Surface profiles calendering

Surface profiles of both sides of a calendered and an uncalendered sheet were recorded with a Talysurf 5 instrument (Rank Taylor Hobson, England), and are reported in Fig. 13. The surface is different in each case, but the bulk conductivity is not significantly altered. The pressure applied to the electrodes within the cell has not changed the surface profile of the sheet for the calendered sample. Although a difference is observed for the uncalendered sample, the surface is not as smooth as that of the calendered sheet after pressure is applied. 

Figure 13. Surface profiles for a paper sheet with and without calendering, and before and after pressure. (Reproduced, with permission, from Ref. 16. Copyright 1981, American Institute of Physics.)...

Calendering can achieve surprising accuracy on the thickness of a sheet. Typically the tolerance is 0.005 mm but to achieve this it is essential to have very close control over roll temperatures, speeds and proximity. In addition, the dimensions of the rolls must be very precise. The production of the rolls is akin to the manufacture of an injection moulding tool in the sense that very high machining skills are required. The particular features of a calender roll are a uniform specified surface finish, minimal eccentricity and a special barrel profile ( crown ) to compensate for roll deflection under the very high presurres developed between the rolls. 

Many rubber products require uncured components which are not rectangular in cross-section. In such cases, at least one calender bowl may have a peripheral design cut into its surface to produce the desired cross section. This method is particularly useful for long production runs, but becomes expensive in terms of bowl change and bowl inventory necessary when many different sections are required. For shorter run working, the calender bowl may consist of a heavy basic mandrel onto which may be clamped solid cylindrical or split cylindrical steel shells into which the appropriate profile design has been cut. Such calenders often have the bowls outside the frames to improve access and facilitate bowl changing. Consequently the bowls are comparatively short. 

Experimental measurements of pressure profiles in calenders were conducted by Bergen and Scott (34). A strain gauge transducer was embedded in the surface of one of the 10-in-diameter rolls, and traces were recorded at various conditions corresponding to both calendering and roll milling. 

Uses Stabilizer for flexible and rigid PVC compds., calendering, extrusion, inj. molding, powd. molding, slush and rotational molding, hose and profile, filled systems, film and sheet stabilizer for external coatings, roofing sheets, canvas material, tents, portable inflatable structures, coated metal surfaces Trade Names Mark TT... 

Anchorage ag-k(o-)rij (15c) n. Part of an insert that is molded inside of a plastic part and held fast by shrinkage of the plastic onto the insert s knurled surfaces. (1) Property or profile of metal or wood substrate to enhance the adhesion of a coating. (2) Adhesion of rubber to fiber, fabric, metal or other material to which the rubber compound is applied by calendering, welding, cement spreading, or other means. 

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