Define prewashing and setting separately
Prewashing generally describes a washing stage before sale or final delivery. Setting describes a process intended to stabilise dimensions or shape under controlled conditions; its nature depends on the textile and route. They are not identical operations.
Do not assume every microfiber cloth is prewashed or heat-set, or that every use of those terms describes the same conditions. Ask which stage applies to the selected item and what finished requirement it is intended to meet.
Why a cloth can change after care
Fibres, yarns, loop geometry, finishing and residual tensions can contribute to a dimensional or shape change. Edges and labels may behave differently from the main fabric. Several causes can coexist, so a change does not automatically identify one missing factory operation.
Inspect more than overall size: skew, curl, edge puckering and a change between face and reverse can affect handling or retail appearance. Keep observations and suspected causes separate until the supplier has investigated.
Measure length and width under defined conditions
Record the initial measuring points, preparation and condition. Apply the proposed care routine, then measure at the same points under the agreed post-care condition. Keep length and width results separate instead of averaging them into one shrinkage number.
Use dimensional change = (after − before) / before × 100%. Under that convention a negative result indicates shrinkage. State the sign convention in the record so a reported percentage is not ambiguous.
An illustrative calculation, not a product result
If an example length changes from 30.0 cm to 29.4 cm, the change is −2.0%. If the width changes from 30.0 cm to 30.3 cm, the width change is +1.0%. These invented values explain the arithmetic; they are not measured SINOCLEAN results or acceptance limits.
A result should identify the sample, care cycle and measurement procedure. Agree tolerances with the buyer or retailer before production. Do not choose a limit after seeing the sample or describe one screening sample as proof of batch consistency.
| Check | Record | Avoid inferring |
|---|---|---|
| Factory prewash | Whether used, stage and item reference | That a buyer wash test proves the process |
| Length/width change | Before/after values, units and sign convention | One averaged number covers both directions |
| Distortion | Skew, curl, edges and measurement conditions | The manufacturing cause from appearance alone |
| Acceptance | Care routine and agreed limits | The same tolerance for every item |
Approve the process statement and the outcome
SM21001 and SM21016 are catalogue candidates with different listed constructions at the same blend, size and GSM. Compare their care behaviour only with actual samples and keep the codes visible in the record.
If prewashing or setting is part of the contract, request confirmation of the route and its responsible stage in addition to finished-product evidence. A buyer’s own washing trial does not prove the factory prewashes every cloth.
Fields for your supplier enquiry
Item and sample revision: [code]. Record prewash/setting statements, initial dimensions and points, care conditions, post-care measurement condition, length and width change, distortion and agreed limits. Identify whether evidence concerns a sample, production lot or process audit.
Sources and what this guide establishes
The item links below identify published SINOCLEAN catalogue references. They do not establish a specific upstream manufacturing route, test result, factory capability or certification. Confirm any proposal-specific information against the quotation and representative sample.
Related reading: Warp-knitted or weft-knitted microfiber: which construction fits the order?; Ultrasonic, overlocked or heat-cut edges: how should a cloth buyer choose?.