Spray-free materials on the injection molding process and mold requirements:
High gloss and high brightness, mold using high gloss steam mold, injection molding parameters using high temperature and pressure state;
Mineral / metal powder added high mold material wear-resistant material;
For a single gate mold, the size of the product needs to select the appropriate location and the plastic into the plastic mouth shape;
For multi-plastic injection molding products, the way into the plastic need to use the order into the plastic.
Spray-free materials on the product structure design requirements:
Less holes
Less tendons bit
Avoid complex structures
Common spray-free resins, mainly ABS, PMMA / ABS, PC / ABS, high gloss ABS, these materials are suitable for use in products that require better surface gloss, but not all of the product structure can be used spray-free materials Because, especially for the surface has a clear hollow structure; the back of the product has more screws, buckles, stiffeners; product wall thickness, the middle part of the thinner.
Three kinds of typical product structure are easy to produce flow marks and welding lines, but not limited to the above three kinds of products, complex product structure are easy to produce these problems, and to improve these issues must be product structure, mold structure, molding technology, material four In the meantime, the application of spraying-free materials in practical products requires rich experience and systematic solutions to ensure the smooth progress of the project.
1. Appearance of the product has obvious hole-like structure
So that the melt in the filling process, the hole in the peripheral part of the flow re-convergence, and then in the convergence of the weld line problems arising for the ordinary dye material, the weld line is only a small line, and for spray-free material to Said that the 'visual' welding line on both sides of the color there will be differences, so that the weld lines appear more obvious, so the apparent surface of the hole-like product structure, generally not suitable for direct injection-free injection molding materials directly.
2. Product back more screws, buckles, ribs and other product mix
Injection molding process, filling the screw column parts, the melt will produce diversion, part of the melt vertical filling screw / buckle and other structures, part of the melt laterally filled product appearance surface, resulting in the amount of lateral flow of plastic reduced, so in Due to the flow of the parts of the flow of changes in the status of the problem of flow marks.
3. Products uneven wall thickness, the middle part of the structure of thinning
Filling process, compared to the middle of the thinning site, the flow velocity on both sides was significantly faster than the thinning of the site, both sides of the middle to form a coating, it will be formed in the thinning of the distal part of the bonding line.
to sum up:
Although spray-free has many benefits, it is true that these applicability is relatively limited and product defects are more prominent for these difficult-to-handle product structures. However, spray-free products are also widely used in refrigerator panels, air conditioning panels, , Speaker panel, base, LCD TV panel, small household appliances shell, cosmetics packaging.