Intech Power-Core Thermoplastics Engineering Blog

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

Drive sprocket for Escalator handrail extends maintenance intervals

Posted by Simon Barrell on Aug 10, 2010 5:06:00 PM

“Shut down for maintenance, use the stairs please.”shut escalator

We have grown accustomed to signs like these in public places like airports, hotels or department stores. The reason for the maintenance or repair shut down is often wear or broken teeth on the main driving sprocket.

The self-lubricating, precision machined Intech Power-Core™ escalator driving sprocket helps to extend the time intervals for scheduled maintenance, is wear resistant, absorbs shock and vibration, and reduces noise for a smooth and quiet ride. They are also suitable for outdoor use as the sprocket material does not absorb moisture and teeth do not break in sub-zero temperatures, when other plastic materials become brittle.

EscalatorDrive Sprocket for Handrail

Tags: maintenance, Power-Core, precision machined, Self-lubricating, moisture absorption, sub-zero temperatures, drive sprocket, escalator

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