The initial parameter calibration based on welding current and welding time is the lowest-cost and most efficient method for preliminary process setting, which can quickly establish an effective welding process window.

Example (Figure 1):

Taking the welding of an M8 steel stud as the working condition example, the initial parameters determined by empirical formulas are as follows:

• The pilot current is set to 40 A (default value for automatic welding guns),and the pilot time is 8-10 ms
• The initial welding current is calculated as I_weld = 8 × 100 = 800 A
• The initial welding time is calculated as T_weld = 8 × 4 = 32 ms
• The forging time is set to 6-8 ms
• The lift height is approximately 1.2 mm

1.2 Mechanical Parameter: Lift Height

Lift height is a core mechanical parameter that is frequently overlooked. It directly determines the welding arc voltage and arc energy density, and critically governs arc stability and weld forming quality.

• Electromagnetic welding gun: The lift height is generally non-adjustable or with a very limited adjustment range, and the typical reference value is 1.2 mm.

• Servo motor-driven welding gun: It supports high-precision continuous adjustment. For ordinary steel studs, the recommended initial parameter range is 1.2~1.5 mm. For thin plate welding, the lift height should be appropriately reduced to 0.6~1.0 mm to lower the arc voltage and heat input, so as to effectively prevent workpiece burn-through defects.

2. Systematic Commissioning Procedure and Process Window Optimization

In practical applications, workpiece material, surface condition, and grounding configuration vary significantly. Empirical formulas only provide an initial reference for a safe process range. It is therefore necessary to proceed to the parameter fine-tuning stage, with the core objective of identifying a stable and reliable process window.

2.1 Step 1: Stepwise Approximation via Single-Factor Method

Commissioning Rule: Adjust only one parameter at a time while observing and evaluating the welding result. This avoids misinterpretation caused by multi-variable coupling.

Optimization Path 1 – Current Priority:

• Insufficient current: The fusion ring around the weld is narrow, and the stud detaches easily under minor force.
• Optimal current: The deposited metal forms a regular ring with full weld penetration. During torque or tensile testing, fracture occurs in the stud base material rather than at the weld (determined as the optimal state).
• Excessive current: Severe spatter occurs, potentially leading to workpiece burn-through and excessively deep weld penetration.
• Procedure: Keep the initial welding time and lift height unchanged, and adjust the welding current incrementally in steps of ±30~50 A.
• Evaluation criteria: As described above.

Optimization Path 2 – Time Fine-Tuning:

• Procedure: After determining the optimal current, fine-tune the welding time in steps of 1–2 ms.
• Purpose: Precisely control the total heat input while maintaining sufficient current. Avoid reducing heat input by drastically lowering the current when the current is already too high, as this can cause the weld pool to solidify too slowly and compromise joint quality.

2.2 Step 2: Finding the Energy Balance Window

Welding energy (defined as E=(I*I)×t/k​, where I= current,t= time, and k= correction factor) is the key factor determining joint strength. The commissioning process must identify the stable feasible window between the lower energy limit (cold joint defect) and the upper energy limit (overburn defect).
The following is a conceptual diagram of the process window, developed based on Analysis of Defect Criteria and Solutions for Stud Welding and the quality control logic of major equipment manufacturers.

Commissioning Objective: Within the process window, prioritize parameter combinations featuring high current + short welding time. This aligns perfectly with the core characteristics of short-cycle drawn arc stud welding: concentrated heat input, minimal heat-affected zone, low workpiece distortion, making it particularly suitable for thin-plate applications.

2.3 Special Condition Commissioning: Galvanized and Thin-Plate Welding

The technical document Solutions to Burn-Through Issues in Stud Welding of 0.7mm Galvanized Steel Sheets provides an excellent reference case for commissioning.

