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Quality Control for Drawing-Based Manufacturing
Quality Control & Inspection Capabilities
Taiyuanfeng supports custom fasteners and precision metal parts with inspection focused on fit, function, coating performance, hardness, corrosion risk and batch consistency. Send us your drawing package and we will align inspection points with the features that matter in your assembly.
- IATF 16949:2016
- ISO 14001:2015
- Drawing-based checks
- Custom fasteners and precision parts
QC
DimensionsThreadsCoating
Inspection is planned around the buyer's risk
For custom parts, a passed sample is not enough. We focus on the dimensions, surfaces and performance points that can create assembly failure, corrosion problems, loose fit or batch variation after mass production starts.
Will the part fit?
Critical diameters, lengths, shoulders, heights, depths, profiles and runout are checked against drawings and practical assembly needs.
Will the thread assemble smoothly?
External and internal threads can be verified with GO/NO-GO gauges, plug gauges and profile inspection where required.
Will plating affect function?
Coating thickness and surface condition are reviewed because excess buildup can affect thread engagement and fit.
Is the strength condition appropriate?
Hardness, torque, ductility and selected mechanical-risk checks support parts with strength or assembly-critical requirements.
Can the batch stay consistent?
Optical sorting and full inspection can be used for high-volume parts where small dimensional or appearance variation creates downstream risk.
What documentation may be needed?
RoHS-related documentation, salt spray results or partner-arranged load testing can be discussed based on the application and buyer requirements.
Core inspection capability areas
The inspection plan can combine dimensional measurement, thread verification, surface and coating checks, hardness testing, corrosion evaluation and sorting according to the part drawing and use environment.
Dimensional & Profile Inspection
Profiles, contours, thread forms, heights, depths, concentricity and runout for drawing-controlled parts.
Thread & Fit Verification
Metric and Unified thread acceptance with gauges for external and internal threaded components.
Surface Finish & Coating Control
Roughness, plating thickness and coating consistency checks for fit, appearance and corrosion performance.
Hardness & Torque Checks
Vickers, Rockwell and torque-related testing for selected heat-treated or assembly-critical parts.
Corrosion & RoHS-related Support
Neutral salt spray testing and Cr(VI) screening support for plated parts when documentation is requested.
Optical Sorting & Full Inspection
Configured sorting for high-volume parts with tighter outgoing quality-control requirements.
Inspection equipment and checks
These capabilities are used selectively according to drawings, material, finish, assembly risk and buyer requirements. Some tests are customer-specific or arranged through qualified partners when required.
Coating & Plating
Coating Thickness Gauge
Zn, Ni, Cu layers
Plating thickness and coating consistency.
Typical use: Plated screws, bolts, nuts and precision metal parts.
Dimensional Inspection
Profile Projector / Optical Comparator
Optical measurement up to 300 mm
Dimensions, contours, profiles and thread forms against drawings.
Typical use: Custom fasteners, CNC parts and stamping parts with drawing tolerances.
Surface Finish
Surface Roughness Tester
Ra, Rz and common roughness parameters
Surface roughness and finish condition.
Typical use: Parts with appearance, sliding, sealing or assembly requirements.
Concentricity & Runout
Concentricity / Runout Tester
Small round parts; selected diameter checks from Dia. 3-25 mm and some checks to approx. Dia. 32 mm
Roundness, concentricity, runout, face flatness, screw eccentricity and bending.
Typical use: Shafts, pins, screws and round precision parts.
Height & Depth
Height Measuring Instrument
0-25 mm range for selected height/depth checks
Total length, head thickness, step height, boss height and depth.
Typical use: Screws, rivets, turned parts and stamped components.
Corrosion Resistance
Salt Spray Tester
Neutral salt spray testing
Corrosion resistance of plated or coated parts, with rust evaluation based on finish requirements.
Typical use: Parts used in humid, outdoor or corrosion-sensitive environments.
Hardness
Vickers Hardness Tester
HV100-800
Surface hardness and core hardness for selected materials and parts.
Typical use: Raw materials, heat-treated parts and finished fasteners.
