How to use this guide
Use this guide to prepare your requirements. Contact us if you need help choosing a configuration.
A filled bottle that is sealed badly loses everything upstream: the fill was accurate, the closure was not. Cap problems rarely appear in a machine catalogue — cross-threads appear in the first week of running mismatched tooling, and leakers appear in the destination market. Capping selection is mostly about your closures and containers; the machine class follows from there. This guide sets out how to reason from production pattern to capping route, and what to check before comparing offers.
1. Start from the closure, not the machine
Describe the cap exactly: screw type and start count, press-on or plug, liner material, tamper band, and the torque window your quality team accepts (applied and removal). “28 mm cap” is not a specification — two caps with the same nominal size can need different chuck grips and different torque behaviour. Then describe the container at the moment of capping: filled weight, neck condition (wet, oily, product in the threads), whether it is glass or PET, and how stable it is under rotational force. The cap torque and closure validation checklist covers this input set in detail and is the document a serious capping quotation should reference.
2. Match the machine class to your production pattern
An automatic capping machine must match the closure mechanism first. Belt screw capping, vacuum twist-off capping and three-knife metal-cap sealing are different routes; they are not interchangeable settings on one machine.
| Model and route | Container or closure range | Rated output | What to confirm |
|---|---|---|---|
| AT-XG belt screw capper | Screw caps 12–70 mm; bottle diameter up to 100 mm | Up to 5,400 bottles/hour | Bottle stability, cap grip and required closure torque |
| AT-XG-ZK vacuum twist-off capper | Glass jars with matched twist-off caps; jar diameter 30–85 mm, height 80–250 mm | Up to 3,600 bottles/hour | Jar and cap compatibility, vacuum requirement and seal acceptance |
| AT-SG three-knife metal-cap machine | Matched metal caps 12–35 mm; bottle height 35–320 mm | 30–60 bottles/minute | Cap material, neck geometry and the finished closure profile |
Output depends on the bottle, cap and operating conditions. Compare accepted sealed bottles, not unloaded machine cycles. For ordinary screw caps, begin with the belt-capping route. For glass jars requiring vacuum twist-off closure, evaluate the vacuum route. For a compatible metal cap requiring three-knife forming, evaluate AT-SG. Send press-on caps or plugs for separate configuration review rather than assuming any of these three routes supports them.
Use the capping, labeling and sealing range to plan adjacent operations. A capper closes the container; a labeler applies the label and a separate seal operation may still be required. Define those operations individually when requesting a line quotation.
3. The questions that expose a bad fit
- Changeover: how many bottle/cap pairs must the machine accept, and what physically changes between them — guides, chuck, torque setting, starwheel? Ask for the changeover task list, not a “quick change” claim.
- Cap presentation: bowl elevator or cap sorter is application-specific; confirm who supplies it and which cap diameters it handles.
- Reject path: what happens to a cross-threaded bottle — does it stop the line, or leave quietly for inspection?
- Upstream coupling: a filler that drips creates wet necks; capping quality is downstream of filling hygiene, which is why the line layout checklist exists.
4. Validate the closure before the machine
Run your actual bottles, caps and (where realistic) product condition at target speed. Measure, don’t eyeball: applied and removal torque on a calibrated gauge for a defined sample count; visual criteria for tilted caps, scuffs and damaged tamper bands; a leak or seal check where the product demands it. Retain accepted and rejected samples from the run. A machine demonstration with ideal, empty, clean bottles proves the motor turns — not that your closure works. Put the outcome into the decision record described in the compact line RFQ checklist, and carry the unresolved items into the FAT acceptance checklist.
5. How torque is produced and controlled
Two cappers can reach the same bottle and deliver very different consistency. Ask where the applied torque comes from — a slip clutch, an electronic servo head, or a fixed-torque friction drive — and how the setting is changed between cap sizes. Different drive and control arrangements need different adjustment and verification methods. Ask which arrangement is fitted to the quoted machine; do not infer servo control, torque feedback or automatic rejection from the word “automatic.” Request the torque decay curve across a run rather than a single first-bottle reading, and confirm whether the removal torque your quality team cares about has any proven relationship to the applied torque the machine reports. These questions separate a machine that caps one bottle from a machine that caps ten thousand the same way.
Minimum capping enquiry package
- Cap drawings or samples with liner, start count and torque window.
- Bottle drawings for every launch format, including the least stable.
- Product condition at the cap: wet neck, temperature, settling time.
- Bottles per hour for the slowest and fastest format.
- Acceptance method: torque gauge model, sample count, pass criteria.
Send your bottle and cap samples to MUJIU. Closure validation comes first; the machine class is simply what survives your data.