For a buyer new to composites, the development process can feel opaque: a drawing goes out, a sample comes back, and the relationship between the two is unclear. This article sets out the stages a composite part normally passes through, what happens in each, and what the customer needs to decide before the next stage can start.
The sequence applies to pultruded profiles, roll-wrapped tubes, compression molded parts and autoclaved components, with the tooling step differing most between them.
Stage 1: RFQ and technical review
A useful RFQ contains the drawing or 3D model, the annual and first-order quantities, the load case or application, the cosmetic requirement, and the mating parts. From those, the factory can select a process and propose a tolerance band.
This is where the most valuable engineering happens. If the RFQ specifies only dimensions, the quotation will be based on assumptions, and assumptions become disputes later. Expect a good supplier to come back with questions — that is a sign the drawing was read.
Stage 2: DFM feedback and quotation
The supplier reviews the part for manufacturability and returns comments: draft angles, radii, wall uniformity, parting line position, insert strategy, and any dimension that cannot be held economically. The quotation should be tiered by volume, because composite economics change sharply with quantity, and it should state what is included — tooling, samples, finishing, inspection, packaging.
Decision gate: approve the design changes, the process route and the volume tier.
Stage 3: Tooling
Tooling is the longest lead item in most programmes. Pultrusion dies, roll-wrapping mandrels, compression molds and autoclave tools all have their own design and build time, and the cosmetic requirement drives how much polishing and fitting the tool needs.
While the tool is being built, the process specification is written: layup, cure cycle, inspection plan and acceptance criteria. Doing this in parallel with tooling is what keeps a programme on schedule.
Decision gate: approve the tool design and freeze the drawing. Changes after this point restart the clock.
Stage 4: First article sample
The first parts from the production tool — not from a prototype tool — are the real test. They should be accompanied by a dimensional report, material and cure records, and, for cosmetic parts, a physical sample for approval against the agreed standard.
Expect the first article to reveal something. That is normal. What matters is whether the supplier identifies the cause and corrects the tool or the process, rather than adjusting the part by hand.
Decision gate: sign the master sample and the dimensional report. This becomes the reference for the life of the programme.
Stage 5: Validation and qualification
Depending on the industry, this stage includes mechanical testing, environmental ageing, UV or salt spray exposure, and for automotive parts the PPAP documentation set. Validation is the customer's responsibility in most cases, but the supplier must provide the material data, coupons and process records that make it possible.
Building validation into the schedule at this point — rather than after the first shipment — is what prevents a production batch from being held at the border of a customer's quality gate.
Stage 6: Pre-production run
A small production run confirms that the process is stable at rate: cycle times, yield, inspection time and packaging. This is where a process that worked in the sample cell either scales or reveals a bottleneck — usually in finishing, which is labour-intensive and hard to accelerate.
Decision gate: approve the pre-production batch and confirm the delivery schedule.
Stage 7: Mass production and change control
Once in production, the discipline shifts to consistency: retaining the master sample, auditing the process, recording cure cycles, and controlling changes. Any change to material, sub-supplier or process should be notified and approved before it is implemented, because an unannounced change can invalidate a customer's validation.
The delays that are avoidable
- Unclear cosmetic standard. The single most common cause of a failed first article.
- Late drawing changes. Every change after tooling restart costs both tooling time and queue position.
- Missing mating parts. Tolerances cannot be optimised against a part nobody has measured.
- Validation planned after production. If testing is scheduled after the first shipment, the schedule has a hidden failure built in.
- Underestimating finishing. Cosmetic parts take time to polish and inspect; quoting a schedule that assumes otherwise creates a permanent backlog.
How Shengtian runs programmes
Guangdong Shengtian Technology manages composite programmes from RFQ through to container shipments, with in-house tooling, pultrusion, roll-winding, compression molding, autoclave curing, machining and dust-free painting under one roof. That vertical integration shortens the loop between a design question and a physical answer: a tool can be modified, a sample re-run and a cosmetic standard re-approved without coordinating three separate suppliers.
For new programmes we ask for the drawing, the application and the target volume, and return a process recommendation with a stage-by-stage schedule — including the decisions we need from you at each gate.
