Meaning
Production metric that quantifies the percentage of raw material converted into non-conforming parts or waste during a manufacturing run assists in tracking process efficiency. A scrap rate calculation is performed by dividing the total weight of scrap generated by the total weight of resin consumed in the run. This metric is a primary driver of cost control in high-volume injection molding and extrusion plants.
Production Efficiency
Monitoring this calculation allows plant managers to identify machines or molds that are performing poorly.
Financial Consequence
High scrap rates quickly erode the profitability of a molding project, especially when using expensive engineering resins. Scrap material that cannot be recycled as regrind must be written off as a total loss, adding to the unit cost of the acceptable parts. This financial impact makes waste reduction a priority for process engineers.
Process Optimization
Analyzing the trends in these calculation results helps engineers justify investments in better tooling or process controls. If a mold consistently generates high scrap due to part flash, the tool is scheduled for maintenance or retrofitted with a more rigid clamping system. This action restores the process to its optimal operating window, lowering the cost per part produced.
