Quality Control

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

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.

Critical diameters, lengths, shoulders, heights, depths, profiles and runout are checked against drawings and practical assembly needs.

External and internal threads can be verified with GO/NO-GO gauges, plug gauges and profile inspection where required.

Coating thickness and surface condition are reviewed because excess buildup can affect thread engagement and fit.

Hardness, torque, ductility and selected mechanical-risk checks support parts with strength or assembly-critical requirements.

Optical sorting, or manual sorting where the part structure does not suit optical sorting, can be used for high-volume parts where small dimensional or appearance variation creates downstream risk.

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.

Profiles, contours, thread forms, heights, depths, concentricity and runout for drawing-controlled parts.

Metric and Unified thread acceptance with gauges for external and internal threaded components.

Roughness, plating thickness and coating consistency checks for fit, appearance and corrosion performance.

Vickers, Rockwell and torque-related testing for selected heat-treated or assembly-critical parts.

Neutral salt spray testing and Cr(VI) screening support for plated parts when documentation is requested.

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

2D Vision Measuring System / 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.

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.

Riveting Performance

Riveting Test

Customer-specific test

Cracking, chipping or failure after riveting.

Typical use: Rivets and custom assembly parts.

Optical or Manual 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.

Other In-House Tests & Gauges

• Surface Roughness TesterRa, Rz and common roughness parametersSurface roughness and finish condition.Typical use: Parts with appearance, sliding, sealing or assembly requirements.
• Concentricity / Runout TesterSmall round parts; selected diameter checks from Dia. 3-25 mm and some checks to approx. Dia. 32 mmRoundness, concentricity, runout, face flatness, screw eccentricity and bending.Typical use: Shafts, pins, screws and round precision parts.
• Hydrogen Embrittlement TestSelected high-strength or plated partsCracking or fracture risk under load after plating or related processes.Typical use: High-strength or plated fasteners where hydrogen embrittlement risk must be controlled.
• Hexavalent Chromium Cr(VI) ScreeningRoHS-related documentation available upon requestScreening for hexavalent chromium on plated metal parts.Typical use: Plated components with environmental compliance requirements.
• Inclined Plate TestCustomer-specific testDuctility, deformation behavior and head breakage risk.Typical use: Selected custom screws and special customer requirements.
• GO/NO-GO Thread GaugesMetric 6e / 6g / 6h; Unified 1A / 2A / 3AExternal thread acceptance and assembly fit.Typical use: Screws, bolts and externally threaded parts.
• Plug GaugesMetric 6H / 7H; Unified 2B / 3BInternal thread acceptance and fit.Typical use: Nuts, inserts and internally threaded parts.
• Tensile / Load TestArranged through qualified testing or heat-treatment partner when requiredTensile strength, load capacity and material strength verification.Typical use: Load-critical parts and customer-specified mechanical requirements.

From drawing to outgoing quality control

For RFQs with drawings or samples, we connect inspection work to the features that influence real product use.

Confirm critical dimensions, threads, finishes, tolerances and application conditions.

Separate routine dimensions from risk-sensitive features that affect fit or function.

Use measurement, thread, surface, hardness or coating checks according to the drawing.

Align checks with production routing and finish requirements before batch shipment.

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

IATF 16949 : 2016

pdf  |  2MB |  English

ISO 9001 : 2015

pdf  |  2MB |  English

ISO 14001 : 2015

pdf  |  1MB |  English