For FAQ/article content,covers tube shrinking,expanding,crimping,punching,notching hydraulic pipe processing machinery;fault phenomenon,root cause,troubleshooting.
1.Workpiece forming defects(product quality problems)
1.1 Workpiece cracking during forming(shrinking/expanding/crimping)
-Causes:Single‑pass deformation too large;sharp die fillet;material hardness too high;excessive wall‑thickness;insufficient lubrication.
-Solutions:Adopt multi‑stage progressive forming dies;increase die fillet radius;reduce single‑stroke deformation;add lubricant;do not process over‑thick or high‑hardness pipes.
1.2 Tube wrinkling,indentation,collapse deformation
-Causes:Ultra‑thin‑wall pipe;excessive hydraulic pressure;insufficient internal support;die wear;unstable clamping.
-Solutions:Use inner mandrel for thin‑wall tubes;lower forming pressure;replace worn dies;increase clamping force;control single‑pass deformation volume.
1.3 Uneven forming/oval after processing
-Causes:Misalignment between pipe and die/mandrel;uneven die wear;insufficient pressure‑holding time;workpiece skewed while clamping.
-Solutions:Readjust coaxial centering;replace worn die segments;add pressure‑holding dwell time;check fixture clamping status.
1.4 Large burrs after punching/notching
-Causes:Die clearance mismatched for wall thickness;punch and die blunt;insufficient cutting pressure.
-Solutions:Adjust die clearance according to wall thickness;grind or replace punch¨appropriately increase working pressure.
2.Hydraulic system failures
2.5 Insufficient forming pressure,incomplete forming
-Causes:Hydraulic oil level low;oil contamination;hydraulic seal aging;pump wear;pressure valve mis‑adjusted.
-Solutions:Fill up qualified hydraulic oil;replace dirty oil and filter;check oil‑seals;recalibrate system pressure;inspect hydraulic pump.
2.6 Machine jamming,punch/mandrel stuck in workpiece
-Causes:Exceed machine rated wall‑thickness;wrong die clearance;workpiece slipping during processing.
-Solutions:Do not keep pressing operation button repeatedly.Jog reverse return;release pressure,loosen die assembly to take out workpiece;inspect dies for damage before restarting;strictly follow material thickness limit.
2.7 Hydraulic oil leakage
-Causes:Aging oil‑seals;loose pipe joint;cylinder rod scratch.
-Solutions:Replace oil‑seals;tighten hydraulic fittings;repair or replace damaged cylinder rod.
2.8 Slow cylinder movement
-Causes:Viscosity of hydraulic oil too high/low;oil filter blocked;insufficient system pressure.
-Solutions:Use specified hydraulic oil;clean or replace filter element;adjust pressure setting.
3.Clamping&positioning failures
3.9 Workpiece slips or shifts during processing
-Causes:Clamping force too small;jaw surface worn;pipe surface oily.
-Solutions:Increase clamping pressure;repair or replace fixture jaws;clean grease on pipe surface.
3.10 Positioning dimension unstable,batch size fluctuation
-Causes:Loose limit sensor/stop block;guide rail gap too large;workpiece bounce‑back ignored;fixture loose.
-Solutions:Fasten sensors and mechanical stops;adjust guide‑rail clearance;add pressure‑holding time to compensate spring‑back;retighten fixture bolts.
4.Electrical&control failures
4.11 Cylinder does not act after pressing button
-Causes:Power supply failure;relay/solenoid valve burnt out;emergency stop not reset;travel limit triggered.
-Solutions:Check power circuit;reset emergency‑stop;inspect solenoid valve and relays;check whether limit switch is triggered.
4.12 Automatic model cumulative position error
-Causes:Servo parameter drift;sensor dirty;mechanical clearance;hydraulic pressure fluctuation.
-Solutions:Perform origin reset;clean sensor;compensate mechanical clearance;check hydraulic oil condition.
Daily preventive maintenance tips
1.Change hydraulic oil and filter element regularly according to working hours.
2.Clean die cavity and fixture jaws of metal chips after each shift.
3.Check whether bolts of frame,cylinder and die‑seat are loose weekly.
4.Apply lubrication for guide‑rails and moving parts.
5.Test‑run with jog mode before mass‑production for new pipe specifications.
Conclusion
Most pipe‑end forming and punching equipment faults come from three aspects:improper process parameters(deformation amount,pressure,die clearance),wear of dies and fixtures,and aging of hydraulic components.Do not force continuous operation under jamming or over‑pressure status;regular maintenance can greatly reduce failure rate.
References
1.APA 7th
Jiang,H.(2024).Common faults and troubleshooting of hydraulic pipe processing forming equipment.
2.MLA 9th
Jiang,Hao."Common Faults and Troubleshooting of Hydraulic Pipe Processing Forming Equipment.
3.GB/T 7714‑2015
JIANG H.Common faults and troubleshooting of hydraulic pipe processing forming equipment
