A replacement PET sheet quotation arrives below your current purchase price. The material name, nominal thickness and width look similar, so purchasing asks whether production can approve the switch. Production wants to know whether the roll will feed, form, trim and stack like the sheet already running.
Both questions belong in the same comparison. A lower PET sheet roll price per kg is a useful starting point, but it does not establish equivalent material or lower cost per accepted package.
We would first put the two offers against one written specification. Then compare the material consumed and conversion cost needed to produce acceptable parts. That separates a purchasing saving from a change that merely moves cost onto the factory floor.
Why two PET quotations may cover different requirements
“PET, clear, same gauge” leaves several decisions open. One offer may include recycled content, a different surface treatment or a different roll format. Another may cover a structure selected for printing rather than your forming and downstream handling requirements.
Two sheets with the same material name and nominal gauge can run differently because formulation, surface and roll consistency are not identical. Matching the description on the quotation is therefore only the first step.
Our starting question is what the finished package must do: hold its shape, present the product clearly, separate reliably in packing, accept printing or meet a defined functional requirement. Those requirements determine which differences deserve attention.
A lower quotation can be worth pursuing. But if the offered construction or treatment changes, treat it as a material alternative requiring evaluation rather than an equivalent replacement already ready for approval.
Align material structure, recycled content, surface, dimensions and roll format
Send the same specification to every quotation contact and ask each to identify deviations explicitly. An unqualified “yes” against a broad PET description gives purchasing very little protection when the first production roll arrives.
| Comparison point | Put into the inquiry | Purchasing concern it resolves |
|---|---|---|
| Material and structure | PET or APET designation, required structure and relevant formulation requirements | Whether the offers cover the same construction |
| Recycled content | Required percentage, content basis and supporting evidence | Whether the offer meets the purchasing requirement |
| Appearance | Colour, clarity, haze, visible gels and scratch acceptance | Whether acceptable flat sheet becomes acceptable packaging |
| Surface | Treatment type, treated side and printing or bonding requirements | Whether forming and downstream conversion are both covered |
| Dimensions | Nominal thickness, thickness tolerance, width and width tolerance | Whether material consumption and machine fit are comparable |
| Roll format | Core dimensions, maximum outside diameter, net sheet weight, winding direction and splice requirements | Whether the roll suits unwinding and handling equipment |
| Application | Part drawing, forming process, tooling layout and downstream operations | Whether the quotation addresses the actual production route |
PUSITE supplies silicone-oil-coated and embedded anti-block PET/R-PET, corona-treated print-grade PET/R-PET, and three-layer PETG/APET/PETG GAG sheet options with thicknesses of 0.18–1.7 mm and widths of 250–1400 mm. Availability should be confirmed for the selected structure, gauge, colour and roll format.
That breadth makes an exact specification more useful than a request for the lowest PET sheet price. GAG construction and a particular surface treatment should be selected for an application requirement, rather than included or removed simply to change the quotation.
For anti-block sheet, distinguish silicone-oil coating from embedded anti-block. If printing or bonding follows forming, include those operations in the evaluation. Easier separation alone does not settle whether the sheet suits the complete route. We would keep a treatment that solves a demonstrated production problem and question one that has no defined purpose.
Recycled content needs a separate discussion. Specify the required percentage and whether the requirement concerns post-consumer or another recycled source. Do not assume that the term RPET defines either the percentage or the appearance acceptance. For a visible retail blister, agree colour, haze, gels and scratch expectations before comparing alternatives; a hidden support tray may have a different visual acceptance window.
Roll size is equally practical. A larger roll is useful only if the unwinder, lifting equipment and storage arrangement can handle it. Confirm net sheet weight separately from cores and packaging so the quoted kilogram basis remains clear.
Compare formed-part weight, rejects and conversion results alongside quoted price
Once the specifications align, the main question becomes how much acceptable output each offer produces. This deserves more attention than small differences in the quotation description.
We recommend comparing cost per accepted part, using measured trial consumption and the same cost boundaries for each option:
Cost per accepted part = (landed sheet cost consumed + conversion cost − realizable scrap recovery value) ÷ accepted parts produced.
