All About Screws

Published: August 27, 2012, By Tom Bezigian

They are an old and respected manufacturer of plastics and rubber screws, with old affiliations with personalities that I call "From the Golden Age of Plastics". Mike Mieduch, Sales Manager gave me a nice plant tour, and I actually saw something I have never seen before (which I will talk about below).

I also met with Jeff Kuhman, company founder and president of Glycon. Jeff goes back a long way, and he gave me a nice history of the company, and we talked about many mutual old friends, virtual pillars in the extrusion world, such as Imrich Klein, Chan Chung, Bob Barr, Chris Rauwendaal, and many others. Jeff and Glycon donated several extrusion screws of historical importance for the grand opening of the new Engineering building at UMASS-Lowell in November. He also wrote the history of extrusion for the Plastics Engineering Department to be read at the grand opening.

So... here are some of the basics. Glycon has been designing and manufacturing feed screws for 35 years at this location. Their specialty is custom high-performance screw designs which improve mixing while reducing overall melt temperatures at increase specific rates (kg/hr/RPM). Glycon had a long-term affiliation with Bob Barr where he would design and (at the time) Great Lakes Feedscrews would manufacture Barr's ET (Energy Transfer) screws.

Here is a schematic of how this design works:

In addition to manufacturing all types and sizes of screws for extrusion and injection molding, Glycon has its own patented Quick Shut-Off (QSO), non-return valve (US Patent Number 5,097,864) for injection molding. It's a really nifty design and a vast improvement over earlier ball or ring seal-type devices.

Glycon QSO - Quick Shut Off Valves, Conventional Valves

What I haven't seen before is the application of the hard-face to the screw tips. After "hogging out" the location of the future screw tips, applying Colmonoy® via plasma-arc welding is the next step. I haven't seen this before because most screw builders do not do it themselves. In this process, Glycon takes extra special care to prevent cracking or breakage of the screw tip by pre-heating the screw prior to application of the Colmonoy®. They also apply a special bonding metal to the base of the screw tip prior to applying the hard-face. These two steps, base metal and pre-heating, make Glycon screws very durable and give them a long-term mechanical advantage. I call this "German Engineering", where the product is built to last, versus built to planned obsolescence as is commonly done worldwide. I am hoping that on my next visit there that I can take and publish pictures of this process.

More on this topic in future blogs. More info can be found at http://glycon.com/ or by e-mailing or calling me at 315-382-3241 or This email address is being protected from spambots. You need JavaScript enabled to view it.

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