Category Archives: Plastic


Nov28
Understanding Melt Flow Index (MFI) for Quality Control in Plastic Injection Molding

post on November 28, 2024

The “Melt Flow Index” (MFI) of plastic refers to the weight (in grams) of molten plastic that flows through a standardized tube with a specific diameter under a defined load (in kilograms) and temperature (in °C) within a set period … Continue reading →

Plastic     WorkingBear    Views (6,184)     comment (0)

May03
Trouble Shooting Guide for Plastic Injection

post on May 3, 2016

Trouble Suggested Remedies (Solutions) DIMENSIONAL PROBLEMS Shot-to-shot dimensional variations Increase injection pressure Maintain uniform pad (cushion) Repair leaking back flow value if pad cannot be maintained Increase screw forward time Maintain uniform cycle Eliminate un-melted particles (see below) Use larger … Continue reading →

Plastic, Quality     WorkingBear    Views (5,397)     comment (0)

Jun24
Case study for the mold-in insert screw boss broken

post on June 24, 2015

In a previous discussion, WorkingBear identified potential root causes for screw boss cracking after mold-in screw nut insertion. Following a complaint from the field, we asked EMS and the plastic injection supplier to double-check their inventory and found that approximately … Continue reading →

Design, Plastic, Quality     WorkingBear    Views (14,975)     comment (0)
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May01
Why Do Screw Bosses Crack After Mold-In Screw Inserts? Common Causes and Solutions

post on May 1, 2015

This story is long-standing memory, but WorkingBear is documenting it here for reference and as a learning record. One day, we received a customer complaint regarding a product with a plastic housing that had cracked. The issue was visually striking, … Continue reading →

Design, Manufacture, Plastic, Quality     WorkingBear    Views (24,313)     comments (8)
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