PROCESSING | SCREWS AND BARRELS
Extreme Coatings has improved its CarbideX
coating technology for replacement of nitriding and chrome plating on conical and parallel twin feed screws. The company says the move was prompted by environmental concerns with chrome plating and the need for better protection against wear and corrosion. According to the company, equipment operators can achieve two to five times longer equipment life with CarbideX formulations (C1000, C2000, and C9000-nano) of tungsten and chromium carbide encapsulation. Wear resistance capabilities can be improved on a variety of components, including twin extrusion screws, continuous mixing rotors and other parts in the plasticising process.
Above: Coperion has developed a quick-release screw shaft coupling for its ZSK 26 Mc18 extruders
borings through the frequent evaporation of cooling water during normal cooling action. When required, mechanical cleaning of the straight through holes can be applied in-situ with a pipe brush and a power drill after dismounting the fittings,” he says. “As a result, bothersome cleaning with acidic liquids for scale removal can be eliminated and mechanical cleaning efforts can be easily focused on the critical areas of the cooling borings that are exposed to frequent evaporation stresses.”
Tackling wear A constant challenge for wear resistance in compounding extruders - especially for barrels - is the high load of the latest machine types, according to Coperion. The company says customers are increasingly utilising the full torque of the compounder, which increases the mechanical forces inside the process section, so it has recently updated the standard wear protection material for ZSK extruder barrels to WP 043+ for all machine sizes.
With a significantly increased impact energy, the WP043+ coating can better tolerate high forces than the former standard WP043. The result is less damage at similar abrasive wear resistance and increased corrosion resistance. In addition, Coperion’s high performance C-Rock material is now available for ZSK 70 and ZSK 92 twin screw extruders. The company says it offers best-in-class wear and corrosion protection, especially for challenging process conditions. Coperion has also developed the quick-release
screw shaft coupling that enables screw changes to be performed as quickly as possible for ZSK 26 Mc18
compounding extruders. This new addition
means cleaning times are reduced to a minimum when changing between colours and recipes.
62 COMPOUNDING WORLD | August 2020
Chrome replacement The company says its Chrome Plating Replacement (CPR) is virtually non-porous, so corrosive gasses from PVC cannot attack the base of the screw. However, unlike nitriding, it says CPR also adds corrosion resistance as well as greatly increased wear resistance. CPR is also said to be more environmentally friendly than chrome plating. Extreme Coatings says the chromium (vi) compounds used in chrome plating are known carcinogen but the chromium (iii) carbide compounds used in its CPR C4000 system are not known to be carcinogenic or toxic. In some applications where abrasive fillers cause
premature wear, the company says its C1000 or C9000 nano formulations of tungsten carbide encapsulation will provide superior wear resistance combined with a high level of corrosion resistance – minimising wear and maximising profit. Extreme Coatings says its approach to any wear
or corrosion problems is analysis then development of a customised solution to maximise component life. “Advancements in polymer technology demand parallel advancements in feed screw and processing technology,” says Curt Kadau, President of Extreme Coatings. “Extreme Coatings has kept pace with these advancements and will continue to develop new products to meet the demands of our customers.”
Single approach
While most compounding applications are twin- screw, Nordson Corporation has assembled a selection of Xaloy screw and barrel options for single-screw compounding, particularly for abrasive or corrosive ingredients. “The choice depends on the percentage loadings of the additives and fillers and on the point at which these ingredients are metered into the plasticating
www.compoundingworld.com
IMAGE: COPERION
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