A resin change or a shortage, turned into a draft substitution request your team can check.

A resin supplier writes that a grade is being discontinued, that a plant is changing, or that allocation is cut for the quarter. Someone on your side pulls both data sheets, works out which customer part numbers run on that resin, finds what each customer was told about the material, checks which listings or statements name it, and writes to the people who have to agree.

In the test, AI works on copies of substitutions you already handled and drafts the request for each one: the properties side by side, the regulatory or listing statements that may be affected, the customer parts involved and the open questions. Whether any of it holds up is for your reviewer, the person on your team who knows this work best, who compares each draft with what your team found and sent at the time. No customer sees a draft.

Two data sheets may not describe the same test. ASTM D1238 and ISO 1133 both measure melt flow, and ASTM's own note says they address the same subject but differ in technical content; it also says the flow rate is not a fundamental polymer property. For PVC resins, ISO 1628-2 says K-value and reduced viscosity are comparable only when the solution concentrations are identical. A PVC data sheet may report K-value at a stated concentration in cyclohexanone and inherent viscosity under ASTM D5225, while the pipe policy below names ASTM D1243. So the side-by-side carries each property with its method, conditions and units, and leaves a cell empty instead of converting one number into another.

A listed rating belongs to a formulation. The Plastics Pipe Institute's TR-3, 2023 edition, says each recommended rating is specific to the formulation and its mixing procedure, and that changes outside the report's policies make a new composition its listing does not cover. Part E.4 deals with swapping the resin in a PVC pipe formulation: it needs the consent of the Hydrostatic Stress Board's chair, the same D1784 cell class with the new resin as the old, named resin properties such as inherent viscosity and bulk density, and rupture data from commercially produced pipe. Part E.6 treats a new thermal stabilizer the same way, and Part E.2 covers an apparently identical ingredient from a different supplier. Most custom profile carries no PPI listing, but where a pipe or tube part does, the draft names the policy your file relies on and the questions it raises. That is what PPI publishes, not engineering advice.

A card or a listing follows a specific material. A UL Yellow Card lists a grade by color and minimum thickness, beside its flame class, its hot-wire and arc ignition ratings and its relative thermal indexes. UL's colorant FAQ says a Recognized natural resin may be colored only with a Recognized color concentrate, within its let-down limit, and that fabricators can't use non-Recognized colorants with Recognized resins. NSF's public plumbing listings run company by company, then facility by facility, so a change of plant is a line to check as well as a change of material. The draft records which card, file or listing each part rests on as your records show it, and marks what the new grade or supplier may touch.

Food-contact and building statements don't carry over by name. FDA's rules are written polymer by polymer. 21 CFR 177.1020 clears ABS of a stated composition for foods other than those containing alcohol, under conditions of use E, F and G, and 177.1010 sets its own terms for semirigid and rigid acrylics. 21 CFR 178.3790 lists polymer modifiers for rigid vinyl chloride plastics and 178.3297 lists colorants, so a substitute can need its own letter for each component. On exterior vinyl, a compound change can reopen cell class and weathering questions under AAMA 303, so the current edition decides what applies. The draft quotes each statement you hold and lists the ones this change may reopen, and it decides none of them. This is not legal advice.

The where-used list is rarely one report. A resin can sit behind a compound code, a color code, a co-extruded cap layer or an approved list a customer signed years ago. One hoist maker's published supplier change process asks for its form with 90 days' notice before a change, and your customers' agreements may say the same, or stricter. The draft pulls part numbers from the exports and job records you send, notes where a part's material is only described in words, and separates customers with a written approval from those buying to a shared spec. It then lists what someone has to answer before any customer hears about it: how long stock lasts, whether the replacement has been run on your lines, what has been tested, and who signs. The owner names your reviewer, usually the quality manager who handled these requests, and they check every draft against what your team found and sent.

With a yes, each new supplier notice or shortage gets a draft request for about 30 days.

Your quality or engineering lead reads every draft, decides whether the substitution can go ahead and writes to the customer. No request goes out, no compliance statement is signed and no material changes on a draft's say-so, and the scoring table stays in use through the month.