Mold maintenance

If a self-threading screw can be substituted, it will not only appreciably decrease mold maintenance and mold cost but most likely, with proper type selection, also give better holding power. A screw that has a thin thread with relatively deep flights can give high holding power. If the screw or plastic is preheated... 

Wash-action erosion of cavities is minimal and mold maintenance is low since melt flow length is short. 

Mold design and moldmaking IMM reaches moldmak-ers, where product development is further refined, and moldmaking departments inside custom and captive molding operations, where mold maintenance and repair occurs. Without the expertise of the moldmaker, products cannot be produced. 

The crest (tip) of the stud should be designed so that it is slightly larger than a standard size ejector pin if this is not the case, this portion of the mold not only becomes more expensive to produce but also the cost of mold maintenance will increase. Thin ejector pins break fairly easily and frequently, and their replacement is easier and less costly if they do not have to be specially made. 

At our molders, low-volume or special items included pre-colored materials, abrasive compounds, and purchased or consigned components. At the one participant where pre-colored material was an issue, the per-pound material activity cost for pre-colored material was almost triple that for white or black material. We also found that abrasive compounds caused accelerated mold deterioration and higher mold maintenance costs at two of our sites. Finally, purchased components generally required more purchasing and quality control per dollar purchased than compounds and, at one site, the storage and handling of customer-consigned components cost the company close to 30,000 per year. 

For the basic compression, transfer, and injection molding processes, a wide variety of mold types may be considered. Decisions as to the optimum type will often be based on the production volume anticipated and the allowable final part cost, including mold maintenance and amortization costs and hourly cost rates for molding machine and labor. 

In general the size of the pores depends, among other factors, on the particle size of the aggregate. Particle size is the most important parameter in the production of ceramic products it must be optimized to ensure that the desired mechanical and physical properties are achieved. The majority of ceramic products are manufactured by the process of slip casting in a mold. Maintenance of the desired PSD requires control of the dispersion stabUity of the ceramic shp. Like all ceramic materials and castables, in alumina refractories a proper PSD is of importance. 

Examples of molding circuits and automation circuits Mold Desi0n and Maintenance for Dia fnostics (20 hour Module) Design considerations Mold design basics Cavity and core construction Heat transfer considerations Cold runner molds Hot runner systems Freeing mechanism/part ejection Mold maintenance... 

Mold maintenance depends very strongly on the specific conditions of the mold. It is therefore possible that the same rules apply as for standard molds. It is also often necessary to consider the specifics, especially mechanical cleaning methods, which can cause damage in the micro-structured molded parts. 

These plastic mold steels are becoming increasingly important for small and medium mold sizes. As well as avoiding corrosion by aggressive plastics materials such as PVC, these steels reduce the mold maintenance effort required, especially during... 

FiGURE 5.51 Mold maintenance costs, which should be considered in the parts price... 

Processors expense allocations can vary even more widely than those of distributors, depending on their size, the extent to which their operations are fully integrated, and whether they do custom, proprietary, captive work, or some combination of the foregoing. The following example is for a custom injection molder and assumes smaller size and limited integration, for example, mold maintenance, but not mold building, assembly but not decorating, etc. 

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