8mm, cooling time in hours should equal thickness in millimeters divided by four. Cool slowly to avoid thermal stresses; the thicker the part, the slower the cooling rate.

Wait until oven temperature falls below 140°F (60°C) before removing items. Removing a part too soon can offset annealing’s positive effects.

Tips for Annealing Parts Made from Acrylic Sheet

While annealing acrylic sheet parts, support them to avoid stress. For example, a part’s raised center section will need independent support – it can’t be supported from the ends. Lack of support may inhibit relaxation or cause warpage. Be sure parts are clean and dry before annealing. Remove paper masking to avoid baking it onto the material. Remove any spray masking, protective tape, or similar material. Plastic masking may remain in place.

For post machined acrylic parts - Heat to 180°F over a 2 hour period, hold for 30 minutes per each ¼” of thickness, cool at 50°F per hour until room temperature. This must be done in a nitrogen oven.

If the only fabrication you have done is surface machining and you do not need to anneal cemented joints, heating time can be reduced. This reflects the fact that machining forms stresses only at and slightly below the surface – the entire sheet thickness needn’t be annealed. Heat at least two hours; cool the same amount of time. If holes have been drilled entirely through the sheet, position the part so heated air flows through the holes.

What are your Material Fabrication, Machining, and Processing Challenges?

This post focused on a specific process for one material, but any product you work with is going to bring it's own challenges – and have a corresponding “cheat sheet’ that experienced engineers pull out to make it all go smoothly. Our engineering team has decades of combined experience and can provide this information. In fact, we’ve just launched an entirely new Enhanced Materials Division (EMD) to help people with just this sort of thing! We have a full suite of services and products to help you find the best, most cost-effective way forward.

Custom Plastic Fabrication: Get the Guide!

Topics: Q&A
2 min read

What are ‘Fluoropolymers’ and What are their Common Attributes

By Dave Biering on June 12, 2018

The first fluoropolymer was polytetrafluoroethylene, better known by its abbreviation, PTFE

First, a definition: fluoropolymers are a family of plastic resins which are based on fluorine/carbon bonding. The family of products is varied through a manipulation of that bond by adding or subtracting fluorine through other bonds such as chlorine, ethylenes and other chemical agents.

The first fluoropolymer was polytetrafluoroethylene, better known by its abbreviation, PTFE, and by its brand name “Teflon.” It was discovered accidentally by a scientist at DuPont in 1938.

Fluoropolymers are strong, lightweight, and durable. They can also resist heat, water, salt and chemicals and do very well in demanding environments.

PTFE (which is the only fluoropolymer which does not melt) is processed through press and sinter techniques while the other common fluoropolymers (FEP, PVDF, PCTFE, PFA and a few others) are melt-processible. This means they can be compression and injection molded as well.

Fluoropolymers come in several forms:

  • Granulate
  • Melt-processable
  • Films
  • Paste
  • Dispersions

As with anything, there are both positives and negatives to fluoropolymers:

Positive attributes:

  • Chemically inert (with few exceptions)
  • Broad temperature ranges
  • Low friction
  • Excellent dielectric properties
  • Good thermal insulation
  • Good wear properties (with certain additives)

And on the negative side:

  • Cost (they can be expensive)
  • Processability – grades establish which method is used
  • Cold flow with some grades
  • High expansion rates

Typical applications for fluoropolymers are in electrical and electronics, pipe and chemical processing.

Fluoropolymers are an extremely diverse family of plastics and this blog post really just scratches the surface. For a deeper dive into the topic, watch our video (below).

If you think a fluoropolymer is the right fit for your application, we can help you choose the right one.

 

 

Bearing Selection: Get the Ultimate Plastic Bearing Design

Topics: Fluoropolymers
2 min read

Slide Bearings for Pipelines and Bridges

By Dave Biering on May 29, 2018

Slide Bearings for Pipelines and Bridges

Slide plate bearings provide support and a low coefficient of friction while allowing an object to move (or slide) freely along a supporting surface. They consist of an upper and lower component and can be used in both guided and free-moving applications.

Applications for Slide Bearings

Slide bearings are engineered to fit anywhere there is the potential or threat of movement, such as bridges, building footplates, tank farms and petrochemical applications. For example, an oil pipeline — at roughly 800 miles long — could be subjected to a mile of liquid flow movement (hysteresis) within the structure. Such an application requires a bearing designed to resist corrosion, temperature extremes and rugged terrain.

TriStar is your Best Source for Slide Bearings

Here are several materials that we often recommend for slide bearings.

  • Ultracomp, one of our tier one products, is an ideal material for slide bearings. A composite wound bearing, Ultracomp is engineered especially for low speed, high load applications and has a very high corrosion resistance. One interesting application is for the slide bearings used to deploy a retractable swimming pool in an ultra-luxury yacht (cost: $100 million). Ultracomp also excels in railroad and agricultural applications.
  • Rulon materials are ideal for slide bearings and various variants can be chosen based on the specifics of your application. For example, FDA compliant Rulon 1337 has been specified for use in the slide bearings used inside food processing vacuum chambers. Rulon 1337 is ideal for this application due to it’s high load capacity and durability. It’s low abrasion characteristics make it safe to use against softer mating surfaces and high chemical resistance means it can withstand the chemical washdown procedures required for food industry applications.
  • Fluorogold slide bearings easily tolerate thermal expansion and liquid flow movement and hold up well in cold temperatures. They also absorb vibration and impact, making them a preferred bearing material for use in earthquake zones. They also offer outstanding chemical and electrical properties and have proven resistant to radiation, where neither the bearing strength nor the epoxy bond were impacted by doses as high as 10^6 rads.

…And There’s More!

There are many additional materials available for slide bearings and our engineering team has years of experience matching the material to the application. Why not share the details of your application and let us provide our recommendations?

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Topics: slide bearings