Put both quotes on the same basis
A frozen-food co-packer may receive one printed-rollstock quote by mass and another by roll length. Neither unit price alone answers how much packaging material each acceptable finished pack consumes. Start with the same structure, web width, approved print repeat, number of lanes, artwork and delivery scope. A cheaper quote for a different film is a separate technical proposal.
Ask whether the stated mass is film-only or includes cores and other packing. For length-based quotes, distinguish nominal ordered length from the length actually supplied and accepted. Record any quantity tolerance and how the invoice will be settled. Keep setup, freight and other charges visible so an included charge is not added again.
Convert confirmed material into potential packs
For an uncomplicated single-lane layout, potential repeats equal usable film length divided by the approved cut repeat, with both expressed in the same units. If the layout has multiple lanes, use the confirmed number of finished packs per repeat. The line owner should verify the layout; do not infer it from the printed artwork.
ASTM D4321-24 addresses plastic-film yield as area per unit mass. This is different from the number of saleable packs produced on a filling line. For a mass-based quotation, ask for the relevant documented film yield or verified length conversion. Do not insert the density of one resin into a multilayer-laminate calculation and present the result as measured roll length.
| Input | Evidence to request | Keep separate |
|---|---|---|
| Film supplied | Accepted length, or film-only mass with documented yield | Core and shipping-pack mass |
| Pack geometry | Web width, cut repeat and confirmed layout | Finished bag dimensions alone |
| Loss record | Setup use and subsequent rejects by category | Estimates versus observed trial results |
| Price scope | Film charge and individually identified extras | Filling labor, downtime and product losses |
Reconcile each loss once
Use a single loss ledger with mutually exclusive categories. For example, material consumed during setup may already include the first splice adjustment. Deducting that same length again under splice waste understates output. If the co-packer reports an accepted-pack count directly for a known amount of film, do not subtract the already-rejected packs from that count a second time.
Label planning assumptions separately from trial measurements. A short trial may miss changeovers or later running problems. Ask what period, line settings, product, roll lot and acceptance rules the record covers before treating its yield as a repeatable production estimate.
Worked example: theoretical repeats versus accepted output
Hypothetical arithmetic, not a PM quote or recommended waste allowance: a single-lane roll contains 6,000 m of film with a confirmed 300 mm cut repeat. That gives 20,000 theoretical repeats. Suppose setup consumes 200 repeats and another 300 distinct packs are rejected during running. The remaining output is 19,500 acceptable packs.
A hypothetical $900 film charge equals $0.045 per theoretical repeat, but approximately $0.0462 per acceptable pack. Those figures exclude setup charges, freight, labor, food loss and downtime. If comparing a broader delivered-material cost, define its numerator explicitly and apply the same scope to both offers. Do not call a film-only result the total cost of producing a filled bag.
Use the calculation to improve the quotation request
Send the proposed structure, width, repeat, lanes, quantity basis and loss-record assumptions with the printed-rollstock specification brief. Keep the splice specification attached where it affects the line. Missing yield evidence is a question to resolve, not a zero-loss assumption.
PM Packaging quotes printed rollstock for frozen-food packaging projects against the actual line and product requirements. Rollstock quantities and setup are quoted separately; a bag-order MOQ does not establish a rollstock minimum. P&M provides U.S.-based support with owned-factory packaging production in Guangdong, China. A favorable calculation still requires line trials and frozen-package validation for the selected construction.
General educational information only. Materials, performance, compliance, claims, quantities, and timing require confirmation for the exact packaging project.