Parameter Item	Original Value (Mild Steel Plate)	Optimized Value (Galvanized / Thin Plate)	Reason for Adjustment
Welding Current	650 A	580–620 A	Reduce heat input to prevent burn-through of the galvanized layer.
Welding Time	30 ms	22–26 ms	Shorten heating duration to minimize heat accumulation.
Pilot Current	28 A	Maintain at 28 A	Maintain pilot current while extending pilot time to enhance cleaning of oil contamination and coating.
Pilot Time	55 ms	Maintain at 55 ms	Extend arc initiation duration to ensure stable arc ignition.

From the perspective of process commissioning, the key adjustments are summarized as follows:

1. Pilot arc stage: For galvanized plates, the pilot time shall not be reduced, and shall be extended when necessary.
2. Welding energy: Adopt the strategy of slightly reducing current and prioritizing shorter welding time, so that the arc acts on and leaves the weld pool rapidly.
3. Forging stage: Maintain sufficient forging time to cool the weld pool under compression and prevent porosity.

3. Root Cause Analysis of Faults and Parameter Adjustment

When welding defects occur, do not adjust the welding energy arbitrarily. It is recommended to establish a defect-remedy checklist based on actual defect characteristics for targeted parameter modification.

3.1 Correspondence between Common Defects and Parameters

The analysis below is compiled based on Fundamentals of Stud Welding and Criteria and Analysis of Defects in Stud Welding.

Defect Phenomenon	Root Cause	Commissioning Countermeasure
Incomplete Fusion	1. Insufficient heat input 2. Improper lift height (too low or too high) 3. Excessively thick base plate	1. Increase welding current or welding time 2. Set the lift height to 1.5 times the plate thickness 3. Increase forging force
Porosity	1. Insufficient shielding gas (for aluminum welding) or premature gas cut-off 2. Residual oil contamination or zinc coating on workpiece surface 3. Excessively fast cooling of weld pool	1. Increase shielding gas flow rate or extend post-flow duration 2. Raise pilot current or prolong pilot time 3. Extend forging time for slow cooling
Spatter	1. Excessive welding energy (over-high current or over-long welding time) 2. Excessively large lift height 3. Delayed or slow forging action	1. Reduce welding current or welding time 2. Decrease lift height 3. Adjust the advance descent time of the welding gun to speed up stud insertion
Weld Deviation / Stud Tilting	1. Welding gun not perpendicular to the workpiece 2. Misaligned stud inside the collet 3. Magnetic blow caused by poor grounding	1. Calibrate the perpendicularity of welding gun (angular deviation ＜ 1°) 2. Replace or clean the contact tip 3. Add more ground cables and optimize grounding positions

3.2 Real-time Monitoring and Diagnosis

Modern welding machines (e.g., Hongbai PIDS, Hongbai SAW-3600R and Tucker DCE) are equipped with waveform recording and welding quality monitoring functions. Professional commissioning requires the ability to analyze welding waveforms.

Commissioning Application
If the descent at point T2 occurs too early (the arc fails to burn sufficiently), it indicates insufficient welding time or inadequate lift height, both of which need to be increased.
If the arc voltage drops slowly from T2 to T3 (arc trailing), it means the forging action is delayed or the insertion depth is insufficient. Adjust the mechanical descent time of the welding gun accordingly.

4. Advanced Skills and Experience Summary

4.1 Power Deviation and Energy Compensation

Process parameters are not constant. Many welding machines such as Hongbai SAW-3600A/B adopt the mechanisms of upper/lower power deviation and current compensation.

Working Principle: During welding, the machine calculates in real time the ratio between actual output energy and target energy, which is estimated based on current, welding time and desired arc voltage.

Application: When the actual energy falls below the lower limit, the system triggers an alarm and automatically raises the current for energy compensation, so as to guarantee consistent welding quality for subsequent operations. During commissioning, set the lower power deviation to 15%–20%. Avoid an overly strict threshold to accommodate normal on-site variations.

4.2 Summary of Standard Operation Procedures

Combined with the above theories, the standard commissioning workflow for short-cycle drawn arc stud welding machines is illustrated in the figure below.