How are small sauce pots and tubs filled and sealed automatically?
An indexed pot line typically denests containers into carriers, checks pot presence, deposits the product, applies a pre-cut foil or seals lidding film, optionally applies an over-lid, codes the pack and discharges it for inspection or packing. The correct format depends on pot rigidity, rim geometry, product temperature, required seal integrity, shelf-life process and weekly output.
Define the pot, rim and closure system before selecting the machine
Supply production pots, drawings and tolerance information. Thin-wall pots can stick during denesting or distort under sealing pressure, while a contaminated or damaged rim can prevent a reliable seal. Stack height, flange width, taper and static all influence the infeed system.
The closure can be a pre-cut foil, reel-fed film, snap-on lid or a combination of primary seal and over-lid. Each route creates different requirements for tooling, temperature, dwell, pressure, peel behaviour and consumer opening.
Pre-cut foil
Individual foils are picked, placed and heat sealed. Presentation is strong but foil feeding and presence checks need control.
Reel-fed lidding film
Film is indexed, sealed and cut over one or more cavities, suiting repeat production and printed registration where required.
Snap-on lid
A rigid lid is fed or manually placed and pressed onto the pot. Engagement and lid presence must be verified.
Seal plus over-lid
A primary barrier seal can be combined with a reusable presentation lid, adding another feeding and inspection stage.
Coordinate denesting, pot presence, filling, sealing and discharge
The number of lanes and index pitch determine line architecture. A multi-lane machine can increase output but also multiplies fill nozzles, seal cavities, film tracking and change parts. Balance the machine against operator loading and end-of-line collation.
| Station | What to prove |
|---|---|
| Pot denesting | Single release without doubles, damage or frequent stack adjustment across normal pot batches. |
| Pot detection | No-pot/no-fill and no-pot/no-seal logic prevents product or film waste and supports fault diagnosis. |
| Filling | Dose, distribution, cut-off and rim cleanliness with the coldest, warmest or most particulate normal recipe. |
| Seal application | Foil or film presence, registration, seal temperature, pressure, dwell and cooling. |
| Over-lid | Feed, orientation, engagement and detection where a rigid lid is included. |
| Discharge | Gentle ejection, code inspection, accumulation and collation without disturbing warm or freshly sealed packs. |
Select the filling head from product rheology and portion accuracy
Free-flowing dressings, smooth mayonnaise, thick dips, jam and sauces with pieces require different product paths and nozzle behaviour. A piston depositor can suit many viscous portions, while pump or time-pressure systems may be selected for other products. The pot opening and target presentation also influence nozzle number and dive movement.
Avoid contaminating the flange. Strings, tails and splashes can compromise seal integrity. Product temperature, hopper agitation and the time between deposit and sealing should be included in the trial.
Define product and portion range
Record minimum and maximum dose, density, viscosity, pieces, oil separation and temperature.
Define the fill presentation
Set fill height, top surface, piece distribution, headspace and allowable sidewall or rim contamination.
Choose nozzle count and pitch
Match the number of heads to lanes, index time and cleaning practicality.
Control cut-off
Use shut-off, suck-back or nozzle motion proven with the real product.
Verify every lane
Measure dose and presentation by cavity, not only the average across the machine.
Validate the sealing window rather than one successful temperature setting
Heat sealing is influenced by foil or film construction, pot flange material, tooling flatness, pressure, dwell, temperature, contamination and cooling. Establish an operating window that produces an acceptable seal at the low and high limits, not a single nominal setting.
The producer should define seal-integrity tests appropriate to the product and distribution route. These may include visual inspection, peel assessment, leak methods or destructive checks. Any easy-peel target should be balanced against transport security and consumer use.
- Use production pot and lidding-material batches.
- Challenge minor allowable product contamination near—but not on—the defined seal area.
- Check every cavity and lane for pressure and temperature consistency.
- Test start-up, planned stops and restart after tooling temperature changes.
- Confirm printed-film registration and cut position where applicable.
- Define missing-foil, broken-film and seal-failure responses.
Size the machine from good pots per shift and normal operator tasks
Calculate demand from saleable pots, available production time, cleaning, flavour changes, pot and lid replenishment, reel changes, quality checks and end-of-line packing. An indexed machine may have a fast theoretical cycle but lose output through small consumable stacks or manual tray loading.
Include future formats carefully. Very different pot diameters or depths can require major tooling rather than simple adjustments. Document change parts, storage and changeover time as part of the commercial comparison.
Agree pot filling and sealing acceptance criteria
The trial should use production pots, closure materials and the most difficult normal food across every lane and cavity.
- Pots denest singly without unacceptable damage or stoppage.
- No-pot/no-fill and no-pot/no-seal functions operate as specified.
- Dose and product presentation meet limits in every lane.
- Pot rims remain sufficiently clean for the agreed sealing process.
- Seal temperature, pressure and dwell produce acceptable results across the operating window.
- Foil, film and over-lid presence or registration are checked as required.
- Sustained good-pack rate includes normal replenishment and inspection tasks.
- Format change, cleaning and safe tooling access are demonstrated and documented.
Common questions
Often yes, but the extent of change parts depends on diameter, depth, stack and flange geometry. Denesting, carriers, filling pitch, seal tooling and discharge may all need format-specific parts.
They can when the dosing system, valves and nozzles are sized for the largest normal pieces and the pot opening permits clean depositing. Representative recipes should be trialled.
Pre-cut foils are individually picked and placed; reel-fed film is indexed across the pots and cut after sealing. The choice affects consumables, tooling, printing, waste and machine layout.
The producer should define a risk-based method such as visual, peel, leak or destructive testing. Machine settings and checks must be linked to the validated pot and lidding-material combination.