Essential Welding Machine Operations and Quality Inspections

In the actual operation of welding machines, although different welding machines may have slight variations, the basic principles are the same. Therefore, it is crucial to adjust each part of the welding machine according to the welding machine manual, with special attention to the following key points:

(1) Sheet Metal Specifications and Dimensions, Right Angles, and Burr Compliance, Correct Adjustment of the Magazine:
Ensure that the sheet metal meets the specified size, right angles, and burr requirements, and adjust the magazine correctly.
(2) Correct Adjustment of Sucker, Pusher, Double Sheet Detector, Flexer, Pre-roll forming, and Roll-forming:
Ensure the proper adjustment of sucker, pusher, double sheet detector, flexer, pre-roll-forming, and roll-forming.
(3) Working Height Adjustment of Z-Bar and Lower Welding Wheel Welding Position:
Adjust the working height of the Z-bar and lower welding wheel welding position according to the correction amount of the lower welding wheel.
(4) Proper Adjustment of Roller Guider and Welding Calibration Crown:
Ensure the correct tension, up-down, and front-back adjustment of the roller guider and welding calibration crown. Ensure that the can body’s opening shape meets the requirements, and maintain a deviation of less than 0.10 mm in the overlapping amount between the front and rear ends.
(5) Correct Adjustment of Synchronization and over push Amount:
Ensure the correct adjustment of synchronization and over push amount.
(6) Copper Wire Size and Forming Conformance:
Ensure that the dimensions of the copper wire meet the requirements, and the entire process operates smoothly. The tin traces on the upper and lower welding wheels should be centered, with a gap of approximately 1.5 mm. After passing through the welding station, the copper wire elongation rate should be less than 2%-3%, and the temperature should feel normal.
(7) Adjustment of Welding Pressure Based on Plate Thickness and Quality:
Correctly adjust the welding pressure based on plate thickness and quality. Adjust the welding current to the upper limit until the weld seam splatters irregularly, Then adjust it to the lower limit until the weld seam opens or breaks mechanically. Finally, adjust the welding current to its optimal value, usually slightly above 1/3 between the upper and lower limits.

Welding Quality Inspection:
(1) Visual Inspection of Weld Seam Appearance:
During the production process, visually inspect the quality of weld seams inside and outside the can. Visual inspection can identify obvious defects such as weak weld points, virtual welding, burn-through, overheating, uneven weld points, missed welds, splatter points, lack or excess of overlapping amount at the can body’s start or end, etc.
(2) Weld Seam Strength Inspection (Spherical Tester):
Place the sample can on the spherical tester, align the ball with the weld seam to form a straight line, and move the ball along the weld seam of the can body. Expand the weld seam outward by 1-2 mm (adjustable). Remove the can body from the spherical tester and check for any cracks or fractures in the weld seam.
(3) Tear Test:
Take two sample cans, cut 5 mm at one end of a can using scissors or pliers, bend the cut surface upwards, insert the can body onto the test mandrel, clamp the cut surface with pliers, and continuously and uniformly tear the weld seam upwards (at a 45° angle to the seam). Repeat the process on the other end of the second can. Visually inspect the torn weld seam: if the entire weld seam comes off clearly, feels smooth when shaken between the index and middle fingers, the weld seam is of good quality. If the weld seam breaks at a certain point during separation, the welding current is too weak. If the torn edge is irregular and feels rough, it indicates splatter points and excessive welding current. A good-quality weld seam should be flexible and not brittle.
(4) Cone Test:
The main purpose is to test the ductility of the weld points at the front and rear. Place the test can on the cone tester, press the conical body proportionally into the welded can body at a constant speed until it expands into a cone shape. Remove the can body and observe the expansion of the can: if the expansion value is above 20%, the flanging performance is good; 10%-20% expansion is acceptable; if the expansion value is ≤10%, it is considered unacceptable.
(5) Weld Seam Flip Curl Test:
The main purpose is to test the ductility of the weld points at the front and rear. Extract one can body from the welding machine, select the corresponding mold, fix it on the bottom plate of the flip curl tester, and place the can body on the mold. Operate the piston valve, press the plate to contact the can body for flip curling, curling about 10 mm, remove the can body, and observe and identify whether there are cracks in the flipped part. Cracks indicate failure.
(6) Inspection of Welding Before Overlapping, Welding Width, and Thickness:
Generally, use a magnifying glass with a scale or a projector to measure the overlapping width before welding and the width of the weld seam after welding. The weld seam thickness is measured using a pointed micrometer.
(7) Inspection of Inner Diameter Using Internal Diameter Calipers:
Check the inner diameter using internal diameter calipers, ensuring that the difference between the front and rear can diameters is less than 0.10 mm.