Intech Power-Core Thermoplastics Engineering Blog

Power-Core Withstands Pulsed High Voltages

Posted by Alexander Bartosch on Feb 6, 2014 8:57:00 AM

The development of high-voltage pulsed power systems for both research and commercial applications has created a tricky design problem related to electrical insulation. Ceramics would be the traditional choice for bushings that insulate the metal electrodes in these systems, but ceramics are bulky and expensive to manufacture.

Intech Power-Core™ has emerged as compact, cost-effective alternative to ceramics. This gravity-cast nylon 12 polymer offers a combination of electrical and physical properties that make it uniquely suited to high-voltage pulsed power applications. These include:

When used in a recent experimental design for a pulsed electron accelerator, the Power-Core insulation was cast over the system’s stainless steel electrode to form an insulating bushing. Often these bushings will have to separate different insulating media—for example, vacuum on one side and transformer oil on another. So both low-outgassing and chemical resistance can come into play simultaneously.

One advantage of casting in this application has to do with the interface between the polymer insulation and steel electrode. Casting the polymer over a knurled surface on the electrode creates a seamless mechanical interface that helps produce a stable vacuum around the electrode and prevents any leak paths between the different insulating media.

To date, we’ve helped design and test insulation for pulsed electron sources up to 400 kV with pulse durations from 20 to 30 nanoseconds in vacuum, oil and gas environments. However, our experimental data suggests that Power-Core insulation bushings could withstand pulsed voltages to 1 MV. With more development work, Power-Core bushings could go even further—to voltages in the 5 to 10 MV range.

For more detailed information about our work insulating our pulsed power supplies:Contact an Engineer

Tags: cast nylon 12, electrically insulated, PA12GC, PA12C, PA12G, Cast Nylon, Nylon 6 vs Nylon12, Nylon Vs Delrin

Cast Nylons Replace Structural Aluminum and Gluing Delrin Parts

Posted by Alexander Bartosch on Jan 16, 2014 10:23:00 AM

P 500 System resized 600

Robotic arms for e-coat systems have traditionally been made from aluminum, whose strength-to-weight ratio made it seem like a good choice for this application. Aluminum, however, has a downside.

Its electrical conductivity allows the arm to attract paint particles whenever the painting system experiences voltage fluctuations. The resulting paint losses quickly build up—typically to more than $300,000 per paint line annually.

To eliminate those losses, a leading paint robot manufacturer and Intech teamed up to engineer an electrically-insulating plastic arm. That engineering proved to be easier said than done for three reasons.

For one, any plastic used in the arm had to offer high-end structural properties and be capable of insulating against 100 kV charges. For another, the part is big—too big to be cost-effectively injection molded in this application. Finally, the part has a challenging geometry.

When looking for a plastic with the right balance of properties, we quickly ruled out common reinforced plastics. Both fiberglass and carbon-fiber reinforced materials would easily have met the structural requirements, but both were too conductive.

Delrin, another possibility, was a suitable insulator, but it was only available in small chunks. The robot manufacturer had also ruled out the possibility of gluing delrin to form the arm.

Ultimately, Intech's knowhow and innovation allowed for a suitable arm to be cast from  Power-Core™ cast nylon 12 and for the last 3 generations of robots has proved to be the best choice for the job. Because Power-core™ met the structural and electrical requirements and could also be cost-effectively cast into large, complex shapes, the manufacturer has been able to successfully file and receive patent protection on 5 aspects of the arm that would not have been possible were it not for Intech engineers.

Plastic Requires Design Changes

Switching from aluminum to plastics did require a rethinking of the arm design to account for differences in tensile strength. With a 40,000 psi tensile strength, aluminum could carry the robot payloads with a 100 x 100 mm cross section. The cast nylon has a tensile strength of 8,800 psi, so the cross section had to be increased and a minimum wall thickness of 15 mm had to be maintained throughout the part.

The finished arm ended up at 120 x 30 x 18 cm at its widest point. It weighs 45 kg and is capable of carrying a 150 kg.

Result: because of the uniqueness of our engineering approach and our ability to push the boundaries of our material supply beyond where other material suppliers could Intech was proud to be rated a sole supplier to the automotive paint robot supplier.

For more details on the design and manufacturing challenges using polymers, please contact us using the form to your left.

 

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Tags: washdown application, cast nylon 12, electrically insulated, Intech Corporation, forming nylon, non-hygroscopic, PA12C, PA12G, Cast Nylon, Power-Core material, Nylon 6 vs Nylon12, Nylon engineering, fanuc p700, Fanuc P500, Fanuc p1000, Fanuc P-20ia

Large Underwater Gear Highlights Nylon's Moisture Resistance

Posted by Alexander Bartosch on Mar 22, 2013 2:00:00 PM

Wear and moisture resistance are two recurring themes in the engineering problems solved by Intech Power-Core™. Oftentimes, these problems involve small components, such as gears, cam followers or rollers. Yet Power-Core’s wear and moisture resistance properties can just as easily apply to large parts. Consider, for example, the large geared ring produced in our material for underwater use in a nuclear reactor pool. Measuring 2,200 mm across and 80 mm thick, this geared ring weighs in at 100 kg. It withstands a load of 150 kN at 6 rpm.

