| 摘要 |
A collapsing board employed in the manufacture of polyethylene film is formed as an extruded aluminum member with a back plate that fastens onto the collapsing frame and an arcuate front face that urges the moving polyethylene extrusion to a collapsed condition. A low friction material is applied onto the arcuate front face. In one preferred embodiment, the low-friction material is in the form of an extruded plastic replaceable wear cover. In another embodiment, a ceramic coating is deposited onto the arcuate front face of the metal extrusion. The plastic wear cover can have a co-extruded two-layer front web, with a lubricant filled front layer and a backing layer of a distinct color that is revealed when the front layer becomes worn from use.
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