| Quality Management System | Confirm that the supplier operates a documented quality management system covering purchasing, production, inspection, nonconforming output, corrective action, and customer complaints. | Current ISO 9001 certificate, certificate scope, issuing certification body, audit status, and controlled quality procedures. | The certificate is valid, applies to the actual production site, and covers CNC machining or related manufacturing activities. | Inconsistent processes, weak corrective actions, and limited accountability for defects. |
| Certification Authenticity and Scope | Check certificate number, validity dates, legal entity, manufacturing address, scope, and accreditation status of the certification body. | Certificate copy plus verification through the certification body’s public directory or written confirmation from the certification body. | All certificate details match the facility that will manufacture and inspect the parts; no expired or unexplained certificates. | A certificate may belong to another site, cover a different activity, or be invalid. |
| Industry-Specific Quality Standards | Determine whether the application requires additional standards, such as IATF 16949 for automotive production or AS9100 for aerospace-related work. | Relevant certificate, customer-specific requirements, process-control records, and previous industry audit results. | The supplier holds the required standard when contract, regulatory, or customer requirements make it applicable. | The supplier may lack required traceability, risk management, configuration control, or change-control practices. |
| Measurement and Calibration System | Review how calipers, micrometers, gauges, CMMs, vision systems, and other measuring equipment are identified, calibrated, protected, and checked. | Calibration register, current certificates traceable to national or international measurement standards, and out-of-tolerance response records. | Critical instruments are within calibration at the time of inspection and have suitable accuracy for the specified tolerance. | Incorrect measurements can allow defective parts to pass inspection. |
| Material Verification and Traceability | Verify material grade, condition, heat or batch number, supplier documentation, and preservation during storage and production. | Material certificates, purchase records, incoming inspection reports, batch labels, and a traceability flow from raw stock to finished parts. | Material identity remains traceable through cutting, machining, heat treatment, surface finishing, and shipment. | Wrong material, mixed batches, or inability to conduct an effective recall or root-cause investigation. |
| Drawing and Revision Control | Confirm that the supplier controls drawings, 3D models, specifications, work instructions, and revision changes at every production point. | Approved drawing register, revision history, controlled work instructions, and documented engineering-change process. | Only the latest customer-approved revision is available to programming, production, inspection, and subcontractors. | Parts may be produced to obsolete dimensions or outdated technical requirements. |
| CNC Equipment and Process Capability | Assess machine type, turning diameter and length capacity, spindle and tooling capability, machine condition, preventive maintenance, and operator competence. | Equipment list, maintenance records, sample inspection data, capability studies, and production trial results. | The machine envelope and process controls meet the drawing requirements; a common customer target for stable critical features is Cpk ≥ 1.33 when capability studies are required. | Dimensional drift, excessive variation, machine downtime, and unstable production output. |
| First Article and In-Process Inspection | Check whether the supplier verifies setup approval, first-off parts, critical dimensions, threads, surface finish, geometric tolerances, and process checkpoints. | First Article Inspection report, inspection plan, control plan, in-process records, and final inspection report with actual measurements. | Inspection frequency and sample size are defined by risk, customer requirements, process stability, and feature criticality. | Defects may remain undetected until final assembly or customer use. |
| Special Processes and Subcontractors | Identify outsourced heat treatment, plating, anodizing, coating, grinding, passivation, laser marking, or other special processes. | Approved subcontractor list, process certificates, test reports, purchase requirements, and supplier-audit records. | Subcontracted processes are approved, documented, traceable, and verified against the drawing or purchase specification. | Coating failure, incorrect hardness, corrosion, poor adhesion, or noncompliance with restricted-substance requirements. |
| Nonconformance and Corrective Action | Evaluate how defects are segregated, dispositioned, analyzed, corrected, and prevented from recurring. | Nonconformance reports, root-cause analysis, corrective-action reports, effectiveness checks, and scrap or rework records. | Containment is prompt, root cause is evidence-based, and corrective actions are verified for effectiveness. | Repeated defects, uncontrolled rework, hidden concessions, and unreliable delivery performance. |
| Production Planning and Capacity | Review production scheduling, available machine hours, staffing, tooling availability, maintenance planning, and peak-load management. | Capacity plan, machine utilization data, production schedule, on-time delivery history, and business-continuity plan. | Capacity is demonstrated using realistic cycle times, setup times, inspection time, and planned maintenance rather than machine count alone. | Late shipments, rushed inspections, unstable quality, and excessive reliance on unapproved outsourcing. |
| Environmental, Health, and Safety Controls | Assess controls for cutting fluids, metal chips, hazardous chemicals, waste disposal, worker safety, emergency response, and legal compliance. | Relevant permits, safety procedures, waste-transfer records, training records, and ISO 14001 or ISO 45001 certification when required. | Applicable environmental and occupational-safety obligations are identified, controlled, and supported by records. | Regulatory exposure, workplace incidents, shipment restrictions, and supply-chain disruption. |
| Production Audit and On-Site Verification | Compare documented procedures with actual practices on the shop floor, including material flow, machine operation, inspection, labeling, and storage. | Remote or on-site audit report, corrective-action closure records, machine photographs or video, and production-trial observations. | The audited production site, equipment, personnel, and process records correspond to the quotation and approved manufacturing plan. | Misrepresentation of capability, undisclosed subcontracting, and gaps between certificates and actual operations. |
| Documentation and Shipment Release | Confirm that the supplier can prepare complete quality and shipping documentation before release. | Final inspection report, material certificate, special-process certificate, packing list, certificate of conformity, and approved deviation records. | Required documents are complete, legible, linked to the correct lot or purchase order, and reviewed before shipment. | Customs delays, receiving rejection, undocumented deviations, and difficulty proving conformity. |
| Supplier Selection Decision | Use a weighted scorecard instead of selecting only by unit price. Include quality, technical capability, delivery, documentation, communication, risk, and total cost. | Completed supplier questionnaire, audit score, sample approval, pilot-order results, quality metrics, and contract review. | Approve the supplier only after objective evidence confirms capability for the specific part, material, tolerance, volume, and compliance requirements. | Low initial price may be offset by inspection costs, rework, delays, returns, or production interruption. |
