ALUMINIUM SLUGS MANUFACTURING

A collapsible tube is a pliable metal cylinder which can be sealed so as to discharge its content in a desired quality and finger pressures and yet protect the remaining contents from contact with atmospheric air, moisture or light/heat etc. during the entire period of its use. Collapsible tubes are handy flexible packages for pastes & semi-liquids.

The preferred material for the manufacture of collapsible tubes is: Aluminium, tin, tin coated lead or lead-tin alloys. The collapsible tubes of the above metals are made by cold extrusion techniques. A complete collapsible tube consists of the following parts:

a) The main metallic tube,

b) A shoulder to one end of which a screened nozzle with orifice is fitted, and

c) A cap to close the orifice when not in use normally the collapsible tubes are used for fitting tooth paste, shaving creams, ointments, inks etc.

Aluminium collapsible tubes, covered under IS: 3107-1979 (First revision), are suitable for a wide range of liquids, semi-liquids, pastes & formulations containing soluble constitutents. All collapsible aluminium tubes with short screwed nozzle are well specified in this standard. The aluminium collapsible tubes with other types of nozzles designs eg. Eye ointment tube, are covered under IS:7852-1975.

Aluminium collapsible tubes are manufactured from Aluminium grade 19500 as per IS:737-1974. The wrought aluminium & alloys for general engineering purposes belong to this specification. The collapsibility & permeability w.e.f. moisture and easy workability are the main characteristics of the aluminium slugs used for manufacturing collapsible tubes.

Aluminium of 99.70% purity is cast, rolled to predetermined thickness & blanked to provide cylindrical shapes of a defined diameter. These metal pieces are generally referred to in the industry as slugs. Slugs are heat treated to bring them to desired metallurgical state for fabricating into a collapsible tube. Mechanical fabrication an aluminium tube is accomplished in five stages of production, carried out automatically on a mass-production flow line.

The lubricated slugs are converted into tube shapes, by a process of impact extrusion in a specially designed press, with a shoulder & nozzle. The tubes are transferred, next, to an automatic machining lathe for trimming to correct lengths & thread rolling on the nozzle portion.

The severe impact-extrusion forces, involved in the transformation of slug to tube, cause a work-hardening in the tube. To provide flexibility or collapsibility, in the containers, they are annealed at temperature slightly below the melting point of the metal.

This high temperature treatment provides to the tubes, on one hand, the desired collapsibility by removing the stresses of work-hardening, and on the other hand removes traces of pre-applied lubricants and also sterilizes the tube. Further, the tubes are surface finished, printed and filled with right quantity of contants with cover caps of thermoplastics or thermo setting materials. Production of aluminium slugs for collapsible tubes containers, is therefore, the very first step which provides essential raw material for collapsible tube mfg. industry.