Cause: Defective Air/Hydraulic System

A defective air or hydraulic system is one which adversely affects the electrode motion, follow-up, or force application.

Description 

Defective systems can result in excessively fast or slow electrode movement. A fast system may result in electrode bounce, electrode/workpiece damage, etc. A slow system may result in surface expulsion if current initiation occurs before adequate weld force is established. Also cycle time may be increased.

Defective systems may also result in poor electrode follow-up.

Detection 

The condition may be indicated by:

• Cracks & holes
• Electrode wear
• Excessive indentation
• Expulsion/burn through
• Inconsistent weld quality
• Poor electrode follow-up
• Sticking/stuck tips
• Stuck weld
• Undersized weld
• Weld force high
• Weld force low
• Air leak
• Electrode bounce
• High closing impact of electrodes
• Hydraulic leak
• Slow closing or opening of electrodes
• Variation in gun opening or closing speed

Significance 

Quality, Workplace Issues, Cost, Downtime, Maintenance, Throughput (cycle time; PPH), are all potentially affected by this condition.

Subordinate Causes

• Dirty filter(s)
• Broken, worn, kinked hoses and/or seals
• Loose or broken fittings
• Low/no oil in hybrid system reservoir
• Hydraulic pump malfunction
• Air compressor malfunction
• Incorrect valve setting
• Valves not operating properly
• Contaminants in system
• Wrong hydraulic fluid