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

Intech Gears Could Eliminate Noise From Your Segway Gearbox

Posted by Alexander Bartosch on Jan 30, 2014 8:56:00 AM

Does your segway make too much noise? Have you ever wondered where it is coming from? Segway drive gears in the segway gear box are all metal (figure 1)

Segway Helical gear Gearbox

The metal on metal movement, in this beautifully constructed helical drive gearbox, creates noise. This noise can become worse with time as the gears wear.  See the video below for an example of the noise we are talking about.

Intech has conceptualized a segway replacement gear box to dampen vibration and reduce the noise of the segway metal on metal wear. Our simple bolt on attachment benefits from our  PA12GC Power-Core Cast Nylon (polyamide) which doesn't absorb moisture and won't crack in subzero conditions. The self-lubricating material allows our gears to run quietly and oil free. Removing another annoyance from the maintenance of your segway and its gearbox.

Using plastics to design high load, high shock, and highly critical applications is our specialty here at intech and being engineers the segway was always a toy we've wanted to tinker with. Making plastic gears for an application of this type was not without challenges. The first of which is the tooth root stress, you see metal gears can be much thinner and carry far more load than any plastic. The second is power transmission, very few - if any plastics can evenly and continuously transmit the power needed to drive a segway in the way its meant to operate. Imagine a right gear box transmitting less efficiently than the left and the circles or compensation a rider would need to make. Luckily, Intech's Power-core PA12GC material and its unique gravity casting process allows it to chemically bond to a metal core allowing it to transmit power evenly and continuously while perserving the benefit of a self lubricating gearing.

The retrofit is not inexpensive but if noise or vibration are causing you problems a new intech gearbox might be the solution to give you the quite and smooth riding personal movement device you've always wanted.

 Contact an Engineer

 

Photocredit: http://segwaynz.files.wordpress.com/2012/08/gearbox.jpg

Tags: Power-Core gears, cast nylon 12, gear box, gear backlash, gear design, plastic gears, Power Train Design, Plastic gear box, plastic helical gears

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

Lube-Free Rotary Positioning for Cleanrooms and More

Posted by Georg Bartosch on Oct 3, 2012 3:58:00 PM

Intech’s Power-Core® rollers have found uses in applications ranging from industrial machines to transportation. Most of them have seen use in linear motion systems of one kind or another, but there’s no reason that these gravity cast nylon 12 rollers cannot be incorporated into rotary motion systems such as our new rotary index table.


iCam Turntable resized 600.gif resized 600Designed for integration into third-party servo systems, this new rotary index table makes extensive use of rollers and gearing made from Power-Core gravity cast nylon 12. The table’s drive mechanism consists of a pinion-driven ring gear whose helix tooth profile eliminates wear and backlash. The gravity cast nylon 12 gear is machined from a polymer blank that has been cast around an aluminum ring. This ring serves as a circular rail and as the mounting surface for the payload.The Power-Core nylon 12 rollers, which mount on the unit’s base plate, support the rotating gear and integrated mounting surface. They feature enclosed stainless steel bearings, making the unit suitable for washdown and other corrosive environments.

The use of gravity cast nylon 12 for the drive and bearing elements helps this rotary table outperform all-metal designs in several ways:

  •  Low wear without lubrication. This design avoids the metal-on-metal contact that can shorten the working life of motion systems. The only contact is between two Power- Core nylon components in the case of the drive mechanism and between Power-Core and aluminum in the case of the supporting rails. Power-Core nylon is formulated with an internal lubricant, so no external lubricant is needed. The metal bearings are lubed for life too.
  • Backlash free. Power-Core gravity cast nylon 12 gears offer a couple of intrinsic advantages when it comes to reducing backlash. For one, their dimensional stability eliminates the need for the backlash compensation required by moisture-sensitive plastics. For another, the uniform crystalline structure of Power-Core nylon 12 and our gravity casting production methods produce gear blanks with very low internal stresses and uniform machining resistance. These characteristics allow very precision machining of tooth profiles that have been optimized for backlash reduction–and would be difficult to achieve in metal. 
  • Fast and smooth. The low-inertia of the gearing and
    the rollers helps the table operate at higher speeds. By producing a tighter inertia ratio between the motor and driven load, the low inertia of the Power-Core drive components also makes it easier to tune the controls for a smooth, precise motion profile, particularly when moving light payloads. 
  • Washes down, resists chemicals. Power-Core nylon 12’s dimensional stability in the presence of moisture and its thermal stability make this rotary table a good fit for washdown, high-humidity and high-temperature applications that would prohibit the use of less capable polymers. Nylon 6, for example, can exhibit a dramatic loss in tensile properties and undergo dimensional changes when exposed to moisture and high heat levels. Power-Core nylon 12 also offers excellent chemical resistance compared to nylon 6 and other polymers used in power transmission applications. 
  • Cleanroom friendly. Because Power-Core nylon 12 resists wear and does not throw off the particulate associated with externally lubricated metal power transmission components, clean room use is a natural fit for this rotary table design. 
  • Scaleable. By manipulating the size of the gear and roller components, the table design can be scaled to handle payloads ranging from ounces to tons.

