Intech Power-Core Thermoplastics Engineering Blog

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

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