- Silver streaks
- Cold slug
- Sink Mark
- Unmelted particles
- Black Spots
“Quality control” issues occur when parts have been successfully produced in the past or during trials, but are now out of specification. These problems are the result of something in the process changing, the material, or machine and tool.
“Start-up” problems occur during the launch of a new tool or machine.
To resolve Start-up problems, the material’s process window must first be determined to ensure that there is a set of conditions that can make good parts.