Blow Molding: Faster Mold Changes for PET ISBM Machine
SIPA’s single-stage PET stretch-blow molders now change tools 25% faster.
A new quick-mold-change (QMC) system from SIPA of Italy for its ECS SP single-stage injection stretch-blow molding (ISBM) machines reportedly slashes changeover times by about 25%. New features also include added safety and user-friendliness. These hybrid machines are suited to molding containers from pharmaceuticals, cosmetics, personal-care products, and spirits, especially in sizes from 20 to 50 ml. They come with injection clamps of 55 and 88 tons.
The QMC system involves a new automated procedure for loading/unloading the preform core plates; this incorporates additional sensors to ensure that the mold-opening stroke is adjusted to the preform length. Operations for assembling and disassembling the neck-ring plate have also been modified. A new, patent-pending system now allows the procedure to be carried out safely by one person instead of two.
Changing the blow mold is much easier, too, SIPA says. Addition of roller bearings in critical positions means that once the forklift positions the mold next to the clamp unit, the tool can be pushed into position by hand. Height adjustment of the mold in the clamp is also easier.
Finally, modifications have been made to the sealing plate and stretch rods, and standard screw fittings for the water-cooling system are replaced by quick-fit push/pull fittings.
Here’s a quick guide to fixing four nettlesome problems in processing PET bottles.
Conventional molding techniques are not effective with high-temperature materials. Molders need to be aware of certain conditions and parameters to handle problems sometimes posed by high-heat injection molding.
Many conditions must be met to get the best wall distribution in a PET bottle. Skilled operators are, as always, indispensable.