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

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

Anti backlash gear design at the heart of clear tomography imaging

Posted by Alexander Bartosch on Sep 21, 2012 1:58:00 PM

 

Special gear design is at the heart of clear image in multi-axis tomography device.

For the rotational machines used to gather dental X-ray images, motion chatter can produce a fuzzy image, which is not suitable for diagnostic purposes.

Panoramic radiography is a branch of rotational tomography where the creation of images are through the movement of a source and receptor in such a way as to cause the foreground and background structures to blur, leaving a defined focal trough.

As a panoramic radiographic device, the Vantage Panoramic X-ray System, designed and manufactured by Progeny, Lincolnshire, IL, incorporates a DC X-ray source, CCD digital receptor, distributed processing circuitry, and an LCD touchscreen control panel for ease of use. What makes the Vantage system unique is that it is adjustable to the patient’s height via a motorized, 3-speed, telescoping column. The use of multiple lasers is to locate the patient and configure the device to the patient’s morphology. In addition, a workstation coordinates the individual processors.

The system incorporates an overhead, swing arm (lateral Y-axis) that supports a C-arm, which is the rotating member that moves around the patient’s head. The C-arm includes a tube-head, which produces the X-ray beam, and a removable CCD sensor, which is the digital image receptor. If this arm does not operate smoothly, a distorted image results.

The swing arm pivots on bearings located in the mounting casting fastened at the top of the column. Producing its motion is a ball screw drive, one end of which connects to the mounting casting and the other end to the swing arm. A step motor mounts at the column end. Both mechanical connections of the drive assembly are through ball bearing assemblies.

Suspension of the C-arm is on a pair of bearings mounted to the underside of the X-axis translation plate. The C-arm casting incorporates a 10" ID internal tooth ring gear that meshes with a pinion gear on a step motor mounted on the stationary X-axis translation plate. The motor is spring-mounted to maintain positive mesh and to minimize slop. The internal ring gear and pinion are sized and shaped to engage on the inside surface of the C-arm. With activation of the motor, the stationary pinion engages the teeth in the internal ring gear causing rotation of the C-arm.

The engineering team at Progeny worked with Intech to help design the C-arm casting and its interface with the gear drive for the C-arm’s rotation. Design of the company’s Power-Core products is specifically to reduce noise and vibration and run without lubrication, an important factor (a must) for medical equipment designers. Intech components are far lighter in weight than metal parts and offer longer life (less wear) and lower maintenance costs. Intech engineers used a proprietary gear load/life calculation to verify that the gears designed into the dimensionally restricted place would last at least 8,000 hours of operation or about 15 years in field use.

The challenge was to design a backlash free gear to produce a steady rotational movement of the image producing components. There was no room to employ the traditional split gear design. To eliminate backlash, installation of a spring, on slight angle relative to the axis connecting the gear centers attached to the pinion, pulls the pinion toward the 10" ID internal ring gear. The spring arrangement did eliminate the backlash, but caused the gear teeth to bottom out, resulting in chatter. The chatter registered on the X-ray image.

The precision gearing for the Vantage Panoramic X-ray System uses Intech’s Power-Core nylon materials for reduced chatter, resulting in clearer images from the system.

Drawing on its expertise in gear design, Intech engineers designed and precision-machined the pinion and the internal gear to incorporate a special contact surface, which allowed the components to control the center-to-center distance between the inner tooth gear and the motor pinion. Adding the center-to-center distance management element presented a method for precise gear positioning in the mesh, and drastically reduced system vibration generated by the spring force and the resulting bottoming out of the gear teeth in the earlier design.

This configuration provides precise control over gear mesh vibration and backlash, resulting in high image quality in both a clockwise and counterclockwise rotation of the C-arm. It also adds a robust design element, which helps to increase product life so that image quality does not degrade with component wear and tear. With no fuzzy imaging due to chatter, dentists can make better diagnosis and provide better service to their customers.

