Plastic injection molding

Mold Coolers for Plastic Injection Molding. Heat pipes are used for local temperature control in the injection molding of plastics (see Polymerprocessing). A heat pipe is often used to force local cooling within a mold to speed operation, control viscosity, retention of material in a difficult mold area, or to reduce thermal stresses on cooling. 

Process requirements (e.g., in pharmaceutical and semiconductor manufacturing, painting processes, plastic injection molding, and breweries)... 

Process particulate pickup may significantly increase the risk of boiler foaming. This kind of problem happens in the crossover of hot to cold water during manufacturing processes, as in rubber tire factories, food can cookers and retorts, plastic injection molding, and the like). 

In certain processes (such as rubber tire manufacture and plastic injection molding operations), it is common for a valve sequencing system to first provide hot steam followed by cold cooling water and thus for cross-contamination to occur. The result may be the stripping of passivated cooling system surfaces by steam and for the condensate to be infiltrated by cooling water. 

There are many companies today across a broad range of industries for which plastic injection molding and related upstream and downstream manufacturing processes are on the critical path to achieving successful and profitable product launches. These companies face a variety of issues that make it difficult to remain competitive ... 

Lap shear strength of the pieces of wood with plastic injection molded to them was tested on a Instron Model 4200 universal testing instrument. Experimental conditions were as follows room temperature, 23°C room relative humidity 50% crosshead speed, 2.54 mm/min with the sample in hand-fastened grips and an aluminum specimen holder. The lap shear strengths of the wood-plastic samples are summarized in Table 9. The copolymer samples were fractionated by benzene extraction. The reaction product was labeled product A. The benzene extract of the product became ben. ex. Whereas the benzene-insoluble portion of the product was labeled product B. 

Shelesh-Nezhad, K. Siores, E. Intelligent system for plastic injection molding process design. J. Mater. Process. Technol. 1997, 63, 458-462. 

The SAS described are optimized for a resolution of 0.75-1.5°. For higher resolutions up to 0.1° it is necessary to use a different method because of the restriction in size for the plastic injection-molded code disc and mask. One example of an SAS with a higher resolution is shown in Fig. 7.11.11 [13]. 

Wax or plastic patterns (replicas) of the metal parts needed are produced by plastic injection molding techniques. 

At about this time the development of plastic injection molding provided a way to produce multiple identical wax patterns. 

Integral-molded children s car seats feature handles for manual carrying. The entire seat construction is made of a thermoplastic material (PP or ABS). The opportunities and risks of standard plastic injection-molding vs. the gas injection technique (GIT) are explained using the example of the child s seat handle. 

Tools can be produced by electroforming for plastic injection molding. Electroformed molds have been used successfully for injection molding of thermoplastics, for the die casting of zinc, for the pressing of ceramic materials, and for the pressing of glass. 

For the fabrication of ultraprecise parts, monocrystalline diamond tools are used ( diamond mming ). For example, modem optics fabrication processes like plastic injection molding or precision glass molding require ultraprecise steel... 

In the subsequent text, only those machines wiU be discussed, whose major movement mechanisms (plastication, injection, mold opening/closing) are carried out hydraulically, because they are predominantly employed in the field. But it must also be stated, that fidly electric or hybrid machines (with major movements carried out partly hydraulically, partly electrically) are gaining in importance increasingly. 

There are many different types of molding processes for plastic. Injection molding is one of the most common processes (Figure 16-14). The plastic starts out in the form of small pellets. After being melted to a liquid state, the plastic is forced into a mold, known as a die, under pressure. Injection molding is used to form game pieces, dice, and similar products. 

---