Plastic Machines

Collapsible plastic tube fillers

Most people use a collapsible tube every day when they brush their teeth. Most of these are laminate tubes, formed from a strip of laminated plastic with a separate end and cap applied. Other tubes are made of extruded aluminum. Tube filling speeds can range from 20-30 tubes per minute to 400+.

Many products are supplied in plastic tubes that are injection molded. These can be identified, usually, by the way that they return to their original shape after squeezing and dispensing. This retains the smooth cosmetic appearance of the tube but at the cost of allowing air entry as the tube re-expands.

All three tubes are handled the same way except for closing.

The tubes are brought to the tube filling machine open end up in partitioned boxes and loaded in a hopper for automated feeding into the filling machine’s transport pucks. Alternately, they may be placed by hand, or in higher speed machines, by robot directly into the pucks.

After placing in the pucks, open end up, they index to a cleaning station on most machines. A nozzle is lowered into the tube and blows ionized air to remove any debris. A vacuum collar around the nozzle catches the debris.

The tube indexes to the filling station. A nozzle lowers into the tube and dispenses product. The nozzle rises as it dispenses to stay slightly above the product level in the tube. Care must be taken not to splash or drip any product on the tube seal area.

Either before or after filling, the tube is rotated into the proper orientation. Typically the puck and tube are lifted and spun until a registration mark printed on the tube is detected, usually by a photoeye. Rotation is stopped and the puck/tube lowered and locked in position.

After filling, the tube indexes to a hot air station. Heated air is blown around the open end of the tube, softening the plastic.

The tube moves to a sealing area where sealing jaws pinch it closed and, because it has been softened in the hot air station, weld the insides together sealing the tube closed.

Replaceable metal characters are often mounted in the sealing jaws to deboss a lot or date code in the crimp material. Note black on seal registration mark for axial orientation.

The tube indexes to the trim station where excess material is cut off. This provides a clean aesthetic appearance. In some cases, shaped sealing and trim dies provide a shaped end to the tube.

Tubes index to the ejection station. In some fillers an inspection detects and separates good and bad tube, sending the bad tubes to a reject bin.