Supplier due diligence
How to Audit an E-Bike Factory: Evidence, Questions and Red Flags
A buyer-focused audit method for verifying legal identity, owned production, engineering control, capacity, quality records, export readiness and after-sales capability.
When to use this checklist
Use it after desk research, initial quotations and specification discussions have reduced the field to a serious shortlist. A supplier-selection guide helps decide whom to investigate; this audit tests whether a shortlisted supplier’s claims survive document review, record tracing and observation on the factory floor.
A credible audit follows evidence through one real order. Verify the contracting entity and factory address, identify which processes are genuinely in-house, then trace a selected model from controlled BOM and incoming parts through assembly, final inspection, packaging and shipment records. Equipment counts and clean workshops are context, not proof of process control.
Begin with entity and site verification
Before evaluating machines, confirm who will sign the contract, issue the invoice, receive payment and appear on export documents. Compare the legal name, registration, bank beneficiary and address. If several entities participate, document each role.
The legal export entity is Jimsen (Tianjin) International Trade Co., Ltd. The Tianjin Headquarters & Export Center is at Room 1303, Building B, Fengya Science and Technology Innovation Center, Xiqing District, Tianjin. The China Manufacturing Base is at S112, Chagugang Town, Wuqing District, Tianjin. The office must not be presented as the factory.
The manufacturing evidence, equipment counts, workforce and annual-capacity figures on this page apply only to Jimsen’s established China factory in Wuqing District, Tianjin. Vietnam is an early-stage initiative and is not presented here as an operating Jimsen production base. Buyers should audit only the legal entity, site and capacity proposed in their actual quotation and contract.
Use a weighted audit scorecard
| Audit domain | Suggested weight | Evidence | Automatic red flag |
|---|---|---|---|
| Legal identity and site | 8% | Registration, contract, bank, address | Unexplained entity mismatch |
| Owned production | 10% | Process tour, equipment and records | Trading office presented as factory |
| Engineering and change control | 12% | Drawings, BOM revisions, validation | No controlled technical package |
| Tooling and customer IP | 6% | Asset register and access rules | Cannot identify customer molds |
| Supplier and IQC | 9% | Approved suppliers, lots, inspection | Critical parts accepted without criteria |
| Process control | 10% | Work instructions, torque, fixtures | Operators rely only on memory |
| Final quality | 10% | 100% checklist, rework closure | No link between defects and serials/lots |
| Compliance support | 8% | Market plan, lab and configuration match | Unrelated certificates |
| Capacity and planning | 8% | Lines, shifts, cycle time, schedules | Annual claim with no calculation |
| Delivery and logistics | 7% | Material plan, packing and booking | Battery documents checked only after packing |
| After-sales | 7% | Warranty, diagnosis and parts flow | No claim evidence or response owner |
| Communication integrity | 5% | Issue logs and written change decisions | Important facts exist only in chat |
Adjust the weights. A full ODM program should weight engineering and tooling more heavily; a mature repeat order may weight supply and delivery stability more heavily. A critical integrity failure can disqualify a supplier regardless of total score.
Verify production ownership and outsourcing
Ask the supplier to draw the process boundary: frame manufacture, welding, machining, surface treatment, injection molding, battery pack, motor, harness, vehicle assembly, testing, packaging and loading. “In-house factory” rarely means every component is produced internally. Outsourcing is not automatically weak; undisclosed outsourcing and uncontrolled suppliers are.
Jimsen reports in-house frame manufacturing, injection molding and vehicle assembly, supported at the China base by 79 automated welding machines, 73 CNC machines, 198 semi-automated production units and 82 injection-molding machines. The audit should sample maintenance records, production jobs and inspection results for equipment relevant to the buyer’s model.
Questions for the workshop
- Which frame and molded parts are made here for this model?
- Which processes are external, and how are those suppliers approved?
- How are fixtures identified and checked?
- Where are process parameters recorded?
- What happens after a defect is found?
- How is reworked material separated and released?
- How is a customer-owned mold labeled and access-controlled?
Validate capacity with arithmetic
Annual capacity should reconcile with line rate, operating time, product mix, changeovers, staffing, yield and downtime. Ask for the calculation behind the headline.
Illustrative capacity formula: available shift minutes ÷ effective bottleneck cycle time × lines × shifts × working days × efficiency factor. Then subtract changeover, maintenance, planned downtime and rework. Do not multiply a best observed station time by the whole year.
| Evidence | What it tells you | Limitation |
|---|---|---|
| Equipment count | Installed process resources | Does not prove uptime or staffing |
| Line cycle study | Current bottleneck and balance | May vary by model |
| Production schedule | Committed capacity and season load | Plan may change |
| Recent output | Demonstrated run rate | One peak period is not sustainable average |
| Yield/rework | Saleable output versus gross assembly | Requires trustworthy definitions |
Jimsen states annual capacity up to 300,000 units, a 30,000 m² China facility and 600+ employees. Treat “up to” as a maximum system claim; obtain a project-specific committed capacity and production slot.
