Re-check samples
Compare current caps with the samples originally tested or approved.
Troubleshooting
Capping machine troubleshooting guide
Use this guide to diagnose common capping machine issues before changing equipment or requesting new tooling.
Buyer intent
Most capping problems start with bottle control, cap start, torque setup or cap feed consistency.
A capping machine is only as reliable as the bottle, cap and handling around it. Loose caps can come from low torque or poor cap seating; damaged caps can come from excessive pressure; cross-threading can come from cap start issues.
The quickest route is to separate the problem into product presentation, machine setup and change part condition. That makes it easier to decide whether the answer is adjustment, maintenance, new tooling or a different capping route.
Best-fit checks
- Record the exact fault and when it happens.
- Check whether the issue follows one cap batch or one bottle size.
- Confirm guides, side belts and spindle wheels are set consistently.
- Keep known-good samples for comparison.
Specification checks
Fault-finding checks
Use these checks before assuming the machine is the only cause.
| Question | Why it matters | What to send |
|---|---|---|
| Loose caps | Torque may be low or the cap may not be fully seated. | Finished samples, torque target and current setup. |
| Cross-threading | The cap may start at an angle or the bottle may not be held square. | Photos or video of cap start and bottle presentation. |
| Cap damage | Wheel pressure, chuck pressure or cap material may be unsuitable. | Damaged cap samples and machine settings. |
| Feed jams | Caps may be inconsistent, dusty, static-prone or difficult to orient. | Cap samples, feed route and jam location. |
Decision points
Practical fixes to consider
Stabilise bottles
Flexible or lightweight bottles may need better guides or side-belt support.
Review feed route
Cap elevators, bowls and chutes must match the closure shape and orientation.
Related pages
Move to the right capping route
FAQ
Capping machine questions
Why are caps tight on some bottles and loose on others?
Variation can come from bottle grip, cap thread consistency, cap liner behaviour or inconsistent cap seating.
Why does a capping machine cross-thread caps?
Cross-threading usually starts before final tightening, when the cap is not squarely located on the thread.
Can worn parts cause capping faults?
Yes. Worn belts, wheels, chucks, guides or change parts can all reduce repeatability.
When should I ask for supplier support?
Ask for support when faults are repeated, machine settings are unstable or a new bottle or cap has been introduced.
Ready to shortlist?
Send the bottle, cap and target output.
Lancing UK will help identify the most practical capping route and quote the right machinery scope.