Spot Weld Defect Investigation Checklist
The purpose of this investigation is to thoroughly analyse and identify the root cause of spot welding defects, including issues such as burrs, weld failures, excessive expulsion, and similar anomalies.
Unipres
02/10/2025
Spot Weld Defect Investigation Checklist
The purpose of this investigation is to thoroughly analyse and identify the root cause of spot welding defects, including issues such as burrs, weld failures, excessive expulsion, and similar anomalies.
Stage Number
Welding Equipment Information
Welder Type
Gun Type
Defect Information
Part Number
NCR Number
Content of Defect
if the answer is "oneOf [Other]"
Further info here
Image of Defect
Add or drag pictures
Image of tips and the time of abnormality (Movable electrode)
Add or drag pictures
Image of tips and the time of abnormality (Fixed electrode)
Add or drag pictures
Welding Parameter Confirmation
Are welding parameters correct to the blue book?
if the answer is "noneOf [FLAG,FAIL]"
Detail what is incorrect.
Program Name
Is the electrode force within + / - 10% when set at 2000 Nm?
if the answer is "oneOf [FLAG,FAIL]"
Electrode Force (Nm) Set at 2000Nm
Is the electrode force within + / - 10% when set at 4000 Nm?
if the answer is "oneOf [FLAG,FAIL]"
Electrode Force (Nm) Set at 4000Nm
Is the electrode force within + / - 10% when set at 6000 Nm?
if the answer is "oneOf [FLAG,FAIL]"
Electrode Force (Nm) Set at 6000Nm
Welding current is within -5% & +10% when set at 6000 Amp
if the answer is "oneOf [FLAG,FAIL]"
Welding current when set at 6000 Amp
Welding current is within -5% & +10% when set at 9000 Amp
if the answer is "oneOf [FLAG,FAIL]"
Welding current is within -5% & +10% when set at 12000 Amp
if the answer is "oneOf [FLAG,FAIL]"
Welding current when set at 12000 Amp
Tip Dressing
What is the tip dress frequency?
Is there any swarf or burrs on the tip diameter?
Is the tip diameter the correct size?
Does the tip dress camera have any NG images?
if the answer is "oneOf [Yes]"
Attach image of NG camera shot.
Add or drag pictures
Are the correct tips fitted?
if the answer is "oneOf [No]"
What tips were fitted?
Is the tip alignment correct (within 0.5mm)
if the answer is "oneOf [No]"
Add image of NG alignment
Add or drag pictures
Is the tip wear down value within the limit?
if the answer is "oneOf [No]"
Recalibrate and / or detail corrective actions below.
Is the tip dress time correct rotations 5 sec and cut 2 sec?
if the answer is "oneOf [No]"
What is it set at?
What is the operating tip dress pressure in the data register?
Is the tip dress teaching aligned correctly?
Does the tip dresser pulse more than once?
Robot Confirmations
Robot floor bolts are torqued to 350 Nm
if the answer is "oneOf [No]"
Detail corrective action.
Inspect shunt condition for damage , bolts loose and overheating, (leafs are >70%
Check water pipes for splits, rubbing & wear.
Check primary welding cable for damage, wear or overheating.
Check gun for signs of contact or arcing.
Cooling Water
Check water flow with flow meter - SHOULD BE 2.0 ℓ/min. AND ABOVE FOR EVERY TIP.
Visually check flow and return are securely connected.
Check capillary tube is secure and diagonally cut (45 degrees)
Position of capillary tube is correct - FOR STRAIGHT TIP, IT SHOULD BE -5mm FROM THE MARGINAL LINE. FOR SHANKS, MATCH IT TO THE TIP OF THE SHANK.
Capillary tube diameter is correct - φ12/φ13：φ5、φ16 AND ABOVE：φ6
Jig Security
The gap between panels is no more than 2mm
if the answer is "oneOf [FLAG,FAIL]"
Detail corrective action
Part security is good when clamped - PARTS DO NOT MOVE IN JIG
There is no contamination on the jig or parts.
Teaching
The pitch between spot welds is a minimum of 20mm
if the answer is "noneOf [FLAG,FAIL]"
What is the pitch? (mm)
There is no edge welding.
Check weld gun angle [trajectory] USE A SQUARE IF NECESSARY
There is no gap between the fixed electrode and the panel at the spot stand off position.
What is the movement type in the robot program (CNT, Fine etc)
Visually inspect there are no signs of Arcing.
There is at least 3mm clearance between electrodes and jig.
Define the root cause of the problem.
Detail countermeasures and reoccurrence prevention.
Source: Unipres (Community Member)