Shown is the Vantage Panoramic X-ray system with the C-Arm that holds the lasers as well as the removable CCD receptor..

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This article was featured in Today's Medical Developments magazine and can be viewed at http://www.onlinetmd.com/TMD-0912-motion.aspx

Tags: Power-Core gears, vibration, PA12GC, calculating backlash, plastic gears, PA12C, PA12G, anti-backlash backlash gers, Medical

How to avoid design compromises when the equipment function calls for cam followers

Posted by Alexander Bartosch on Sep 10, 2012 10:40:00 AM

 

How to avoid design compromises when the equipment function calls for cam followers

Engineering design is an art of compromise. To achieve a design goal — for example, a certain machine function — engineers select components based on several criteria such as functionality, reliability, component’s availability, cost, and lead times. Pro and cons are analyzed and final selection made.

In the case of cam followers, in the past engineers did not have a choice other than selecting the manufacturer. With few options available, the engineers were forced to accept a host of costly requirements and operational limitations.

Intech iCams

Whether the application calls for high or low load capacity, the design has to provide for lubrication either manually or through a central lubrication system. Rail or cam surfaces have to be hardened. In operation, lack of lubrication of the bearing or the rail surface can lead to a catastrophic failure. Over-greasing can lead to the cam follower’s skidding, causing wear, and excess grease can contaminate the product being processed.

In addition, shock and vibration can cause metal to metal impact that has to be considered. Metal particles and grease contamination often prevent equipment manufacturers from entering the growing clean room market. The relatively low rotating speed of needle bearings, their high rolling resistance, and inertia may be limiting factors in high speed equipment design.

When selecting Intech iCamFollowers® the designer can eliminate most of the disadvantages of metal cam followers. This is especially the case in designs where the cam follower’s primary function is to transmit motion and not its high load carrying capacity.

Today the trend is toward high speed, light weight, and light duty machines in processing, packaging, medical, and semi-conductor machines, which account for about 40 percent of applications. In these applications, Intech iCamFollowers® can easily carry the load, help simplify design, and better achieve the design goal.

Considering the cost associated with design and operation of metal cam followers, it pays to better understand the actual load carried by the cam followers in the application. With load data, including radial and axial forces, load duty cycle, and desired linear speed, Intech engineers can use a unique plastic roller life calculation to quickly assess whether an iCamFollower can be used.

The load capacity of Intech standard iCamFollowers® is listed on Intech’s web site and represents the maximum load the cam followers can safely carry for 100 million cycles, under both static and dynamic loads, without developing a flat or excessive wear. A consultation with Intech engineers may lead to an alternative designs, opening the way to eliminating wear and lubrication as well as the number of modifications in the machine’s design.

If iCamFollowers® can be used, the advantages, compared to metal followers are many:

For New Equipment:
* Simplified design- cost savings
* No need for surface hardening- c
an run on aluminum rails
* No rail or cam wear
* No need for lubrication- manual or automatic
* Reliability
* Higher machine speed- Lower inertia, low rolling resistance
* Shock absorption
* Wash Down- stainless steel bearings and shafts, sealed design
* Sub-zero temperatures
* Elimination of lubrication and metal particles c
an open new markets

In plant Operations:
* Eliminating Lubrication
* Eliminating rail and cam wear
* Cost savings on maintenance

* Cost savings on production shortfall
* Longer maintenance cycles
* Noise reduction
* Low cost to try if iCams work

 

Learn More

 

 

Credits: As featured in Design World May 9 2011. http://www.designworldonline.com/how-to-avoid-design-compromises-when-the-equipment-function-calls-for-cam-followers/#_

Tags: cam followers, reduce noise, reduce shock, reduce vibration, Self-lubricating, cast nylon 12, Clean rooms, moisture absorption, PA12GC, iCamFollowers, PA12C, PA12G, sub-zero temperatures, Cast Nylon