Rejected injection molded parts are plastic parts that your customer will not purchase either because of some type of defect involving the aesthetics of the part or it is outside the quality tolerances that either you or the customer has set.
Did you know that every part must be purchased? If your customer does not buy it, then you better believe that you do…and at a premium price. Maybe even more so than you think. Here are some things to think about to help you realize just how important you scrap rate is and much it is costing you.
For this example, I will be referring to a one cavity tool. The cost will vary on multi-cavity tools depending on the cavitation.
Here are five ways scrap is costing you:
- The cost of one rejected part begins with your machine running cost and all the factors you have included in this. For example, machine cost, operator cost, utilities, and automation must all be considered in your running cost.
- Second is the total Time it takes to mold the rejected part.
- Third is the Time and labor it takes to find the rejected part. Assuming that there’s only one reject which is NEVER the case, you could be going back through hours of production.
- Fourth is the cost in TIME and Labor to dispose of the part. Are you just going to toss it in the garbage or regrind it and reuse the material? Regrinding is going to add to your expense. You may save a little on the material cost but depending on your work cell set-up the labor in regrinding usually outweighs that savings.
- Lastly, there’s the inevitable cost of re-molding and making the part all over again hoping that the next one fill be good.
The point to all this is that the cost to your company of making reject parts drastically reduces your profitability.
Just one reject part can approximately cost you four times the cost of what it takes to make one good part. Even worse, the profit loss in making a reject part may take you approximately up to 7 good parts to recover your loses.
You can easily see the importance of monitoring your scrap rate and also Identifying all the specific defects because the cost to your profits is at stake. Remember in injection molding we sell TIME. If you're making scrap parts, it is a complete waste of time. Running good parts and selling them to your customer at your quoted cycle time is your goal.
Purging compounds dramatically reduce scrap and help you sell MORE TIME.
Ready to reduce your production downtime to protect your profits? Learn more about how purging compounds and process efficiency work in tandem.