Published by Yuefu Electronic
PPM — parts per million — is a unit used to express defect rates at a scale where percentages become difficult to compare. The target value should be defined by the customer or agreed for the specific project rather than assumed from a general factory statement.
A PPM target only becomes useful when the defect definition, measurement point, sampling method, reporting period, and response to a nonconforming result are written down.
For an OEM connector or cable project, the inspection scope is agreed before production release: critical dimensions from the drawing, crimp cross-section or pull-force checks where applicable, continuity and short testing, visual criteria, and sampling levels.
When you prepare an RFQ, the most useful quality information is the requirement itself: which dimensions are critical, what testing you expect per lot, which records you need, and what happens when a result falls outside the agreed criteria.
A clear quality clause in the RFQ shortens the review cycle. It lets the factory quote the actual inspection work instead of assuming a generic level — and it gives both sides the same definition of an acceptable part.
Define the numerator and denominator
For a defective-unit metric, PPM equals nonconforming units divided by units assessed, multiplied by 1,000,000. As an arithmetic example only, 3 nonconforming assemblies among 12,000 assessed assemblies is 250 PPM. Count each affected assembly once even if it has two faults; a count of individual defects is a different metric and must be labeled separately. This example is not a Yuefu performance figure or target.
Keep sample results separate from delivered quality
A zero-defect sample does not demonstrate zero defects across the shipment. Do not divide faults found in a small inspection sample by the entire delivery quantity and call that the lot's measured PPM. State whether the report covers inspected pieces, incoming rejects or customer returns, and use the matching population and time period. AQL sampling acceptance and a PPM performance target answer different questions.
Agree what happens after a failure
Define lot identification, containment, responsibility for sorting and disposition, and the evidence needed to resume shipment. Keep critical safety-related defects under their separately agreed acceptance rules rather than averaging them away with cosmetic defects. The sample-to-production checklist helps connect those rules to released drawings and lot records.
What to send if the issue is on a harness or cable assembly
If the PPM target applies to a finished interconnect, send the defect definition with the product brief. Name the drawing revision, critical dimensions or circuits, sample quantity, and whether continuity, pull-force, or visual checks apply to each lot or only to first articles. State what happens when a result is outside the agreed range.
The custom wire harness page lists the drawing and inspection items that belong in that brief. Keep the defect definition next to the construction details so the quotation prices the actual checks. If you need wire harness OEM and cable assembly production records, name the documents you want per lot. Send the drawing and quality notes through Request a Quote.
