Views: 3127 Author: Site Editor Publish Time: 2017-08-25 Origin: Site
This article mainly introduced the whole production circle of how the aluminum collapsible tubes produced from aluminum slugs.
As a kind of traditional packing approach, aluminum collapsible tube(aluminum tube) are widely used in Pharmacy, food, cosmetic, chemical industries. The major production process loop include: aluminum slug-> slug tumbling->tube extrusion-> tube trimming-> annealing-> inner printing->primer-> printing-> capping-> end gluing-> inspection-> packing.
Raw material-aluminum slug
Aluminum slug is a kind of metal blank made of aluminum alloy with silver color in different thickness and different shapes like circle,oval,rectangle,dome,concave. Aluminum slugs are widely used as industrial metal base which are usually made into collapsible tubes, aerosol cans, deep extrusion shell and automotive filter hosing by impact punching & extrusion process.
In order to increase the aluminum slug transforming and fluidity, reduce the strength of extrusion and abrasion to the dies, the aluminum slugs need to be smeared with polishing powder. For a long being, most of aluminum tube plants use zinc stearate powder as polisher. In the process of tumbling, a batch of aluminum slugs are put into the bucket of tumbling machine and blending with proper quantity of polisher powder and seal the bucket, then start tumbling operation. The bucket spins with a angular velocity by 30 min. During the process of tumbling, the aluminum slugs bumping and impact with the bucket inner wall and between slugs, which coat the powder even on the aluminum slug surface and the burrs on the aluminum slug is eliminated at the same time.
2. Aluminum tube extrusion
The aluminum slugs after tumbling are put into the charging plate of the extrusion machine, along with the rotating charging plate the aluminum slugs are transferred to the slideway and slide down to the end of track, under a concave mechanic device pushing, the aluminum slugs are put into the bottom die cavity precisely. And the slugs are extruded full of the die cavity at the pestle repeating punching movement and the aluminum material flows along the pestle head and drill drift to the direction bearing lowest resistance force and forming basic tube shape after going through the annular gap between bottom die and pestle head. At this step, the collapsible tube are not trimmed with scruffy edge and having no thread on the mouth.
The untrimmed aluminum tubes are cased onto the mandrel of expandable trimming machine by conveyer chain and mechanic set. The mandrel expands after the tube looped on and fix the tube firmly on the mandrel. Then the mandrel starts to rotate with very high speed and the aluminum tube tails are cut and trimmed during spinning meanwhile the collapsible tube mouth are cut even and forming the tube neck with a preset height and thread are rolled onto the mouth by threading insert. After all these process, the collapsible aluminum tubes are transferred to the carrying slot of annealing furnace.
4. Annealing
Since the aluminum tubes extruded from the extrusion machine, they lost flexibility in large scale. Hence the rubes need to recover its origin flexibility by annealing process, at the same time, the high temperature annealing atmosphere evaporated the spare polisher inner and outer of the tube surface, which shall enforce the adhesive force of the inner coating and bottom primer. The aluminum tubes enter and pass the annealing furnace in sequence and stay in furnace for 3~5 minutes then transfer to the cooling area. The annealing temperature are usually set 390~450℃ and the aluminum tubes became very soft after annealing and meet required application requirements.
Since the aluminum material is a kind of active metal, the aluminum tube inner surface need to be sprayed on protective film with good chemical stability to avoid chemical reaction between aluminum and tube contains. The inner coating film is usually chosen with material resin. The collapsible tubes enter the inner spraying fixing cup and get first spraying in high speed of rotation(the liquid coating material spray from the sprayer mouth through the catheter and became fog under the high pressure and coat on the inner surface of the tube smoothly. The aluminum tubes are transferred into curing oven after first time coating and the inner coating cured in curing oven then turn to the second spraying coating same as the first process, and cure in curing oven for the second time. After the second curing, the aluminum tubes transfer to the drying oven to get dry with temperature about 250℃.
In order to cover the origin color of the aluminum tubes and get good printing effect, the aluminum tube need to be daubed with a layer of white primer lacquer, which usually choose polyester as lacquer material. The aluminum tubes are lacquered after drying oven and assess into the printing machine after drying in primer lacquer drying oven.
7. Printing on the collapsible tubes
The aluminum tubes are looped onto the printer mandrel and similar with primer lacquering. The aluminum tube printing carries out by the method of “round-roll-to-round” chromatic printing. The ink went through the ink slot, ink picking roller, rubber roller to the printing face. And the printing face brought graphs and characters onto the rubber fabric roller with proper pressure and get graphs and characters printed onto the aluminum tubes. The tubes after printing enter the drying oven to get dried after printing.
8. Aluminum tube capping
The collapsible aluminum tubes are transferred to capping machine and get the cap spinning fixed onto the tube mouth.
9. Aluminum tube end gluing
In order to improve the sealing performance of the tubes after filling, the tubes are sealed by daubing a layer of glue on the tail. The collapsible tubes reached the conveyor belt with sucking force after capping and the high speed glue sprayer extend to the tail of aluminum tubes and spraying on the inner wall of tube tails. After tail gluing, the aluminum tubes are transferred to packaging operation.
10. Finished aluminum tube packaging
The quality inspectors pick up the aluminum tubes bearing flaws on conveyor belt and pack the perfect collapsible tubes into case.