How does a sauce sachet packing machine work?
A vertical form-fill-seal sachet machine unwinds printed or plain film, forms it around a tube, creates longitudinal and transverse seals, doses the sauce, cuts individual packs and applies variable data. Multi-lane sachet or stick-pack machines can produce several narrow packs per cycle. The correct filler and seal system depend on dose, viscosity, particles, film structure and output.
Choose the flexible-pack format from dose, opening and presentation
A wide pillow sachet can accommodate thicker products and a larger tear opening, while a narrow stick pack provides efficient single-dose presentation but restricts the filling tube and product passage. Three-side or four-side seal sachets may use different horizontal or multi-lane machinery.
Define finished width, length, dose, headspace, tear notch, print repeat, eye mark, seal widths and the maximum acceptable pack thickness. The pack converter should be involved early because film stiffness, coefficient of friction and sealing layer affect machine performance.
Pillow sachet
A VFFS tube creates a longitudinal seal and two transverse seals; suitable for many single-serve sauce doses.
Stick pack
A narrow pack reduces film area but limits tube diameter and can be more challenging for viscous or particulate foods.
Three-side seal
A folded web or preformed structure creates three sealed sides and a broad graphic area.
Four-side seal
Two webs or a specialised arrangement seal around all edges, often used where precise presentation is required.
Specify film structure, registration and sealing window with the converter
Film needs enough stiffness and surface properties to unwind, track and form while delivering the required barrier and consumer opening. Printed film adds registration control; recyclable mono-material structures may behave differently from conventional laminates and should be trialled on the intended machine.
The seal jaws must operate within a validated range of temperature, pressure and dwell. Sauce contamination, wrinkles, misregistration and film tension can create channels or weak seals.
| Film or pack factor | What to define |
|---|---|
| Web width and repeat | Finished pack dimensions, seal allowances, print repeat and eye-mark position. |
| Laminate structure | Sealant layer, barrier, thickness, stiffness, friction and recommended sealing conditions. |
| Print and registration | Artwork safe areas, code panel, eye-mark contrast and allowable registration error. |
| Tear feature | Notch or laser score position, opening force and relationship to the product fill level. |
| Seal appearance | Width, embossing, cooling, wrinkle limits and any easy-peel requirement. |
| Storage and distribution | Temperature, oil contact, abrasion, compression and required shelf-life barrier performance. |
Select a dosing system that fits inside the sachet cycle
The filler must deliver the dose within the available machine cycle while leaving the transverse seal area clean. Thick ketchup or mayonnaise may require positive displacement and a shut-off nozzle; sauces with herbs or particles need adequate passages. Product strings must be cut before the jaw closes.
The fill tube is often the smallest restriction. Confirm the largest normal inclusion against tube, valve and nozzle dimensions. Product temperature and hopper level can affect viscosity and dose timing.
Characterise the sauce
Measure viscosity, density, particles, strings, foam, separation and temperature at the machine.
Set the portion range
Define nominal dose, permitted variation and the number of sachets per retail or catering unit.
Match filler to cycle
Ensure the complete dose and cut-off occur without slowing the intended seal cycle.
Keep the seal clear
Control timing and nozzle position so no product is trapped in the transverse seal.
Verify every lane
On multi-lane systems, measure dose and seal performance by lane throughout the run.
Integrate date coding, registration checks and leak-control measures
Variable data may be printed onto the film before forming using thermal transfer, inkjet or another compatible technology. The code should sit inside a controlled artwork window and remain readable despite film movement and seal texture.
Inspection can include eye-mark detection, film-end warning, code presence, pack count, seal-temperature monitoring or downstream leak testing. The required level should follow product and customer risk.
- Protect code and mandatory text from seal and cut tolerances.
- Detect missing registration marks or excessive print drift.
- Monitor seal-jaw temperature and define the response outside the permitted range.
- Challenge missing dose, low dose, seal contamination and cut-position faults.
- Control rejected or suspect sachets before they enter multipacks or cases.
- Record lane-specific performance where a multi-lane machine is used.
Run a representative trial with production film—not plain test material only
Printed production film, final ink coverage and the actual sauce should be used before sign-off. Include the longest planned run, replenishment, film splice or reel change, a short stop and restart. Warm jaws and stable product can make the middle of the run behave differently from start-up.
Assess dose, pack length, print registration, tear performance, visible seal quality, agreed integrity tests, code readability and sustained good-pack output. Retain approved samples from every lane.
Agree sachet-machine acceptance criteria
The acceptance run should prove forming, dosing, sealing, coding and cutting together using production film and sauce.
- Finished sachet dimensions and print registration remain within agreed tolerances.
- Dose accuracy is demonstrated by lane at start-up, sustained running and low product level.
- The largest normal particles pass through the complete fill tube and valve route.
- Product does not create unacceptable contamination in the transverse seals.
- Seals meet the agreed appearance and integrity tests across the operating window.
- Tear notches or opening features remain correctly positioned and usable.
- Code content, position and readability are verified on the moving film.
- Good-pack output includes reel changes, replenishment, normal stops and reject handling.
Common questions
Yes, when equipped with a suitable paste or liquid dosing system and a fill tube large enough for the product. Cycle timing and clean cut-off are especially important.
Small inclusions may be possible, but the narrowest tube, valve and nozzle set the limit. Large or irregular pieces can block the system or enter the seal, so representative trials are required.
The structure depends on barrier, oil resistance, sealant compatibility, printing, opening and recycling objectives. The film converter should supply production material and a recommended sealing window for trials.
A stick pack is normally narrower and may be produced on a multi-lane machine. It can reduce material but limits fill-tube size, which may not suit very viscous or particulate sauces.