Engineered Precision Hardware Manufacturers

Integrated manufacturing in Suzhou, Yangzhou and Vietnam combines cold heading, cam lathe turning, servo progressive stamping and sheet metal fabrication. This lets us move a project from engineering review and prototyping to pilot production and stable mass supply without splitting the part across unrelated vendors.

Our Product Range and Where Each Family Fits

Each family addresses a different forming problem, material condition and production volume. The table below maps our range to typical applications and the process that carries the part.

Standard Fasteners for Repeat Assembly

Cold heading lines in Suzhou and Vietnam produce M0.8–M16 standard and special high-strength fasteners in one continuous flow. Full-thread and partial-thread hex bolts, flange bolts, socket head cap screws, pan and countersunk machine screws, self-tapping screws and SEMS washer assemblies are held to the dimensional and mechanical requirements of the drawing or referenced standard.

• Property classes 4.8, 8.8, 10.9 and 12.9 with controlled heat treatment.
• Surface hardness HRC38–48, core hardness HRC28–48, carburized layer 0.003–0.005 mm.
• Finishes include electro-galvanizing, zinc-nickel, black oxide, Dacromet and pre-applied Nylok adhesive.
• Neutral salt spray resistance from 72 to 500 hours on standard finishes, with longer cycles available for harsh environments.

Custom Fasteners and Drawing-Based Development

When a standard part cannot meet the joint, we develop the fastener from your drawing, sample or performance target. Shoulder screws, double-end studs, standoffs, brass inserts, anti-loosening screws and special threaded geometries are produced by cold heading, with CNC turning added for multi-step or eccentric features.

Order quantity, lead time, material, finish, tolerance and working environment determine which process route is most efficient. We confirm that route with you before tooling is released, so prototype quantities, pilot batches and mass supply follow the same approved definition.

Riveted Fasteners for Thin-Plate and Single-Side Joints

Rivet nuts, blind nuts, self-clinching nuts and studs, solid rivets, semi-tubular rivets and open or closed-end blind rivets provide permanent fastening where only one side of the assembly is accessible. They suit cabinets, chassis, enclosures and thin-gauge structures where a tapped thread must survive repeated service.

• Knurled and hexagonal shank options for torque resistance in sheet.
• Flat head, hex head and press-fit configurations for different panel preparations.
• Open-end and closed-end blind rivets for sealed or open cavity conditions.

Stamping and Sheet Metal Parts

Servo progressive stamping covers 0.15–3 mm cold rolled steel, hot-dip galvanized steel, aluminum, copper, phosphor bronze and SUS304. Bending and deep drawing tolerances are held at ±0.05 mm under closed-loop servo control. Typical parts include 5G RF shielding cavities, energy storage battery shells, conductive terminals, heat-dissipation shrapnel and equipment brackets.

Sheet metal fabrication adds laser cutting, forming and welding for larger enclosures and structural panels. Post-processing includes zinc, nickel and gold plating, conductive passivation, painting and ultrasonic cleaning, so conductivity, corrosion resistance and appearance are handled in one production chain.

Turned and Miscellaneous Precision Parts

Japanese sliding-head CNC lathes and cam automatic lathes handle micro and complex shapes that cold heading cannot form. Outer diameters run from Φ1.0 to 32 mm, total lengths from 1.5 to 200 mm, with conventional mass-production tolerance at ±0.01 mm and high-precision custom parts controlled to ±0.003 mm.

This family includes Cylindrical Pin, Slotted Spring Pins, cotter pins, locating pins, hinge pins, compression springs and parallel keys, alongside stepped shafts, PCB threaded inserts and eccentric-groove parts.

Materials, Finishes and Working Environment

We process low carbon and medium carbon steel, 40Cr and SCM435 alloy steel, SUS304 and SUS316 stainless steel, H59 brass, 6061 and 6063 aluminum, with small-batch titanium turning available. Incoming material is sampled by spectrometer before release to production.

Finish selection follows the corrosion, conductivity and appearance requirement of the application. Zinc-nickel and Dacromet are used where salt spray exposure is severe; conductive passivation and gold plating are used where contact resistance matters; black oxide and PVD are used for wear and appearance.

Quality Control and Acceptance Evidence

An enclosed precision testing laboratory supports incoming inspection, in-process patrol and final inspection across all four workshops. Equipment includes Zeiss 3D CMM, 2.5D optical vision measurement, automatic CCD sorting, contour and roughness measurement, universal tensile testing, torque testing, Rockwell and Vickers hardness testing, salt spray chambers, spectrometer, metallographic microscope and XRF RoHS screening.

• System compliance: IATF16949, ISO9001, ISO14001, ISO45001 and QC080000.
• Reports available on request: material certificates, dimensional inspection reports, salt spray reports, mechanical test reports, RoHS certificates, 8D reports and PPAP documentation.
• Testing schemes can be aligned to customer AQL plans and to internal standards used by overseas OEMs.
• All test instruments are calibrated annually by third parties.

Information We Use to Configure Your Solution

A workable proposal depends on the working point, not only the part outline. We review the following inputs before recommending a process route, tooling plan and inspection scheme.

• 2D drawing or 3D model with critical dimensions, tolerances and datum scheme.
• Material grade, temper and any conductivity, hardness or strength requirement.
• Finish specification and expected corrosion or environmental exposure.
• Assembly method, mating parts, torque target and access constraints.
• Annual volume, batch size, packaging format and delivery destination.
• Applicable standard, compliance documents and acceptance test method.

From Prototype to Mass Production

Our workflow runs through prototype development, engineering validation, pilot production and mass production. Suzhou handles new product R&D, sampling and small-batch high-precision orders; Yangzhou and Vietnam carry volume fastener, stamping and sheet metal programs. This split keeps development responsive while giving long-term OEM supply a stable production base.

Packaging, labeling, documentation and delivery scope are agreed per project, including tape-and-reel, bulk, kit or customer-specified formats. Spare tooling, replacement parts and process records are retained so repeat orders follow the approved definition.

Frequently Asked Questions

What size range can Yongji manufacture?

Cold heading covers M0.8–M16 fasteners, with single and two-die machines handling M0.8–M3 up to 30 mm and multi-station formers handling M4–M16 up to 190 mm. Nut machines cover M2–M14. Turning covers Φ1.0–32 mm and lengths of 1.5–200 mm.

Can you produce from our drawing or sample?

Yes. We develop special parts from drawings, samples, technical requirements and target application scenarios. Engineering review confirms the process route, tolerance capability and inspection plan before tooling is released.

Which industries do your products serve?

Our parts are used in telecom and networking, new energy vehicles, displays, notebooks, energy storage, AI computing and industrial automation. Each application has different requirements for strength, conductivity, corrosion resistance and assembly access.

What quality documents can be supplied?

Depending on the project, we can issue material certificates, dimensional inspection reports, salt spray reports, mechanical test reports, RoHS certificates, 8D improvement reports and PPAP documentation. Testing follows IATF16949, ISO9001 and ISO14001 system requirements.

Do you support small batches as well as mass production?

We support prototype quantities, pilot production and stable mass supply. Suzhou is set up for sampling and small-batch high-precision work, while Yangzhou and Vietnam provide volume capacity for fasteners, stamping and sheet metal parts.

How do you handle surface treatment and corrosion requirements?

In-house lines cover electro-galvanizing, zinc-nickel, black oxide, Dacromet, anodizing, PVD, gold plating and conductive passivation. Standard finishes reach 72–500 hours of neutral salt spray, and longer cycles can be developed for harsh environments.