PISTON FILLER+AUTOMATIC 4SIDE SEALING SACHET BAG PACKING MACHINE

Support bag length: 40-160mm width:20-150mm

Machine rough size 950mm*850mm*1000mm, suit for small factory and homeuse, save budget but high efficiency

Also could be widely used as paste packing machine, ketchup packing machine, fittings packing machine, coffee powder /ground coffee vertical packing machine, detergent powder vertical packing machine, spcice powder vertical packing machine, milk powder vertical packing machine combine with different weighing system

An Automatic 4-Side Sealing Sachet Bag Packing Machine is a high-efficiency, fully automated packaging device dedicated to producing small-sized sachets with sealed edges on all four sides (top, bottom, left, right). Designed for single-use or portion-controlled packaging, this machine integrates film unwinding, bag forming, precise filling, four-side sealing, and cutting into a continuous, one-step workflow. It is widely applied in the food, pharmaceutical, cosmetic, and household chemical industries for packaging powders, liquids, pastes, and granular materials in compact, leakproof sachets.

Core Working Principle & Operational Workflow

The machine operates with a fully automated, linear process optimized for small sachet production, with the following key steps:

1. Film Unwinding & Tension ControlThe machine feeds a roll of packaging film (usually high-barrier composite films like PET/AL/PE, BOPP/PE, or aluminum foil for moisture and oxygen resistance) into the film handling system. Built-in tension rollers maintain consistent film tightness, preventing wrinkles or misalignment during processing. Most models support two modes: single-film mode (folding a single roll of film into a double layer) or dual-film mode (joining two separate film rolls together) to form the sachet’s basic structure.
2. Vertical Sealing (Left & Right Sides)The film passes through the vertical sealing station, where heat-sealing bars compress the left and right edges of the film at a precisely controlled temperature and pressure. This step forms the first two sealed sides of the sachet, creating a closed film cavity that prevents material leakage during filling. The sealing parameters are calibrated to the film material to avoid overheating (which causes film melting) or insufficient sealing (which leads to leaks).
3. Precision Filling for Small PortionsThe formed film cavity moves to the filling station, which is equipped with a material-specific metering system tailored to sachet-sized portions (typically ranging from 1g to 50g):
   • Auger fillers for fine powders (e.g., instant coffee, sugar, pharmaceutical powders)
   • Peristaltic or piston pumps for liquids and pastes (e.g., ketchup, lotion, liquid medicine, honey)
   • Volumetric cup fillers for small granules (e.g., tea leaves, seasoning crystals, capsule pellets)A PLC (Programmable Logic Controller) system regulates the filling volume with high accuracy (error margin ±0.5–1%), ensuring uniform portioning for every sachet. For viscous materials, the filling nozzle is designed with anti-drip features to prevent residue from contaminating the sealing edges.
4. Horizontal Sealing (Top & Bottom Sides) & CuttingAfter filling, the film cavity advances to the horizontal sealing station. Heat-sealing bars simultaneously seal the top of the current sachet and the bottom of the next sachet, completing the four-side sealed structure. Advanced models integrate additional functions at this stage:
   • Vacuum sealing: Removes air from sachets to extend shelf life (ideal for food and medicine).
   • Gas flushing: Fills sachets with nitrogen or carbon dioxide to prevent oxidation and maintain product freshness (suitable for snacks, coffee, and baked goods).Finally, a sharp cutting blade (rotary or flat) separates the continuous sealed film into individual sachets. Some machines add a notch-cutting function to make sachets easier to tear open.
5. Discharge & SortingFinished sachets are discharged onto a conveyor belt, which transports them to downstream processes such as visual inspection, metal detection, batch coding, or case packing.

Key Features & Advantages

1. Fully Automated High-Efficiency ProductionThe machine requires minimal manual intervention—operators only need to load film rolls and replenish materials. Production speed ranges from 80 to 200 sachets per minute, depending on sachet size and material type, making it ideal for large-scale mass production of portion-controlled products.
2. Superior Leakproof & Barrier PerformanceThe four-side sealed structure eliminates edge gaps, providing 100% leakproof protection for liquids, pastes, and fine powders. Compatible with high-barrier composite films, it effectively blocks moisture, oxygen, and light, preserving product quality and extending shelf life.
3. Precision Portioning for Small SachetsThe customized metering systems ensure accurate filling for small portions (1–50g), solving the problem of uneven portioning common in manual or semi-automated packaging. This is critical for products with strict dosage requirements (e.g., pharmaceuticals, nutritional supplements).
4. Flexible & Easy Size AdjustmentOperators can adjust sachet dimensions (length: 30–150mm, width: 20–100mm) by modifying parameters on the touch screen PLC, without replacing a large number of mechanical parts. Quick-change filling nozzles and sealing bars enable fast switching between different materials and sachet sizes, reducing production downtime.
5. Food-Grade & Hygienic DesignAll parts in contact with materials are made of 316 stainless steel, compliant with international food safety standards (FDA, EU 10/2011). The filling system and sealing station feature quick-disassembly designs for easy cleaning and sterilization, avoiding cross-contamination between batches. The machine also has a closed hopper design to prevent dust pollution.

Typical Application Scenarios

This machine is a staple in industries that require small, single-serve packaging:

• Food industry: Instant coffee sachets, sugar packets, seasoning sachets, honey sticks, milk powder portions.
• Pharmaceutical industry: Powdered medicine sachets, liquid oral drug sachets, herbal extract portions.
• Cosmetics & personal care: Lotion samples, shampoo sachets, facial mask essence packets, hand cream portions.
• Household chemicals: Laundry detergent pods, dish soap sachets, desiccant packets.