Symptoms

Excess median diameter and insufficient outside diameter

1. Main live axle too far;
2. Hydraulic time too short;
3. Hydraulic pressure too low

Excess median diameter and acceptable outside diameter

Excess workpiece diameter

Acceptable median diameter and insufficient outside diameter

Insufficient workpiece diameter

Acceptable median diameter and excess outside diameter

Excess workpiece diameter

Insufficient median diameter and excess outside diameter

1. Insufficient center distance of main axle;
2. Excess hydraulic time;
3. Excess hydraulic pressure

Median diameter not conical and outside diameter conical

Conical workpiece

Insufficient conical median diameter

2 rolling dies not parallel

Particles or flakes from hydraulic pressure

1. Tooth location not properly adjusted;
2. Excess hydraulic time

Workpiece jumps up under hydraulic pressure

1. Excess height of supporting shoe;
2. Two rolling dies with different diameters

Workpiece screw top worn

1. Supporting shoe too low;
2. Insufficient degree of supporting surface finish

rolling die thread face-off damaged

1. rolling die face-off excessively steep or small
2. Rolling die end surfaces not in alignment

Workpiece radial movement under hydraulic pressure

1. Excess or insufficient workpiece diameter;
2. Excess or insufficient rolling die diameter;

Pressure meter hand vibration

Oil suction blocked

Main live axle feeding too slow

1. Pipe leaks, to be repaired;
2. Oil cylinder seal damage; to be replaced

Main live axle vibrates while feeding and returning

1. Air in oil cylinder, to be discharged;
2. Lack of lubrication oil in sliding sleeve; to be added lubrication oil

Oil temperature too high

1. Excess oil viscosity;
2. Excess time for hydraulic pressure;
3. Excess hydraulic pressure;
4. Ambient temperature too high; cooler added

Failure to increase the pressure

1. Oil pump damaged; to be replaced
2. Insufficient oil viscosity; new oil to be used
3. Overflow relief valve failed; to be replaced

Oil with bubbles

Oil level too low in the tank or air in oil pump

Main live axle fails feed motion

Oil pump motor rotates in wrong direction.

Main live axle fails return motion

Return spring does not work.

High temperature of workpiece

1. Main axle rotation speed too fast;
2. Feed speed too fast;
3. Excess hydraulic pressure

rolling die broken or cracked

1. workpiece shoulder contacts rolling die end surface;
2. workpiece shoulder contacts supporting shoe end surface;
3.Supporting shoe not properly located and workpiece stuck
4. Excess feed to thread length