Top 10 Common Mold Mistakes, Mishaps And Disasters to Watch Out For

1. When building a mold with a slide/tear tab feature on a lid (two-cavity), we failed to realize that we designed the slide on the core side and at the bottom of the mold on a free fall part ejection. When the part went to eject it basically just stayed on the slide (gravity). We were unable to turn the mold upside down or rotate cores and cavities because of water pick ups, so a new stack up was required.
2. Designed an entire mold from the inside of the part (left hand instead of right hand) and it wasn’t caught until sampling.
3. Set a new cavity stack on a CNC EDM and promptly tried to burn the cavity shape 2 inches off location and through the magnetic vise.
4. Mirrored the part data by accident and cut the part into the mold inverted.
5. Drilled water through a diamond-finished cavity.
6. Left the cover off the bed of the pick-up to deliver a mold in halves and forgot there was sand from a weekend yard project—the mold had to be completely torn back apart and cleaned. Six more hours of work for free.
7. Welded a block cold and it cracked.
8. Did not clamp the block down to the table before cutting.
9. Did not secure a mold well in the bed of my pick-up truck and when I had to stop fast in stop-and-go traffic, it slid forward and bent the bed of the truck.
10. To sum it up in two words: wrong assumptions. Actually assuming anything in the mold design and fabrication process is a recipe for disaster. The biggest mistakes are usually the ones made in the planning or quoting stages. This is where the temptation is great for rushing through the evaluation and assessment. You really need to do some level of mold design either on paper or in CAD to ensure against a calamity downstream.

This list is compiled from the most popular answers to a reader poll.