When you approach a custom injection molder to produce complex plastic parts or components, determining if the product is suitable for a streamlined injection molding process is one of the first steps.
It can occur in just about any injection-molded part or product — yet the experienced injection molder knows how to eliminate warpage from the production cycle and maintain a steady throughput of high-quality product that meets all customer specifications, including dimensional accuracy and tight tolerances.
For many OEMs, multi-material injection molding is a smart and versatile solution to producing complex components and parts. The ability to incorporate multiple polymers, metals and other non-plastics into the molding process to accommodate threaded holes, inserts, lenses, etc., simplifies assembly and generally enhances end-product performance.
Not taking the time to properly determine shrink rate can have a big impact on the quality of an injection molded part's geometry, performance, and appearance.
To facilitate this calculation, materials suppliers typically provide shrink rate numbers based on ASTM Standard D955 and a .125-inch thick plaque with a specific gating size and location. Although a good place to start, this value is usually not accurate enough for many products, especially critical, highly complex parts.
Almost any reasonable design looks good on paper or even as a prototype, but that doesn’t mean it’s a sure thing when it comes to manufacturing it. On the other hand, using Design for Manufacturability (DfM) to improve part design, injection molding processes and material selection ensures a product or component can be manufactured in a streamlined, efficient, validated, and repeatable way — saving time and money.
Cooling is one of the most critical parts of the injection molding process. Not only is it the longest part of the process — taking up more than 80 percent of the cycle time — but it's not smart to cut corners when it comes to cooling. In order to achieve precise, tight tolerances, the cooling rate must be carefully controlled — not rushed to completion.
There is more than one way to produce an effective plastic injection-molded part. The question is: is complex tool design the answer or is it better to utilize machining technologies to complete the task?
Tooling is arguably the most important part of the entire injection molding process. Not only does the tool need to be perfect to ensure all design specifications are met, but it’s also one of the most expensive, time-consuming fixes if something isn’t right—especially if you’re working with a third-party toolmaker. Working with an outside toolmaker for projects requires a lot of back and forth communication, leaving room for misinterpretations and sometimes delayed responses.
Injection molding is a dynamic, complex process that, simply by the nature of its many variables, requires some testing and adjustments to get it just right before you can start production. Some manufacturers, however, choose to focus on completing the mold first and then build the process around the finalized mold, thinking this saves time and money. However, this approach typically results in production problems that slow the whole process down, and reduces quality and repeatability.