| Sample Specification Match | Confirm that the sample matches the agreed motor rating, battery capacity, dimensions, materials, lighting, display, charger, and accessories. | Signed specification sheet and sample inspection report | 100% of critical specifications match | High | Reject or revise the sample if any safety-related specification differs from the approved version. |
| Battery Safety and Traceability | Check cell source records, battery management system functions, protection against overcharge and over-discharge, labeling, and batch traceability. | Battery test report, production batch code, safety documentation, and inspection photos | Traceability for every battery batch; no critical safety defects | Critical | Do not place an order without documented battery controls and a corrective-action process. |
| Functional Sample Testing | Test braking, folding, acceleration, steering, lights, charging, display functions, water resistance features, and abnormal-noise behavior. | Test checklist with videos, measurements, and signed approval record | All critical functions pass before mass production | High | Use an approved golden sample as the physical reference for production inspections. |
| Durability and Road-Test Review | Evaluate frame strength, folding mechanism wear, tire performance, brake consistency, vibration, and range under representative operating conditions. | Repeated-use test log and defect record | No structural, braking, or steering defect during evaluation | High | Document test conditions because actual range and durability depend on load, speed, temperature, and terrain. |
| Factory Capability Audit | Verify production capacity, equipment, staffing, process flow, maintenance controls, storage conditions, and in-process inspection points. | On-site audit report, dated photographs, process map, and production records | All critical processes have documented controls and responsible personnel | Medium | Prefer an independent audit or an unannounced follow-up when the order value is significant. |
| Quality Management System | Assess incoming inspection, first-article approval, in-process checks, final inspection, calibration, nonconformance handling, and corrective actions. | Quality manual, inspection forms, calibration records, and corrective-action reports | Records are complete, current, and linked to production batches | Medium | A certificate alone is insufficient; verify that the system is actively used on the production line. |
| Production Capacity and Lead Time | Check monthly capacity, component availability, peak-season constraints, tooling readiness, and the lead time from order confirmation to shipment. | Capacity plan, material schedule, historical delivery records, and production calendar | Written lead-time commitment with defined delay notification rules | Medium | Avoid relying on verbal promises; separate production time from shipping and customs time. |
| Pre-Shipment Inspection | Inspect appearance, dimensions, accessories, charging, brakes, folding, labels, packaging, and random carton quantities before shipment. | Independent inspection report with sampling plan and defect photos | Zero critical defects; major and minor defects within agreed limits | High | Do not release the final payment until inspection results meet the contract requirements. |
| Contract Specification Control | Define the approved model, revision number, bill of materials, packaging, labeling, testing method, and change-approval procedure. | Signed purchase agreement and controlled technical annex | One unambiguous specification set signed by both parties | High | Treat undocumented substitutions or design changes as nonconformities requiring written approval. |
| Warranty and Corrective Action | Clarify warranty duration, covered components, response time, spare-parts availability, repair responsibility, and replacement procedures. | Warranty clause, service workflow, spare-parts list, and escalation contacts | Written response and corrective-action deadlines | Medium | Specify who pays for replacement parts, labor, transport, and verified product recalls. |
| Payment and Shipment Protection | Link payment milestones to sample approval, production completion, inspection results, and shipping documents. | Payment schedule, inspection-release condition, shipping terms, and document checklist | Final payment conditional on passing inspection and complete documentation | High | Use clearly defined remedies for late delivery, failed inspection, missing documents, or unauthorized substitutions. |
| Overall Supplier Decision | Combine sample performance, audit findings, contract readiness, communication quality, and corrective-action capability. | Weighted supplier evaluation scorecard | Minimum 80/100 with no unresolved critical finding | Decision Gate | Approve only when evidence is consistent across samples, audits, and contract commitments. |