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.

 

Contact an Engineer

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

Introducing Intech Non-lubricated Linear Slides

Posted by Alexander Bartosch on Feb 2, 2012 1:09:00 PM

Below is the first look at our newest product: A non-lubricated linear Slide.

Tags: cam follower, cam followers, maintenance, Power-Core, precision machined, minimum resistance, iCam Followers, lubrication-free, reduce noise, reduce shock, reduce vibration, plastic rollers, Self-lubricating, wear life, composite material, cast nylon 12, Linear Motion Devices, Precision Linear Slides, electrically insulated, energy efficiency, Clean rooms, Wash-downs

Electrically insulated gear box for electrolytic metal deposition

Posted by Simon Barrell on Mar 28, 2011 11:53:00 AM

To increase the capacity of their metal deposition furnaces with typically one cathode and one anode, we were approached by a metal refining company to design an electrically insulated gearbox that would rotate a multitude of electrodes suspended in a electrolyte solution. The design called for three stationary and one rotating cathodes and three rotating anodes.  In the electrolytic process, exotic metal is transferred from the cathodes to the anodes and the rotating movement ensured an even deposition of the metallic particles.

The task was twofold, to rotate and electrically insulate in the gear box cathodes and anodes suspended in the electrolyte solution. Picture 1 shows the final solution. Intech engineers designed a planetary gear arrangement using Intech Power-Core™ gears with 316 stainless steel core, mating with a stainless steel sun gear. The drive gear was connected to one of the planetary gears. The electrodes are inserted through the extended, hollow gear hubs and clamped in place.

electrically insulated gear box lower plate

Picture 1) Intech Power-Core™ lower and upper plate (not shown) were used to anchor shafts with bearings and to electrically insulate them.

The electrical current is applied to the protruding electrical ends. To provide precise gear mashing and good gear life, precision SS bearings were pressed onto the hubs. While Power-Core gears have insulating properties, the electrical current could still escape through the hub/bearing/housing connection. To insulate the current, two Power-Core cover plates were precision machined to construct a housing for the gear box.  The Power-Core gear box was then mounted on the metal cover of the furnace, see Picture 2.

electrically insulated gear box

Picture 2) Power-CoreTM electrically insulated gear box is mounted on the metal cover of the furnace.

In an earlier design, Picture 3 below, with a central drive and anodes and cathodes rotating, ceramic bearings were used to insulate the gear carrying plate.  Using Power-Core plates and sealed SS bearings to anchor the gears in the gear box housing proved less costly and more reliable in the harsh conditions present in the electrolytic metal deposition environment.

Main electrical properties of Intech Power-Core

  • Volume resistivity at 10e10 to 10e14 (ohm.cm)
  • Dielectric strength at 16-17kV/mm
  • Dielectric constant of 4.0 (air dry), 50Hz)

 

ceramic bearings gear box

Picture 3) In an earlier design ceramic bearings were used to insulate the gear carrying plate

Tags: Power-Core gears, electrically insulated, gear box, gear life, metal deposition, stainless steel core, stainless steel bearings