Hydraulics and industrial maintenance
Plastics purging cost
Calculate recorded or assumed injection-molding and extrusion changeover expense from purge material, transition resin, separate scrap, labor and downtime.
Your inputs
Complete the fields for your selected method. Zero means intentionally zero, not unknown. Currency selection labels amounts; it does not convert exchange rates.
How this calculation works
cost/changeover = purge mass × price/mass + transition resin mass × price/mass + separate scrap cost + labor hours × labor rate + downtime hours × non-labor machine rate + other costs
For plastics processing only, not gas-line, tank, HVAC, medical or hazardous-system purging. Input material consumption from weighed usage, invoices or an explicit estimate; no barrel volume, purge quantity, process temperature or safe procedure is prescribed. Do not count resin or purge material again in scrap, and exclude labor from the machine rate when entering labor separately. Opportunity-cost downtime rates are assumptions, not guaranteed recoverable cash savings. Monthly and annual totals assume the same entered frequency throughout.
What information do I need?
Use records for the same job, equipment or accounting period. Only the fields for your selected entry method are required. An unknown amount is not zero.
Input definitions and where to find them
- Purge material consumed per changeover (lb): Use your own matching records, supplier quote or explicitly stated estimate. The prefilled figure is illustrative; zero means an explicitly excluded or zero cost, not an unknown value.
- Purge material price per matching mass (currency/lb): Use your own matching records, supplier quote or explicitly stated estimate. The prefilled figure is illustrative; zero means an explicitly excluded or zero cost, not an unknown value.
- Additional transition resin consumed (lb): Use your own matching records, supplier quote or explicitly stated estimate. The prefilled figure is illustrative; zero means an explicitly excluded or zero cost, not an unknown value.
- Transition resin price per matching mass (currency/lb): Use your own matching records, supplier quote or explicitly stated estimate. The prefilled figure is illustrative; zero means an explicitly excluded or zero cost, not an unknown value.
- Separate startup scrap cost not included in material above (selected currency): Use your own matching records, supplier quote or explicitly stated estimate. The prefilled figure is illustrative; zero means an explicitly excluded or zero cost, not an unknown value.
- Total person-hours per changeover (person-hours): Use your own matching records, supplier quote or explicitly stated estimate. The prefilled figure is illustrative; zero means an explicitly excluded or zero cost, not an unknown value.
- Loaded labor cost per person-hour (selected currency): Use your own matching records, supplier quote or explicitly stated estimate. The prefilled figure is illustrative; zero means an explicitly excluded or zero cost, not an unknown value.
- Machine downtime per changeover (hours): Use your own matching records, supplier quote or explicitly stated estimate. The prefilled figure is illustrative; zero means an explicitly excluded or zero cost, not an unknown value.
- Non-labor machine downtime cost per hour (selected currency): Use your own matching records, supplier quote or explicitly stated estimate. The prefilled figure is illustrative; zero means an explicitly excluded or zero cost, not an unknown value.
- Other costs per changeover not already included (selected currency): Use your own matching records, supplier quote or explicitly stated estimate. The prefilled figure is illustrative; zero means an explicitly excluded or zero cost, not an unknown value.
- Changeovers per month (changes): Use your own matching records, supplier quote or explicitly stated estimate. The prefilled figure is illustrative; zero means an explicitly excluded or zero cost, not an unknown value.
Use the Where to find this value controls beside the inputs for available work-it-out helpers. Estimates remain your assumptions; a helper does not verify the source figures.
Worked example
Example amounts use US dollars (USD).
Example answer: Cost per purging changeover is $150.00 for the illustrative inputs below.
Example inputs
- Purge material consumed per changeover: 10.00 lb
- Purge material price per matching mass: 5.00 currency/lb
- Additional transition resin consumed: 5.00 lb
- Transition resin price per matching mass: 2.00 currency/lb
- Separate startup scrap cost not included in material above: $20.00
- Total person-hours per changeover: 1.00 person-hours
- Loaded labor cost per person-hour: $30.00
- Machine downtime per changeover: 0.50 hours
- Non-labor machine downtime cost per hour: $80.00
- Other costs per changeover not already included: $0.00
- Changeovers per month: 20 changes
- Cost per purging changeover
- $150.00
- Monthly changeover cost
- $3,000.00
- Annual cost at the same monthly frequency
- $36,000.00
- Purge and transition material cost
- $60.00
- Separate scrap cost
- $20.00
- Labor cost
- $30.00
- Non-labor machine downtime cost
- $40.00
These illustrative values are not recommended rates or industry averages. Replace every example input with your own figures.
Use the result well
Calculate recorded or assumed injection-molding and extrusion changeover expense from purge material, transition resin, separate scrap, labor and downtime.
Keep inputs on the same scope and time basis. Calculations retain precision internally; displayed values generally round to two decimal places, with extra precision for very small values and whole-unit rounding where required. Economic comparisons describe your supplied assumptions and do not guarantee future results.
This tool provides business arithmetic. It does not approve engineering designs, establish legal or tax treatment, select equipment or certify safe operating conditions.