PETpla.net Insider 10 / 2018

MOULD MAKING PET planet Insider Vol. 19 No. 10/18 www.petpla.net 20 A petaloid mould base for CSD Almost a year after the commercial launch of BaseMax, Moldintec’s bases for CSD PET bottles, two new releases have evolved that use laser machining technology and a propri- etary software development for freeform laser metal ablation. Testing takes place in cus- tomer plants as well as with manufacturers of OEM blowing machines. The blowing of CSD beverage bottles is increasingly challenging in terms of speed, energy consumption and the unprecedented lightweight- ing possibilities. As far as bottle bases are concerned, Moldintec’s engineer- ing team used the BaseMax original mould design as a starting point to redefine the cooling circuit, improving the heat transfer for reduced contact time between the PET and the alumin- ium base. The blower operating as a standalone machine emphasises the cooling of the mould as no water jets, spray or air cooling after blowing are permitted for global bottling systems. The geometry of the BaseMax pet- aloid is designed to be copiable even at extremely low pressures, but the pushup-less design requires that the mould accurately controls the material cool down even at 2,550 b/m/h. The design and manufacturing of these two test base sets involved the integration of a multiplicity of resources. The first version is a mono-mate- rial BaseMax laser, which evolved by applying a freeform venting frame machined by laser. The 5-axis laser ablation capability enables Moldintec’s engineers to design the venting chan- nels freely, ensuring that the pressure between the preform and the mould always remains low, even on the complex shape of a BaseMax petaloid surface. The patented continuous venting concept provides a solution to extract- ing the air exactly where it is pushed by the preform during the blowing stage. The laser ablation creates a singular shape without the limits of small milling tools. “electrical discharge machining (EDM) is not an option for us”, says Diego Taboada, CTO of Moldintec “due to the extra delivery time and costs that are related to EDM. A laser offers unique technology to go from CAD to the part in a single step.” The second version is a BaseMax- Hybrid solution. This mould concept combines the Moldintec technology of 3D continuous venting, thermal isola- tion from multi-material construction and the innovative laser manufactur- ing process. This hybrid concept is under development mainly for large-sized containers, where the thermal control of the cavity is critical to improving the stress cracking performance. The manufacturing concept allows optimal cooling of the amorphous zone while the energy from the oven is retained to improve heel formation. Test run under real plant conditions Reducing the final blowing pres- sure immediately translates into a multiplicity of savings. These include a lower consumption of electrical energy, less maintenance of the air compression equipment, less equip- ment investment and the consequent MOULD special