Capacitor Discharge Welding for Fast, Low-Heat Nut and Screw Attachment

Combines capacitor discharge technology with manual load/unload and automatic welding operation. Delivers 10-50ms weld cycles for projection welding of nuts, screws, bolts and studs — with minimal heat impact on coated and galvanized materials.

The capacitor discharge (CD) method stores energy in a capacitor bank and releases it in a single, precisely controlled pulse — typically within 10 to 50 milliseconds. This fundamentally differs from traditional AC resistance welding in several ways that directly impact production quality and cost.

Galvanized Sheet Metal Nut Welding

Requires low heat input to prevent zinc coating burn-off around the weld zone. The CD discharge pulse (10-50ms) limits the heat-affected zone, preserving corrosion resistance of galvanized nuts and plates. Suitable for electrical cabinets, automotive brackets and construction hardware components.

Stainless Steel Screw and Bolt Projection Welding

Stainless steel fasteners require consistent projection collapse with minimal oxidation. The short CD pulse reduces surface discoloration, minimizing post-weld cleaning requirements. Suitable for kitchen equipment, medical device housings and food-grade container manufacturing.

Mixed Fastener Batch Production

The manual load/unload + automatic weld operating mode enables rapid changeover between different nut sizes, screw types and stud bolt specifications. Operators place the workpiece and press start — the machine automatically executes squeeze, discharge, hold and release. Suitable for contract manufacturers and hardware suppliers running mixed production schedules.

The complete welding cycle finishes in 10-50ms. The operator manually loads the workpiece and initiates the program. All subsequent steps — squeeze, discharge, hold, off — are automatic.

Xinwei Welding Technology Co., Ltd. operates an 18,000 square meter manufacturing facility with a dedicated R&D team of over 20 engineers. ISO 9001, CE and RoHS certified. Serving customers in more than 30 countries worldwide.

As a resistance welding specialist, Xinwei designs and manufactures capacitor discharge projection welders with customized electrodes and fixtures for specific fastener applications. Every machine undergoes welding cycle verification and parameter optimization before shipment.

Send us your nuts, screws, bolts and sheet metal samples. Our welding engineers will test the optimal capacitor discharge parameters on your actual materials and provide a detailed report including weld nugget inspection, pull-out test results and recommended machine configuration — free of charge.

Send your fastener samples for a free CD welding test

✓ Weld Nugget Cross-Section Inspection Per Machine

✓ Pull-Out Force Testing on Welded Fastener Samples

✓ Surface Coating Integrity Check for Galvanized Materials

✓ ISO 9001:2015 Certified Quality Management System

✓ CE and RoHS Compliance for International Markets

Q: How is capacitor discharge welding different from AC resistance welding?

Capacitor discharge welding stores energy in a capacitor bank and releases it in a single 10-50ms pulse. This is significantly faster than AC welding (200-500ms). The short pulse produces less heat on the workpiece, preserving coatings on galvanized materials, and draws power gradually from the grid rather than creating a high-current surge.

Q: Can this machine weld coated or galvanized fasteners?

Yes. The short CD discharge pulse (10-50ms) generates minimal heat input at the weld zone, making it particularly suitable for galvanized nuts, zinc-coated screws and other surface-treated fasteners where coating preservation is critical.

Q: What materials and fastener types are compatible?

The machine handles carbon steel, stainless steel, aluminum and galvanized materials. It supports projection welding of nuts, screws, bolts and studs, as well as standard spot welding of metal sheets up to the rated capacity of each model (3.0+3.0mm to 6.0+6.0mm depending on model).

Q: Does capacitor discharge welding reduce electricity costs?

Yes. Unlike AC welders that draw high current continuously, the CD system charges capacitors at a lower power level between welds and only discharges during the brief welding pulse. This eliminates idle transformer losses, avoids workshop voltage drops and can reduce electricity costs for facilities with time-of-use pricing.

Tell us your fastener type, material, sheet thickness and production volume. Our engineers will recommend the right DN model and design the electrode configuration for your application.

12-Month Warranty | Free Welding Test | Factory Direct from Xinwei