During the production of carrier tapes on flatbed (intermittent) machines, if the clamping or pressing action speed fluctuates (sometimes fast, sometimes slow), it severely affects forming precision and production stability. This phenomenon is usually caused by the following four core reasons, which need to be troubleshooted one by one.

1. Electrical or Wiring Faults

This is the most easily overlooked but also the easiest cause to resolve:

• Wiring Check: Inspect the wiring from the PLC point to the solenoid valve for damage or wear.
• Connector Check: Check all connectors for looseness or poor contact. Poor contact can cause intermittent signal interruptions, leading to action delays.

2. Solenoid Valve Failure

Solenoid valves are consumables in pneumatic systems and are prone to issues after long-term use:

• Initial Treatment: First, try cleaning the solenoid valve and adding specialized lubricating oil. If the action returns to normal, production can continue, but replacement is recommended.
• Replacement Suggestion: If the speed remains inconsistent after cleaning, it is recommended to directly replace the solenoid valve with a new one. This is the fastest and most effective way to solve intermittent pneumatic system faults.

3. Air Cylinder Damage

If electrical wiring and solenoid valve issues are ruled out, the fault point may have shifted to the actuator—the air cylinder:

• Diagnosis: Wear on the internal seals of the cylinder or piston rod sticking can cause uneven resistance, manifesting as fluctuating action speeds.
• Handling: Cleaning cylinders is complex and the effects are not lasting. It is recommended to directly replace the air cylinder with a new one of the same specification.

4. PLC Control Point or Program Issues

This is the most complex cause, usually checked last:

• Point Delay: The PLC output point may experience logical delays due to internal program or hardware issues, causing unstable drive signals for clamping/pressing actions.
• Secondary Forming Conflict: For machines not suitable for secondary forming, pressing during the mold pushing stage may also cause uncoordinated action speeds.