Screw for a plastics processing machine, and method of regenerating a screw
AssigneeKrauss-Maffei Kunststofftechnik GmbH
InventorAchim Haberer
Life of this patent
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Abstract
A screw for a plastics processing machine includes a screw body made of a base material, which is no longer useful as a consequence of wear. A single-ply or multi-ply a buffer layer made of magnetically conductive metallic material is applied onto the crest of the screw body by means of a thermal spraying process, and a wear-reducing coating made of molybdenum or a molybdenum-containing alloy and applied onto the buffer layer by means of a thermal spraying process This provides a simple way of ensuring that the regenerated screw has a long service life and is resistant to heavy loads.
Claims14
A screw for a plastics processing machine, comprising:
- a screw body made of a base material, which is no longer useful as a consequence of wear, said screw body including a screw flight having a crest;
- a buffer layer made of magnetically conductive metallic material and applied onto the crest of the screw body by means of a thermal spraying process to compensate for a diameter reduction of the screw body as a consequence of wear and abrasion, wherein the buffer layer is made of chromium steel with a content of Cr of 10 to 16 wt. %;
- and
- a wear-reducing coating made of molybdenum or a molybdenum-containing alloy and applied onto the buffer layer by means of a thermal spraying process.
A method of regenerating an extruder screw which has been reduced in diameter through wear during use, comprising the steps of:
- abrading the crest of screw flights of a screw body to a uniform diameter;
- depositing a buffer layer of magnetically conductive metallic material onto the crest at a thickness to compensate for the diameter reduction of the screw body as a consequence of wear and abrasion to a uniform diameter, wherein the buffer layer is made of chromium steel with a content of Cr of 10 to 16 wt. %;
- and
- applying a wear reducing coating of molybdenum or a molybdenum-containing alloy onto the buffer layer through a thermal spraying process.
Dependencies are inferred from the claim text.