Ram or Cold Extrusion

and profiles are extruded at low temperatures and require an extruder producing a minimum of heat huild-up, approaching the ideal of adiabatic performance where all, or nearly all. 

Polymer Temperature along the extruder (°C) Rotation speed (rpm) Density (g/cm ) Concentration of the blowing agent (%) 

UHMWPE powder compaction and sintering by either extrusion or compression moulding yields similar values in terms of the final mechanical properties of the polymer. The resultant moulded semi-forms can be easily shaped (cut, turned, sawed, milled, or punched) using standard machine tools. UHMWPE is difficult to bond using adhesives but parts can be joined effectively by butt welding or mechanical fasteners. 

Die drawing allows bars, tubing, and large-size sheets to be obtained. The polymer is drawn through a heated die with a conically shaped entrance. Sheets of oriented polymer can be produced by roller drawing while highly oriented films and rods can be obtained by co-extmsion. 

It is convenient for the extrusion of LLDPE to blend it with about 10% LDPE to increase flow, reduce weld lines, and improve the general qnality and homogeneity of prodncts. 

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