Doypack Pouch Filling Machine

Overview

A doypack filling machine fills and seals pre-made stand-up pouches, the flat- bottomed bags that hold juice, sauce, pet food, detergent and baby food on retail shelves. Unlike a form-fill-seal machine that builds the bag from film, this machine starts with empty pouches already made and printed by a converter. Its job is to pick each pouch, open it, fill it, optionally fit a spout, and seal the top, all on a rotating turret that carries the pouch past fixed stations.

The pouch travels gripped by its top edges around the Frame and Turret turret. It is drawn from the Pouch Magazine by the Pick and Place, spread open by the Pouch Opener, charged by the Filling Station, fitted with a spout by the Spout Applicator where required, closed by the Top Sealer, and released at the Discharge. The Control Cabinet cabinet sequences the indexing turret and every station.

The rotary turret

The heart of the machine is a turret that indexes one station per cycle. Around its rim sit pairs of Pouch Gripper clamps, each holding one pouch by the top two corners so the mouth hangs free for opening and filling. The Turret Plate steps round under the Index Drive, which is either a mechanical cam indexer that gives precise dwell, or a servo box for recipe-flexible positioning. Eight to sixteen stations sit around the circle, so several pouches are at different points in the cycle at once and the machine produces one finished pouch each index.

Rotary layout suits the deliberate handling a stand-up pouch needs. The bag is floppy, so each step, opening, filling, sealing, wants a stationary dwell rather than the continuous motion a film machine can use.

Loading and opening

Empty pouches arrive as a flat stack in the Pouch Magazine, kept square on the Magazine Rail and pushed forward by the Stack Pusher. The Pick and Place uses a Vacuum Cup pair fed by the Vacuum Generator to lift the lead pouch and swing it into the open grippers, which then clamp the top edges.

Opening a stand-up pouch reliably is the trickiest part. The Pouch Opener uses Opening Cup vacuum cups on each face to pull the walls apart, then an Air Blow Nozzle puffs air to balloon the pouch fully open, and Spreader Finger fingers hold the mouth square. If the pouch does not open cleanly the fill will spill onto the seal zone and ruin the seal, so machines watch the opening with a sensor and reject any that fail.

Filling

The Filling Station meters product to match its viscosity. Thin liquids and sauces use a Piston Filler driven by a Servo Motor that draws a precise volume and pushes it in; thick pastes use a larger piston or a lobe pump; granules and powders use an auger or a weigher that drops a checked weight. The Fill Lance reaches deep into the pouch and fills from the bottom up so the product does not splash the seal area, and the Fill Valve shuts cleanly to stop dripping between cycles.

Hot-fill products such as sauces are filled near boiling to sterilise the pack; the hopper and lines are jacketed to hold temperature. A Pressure Sensor on the fill line catches a blockage or a missing pouch.

Spouts and sealing

Many doypacks carry a screw-cap spout for resealable juice and baby food. The Spout Applicator takes oriented spouts from the Spout Feeder, inserts one into the pouch top, and the Spout Seal Jaw heat-seals its flange between the pouch walls. Getting a leak-free spout seal is exacting because the rigid spout and the flexible film must fuse around a contoured flange.

For plain pouches without a spout, the Top Sealer simply closes the top. A Heat Seal Bar melts the inner film layers, then a Cooling Bar holds the seal under pressure while it sets, which prevents the hot seal from peeling open when the gripper releases. Each bar runs a Heating Element under a PID loop reading its Seal Thermocouple.

Control, discharge and use

The Control Cabinet cabinet holds the PLC, the Servo Drive units for the turret and filler, and the Valve Bank that drives the grippers, vacuum cups and air blasts. The operator sets pouch size, fill volume and seal temperature on the HMI Touchscreen. At the end of the circle the grippers release the finished pouch onto a Drive Belt, and a Reject Diverter diverts any pouch flagged for a fill or seal fault.

The machine runs 20 to 60 pouches a minute, slower than a form-fill-seal line but able to handle the printed, shaped, spouted pouches that retail brands want. Buyers are co-packers and brand owners in food, beverage, household and pet care who value shelf appeal and resealability over raw speed. Dual-lane and twin-turret versions roughly double the output where volume justifies the larger machine.