Roller blanking

Figure 4.19. Layout of a unit for centrifugal casting (molding) of tubular blanks 1 - rotary mold 2 - mold rotation rollers 3 - heating chamber 4 - blank 5 - rotary gripper of finished pipe extender 6 - exhaust ventilation.

Formerly the edges of the heated blank were welded upon the mandrel by the successive blows of a trip-hammer, or a dit)p, dies intervening between the iron tube and the drop and anvil respectively. A portion only of the seam is closed at a time by this means, and the o[ieration is more tedious an l expensive than the rollers just described. The rolling process was introduced from England. 

A special setup is used for manufacture of a three-layered inhibited film whose middle layer is embossed and the cells are filled with a non-drying inhibiting composition (Fig. 2.14). The setup consists of extruders 1 with slot heads 3, vacuum-forming drum 4 and Cl batcher 2 [4,83]. The film blank is directed by guide rollers 5 and 6 to the assembly unit of the laminated material equipped with a heat chamber 7. 

The blank is typically formed in a single roller pass. Blank shape can be either a flat sheet or a preform produced by other means. Generally, a single roller is used to form the sheet however, in case of high-strength and thick-walled components, a multiple roller configuration may be used. 

The material to be spun, almost always in a round blank, is clamped against the front of the tool and held in place with the tailstock. While the lathe is rotating the tool and the material, pressure is applied to the outside of the material by a spinning tool, which can be a blunt-ended tool of various shapes (which creates friction when contacting the rotating material being spun) or a roller mounted on... 

In shear spinning, only one spinning pass is required. Each portion of the blank is touched only once by the spinning roller, so in-process annealing is not required for materials that normally require in-process annealing. However, the resulting spun part will be substantially work hardened and that must be taken into consideration for subsequent operations or uses of the part. 

The active mass is either pressed into briquettes, which are fed into the preshaped perforated strip, or fed into the preshaped strip as a powder. The upper and lower steel strips are folded together by rollers. A number of these folded strips are arranged to interlock with each other to form long electrode sheets, which are then cut to electrode blanks. Electrodes are made from these blanks by providing them with steel frames for mechanical stability and for current takeoff. 

The tool used for roll embossing is a wheel or roller with built-in heating. The plastic molding follows a linear track as it passes underneath the tool on a conveyor belt, for example. By contrast with stroke embossing, the force is applied only locally, mapping the line of contact between roller with film and the blank. The ability to produce large, uninterrupted surfaces without air inclusions is one of the big advantages of this process [48]. 

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