Before jumping into how Nordic ski gear is made, I thought it prudent to spend some time explaining several manufacturing techniques. These methods are used in almost every piece of gear we use. While eager to start explaining individual pieces of ski gear, having the back ground and basic understanding of manufacturing techniques will keep all of us speaking the same language and hopefully give the reader a better insight into the production and hidden costs of our beloved equipment.
Don’t believe I’m pulling the old “bait and switch†when you’re looking to read about honeycomb cores with carbon fiber nano-tube matrix layup but have to start with injection molding plastics. It’s cliché and unimaginative writing to use the line about plastics from “The Graduate†but Mr. Robinson was correct; plastics are everywhere. Injection molded plastic has none of the sex appeal of carbon fiber but it is a very important part of ski equipment. Components of bindings, boots, pole grips, baskets, and many other pieces of ski equipment are all made by injection molding plastic.
In the simplest of terms, Injection Molding (IM) is forcing liquefied plastic into the cavity of a mold, waiting for the plastic to harden (cool) and ejecting the finished part. Repeat until the number of finished pieces has been made. Putting water into an ice cube tray, allowing it to freeze before popping the ice out and refilling the tray is not much different.
Len Johnson, owner of Jenex V2 Rollerski agreed to help with the How it’s Made series. In addition to explaining rollerski manufacturing, Len was kind enough to set up tours and spend a day with me at three of his vendors explaining how Jenex products come to market. One of these shops, Poly-Ject, Inc. (www.polyject.com), handles all of Jenex’s injection molded plastics supplying Jenex with over twenty molded parts used in their line of rollerskis and tuning tools. The photos are for illustration purposes and most are not of the Jenex products.
Steve Thibeault, President of Poly-Ject, starts the tour in the machine shop where the molds are made. The mold for the Jenex split rim is placed onto a table.
 milling equipment and carbide cutting tools before being sent to the polishing department for finishing. . <p><center><img src=)
 are sucked through a hose and deposited into a metering hopper which determined how much plastic is injected per cycle. Any coloring or reinforcement is added here. The glass reinforcement in the Jenex rims make up 33% of the volume of the part and are approximately ¼†long and much finer than human hair.. <p>From the metering hopper, the plastic mixture moves by crew augur into the melting chamber. The augur moves and mixes the plastic as it transforms from room temperature beads into a homogenized liquid with a temperature of 500 degrees F. waiting its turn to be forced into the mold.. <p>The mold halves come together and are held with a clamping force of 385 tons. When the augur chamber moves into the mold the plastic is forced into the cavity at predetermined pressures between 8,000 and 30,000 PSI and held for one to three seconds while cooling water begins to circulate. Cooling takes about 30 seconds. The mold opens and the ejection pins push the cooled part out of the mold.. <p><center><img src=){kind=spacer}