Read More About Indexing Tables

Tags: washdown application, cam follower, cam followers, cast nylon 12, Clean rooms, PA12GC, anti-backlash backlash gears, Index table

Plastics Improve Roller and Cam Follower Performance

Posted by Alexander Bartosch on Oct 1, 2012 4:42:00 PM

When designing motion systems that require rollers or cam followers, many engineers still believe that only all-metal components will fit the bill. Yet rollers and cam followers with polymer bearing surfaces have emerged as a high-performance alternative to traditional metal components. 

In heavily loaded applications, polymers can withstand enormous forces if designed properly. For example, we’ve engineered and delivered polymer rollers that can withstand continuous forces up to 8 tons.

Most applications, however, are not so heavily loaded. The primary role of the roller or cam follower is to transmit motion, rather than support hefty loads. In these applications, off-the-shelf rollers and cam followers will do a good job without the need for custom engineering.

And increasingly, these off-the-shelf products are not made entirely from metal. Instead, they are hybrid designs that consists a polymer load bearing surface over a metal roller bearing or structural hub. Sized as drop-in replacements for standard sized metal rollers, the hybrid rollers offer some compelling technical advantages thanks to their use of polymers. 

These advantages include:

  • Self-lubrication. The engineering polymers best used for rollers, most notably gravity cast nylon 12, exhibit an internal lubricity that lasts for the life of the component. Bearing surfaces made from these polymers require no external lubrication between the roller and the rail, eliminating on-going maintenance costs and reducing the risk of failure.

  • Improved Wear. Even with some lubrication, metal-on-metal contact can result in excessive wear and galling. Plastic rollers eliminate this wear mechanism altogether. 

  • Contamination Reduction. Self-lubricated polymers eliminate two potential sources of contamination—stray lubricant and particulate from metal-on-metal contact. 

  • Smooth and Quiet Operation. Unlike metals, polymers such as gravity cast nylon 12 have the ability to dampen shock and vibration. 

  • Speed and Efficiency. Because they weigh about 40% less than similarly-sized metal rollers and cam followers, polymer products facilitate high-speed, energy-efficient motion.

  • Environmental Tolerance. Rollers made from gravity cast nylon 12 do not swell in moisture and also tolerate chemical exposures and temperature fluctuations. 

  • Cost Reduction. The true cost of cam followers and rollers has very little to do with their purchase price and everything to do with their lifecycle cost. Polymers save money over the long haul by eliminating the need for lubrication, extending maintenance intervals and eliminating metal-on-metal wear.

Our latest white paper delves into the technical advantages of gravity cast nylon-12 rollers and cam followers. It includes detailed comparisons nylon 12 with both metals and other plastics. Download it now.

Intech Cam Followers Out Perform MCGill and RBC Metal CamfollowersLearn More

Tags: cam followers, plastic rollers, cast nylon 12

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

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

Effects of Moisture on the Tensile Strength of Nylon 12

Posted by Simon Barrell on Dec 9, 2009 11:26:00 AM

Continuing the theme of our last blog entry, moisture absorption is also a factor in determining the tensile strength of nylon 12, as shown by this chart:


Moisture Absorption vs Tensile Strength


You can learn more by reading a complete article on this topic that appeared in Machine Design at: http://www.intechpower.com/Machine%20Design%20Nylon%20Article.pdf

Tags: cast nylon 12, moisture absorption, Tensile strength

Moisture Absorption, Swelling in Nylons, except Cast Nylon Powercore

Posted by Simon Barrell on Nov 25, 2009 12:07:00 PM

Moisture absorption is a key factor to consider during nylon material selection. Design engineers need to take account of the application and tolerances because, machined component dimensions for a particular nylon grade will change if they were originally designed for a dry environment but are then used in a humid location. Moisture is absorbed by the part, and at some point when it reaches equilibrium, swelling can occur, and the fact that the dimensions of the part are subsequently altered increases the likelihood of premature part failure.

Injection molding, extrusion, and casting can all be used to form nylon, and the process used will influence material properties. In the case of injection molding, nylon is subjected to high compression and decompression within a short period of time. Correct mold design, timing, and precise pressure control are vital, and accurate thermal history for the part when both inside and outside of the mold should be maintained.

If water is present where extrusion is used in forming a part, severe problems can result. Therefore, moisture content and cooling rates should be monitored rigorously as they will both influence the physical properties of the extrusion.

Extruded rods or slabs can also be susceptible to shrinkage voids that are caused while the inside is in a molten state but the exterior surface begins to solidify. While the interior cools and shrinks under thermal contraction and crystallization, a void forms as the exterior no longer contracts. One solution is for extruders to use controlled water or vacuum quenching to cool formed parts. Note that even where forming processes can be precisely controlled, physical properties and dimensions may change over time when exposed to changing transport and storage conditions.  

Chart - Dimensional change polyamides versus moisture

The diagram shows moisture absorption causes swelling which results in up to 3.3% dimensional change in the nylon 6 family. When designing with nylon 6 or 6/6, this has to be taken into consideration, for example, when calculating backlash in gears, or when storing precision parts for prolonged periods of time in changing environments. For cast nylon powercore such change is negligible, even when permanently immersed in fuels, oils, and chemicals.

Tags: cast nylon 12, moisture absorption, calculating backlash, dimensional change, forming nylon, gear backlash, injection molding, material shrinkage, moisture content, polyamides