2026/7/27 - Vertical Medium Frequency Spot Welding Machine for M3/M4 Waterproof Bolts on 1.5mm Stainless Steel

On July 27, 2026, PDKJ conducted a sample welding test using a vertical medium frequency spot welding machine for welding M3/M4 waterproof bolts onto 1.5mm stainless steel.

The application focused on evaluating the welding process for small-diameter bolts and stainless steel sheet. Stable welding current, accurate electrode positioning, and repeatable welding parameters are important for achieving reliable bolt attachment.

Application Overview

Sample Welding Requirements

The test involved welding M3 and M4 waterproof bolts onto 1.5mm stainless steel sheet.

Small bolts require controlled welding parameters to ensure that the bolt is correctly positioned and firmly attached to the sheet without unnecessary deformation of the base material.

The sample test was designed to evaluate welding performance and determine suitable process parameters for the actual workpiece.

The main requirements included:

• Stable welding current
• Accurate bolt positioning
• Consistent electrode pressure
• Reliable bolt attachment
• Repeatable welding quality
• Controlled welding heat input

Vertical Medium Frequency Spot Welding Solution

PDKJ used a vertical medium frequency spot welding machine for this sample application.

The machine uses a medium frequency inverter power supply to provide controlled welding current and welding time. The vertical structure allows the electrodes to approach the workpiece in a controlled direction, making it suitable for specific bolt welding and sheet-metal applications.

For M3/M4 waterproof bolt welding, parameters can be adjusted according to the bolt material, stainless steel grade, sheet thickness, electrode configuration, and required welding strength.

Welding Process

The stainless steel sheet is positioned on the welding fixture, while the M3 or M4 waterproof bolt is accurately placed at the designated welding position.

The electrodes then apply the required pressure to the bolt and sheet. The welding controller supplies the preset current for a specific period, generating resistance heat at the contact area and forming the welded connection.

During sample testing, parameters can be adjusted to evaluate:

• Welding current
• Welding time
• Electrode pressure
• Electrode alignment
• Bolt positioning
• Welding cycle time

The objective is to establish a suitable welding process for the M3/M4 waterproof bolt application.

Key Advantages

Stable Medium Frequency Current

The medium frequency inverter system provides controlled welding current, helping maintain consistent welding conditions during repeated operations.

Accurate Welding Control

Welding current and welding time can be adjusted according to the bolt size, stainless steel thickness, and required welding performance.

Suitable for Small Bolts

The controlled welding process is suitable for applications involving relatively small threaded components such as M3 and M4 bolts.

Consistent Bolt Positioning

A suitable fixture helps position the waterproof bolt accurately before welding, supporting repeatable production results.

Flexible Machine Configuration

The vertical spot welding machine can be configured according to different electrode structures, workpiece dimensions, fixtures, and production requirements.

Welding M3/M4 Waterproof Bolts to Stainless Steel

Waterproof bolts can be used in metal components where threaded fastening points are required.

When welding M3/M4 bolts to 1.5mm stainless steel, the welding process needs to balance welding strength with heat input.

Excessive welding energy may affect the surrounding sheet, while insufficient energy may result in an inadequate welded connection. Therefore, appropriate welding current, time, pressure, and electrode configuration should be determined through actual sample testing.

Why Conduct a Sample Welding Test?

Sample welding provides a practical way to verify the welding process before moving into mass production.

For this M3/M4 waterproof bolt application, the test can help evaluate:

• Bolt welding strength
• Welding appearance
• Sheet deformation
• Welding current
• Welding time
• Electrode pressure
• Bolt positioning accuracy
• Production cycle time

The results can then be used to optimize the final welding parameters and machine configuration.

Applications of Bolt Spot Welding

Medium frequency spot and projection welding equipment can be used for various metal component applications, including:

• Waterproof bolts
• Threaded studs
• Nuts
• Brackets
• Fasteners
• Sheet-metal components
• Electrical enclosures
• Hardware products
• Automotive components

The appropriate welding process depends on the fastener type, material, dimensions, sheet thickness, and required welding strength.

From Sample Testing to Production

After completing the sample welding test, the welding parameters can be further optimized according to the customer's production requirements.

For mass production, PDKJ can customize the welding machine with suitable fixtures, electrode assemblies, feeding systems, and automation components.

This allows the welding equipment to be integrated into a more efficient and repeatable production process.

Conclusion

This July 27, 2026 sample welding case demonstrates the application of a vertical medium frequency spot welding machine for welding M3/M4 waterproof bolts onto 1.5mm stainless steel.

Through controlled welding current, accurate electrode positioning, and adjustable welding parameters, the solution provides a practical approach for small bolt welding applications.

PDKJ provides medium frequency spot welding machines and customized resistance welding solutions for stainless steel sheet, nuts, bolts, studs, brackets, hardware components, and other metal products.

For a specific bolt or fastener welding application, welding parameters can be developed based on the bolt size, material, sheet thickness, joint structure, and required welding strength.