Composite Can
Description
For decades, spiral-wound composite cans have been recognised in many fields of the food product market in standard packages, i.e snacks, instant drinks, soups or sauces. Commerce and consumers equally appreciate their high convenience as well as their excellent product and flavour protection.
For the production of spiral-wound cores complete installations can be supplied consisting of various interlinked machines. Design and performance are always provided according to the customer requirements. A typical installation consists of paper unreeling, winding machine, knife cutter, labelling machine, a machine for application of a closure onto a can body as well as a collective packaging.
The can is filled by the filler through the bottom and then closed by a seaming machine for metal ends (tinplate/aluminum) or a sealing machine for cardboard ends.
Process Diagram
Unreeling and Glueing
The unreeling operation consists, according to application, of several suspensions for paper coils, guide rollers for the removed paper web with loop control for the web tension as well as adhesive appliances (glue pods), which apply glue onto the paper so that later on the layers can be securely glued together within the winding unit.
Spiral Winding
The spiral winder strips paper webs from the unreelings and forms an endless spirally wound tube. According to requirement different internal layers are wound onto the core, with or without coating and/or sealing in order to obtain high impermeability of the tube.
Recutting
The core leaves the spiral winding machine as an endless tube. In order to obtain a can body, this endless tube must be separated into identical long sections. Normally an inline cutting unit, which is connected directly with the spiral winder, comes to use.
Basically two types of cutting units are distinguished; single-knife cutting unit (MS) and multi-knife cutting unit (QS).
single-knife cutter (MS)
With one knife an approx. one-meter long tube is cut, fitted for the parallel labelling machine.
multi-knife recutter (QS)
A spiral-labelled endlessly wound tube is cut according to the printed image into ready length bodies by the means of a multi-knife cutting unit.
Labelling (Convolute Labels)
A label sheet is glued with the labelling machine onto an approx. one meter of a tube, then the labelled core is cut into ready fit length of bodies.
Flanging, Sealing, Capping
The labelled can bodies are fed to a forming and sealing machine. A typical processing for chips cans consists of forming an outside flange, sealing of a membrane onto the flange, application of a plastic lid and preparation of open can ends for the application of a metal or cardboard end for the filler.
Bottom Seaming
After filling the cans through their bottom aperture, the composite can is closed either with a metal or paper bottom.
Metal Bottom
Prefabricated tinplate or aluminum sanitary ends are double seamed to the bottom side of the composite can on a seaming machine. For this process, Blema has further developed the trusted and tried technology of seaming metal food cans for the application on composite cans.
Paper Bottom
Pre-punched paper ends are heat-sealed with the bottom end of the composite can in a heat-sealing machine. The technology developed by Blema not only nets significant cost advantages but constitutes a further step towards greater sustainability of the complete package. The paper bottom is another important differentiation feature against other classical packaging solutions.