Intech Power-Core Thermoplastics Engineering Blog

Large Underwater Gear Highlights Nylon's Moisture Resistance

Posted by Alexander Bartosch on Mar 22, 2013 2:00:00 PM

Wear and moisture resistance are two recurring themes in the engineering problems solved by Intech Power-Core™. Oftentimes, these problems involve small components, such as gears, cam followers or rollers. Yet Power-Core’s wear and moisture resistance properties can just as easily apply to large parts. Consider, for example, the large geared ring produced in our material for underwater use in a nuclear reactor pool. Measuring 2,200 mm across and 80 mm thick, this geared ring weighs in at 100 kg. It withstands a load of 150 kN at 6 rpm.

Intech Underwater GearLarge Part Size, No Problem. The sheer size of the part stands stands out, but our gravity casting process actually allows us to scale up the size of our components easily. Gravity casting results in low internal stresses, even when the parts have metal structural inserts. So going “big” is not really an issue for Power-Core.

Physical Property Advantage. What was even more important in this underwater application were the physical properties of the polymer. The geared obviously needed to be produced from a material that resists continuous exposure to liquids and corrosion. Various metals fell short due to their poor corrosion performance compared to polymers such as Power-Core.

Many other polymers, however, do not tolerate long-term exposure to moisture. Power-Core does. Its ultra-low moisture uptake allows it to remain dimensionally stable even when submerged in water for long periods of time. In this nuclear application, Power-Core’s radiation resistance also weighed in its favor over other polymers. And its wear properties allow it to avoid the fretting that can occur when component surfaces rub together in the presence of water.

In this application like in most applications engineers had a selection of materials to choose from. The common conception of most engineers when it comes to wet environments is that a polyester material such as ERTALYTE or an Acetal (POM) would be the best choices. In many cases these engineers would be on the right track - both materials are excellent in many applications - however for underwater gears specifically these materials wouldn’t be able to accomplish the task. For one the size of the gear leaves only very few material options, second when using Ertalyte or Acetals you have to be very careful what type of environment you expose them to – chlorine – like that found in drinking water could destroy the polyester compound over time and Acetals don’t react well to acids such as those used in wash downs, and booth are susceptible to weakening caused by extended UV exposure. 

Most Nylons, on the other hand, perform poorly when submerged in water, so naturally engineers tend to steer away from the entire nylon family when designing underwater motion systems. Powercore has a unique place in the family of Polyamides in that its moisture absorption, even when fully submerged, is negligible.  Our site contains numerous studies and documentation showing the effects of moisture absorption on nylon and nylon 6 and nylon 12’s dimensional change when submerged. When designing your next motion system of marine or underwater use please remember to consider the environment and look of a suitable polymer for your application.  

Learn more about Power-Core’s moisture resistance

Tags: gear design, Nylon 6 vs Nylon12, ultraviolet resistance, Nylon Vs Delrin, underwater gear, ertalyte

No Embrittlement on Guide Rollers for Whistler Peak 2 Peak Cable Cars

Posted by Simon Barrell on Mar 31, 2010 1:56:00 PM

When you are hanging a record 1,430 feet above the ground in a heavy cable car you want to be sure that the rollers it is running on don’t suffer from embrittlement at low temperatures (-40°C). The Peak 2 Peak Gondola recently opened in Winter Olympics venue Whistler, British Columbia holds world records for the longest free span between ropeway towers (1.88 miles) and the highest point above the ground—436 meters (those same 1,430 feet).

Cable Car Rollers for Doppe resized 600
Intech Power-Core Roller Mounting for Cable Car

Each of the 28 gondola cabins suspended on the 2.73 mile long cable is carried by a sophisticated roller mounting that has high resistance to abrasion under extreme conditions, as well as sound ultraviolet resistance. Those rollers are made with Intech Power-Core™ material and a rolled aluminum core, and they have a life-span in excess of 10 years to satisfy stringent safety requirements.

If you are lucky enough to spend some time in beautiful Whistler, and travel on the Peak 2 Peak gondola, do so confident in the high fatigue limit of the rollers that are carrying you across the valley. Intech Power-Core™ material is the only existing high-performance plastic which fulfills the broad spectrum of requirements set down by the cable car manufacturer to ensure your safety.

Tags: Power-Core rollers, low temperatures, Power-Core material, aluminum core, embrittlement, fatigue limit, roller mounting, ultraviolet resistance