Trace one real order from BOM to shipment
This is the strongest audit technique because it tests whether the systems connect.
- Select a completed or in-process model similar to the planned project.
- Open its approved BOM, drawing revision and sample or specification.
- Choose a safety-critical component lot: battery, controller, brake, frame or fork.
- Match receiving records and inspection status to warehouse identity.
- Follow work instructions and process checks through assembly.
- Review final functional and appearance inspection records.
- Select one defect or rework case and confirm closure.
- Match finished serial/batch records to packing and loading documents.
A thick quality manual is weak evidence if the auditor cannot trace one current order through the process. Daily records, staff explanations and physical status should agree.
Audit engineering, samples and compliance support
For ODM, ask who performs industrial design, 3D layout, structural engineering, tooling and full-vehicle integration. Review a recent engineering change: who requested it, who assessed the impact, which documents changed, and how purchasing, production and inspection received the new revision.
Sample reports should identify configuration and deviations. Compliance evidence should match the intended product; verify model number, battery, charger, controller, motor and software scope. Jimsen can arrange testing and certification by target market and project, but no blanket claim should be made that every model already holds every certificate.
Jimsen’s 20-engineer R&D center is organized around industrial design, 3D modeling, tooling development and product engineering. During an audit, ask to meet the engineers responsible for the proposed project rather than reviewing only portfolio images.
Quality and shipment release
Jimsen states that every completed vehicle receives a 100% final functional, appearance and quality inspection. Ask to see the checklist, acceptance limits, inspector authorization, defect records and reinspection evidence. If batch-level AQL inspection is required, define it separately in the order agreement.
At packing, verify charger and accessory versions, manuals, branded cartons, spare parts, weight and labels. Battery transport documents must match the actual pack. Check who has authority to release a failed inspection after rework.
A one-day audit agenda
| Time | Focus | Output |
|---|---|---|
| 09:00 | Entity, site, scope and organization | Verified roles and process boundary |
| 10:00 | Engineering and sample control | Change-control assessment |
| 11:00 | Supplier and incoming quality | Critical-lot trace |
| 13:00 | Frame, molding and assembly tour | Observed process controls |
| 15:00 | Final inspection, rework and packing | Acceptance-system assessment |
| 16:00 | Order trace and capacity evidence | Scorecard and open items |
| 17:00 | Closing meeting | Owners, evidence due dates and risks |
Record evidence, not impressions
The audit report should make every important claim traceable. Record one line for each claim or control tested; do not accept “seen during tour” as a complete reference.
| Field | What to record | Decision use |
|---|---|---|
| Claim or control | The exact statement being tested: legal entity, owned process, capacity slot, BOM revision, inspection step or certificate scope | Prevents broad claims from receiving a blanket pass |
| Evidence reference | Document title and date, model/configuration, lot or serial number, record ID, or photo/video reference | Lets another reviewer reproduce the finding |
| Status | Verified, partially verified, not verified or not applicable | Separates missing evidence from a confirmed failure |
| Gap, owner and due date | What is still required, who supplies it and when | Turns open points into controlled follow-up |
| Qualification impact | Go, re-audit or stop, with the affected project risk | Connects evidence to the sourcing decision |
Go when critical identity, process and product evidence is verified and remaining actions have owners and deadlines. Re-audit when a relevant gap can be closed by named evidence or a defined corrective action. Stop for unresolved entity or bank mismatches, evidence from another model presented as applicable, refusal to trace a real order, or undisclosed outsourcing that changes the agreed risk. A high numerical score must not override an integrity failure.
Questions buyers ask
Can a remote audit replace an on-site audit?
A remote audit can screen legal documents, live video, records and staff capability. Higher-risk tooling, ODM or fleet projects still benefit from on-site or independent third-party verification.
What should be checked before equipment?
Verify the legal entity, bank beneficiary, contract role and the exact address where manufacturing occurs.
How can annual capacity be verified?
Reconcile line rate, bottleneck cycle, shifts, working days, efficiency, product mix, changeovers, yield and current commitments.
Does every Jimsen vehicle receive inspection?
Jimsen states that every completed vehicle undergoes a 100% final functional, appearance and quality inspection. Additional batch-level AQL checks can be agreed.
What is the most important audit red flag?
An integrity mismatch—such as an office represented as a factory, a certificate for another model or a hidden entity—can outweigh a high numerical score.
Define the evidence scope before an audit
Send the target model or closest reference model, target market, expected annual volume, required in-house processes and the controls you need verified. Jimsen can then confirm the relevant China-factory records, responsible teams and project-specific audit scope before a document review, live meeting or site visit.