Five Parameters for Injection Molding Parts Design
Injection molded parts design evolves through many phases of development which are very critical as design changes or corrections can be made any more without significantly adding cost or projects delays. Before all the parts are released to a molder for production. But plastic part design mistakes will be uncovered only after first article parts are inspected and evaluated by the project team, even with today’s booming technology such as 3D CAD interference checks, rapid prototyping. It is impossible to predict potential problem for an injection molded part. Luckily, there is a very simple, low-cost method for minimizing potential problems and virtually ensuring perfect parts. Let’s read this article aboutInjection Molding Parts Design.
Every mold maker has his or her own tooling preferences and techniques that have a significant effect on part design for molding parts. These subjective preferences can influence material options and consequences, critical tolerances, sink marks, steel safe areas, gates location, shut-off angles, draft angle orientation, texture, scheduling of critical start-up phase and secondary operations and fixtures.
Materials are usually chosen in the early stage of design process. A designer may discover certain high-performance resins may not be ideally suited for a molder due to viscosity, high glass content or crystallinity. Mold making choose a resin for specific physical or chemical-resistance properties but it is not easy to mold or maintain specified tolerance. Molders should be in agreement with specified resins and overall part requirements as they will be required to actually mold the parts.
Although designers provide generous tolerances, there are many times tight tolerances must be maintained for fit, function or appearance. One of the greatest challenges is providing enough clearance in the design for tolerance variation. Tolerance variation depends on materials, process control and tool design. It’s important that designers discuss reasonable critical tolerance specifications with a molder and consider options for possible mold revisions. Molders could offer suggestions for maintaining tight tolerance control, including post machining, fixture and gate locations.
Designers will faced with he challenge of avoiding sink marks in Injection Molded Parts. Molders are reluctant to guarantee a cosmetic surface will be devoid of any sink marks if ribs and bosses are added to the opposite side. The challenge is compounded when the ribs and bosses include draft. If establish acceptable surface quality with the molder, then some production problems can be avoided.
When people design injection molded parts, they will be faced with he details requiring tight tolerances such as snap fits, alignment features or interlocking parts. It’s easy to align and match these features in CAD, but it is not easy to produce repeatedly during production.
Gate location should be specified by a designer, molder and tool maker ideally. Gate location is critical to virtually every attribute of an injection molded part. It affects appearance, warp, tolerances, surface finish, wall thickness, molded in stresses and physical properties, to name a few.
TEAM Rapid is one of the leadingCustom Injection Molding Companies in China. We have an in-depth rapid manufacturing knowledge of designing parts in numerous processes and materials, including plastics, metals and composites. If you need any help on your injection molding projects, contact us at [email protected] today!
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