Meaning
Establishing the financial viability of a molded component requires a structured determination of all cost components associated with producing a single unit. This estimation is performed through a piece price calculation, which integrates material costs, cycle time, machine rate, post-molding operations and scrap rate. It forms the commercial basis for supply agreements between the molding company and the customer.
Material Allocation
Polymer resin represents a major portion of the unit cost of a molded part. Accurate piece price calculation accounts for the part weight and sprue weight, balancing these against the cost of virgin material. If the regrind ratio is ignored, the material cost estimation will be incorrect, affecting the margin of the project.
Process Overhead
Machine hourly rates and cycle times dictate the processing cost of each shot. The calculation incorporates the multi-cavity tool efficiency, dividing the hourly machine rate by the number of parts produced per hour to find the processing cost per unit. This step ensures that the cost of running larger, more expensive presses is recovered.
Risk Management
Yield rates fluctuate during production due to startup scrap and quality audits. Including a realistic scrap factor in the piece price calculation prevents unexpected losses during mass production, protecting the molder from margin erosion caused by minor process instability.
