Injection Molding

Injection Molding: Fill Based on Volume, Not Weight
Most parts should be 90-99% full after first-stage—by volume not weight. Here’s why that’s important and how to make a first-stage-only part.

Get Free Guidance on Molding Resins
Mobile Specs app and website provide processing parameters on thousands of resins … at no cost.

Injection Molding: Safety First—Know the Compatibility of Different Resins
Certain materials don’t play well together when mixed. So it’s best not to. Here are some guidelines.

Injection Molding: Process Documentation Is Crucial to Making ‘Identical’ Parts
Use a machine/mold setup sheet to document plastic parameters and use them on any acceptable machine into which the mold is placed.

Injection Molding: A Practical Approach to Calculating Residence Time
Toss the formulas. The best way to determine residence time is to conduct a simple experiment.

Injection Molding: How Backpressure Adjustments Influence Shot Size
Raising backpressure results in increasing shot size, which can cause a host of other problems.

Tooling: Hot Sprues—Mold a Disk or Not?
Having a hot sprue shut off against the parting line versus intentionally molding a thin disk has been the subject of controversy for many years.

Injection Molding: How to Set Barrel Zone Temps
Start by picking a target melt temperature, and double-check data sheets for the resin supplier’s recommendations. Now for the rest...

Tooling: Tunnel Gates for Processors, Part 2
What you need to know to overcome problems out on the production floor.

Injection Molding: Melting Amorphous vs. Semi-Crystalline Plastics
Understanding the differences in how each melts is crucial to obtaining melt uniformity.