You spend a lot of money on your plastic injection molds. Maintaining and repairing them can keep them running for years, providing a valuable return on your investment.
Short of a mold totally crashing, how do you know when a mold needs repair or maintenance? This article will tell you. We identify a plastic part defect that can be a sign of mold repair and maintenance. This article is part of a series discussing injection mold maintenance and repair.
Signs That Your Injection Mold Needs Repair or Maintenance
How do you know when a mold needs maintenance or repair? Short of a complete failure, here are the 7 tell-tale signs to look for in the parts that are produced by the mold.
- #1: Short shots where parts are ejected in an incomplete state
- #2: Burrs and flashing caused when excess plastic seeps into gaps in the mold
- #3: Flow marks caused by uneven injection speed or cooling
- #4: Blistering, stress cracks, and burn marks brought on by prolonged exposure to high temperatures
- #5: Drag marks caused by a misaligned ejector system
- #6: Voids or depressions from non-uniform heating or cooling of materials
- #7: Streaks
I this article, we discuss warning sign #7, Streaks.
Injection Mold Warning Sign #7: Streaks
Discoloration, or “color streaking”, occurs when a molded part is a different color than intended. Often the discoloration is limited to a localized area or a few streaks of abnormal color on a molded part. This defect typically affects the appearance of the part without reducing its strength. A common cause of discoloration is leftover pellets in the hopper or residual resin in the nozzle or mold from a previous production run. Take the following precautions to limit the risk of discoloration in your injection-molded products:
- Ensure that workers properly clean the hopper, nozzle and mold between production runs to eliminate any residual pellets or base material
- Consider using a purging compound to remove excess color from the machine
- Ensure you or your supplier is using a color agent with adequate thermal stability
- Ensure that the masterbatch is evenly mixed for consistent color output
Choose an Injection Mold Maintenance and Repair Partner You Can Trust
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