Specifically designed for the practicing molder, this workshop focuses on developing new and enhancing existing shop floor troubleshooting skills for solving molded-part defects and improving part quality problems. Each day, participants will rotate through six to eight microprocessor-controlled machines that have been set up with special, case-study molds. These molds have been modified over time to produce a specific molded part defect under a given set of less-than-optimal molding conditions. Participants will analyze and attempt to solve real molding problems.
This two-and-one-half-day workshop is geared to those who wish to improve their knowledge of thermoplastic injection molding. It is designed to provide the greatest value possible to injection molding practitioners who troubleshoot problem parts to increase molding efficiency and decrease part defects/rejects. Beyond machine operators, a variety of others can benefit from the workshop, including process and project engineers, manufacturing engineers, and team leaders.
1. Surface Defects
- Flow lines and jetting
- Splay (moisture or trapped air)
- Haze, blush, and poor gloss
- Orange peel and surface ripples
- Gate blush and gate splay
2. Burning and Contamination Problems
- Burn marks and black specks
- Burn streaks
- Discoloration or poor color match
3. Physical Problems
- Flash and short shots
- Sink marks
- Vacuum voids and bubbles
- Blisters and delamination
4. Geometry Maintenance Problems
- Under- or over-sized dimensions
- Poor dimensional repeatability (poor Cpk)
- Warpage and bowing
5. Structural Defects
- Cracking, crazing, and brittleness
- Weld lines
- Stuck parts and pin push marks
- Long gates and plugged gates
- Drag marks and mold damage
6. Troubleshooting Procedures and Logic
- How to effectively approach, analyze, and implement troubleshooting procedures.
7. Exploring Root Causes
- Explore the root causes of the various defects from the perspective of the plastic material as it fills, compresses, and cools within the cavity.
8. Part Defectives and Potential Solutions
- Some attention will be given to potential design-related problems, but the emphasis will be on how to optimize the part quality with process-related solutions.
9. Troubleshooting Guides (The Good, The Bad, The Efficient)
- A comparison of the different troubleshooting guide formats, including which tend to be most effective for solving molded part problems.
10. Interpreting Velocity and Pressure Shot Traces
- The graphical outputs of the injection pressure and injection velocity traces provide a window into the mold that was not previously available on older machines. Proper interpretation of these shot traces can simplify and speed up the troubleshooting process.
11. Applying Designed Experiments for Advanced Troubleshooting
- Insight into how and when to implement designed experiments (DOEs) for difficult-to-solve defects or quality problems with poor repeatability.
12. Evaluating Attendees' Molded Part Samples
- Defective part samples brought in by the participants will be discussed in a group format. An understanding by the participants of the processing conditions or a current process set-up sheet will greatly facilitate this discussion.