Automatic Molding

A higher pressure than ordinary compression molding is required for automatic molding because 

---

Automatic molding — A PTFE molding technique for small parts in automatic presses, which is faster than standard compression molding. 

This problem was approached from the material side, through a search for suitable internal releases, and through the development of improved external mold release compounds. From the equipment side, the development of automatic molds was required if the RIM process was to compete with classical injection molding with respect to mold cycle times and efficient production. 

Flash removal at the end of each cycle is important for successful automatic molding. 

In automatic molds, it is vital to ensure that the undercuts, hold down pins, and the molded part... 

Automatic Molding Small round A few millimeters to a few centimeters in diameter A few grams to a few hundred grams... 

Isostatic molding is a suitable alternative to compression and automatic molding techniques for the production of PTFE parts with complex shapes in a wide range of sizes. Compression molding can supply a stock shape which can be machined to obtain the desired shape. The drawback to this option is the... 

Seals and gaskets Automatic molding, compression molding PTFE... 

Compression molds can be divided into hand molds, semiautomatic molds, and automatic molds. The design of any of these molds must allow venting to provide for escape of steam, gas, or air produced during the operation. After the initial application of pressure the usual practice is to open the mold slightly to release the gases. This procedure is known as breathing. 

A submarine gate (Figure 2.1 Ih) is one that goes through the steel of the cavity. It is very often used in automatic molds. 

Where fully automatic molding machines are used, hydraulic ejection with perhaps a joggle facility is necessary, since thermosets have a tendency to stick in the mold. 

Automatic control n. In processing, control achieved by instruments that Automatic mold. A mold for compression, transfer, or injection molding that is equipped to perform all operations of the molding cycle, including ejection of the molded parts, in a completely automatic manner without human assistance. 

Figure 6.10 Schematic diagram of screw preplasticizer for preheating thermosetting molding compounds before molding. Preplasticizer may be integrated with molding press for fiilly automatic molding.

Figure 6.21 Parting line injection molding machine for semi-automatic or fully automatic molding of thermosetting plastic parts.

Ejection of molded part. In designing molded parts, and the molds used to produce them, it is necessary to consciously determine how the part will be removed from the mold cavity or force and to maintain positive control of the part during mold opening, such that it is ejected as intended. This positive control is especially vital in automatic molding. 

In many insert molding operations, fully automatic molding becomes possible when mechanisms are installed to put the insert into place before each cycle and to remove the insert with the molded part following each cycle. 

SPMC materials are developed specifically for use in automatic molding systems such as injection, transfer, and compression molding. SPMC is available in various colors, flow grades, and shrinkage factors. 

---