Include rejected material and startup losses within the sheet consumed. Define conversion cost consistently so downtime, labour or energy is not counted twice. Credit scrap only at a recovery value your operation can actually realize, after relevant handling costs.
Start with the material mass entering the line and the number of accepted parts leaving it. Finished-part weight is useful, but it excludes the surrounding trim web, startup waste and rejects. A lighter tray does not automatically mean less purchased sheet per saleable tray.
Width and tooling layout matter here. Additional sheet width that becomes trim may increase material consumption without adding a cavity. Likewise, a lower nominal gauge is not a saving if the part needs adjustment to restore wall distribution, stiffness or handling performance.
Record average part weight and its variation alongside the agreed functional checks. If the candidate needs a different gauge to pass, compare the validated specifications and their resulting costs. Keeping the original thickness solely to preserve the appearance of an equivalent quote defeats the exercise.
The trial also needs to follow the conversion route far enough to reveal downstream losses. Depending on the package, that may include trimming, stacking, denesting, printing, bonding or packing. A sheet that forms successfully can still require additional handling or create rejects later.
When results differ, we would separate material, machine, mould and handling factors before assigning a cause. Begin with a documented baseline, record necessary adjustments and change one variable at a time where practical. Each candidate can be evaluated at suitable operating settings, but the time and adjustments needed to reach acceptable output belong in the comparison.
Paying more per kilogram may be justified when measured results show lower total cost or more reliable acceptable output. Equally, a lower-priced alternative deserves approval when it meets the same requirements and demonstrates a useful production saving. Neither conclusion follows from roll price alone.
Resolve quotation exclusions and agree trial acceptance
Before ordering trial material, make the commercial comparison equivalent too. Check currency, quotation validity, quantity basis, payment terms, delivery terms and destination. Identify which transport, packing and handling costs are included, and which remain with your operation.
Ask for proposed order quantities and delivery arrangements rather than assuming they match the existing supply. If food-contact or another application requirement applies, define the intended use and destination-market documentation needed for the selected sheet.
A PET sheet sample for thermoforming trial should represent the proposed supply specification. A small flat sample can help assess appearance, but it cannot establish roll feeding or sustained production behaviour.
Agree these points before the trial:
- The candidate structure, recycled-content requirement, surface, gauge, width and roll format.
- The machine, mould, baseline settings and adjustments to be recorded.
- The accepted-part requirements, inspection methods and defect limits.
- The measurements for sheet consumption, part weight, rejects and conversion performance.
- The downstream operations that must pass, and who will approve the results.
We would carry the approved trial specification into the purchase order and agree how later changes will be communicated. Otherwise, successful sampling and repeat supply can become two different purchasing decisions.
If the quotation leaves material structure or acceptance conditions unresolved, request clarification before ranking it. A cheap offer with open requirements is still an incomplete offer.
FAQ about comparing PET sheet quotes
Can I compare a quotation per kilogram with one per roll?
Yes, if the net sheet weight per roll and the quoted cost inclusions are defined. Divide the roll price by its net sheet weight to obtain a material price per kilogram. Keep core, packaging and delivery charges identifiable, then compare both offers on the same landed-cost basis.
What if the trial sample has a different surface or recycled content from the quotation?
Use it only for preliminary evaluation of the characteristics it represents. Request trial material matching the proposed production specification before approving the purchase. Results from a different surface or recycled-content formulation do not establish performance for the quoted sheet.
Should I reject a candidate that needs different heating settings?
No. Different settings do not automatically make the sheet unsuitable. Record the adjustments, time needed to establish stable operation, accepted output and downstream results. Reject it if it cannot meet the agreed requirements or if the resulting production cost and risk do not justify the change.
How much material should I request for a thermoforming trial?
Agree the quantity with the people running the trial based on machine threading, startup adjustment, stable operation and downstream checks. The sample must provide enough material to collect meaningful consumption and acceptance measurements. A universal sample weight cannot cover every machine, mould and package.
Share the application and comparable specifications for a sourcing review
Share your target application, part drawing, required PET structure, recycled-content requirement, thickness, width, surface, roll format, forming process, estimated quantity and destination market with PUSITE. Include the trial acceptance requirements so we can help review suitable sheet options and compare quotations on a consistent basis.