Small-format flexible packs
Specify sachet packaging as a complete pack-forming, dosing, sealing and cutting process using the actual product and final film structure.
Pack design
A sachet packing machine must coordinate film feed, pack formation, product dosing, seal creation, cutting and any printed code. Suitability depends on the product, required sachet dimensions, film structure, seal area, dose range and how finished sachets are counted, inspected or transferred to the next process.
A sachet is not just a smaller bag. Its narrow seal areas, short product drop and limited free space can make contamination, trapped product and air management more significant. Powder dust, liquid splashing, stringing paste or irregular granules can all reach the seal zone if dosing and timing are not controlled.
Film must be assessed as the specified laminate or material, not by nominal thickness alone. Seal initiation, dwell, pressure, cooling, print registration and cut quality can change with the film supplier and construction. Final artwork and eye-mark positions also influence the achievable finished appearance.
Product compatibility
The sachet machine and dosing unit must be treated as one coordinated system. The product determines how dosing starts and stops, while the pack geometry determines how cleanly it can enter without compromising the seals.
| Product behaviour | Machine issue to assess | Trial evidence |
|---|---|---|
| Fine or dusty powder | Dust migration into seals, bulk-density variation and product settling. | Repeated dosing, clean seal zones, pack appearance and restart behaviour. |
| Free-flowing granules | Product bounce, trapped particles and consistent cut-off. | Largest and smallest particles, segregation and seal contamination checks. |
| Thin liquid | Splashing, dripping, air displacement and seal timing. | Leak checks, fill consistency and behaviour across start/stop cycles. |
| Viscous liquid or paste | Stringing, product tails and clean nozzle withdrawal. | Final recipe at production temperature and inspection of the seal area. |
Validation
Trials should use final or production-equivalent film, enough product to stabilise the feed system and representative coding data. The acceptance plan should define what will be checked: dose, seal continuity, leak performance, registration, cut position, tear behaviour, code readability and finished-pack handling.
A stable sample run should include normal stops, reel changes, replenishment and restart. A short sequence of visually acceptable packs does not prove how the system behaves after film tracking changes, seal faces become warm or the product supply level falls.
Buyer questions
Sachet packing machines can be configured for certain powders, granules, liquids or pastes, but the dosing and sealing system must match the product. Flow, dust, particulates, temperature, splash, stringing and seal contamination should be tested with the real product and final film before suitability is confirmed.
A sachet machine and a vertical form fill seal machine can use related form-fill-seal principles, but the terms are not always interchangeable. Sachet equipment is commonly specified for small portion packs and particular seal layouts, while VFFS can cover a wider range of bags. The final pack format should define the category.
Sachet film is selected from product protection, sealability, print, stiffness, friction, tear behaviour and the machine’s reel and forming requirements. The actual laminate, artwork repeat and unwind direction should be approved with the machinery supplier because a nominally similar film can seal and track differently.
Sachet seals can leak because of product contamination, incorrect temperature, pressure or dwell, damaged seal faces, film variation, wrinkles, poor cooling or pack tension. Diagnosis should separate material, product and machine causes, then confirm the correction through repeated packs and an agreed seal-integrity test.
