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.  

Insert molding is an injection molding technique that can provide effective solutions for a wide range of design and production needs.

The first step is custom-building a tool to accept a solid component or product (insert). The insert is placed into the tool, and thermoplastic resin is injected into the tool cavity, coating the insert/product in a smooth layer of plastic. After cooling, the tool is opened and the product is removed and inspected.

Injection molded parts and components can be cost-effective solutions for projects spanning a breadth of industries, yet project budgets can quickly escalate if design flaws or tooling deficiencies lead to re-work. No OEM can afford the wasted time, money or materials, not to mention the lag in getting products to customers or to market.

Maintaining tight tolerances is a top priority for many complex injection molded parts and components. Understanding the nuances of resins and how they impact tight tolerances and overall product performance can be complicated. It's essential that an injection molder's engineers be looped into the project early — ideally in the design phase — to weigh in on resin selection. Otherwise, certain material characteristics that could affect tight tolerances and, ultimately, influence outcomes may be inadvertently overlooked.

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.

Quality is an important benchmark in all aspects of an injection molding project, and rightfully so. Producing high-quality plastic parts is always the goal, but how often do you stop to consider what a supplier misstep, a materials snafu or a process miscalculation could do to a project overall? Poor quality — in any form and to any degree — can have far-reaching impact. The solution is partnering with an experienced injection molder that can help you keep quality at the forefront in every aspect of a project:

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.

Medical Design & Manufacturing (MD&M) Minneapolis — the midwest’s largest medical technology trade show — is slated for October 31-November 1, 2018 at the Minneapolis Convention Center, and it’s a can’t miss event for anyone involved in the design, manufacture or distribution of medical devices and components.