Before Extreme Coatings, 3 months processing glass filled nylon.

If abrasive wear is your problem, we guarantee at least 2X life improvement with our carbide encapsulation.

After encapsulation with carbide, 10 months in the same process.

The ASTM G-65 wear test simulates low-stress sliding abrasion and provides a comparison between wear resistant materials. Volume loss is calculated and used to compare these materials. Our tungsten carbide is more than three times more wear resistant than the next best material tested. These test results give us the confidence to guarantee AT LEAST double the wear life of our carbide encapsulation over your current feed screw. See Wear Data

In response to market demand, Extreme Coatings has developed the ability to apply our long lasting tungsten carbide to just the screw flight land. FliteGuard is an ideal option for applications where OD adhesive wear shortens service life and where root erosion/wear is not an issue. Technological advances allow the root of the screw to be completely masked coating just the wearing portion of the feed screw, the flight land.

FliteGuard can be applied to new or rebuilt feed screws and the carbide application can be carried out before or after a feed screw is chrome plated.

The carbide coating thickness is limited to .005” (0,125 mm) per side or .010” (0.25 mm) overall.

Productivity in an extrusion processes is especially sensitive to screw OD wear. Doubling the screw to barrel clearance can reduce output and melt rates by as much as 25% in low viscosity resins. In a high fill, highly abrasive extrusion process our carbide coating provided three times the wear life and 25% more production output compared with the previous feed screw. (Case History 2005-2 Extrusion Severe Abrasion) This is a solid example of the value that minimizing wear can have on a close-tolerance system.

FliteGuard PDF Data Sheet (425k)

Extreme Coatings does not make or repair feed screws, we encapsulate screws to make them last longer. All you need do is ask for Extreme Coatings and we will take care of the details with your supplier of choice. Be sure to ask about the Purchase Encouragement Program (PEP) which allows you to evaluate our carbide encapsulation at no charge for six months. Furthermore, our Rebuild Certificate states that we will return your feed screw to its pre-encapsulation condition if you are not completely satisfied with the screw performance.

The importance of maintaining a tight tolerance between the feed screw and barrel in plastic extrusion machinery is observed by a measurable reduction in the out-put of the machine, either in pounds per hour or feet per minute. It has been determined in lab testing that a doubling of feed screw/barrel clearance may reduce the output of an extruder by as much as 20-25% in low viscosity resins and 10-13% in higher viscosity resins. Furthermore, as the outside diameter of the screw wears, the flight to barrel scraping or wiping action decreases which, with some polymers, leaves a thin residue of molten plastic on barrel that may burn or retard thermal conductivity. Additionally, back flow increases potentially causing excess shear and subsequent polymer degradation. Scrap or reject rates may increase, but more importantly, the physical properties of the polymer may be jeopardized. Even a small percentage of abrasive filler may cause unacceptable wear to occur 3-4 times quicker. Processing non-abrasive polymers such as clear LDPE have little to no effect on screw wear, but for those running 24-7, adhesive wear will be obvious in as little as 2 years.

Maintaining a tight tolerance between the feed screw and barrel in a plastic injection molding machine is of vital importance to the production efficiency of the machine and the quality of the parts being produced. The principles of plasticizing in an injection molding machine are almost identical to those of an extruder. The main difference is that the injection screw is extruding plastic into the barrel to create a shot rather than through a die to form a product. As this is the case, wear on the O.D. of the screw may be observable as an increase in the feed screw recovery time or maybe even the cycle time. In applications where the cycle time maybe much greater than the recovery time, it may be misinterpreted to be acceptable to continue with production if the cycle time is not affected. In contradiction, an increase in residence time may cause polymer degradation or burning. In the case of glass filled resins, back flow may cause excessive shear affecting the integrity of the fibers. Both, if not held to a minimum, will adversely affect the physical properties of an engineered polymer. Further to this, especially in the case of low viscosity resins without a new check ring, it may be difficult to hold a cushion and short shots may be evident. With respect to machinery down-time, one can expect an encapsulated feed screw to last at least twice as long as any feed screw on the market today, even CPM9V* tool steel, thus, eliminating the time associated with numerous maintenance inspections.

Extreme Coatings: Encapsulating a plastic injection molding or extrusion feed screw with a wear and corrosion resistant tungsten or chromium carbide coating will reduce your average amortized monthly feed screw costs by up to 50% regardless of the type of polymer being processed. There are two primary modes of wear that cause processing problems in plastic injection molding machines and extruders.

1.) Adhesive wear (metal to metal) is caused as the feed screw flight lands rub against the barrel I.D.

2.) Abrasive wear occurs when hard fillers such as fiberglass or Titanium Dioxide are compressed against the screw flight and barrel surfaces causing material removal. The high concentration of extremely hard tungsten or chromium carbides in our coatings provides adhesive and abrasive wear characteristics unmatched by common hard facing alloys or tool steels. In most cases, one can expect an encapsulated feed screw to last at least twice as long as any other feed screw on the market. This is backed by our Double Life Guarantee and also a component of our Purchase Encouragement Program (PEP).