Intech Underwater GearLarge Part Size, No Problem. The sheer size of the part stands stands out, but our gravity casting process actually allows us to scale up the size of our components easily. Gravity casting results in low internal stresses, even when the parts have metal structural inserts. So going “big” is not really an issue for Power-Core.

Physical Property Advantage. What was even more important in this underwater application were the physical properties of the polymer. The geared obviously needed to be produced from a material that resists continuous exposure to liquids and corrosion. Various metals fell short due to their poor corrosion performance compared to polymers such as Power-Core.

Many other polymers, however, do not tolerate long-term exposure to moisture. Power-Core does. Its ultra-low moisture uptake allows it to remain dimensionally stable even when submerged in water for long periods of time. In this nuclear application, Power-Core’s radiation resistance also weighed in its favor over other polymers. And its wear properties allow it to avoid the fretting that can occur when component surfaces rub together in the presence of water.

In this application like in most applications engineers had a selection of materials to choose from. The common conception of most engineers when it comes to wet environments is that a polyester material such as ERTALYTE or an Acetal (POM) would be the best choices. In many cases these engineers would be on the right track - both materials are excellent in many applications - however for underwater gears specifically these materials wouldn’t be able to accomplish the task. For one the size of the gear leaves only very few material options, second when using Ertalyte or Acetals you have to be very careful what type of environment you expose them to – chlorine – like that found in drinking water could destroy the polyester compound over time and Acetals don’t react well to acids such as those used in wash downs, and booth are susceptible to weakening caused by extended UV exposure. 

Most Nylons, on the other hand, perform poorly when submerged in water, so naturally engineers tend to steer away from the entire nylon family when designing underwater motion systems. Powercore has a unique place in the family of Polyamides in that its moisture absorption, even when fully submerged, is negligible.  Our site contains numerous studies and documentation showing the effects of moisture absorption on nylon and nylon 6 and nylon 12’s dimensional change when submerged. When designing your next motion system of marine or underwater use please remember to consider the environment and look of a suitable polymer for your application.  

Learn more about Power-Core’s moisture resistance

Tags: gear design, Nylon 6 vs Nylon12, ultraviolet resistance, Nylon Vs Delrin, underwater gear, ertalyte

Powercore Offers Unique Balance Of Properties

Posted by Alexander Bartosch on Jan 7, 2013 2:40:00 PM

From cheap plastics to the world’s most expensive composites, many types of polymers have been machined, molded or cast into power transmission components.  We’ve focused our development efforts on the use of a proprietary, gravity cast Polymer called Power-Core®.

Thanks to the interplay of its intrinsic physical properties and low-stress casting process, Powercore represents the ideal material choice for power transmission applications. Here’s why:

Remains Stable and Dampens Vibrations.  Power-Core has an unparalleled ability to maintain its physical properties under a broad range of operating conditions. This stability allows us to make highly accurate predictions of the material’s behavior and lifecycle even when the application has variations in moisture, temperature and chemical exposure.

In particular, Power-Core’s stability in persistent high-humidity or total-immersion conditions makes it uniquely well-suited to power transmission applications and sets it apart from other polymers. Unlike Power-Core, most high-performance polymers absorb moisture. As they do, they lose their tensile strength and swell. Power transmission components made from moisture absorbing, or “hygroscopic,” polymers can end up too weak to carry the loads they were designed for and too swollen to work with mating components.

For an idea of how severe the moisture problem can be, consider the difference between Power-Core and the much more common nylon 6. While both are nominally “polyamides,” powercore outperforms other nylon 6 and nylon 12's dramatically as moisture content increases.

Power-Core also exhibits excellent vibration damping characteristics, which contributes to its ability to reduce noise and absorb the shock loads commonly seen by power transmission components.

 

Eliminates Internal Stresses. Power-Core isn’t just a material but also a manufacturing approach that encompasses gravity casting and precision machining. We gravity cast the Power-core over metal hubs or thermally install it over rollers bearings to produce the beginnings of a cam follower, roller or gear. We then precision machine these blanks to form a finished component.

With engineering polymer applications, the interplay between manufacturing methods and the inherent polymer properties matters as much as the choice of the polymer itself.

Power-Core is no exception. In this case, the gravity casting contributes to low internal stress state that gives the polymer an inherently uniform crystalline structure. As a result, Power-Core components have a consistent machining resistance that improves overall machining precision–and allows the material to retain that precision over time. And under external load, the dense crystalline structure helps thwart the stress-induced cracks or swelling that sometimes force molded plastic components to fail prematurely.

 Contact an Engineer

Tags: Power-Core, plastic rollers, Self-lubricating, plastic gears, PA12G, Power-Core material, Nylon 6 vs Nylon12