Punch forming

The best products have smooth, natural curves and drawn sections that are spherical or nearly so in shape. Their walls will be more uniform, they will be more rigid, their surfaces will be less apt to show tool marks, and their tooling and molds will be lower in cost. Notches or square holes should be avoided when punching formed products. Round holes are preferred to oval ones for minimizing stress buildup. 

When punched plates are used they should be installed with the direction of punching upward. Punching forms a slight nozzle, and reversing the plate will increase the pressure drop. 

Extrusion is the shaping of a plastic by pushing the plasticized or melted material through a die, and possibly a punch forming an air gap, having roughly the form of the final section of the profile. 

Film Processing Methods Type HN film can be laminated, metallized, punched, formed, or adhesive coated. 

Punch forming is used in the manufacture of very low cost, single-sided PCBs such as are used in many consumer electronic products. The process involves printing and etching the conductor patterns on one side of a laminate substrate, usually paper-reinforced epoxy. All holes are punched in a single stroke by a die containing a pin and opening for each hole. The PCB outline is formed in a second die that blanks it from the panel in which it is processed. 

Products, such as point-of-purchase and berry box rigid containers often require multiple punch steps. The first punch forms holes or slots in the product. The second punch separates the product from the trim. Although multiple punches can be accomplished on a single trim press, there is always a concern about the first punch trim-out causing problems with the second punch. As a result, tandem trim presses are usually used (Fig. 16.15). Set up and alignment of two presses often take substantially more time than the set-up time of the thermoforming forming press. 

Draw die, bending die, pierce punch, form roll, embossing punch, coining... 

Fermentation is generally divided into several stages yeast activation, degas-sing-punching-forming, and proofing or final fermentation. In terms of time, yeast... 

Variational inequality characterizing an interaction between the punch and the plate can be written in the form... 

The nonpenetration condition is imposed both in the domain and on T. Thus, let the equation 2 = (a ,y) describe the punch shape, (a , y) G fl, G C°°(fi). Then the nonpenetration condition for the plate-punch system in a linear approach takes the form... 

Provided due care is taken with respect to predrying and to crazing tendencies, polycarbonates may also be thermoformed, used for fluidised bed coating and machined and cemented. Like metals, but unlike most thermoplastics, polycarbonates may be cold formed by punching and cold rolling. Cold rolling can in fact improve the impact resistance of the resin. 

The integrations are carried out over all non-zero values of p r). By judicious choice of p r), u R) can be made to have particular forms such as constant, representing a flat bottom punch and spherical representing a spherical (Hertzian) punch. 

---