Hardness
Rockwell Hardness Tester
HRC20-70
Core hardness for hardened or strength-related parts.
Typical use: Bolts, screws, pins and other strength-critical parts.
Torque Performance
Torque Tester
0-450 kgf-cm, approx. 0-44 N-m
Torque-to-failure, screw breakage and thread slipping risk.
Typical use: Threaded fasteners and assembly-critical screws.
Sample Preparation
Vertical Cutting Machine
Sample cutting before inspection
Sample cutting for cross-section, hardness or structure-related checks.
Typical use: Internal sample preparation before selected quality checks.
Sample Preparation
Mounting Machine
Sample mounting for grinding and polishing
Sample preparation before hardness checks, carburizing layer checks, metallography or section measurement.
Typical use: Cross-section and material-related inspection.
Mechanical Risk Check
Hydrogen Embrittlement Test
Selected high-strength or plated parts
Cracking or fracture risk under load after plating or related processes.
Typical use: High-strength or plated fasteners where hydrogen embrittlement risk must be controlled.
RoHS-related Screening
Hexavalent Chromium Cr(VI) Screening
RoHS-related documentation available upon request
Screening for hexavalent chromium on plated metal parts.
Typical use: Plated components with environmental compliance requirements.
Riveting Performance
Riveting Test
Customer-specific test
Cracking, chipping or failure after riveting.
Typical use: Rivets and custom assembly parts.
Ductility / Head Integrity
Inclined Plate Test
Customer-specific test
Ductility, deformation behavior and head breakage risk.
Typical use: Selected custom screws and special customer requirements.
External Thread Inspection
GO/NO-GO Thread Gauges
Metric 6e / 6g / 6h; Unified 1A / 2A / 3A
External thread acceptance and assembly fit.
Typical use: Screws, bolts and externally threaded parts.
Internal Thread Inspection
Plug Gauges
Metric 6H / 7H; Unified 2B / 3B
Internal thread acceptance and fit.
Typical use: Nuts, inserts and internally threaded parts.
Load Performance
Tensile / Load Test
Arranged through qualified testing or heat-treatment partner when required
Tensile strength, load capacity and material strength verification.
Typical use: Load-critical parts and customer-specified mechanical requirements.
Full Inspection / Sorting
Optical Sorting Equipment
Configurable OD and length thresholds down to 0.01 mm depending on part geometry and setup
High-volume dimensional and appearance sorting.
Typical use: High-volume fasteners requiring tighter outgoing quality control.
From drawing to outgoing quality control
For RFQs with drawings or samples, we connect inspection work to the features that influence real product use.
Review drawings
Confirm critical dimensions, threads, finishes, tolerances and application conditions.
Identify control points
Separate routine dimensions from risk-sensitive features that affect fit or function.
Inspect samples
Use measurement, thread, surface, hardness or coating checks according to the drawing.
Control production
Align checks with production routing and finish requirements before batch shipment.
Support documentation
Provide or arrange relevant inspection information when the buyer's project requires it.
What to send with your RFQ
- 2D drawing in PDF format
- 3D model such as STEP or STP if available
- Material, finish and surface-treatment requirements
- Critical dimensions, thread callouts and assembly concerns
- Expected quantity and application environment
Conservative testing notes
- Hydrogen embrittlement checks apply to selected high-strength or plated parts.
- Tensile or load testing may be arranged through qualified testing or heat-treatment partners when required.
- RoHS-related documentation and Cr(VI) screening are handled according to buyer request and part finish.
- Optical sorting thresholds depend on part geometry, setup and agreed inspection criteria.
Send your drawing package for a manufacturability and inspection review.
Upload your drawing, model or sample requirements through the RFQ form. We will review the key control points before quoting.
Certificates
Inspection Equipment & In-House Checks
Optical Sorting Machine
Automatic machine-vision inspection of dimensions and surface defects, with OD/length discrimination to 0.01 mm.
Profile Projector / Optical Comparator
Measures dimensions, contours, profiles and thread forms against the drawing (range up to 300 mm).
Concentricity / Runout Tester
Checks concentricity, bend and end-face runout for pins, studs and shafts (Φ3–25 mm).