Tube Filling Machine

Overview

A tube filling machine packages creams, gels, pastes and ointments into collapsible tubes, toothpaste, cosmetics, pharmaceutical topicals, adhesives. The tube arrives as an empty sleeve with the cap already on the nozzle end; the machine works through the open bottom: orient, fill, and close. Plastic and laminate tubes are welded shut with hot air or ultrasonics, aluminium tubes are folded and crimped. A mid-range machine runs 60–120 tubes per minute around an indexing carousel with eight to twelve stations.

How it works

Operators dump empty tubes into the Tube Cassette magazines, where they feed by gravity to the Tube Elevator. The vacuum Pick-up Arm, supplied by the Vacuum Pump, swings each tube cap-down into a Tube Holder on the Carousel Plate. Holders are change parts machined to the tube diameter; converting from a 25 mm to a 40 mm tube means swapping holders, nozzle and seal jaws, typically a 30–45 minute job. The Tube Presence Sensor flags empty holders so downstream stations skip them rather than dose product into a bare cup.

The Cam Index Drive, a globoidal cam unit driven through a Helical Gear Pair by a Servo Motor, gives the carousel its characteristic dwell-and-snap motion: stations act only while the table is stopped, and the cam guarantees the same stop position every cycle.

At the Tube Orientation Station station, the Spin Spindle rotates the tube while an CMOS Image Sensor watches for the printed eye-mark under the Eye-mark Illuminator. When the mark is found the spindle stops, so the rear seal lands square on the artwork, the difference between a tube that looks made and one that looks misprinted.

Filling uses a Piston Doser fed from the agitated Product Hopper; the Hopper Agitator keeps shear-thinning products moving and the jacket can hold heat for waxy formulas. The Product Shutoff Valve switches the piston between suction and discharge, and the Diving Fill Nozzle dives to the bottom of the tube and rises as it fills. Bottom-up filling matters with viscous product: dosing from the top traps air pockets that later spit at the consumer and falsify the fill weight. The nozzle tip closes at end of stroke to prevent tailing strings of product landing in the seal area, where contamination guarantees a leaking weld.

Sealing

For plastic and laminate tubes, the Hot-Air Nozzle enters the open end and blows 300–450 °C air, heated by a cartridge Heating Element and pushed by the Seal Air Blower, onto the inner surfaces only. One index later the Sealing Jaws, driven by the Jaw Actuation Cylinder, press the softened walls together at 2–4 kN. The jaws are water-cooled so the weld freezes under pressure; releasing it hot would let the seam peel back open. The Seal Temperature Probe closes the loop on air temperature, the single most important seal parameter. Ultrasonic sealing replaces the hot air with a sonotrode that welds through product contamination in the seal area, which is why pharma lines favour it.

Aluminium tubes skip the heat entirely: the Folding Jaws make a double or saddle fold and crimp it, the traditional closure for artist paints and pharmaceutical ointments.

After sealing, the Trim Knife shears the seal edge to length and the Coding Dies emboss lot and expiry into the still-warm weld, both driven by the Trim Actuator. The Tube Ejector then lifts the finished tube onto the Outfeed Belt; tubes that failed orientation or seal checks are blown aside at the Reject Gate.

Controls

The PLC Controller sequences every station against the index cam position, stores recipes (fill volume, seal temperature, orientation offset) per product, and tracks rejects. The operator works through an LCD Panel with Touch Digitizer; an Microcontroller-based PID loop holds seal air temperature within a few degrees. Pharmaceutical builds add electronic batch records and audit trails to meet cGMP, with all product-contact parts in 316L stainless and tool-free removal for cleaning validation.

Throughput scales by adding lanes rather than speed: double-index machines fill and seal two tubes per cycle, and high-speed toothpaste lines with four lanes reach 300 tubes per minute while each individual station still works at a sedate 75 cycles per minute.