Custom injection molding is a viable solution for many projects, but there’s often hesitation in using it because of confusion about which material matches the job. While “thermoplastic” and “thermoset” sound similar and both are appropriate for a wide range of applications, the material properties of these two resin categories and how they behave during processing ultimately reveal the best choice for your injection molding project.
Some injection molders claim to provide custom services, but the industry lacks a clear definition of what “custom” really means — resulting in some manufacturers contracting with molders that are woefully unqualified to accurately produce highly specialized designs. Just because a molder can facilitate development of an original tool doesn’t constitute a truly custom service (or ensure a desirable outcome). Many of these molders are limited to producing simplistic designs and lack the ability to engineer complex plastic parts with precise specifications and tight tolerances.
The practice and purpose of qualifying a tool is at the very core of scientific molding. This critical step ensures consistent and repeatable production of flawless molded parts by having engineers push the tool relentlessly under realistic conditions (and sometimes beyond). Their goal is to identify and correct weaknesses before the tool is called into action.
Here’s a look at the basic step-by-step process of scientifically qualifying a tool:
The Kaysun Blog is a valuable year-round resource for advice and information about complex injection molding. We have our subscribers to thank for its continued popularity, and look forward to providing you with even more helpful insights throughout 2019.
For now, let’s take a look back at the four most popular blog posts of 2018:
Up until the 1940s achieving necessary product functionality at the lowest cost was usually done by any means necessary. However, during the height of World War II the scarcity of materials and components drove General Electric engineers to find material substitutes, many of which reduced project costs and improved overall product performance. Thus, the approach of finding cost-effective manufacturing solutions without compromising product functionality or quality — later dubbed “value engineering” — was born.
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.