| Material Grade | Use implant-grade titanium such as Ti-6Al-4V ELI or commercially pure titanium, selected according to the screw design and intended application. | Material certificate with heat or lot number, chemical composition, mechanical properties, and full traceability. | Material grade affects strength, fatigue performance, corrosion resistance, biocompatibility, and compatibility with sterilization processes. |
| Material Standards | Specify applicable standards such as ASTM F136 for wrought Ti-6Al-4V ELI, ASTM F67 for unalloyed titanium, or ISO 5832-3 where applicable. | Certificate of conformity, incoming inspection records, and documented material acceptance criteria. | Standardized material requirements reduce variation between production lots and support regulatory submissions. |
| Dimensional Accuracy | Define tolerances by drawing and risk assessment; precision-turned features may commonly use approximately ±0.01 to ±0.05 mm, depending on geometry and function. | Coordinate-measuring-machine reports, calibrated gauges, first-article inspection, and capability studies for critical dimensions. | Accurate threads, drive recesses, undercuts, and screw heads support insertion performance and implant compatibility. |
| Thread Profile and Pitch | Control pitch, major diameter, minor diameter, thread form, crest condition, and thread runout according to the approved drawing. | Optical measurement, thread gauges, functional mating tests, and inspection of thread flanks and crests. | Thread geometry directly influences insertion torque, pull-out behavior, bone engagement, and mating with instruments or plates. |
| Surface Finish | Set drawing-specific roughness limits; a common controlled range for machined functional areas may be Ra 0.8–1.6 µm, subject to the validated design. | Calibrated profilometer results, visual inspection under defined lighting, and records for polishing, cleaning, or passivation. | Surface condition affects debris generation, cleanability, corrosion behavior, tissue interaction, and fatigue initiation sites. |
| Burr and Edge Control | No loose burrs, sharp unintended edges, torn material, or machining damage on threads, drive recesses, and bone-contacting surfaces. | Defined visual standard, magnified inspection, tactile inspection where appropriate, and documented deburring validation. | Effective edge control helps limit particulate contamination and protects handling, insertion, and tissue-contact performance. |
| Mechanical Testing | Validate insertion torque, removal torque, torsional strength, axial pull-out, and fatigue performance according to the product risk profile and applicable test methods. | Validated test protocols, raw data, sample traceability, acceptance criteria, and signed test reports. | Mechanical testing confirms that dimensional control and material selection translate into safe clinical performance. |
| Quality Management System | Prefer a supplier operating an audited medical-device quality system aligned with ISO 13485:2016 and supported by documented process controls. | Current certificate, audit reports, nonconformance records, corrective-action history, and change-control procedure. | A medical-device QMS provides controlled design transfer, production, inspection, traceability, and complaint-support processes. |
| Risk Management | Maintain risk-management documentation consistent with ISO 14971, including hazards related to breakage, particulate matter, incorrect dimensions, and contamination. | Risk-management file inputs, process FMEA, control plan, inspection plan, and evidence that production risks are linked to acceptance criteria. | Risk-based controls help prioritize critical features rather than relying only on general visual inspection. |
| Biological Safety Support | Provide material and process information to support biological evaluation under ISO 10993, as applicable to the finished device and contact duration. | Material composition, cleaning-agent information, residual analysis, surface-treatment records, and supplier declarations. | Manufacturing residues and surface treatments can affect the biological safety assessment of an implant. |
| Cleaning and Contamination Control | Use a validated cleaning process with controlled water quality, detergents, handling, packaging, and particulate limits appropriate for the device. | Cleaning validation, residual testing, particle monitoring, environmental procedures, and packaging-integrity records. | Small threaded components can retain chips, oils, and residues if cleaning and handling controls are inadequate. |
| Regulatory Compliance | Confirm the supplier can support applicable Swiss MedDO and/or EU MDR obligations, depending on the legal manufacturer, device classification, and market. | Regulatory responsibilities matrix, technical-documentation inputs, declarations, certificates, and change-notification commitments. | Clear allocation of responsibilities prevents gaps between the component supplier, legal manufacturer, and regulatory submission. |
| Process Validation | Validate special or outcome-dependent processes such as thread rolling, heat treatment, surface treatment, cleaning, passivation, and packaging where applicable. | Validation protocols, approved process parameters, revalidation triggers, and objective evidence of repeatability. | Validated processes reduce the likelihood that acceptable-looking parts will have hidden mechanical or contamination-related defects. |
| Inspection and Measurement System | Use calibrated equipment with documented measurement uncertainty and gauge capability appropriate to the tolerance being inspected. | Calibration certificates, measurement-system-analysis studies, inspection instructions, and equipment-maintenance records. | Reliable measurement is essential when small dimensional differences affect fit, insertion, or mechanical performance. |
| Traceability | Maintain traceability from raw-material heat or lot through machining batch, inspection results, cleaning, packaging, and shipment. | Batch records, traveler documents, certificates, labeling records, and electronic or controlled paper genealogy. | Traceability supports efficient investigations, targeted containment, and regulatory reporting when required. |
| Supplier Change Control | Require advance notification and approval for changes to material source, tooling, CNC program, process parameters, subcontractors, inspection methods, or packaging. | Formal change-control procedure, change-impact assessment, requalification plan, and retained approval records. | Uncontrolled changes can alter thread accuracy, surface condition, fatigue strength, or cleanliness without obvious visual differences. |
| Capacity and Delivery Reliability | Assess available Swiss-type turning capacity, approved subcontractor controls, lead-time consistency, safety stock options, and business-continuity planning. | Capacity plan, historical on-time-delivery data, contingency plan, production schedule, and escalation contacts. | Stable supply is important for surgical-device production, especially when screws are matched to instruments or implant systems. |
| Supplier Selection Scorecard | Suggested weighting: quality and compliance 30%, technical capability 25%, traceability and documentation 15%, delivery reliability 15%, total cost 10%, communication and support 5%. | Completed audit checklist, weighted supplier score, documented corrective actions, sample approval, and management review. | A weighted scorecard prevents low price or short lead time from outweighing patient-safety and regulatory risks. |
