PETpla.net Insider 04 / 2016

PREFORM PRODUCTION 20 PET planet insider Vol. 17 No. 04/16 www.petpla.net The injection moulding process has its limits, in terms of design to produce tailor made preforms, especially in regards to the base wallthickness and undercuts. Blow moulding systems can not manufacture perfect bottle bases with the available preforms on the market. Reality is that these two facts results in blown bottles where almost on all bottle bases a waste rate of 2-10% of PET material appears. Mahir Aktas, CEO Creative Packaging Solutions (CPS), Turkey, therefore came to the conclusion that the base area has to be formed outside the tool and invented the minting of the preform base geometry in the post mould cooling station. There are already different solutions on the world market to save PET mate- rial focusing: the neck, wall thickness of preforms, stabilising bottle shapes and the base of the bottle. Despite these existing lightweight solutions though there is still too much material in the fin- ished bottle bases. The preform’s injec- tion moulding process does not allow for any further reduction of material in the area of the injection point. Together with his partners Netstal- Maschinen AG, MHT AG and Otto Hofstetter AG, CPS developed a new conical geometry. The base thickness can be reduced to less than 1mm for a water bottle and down to 1.5mm for CSD bottles. The restricting factor is now no longer the injection moulding process but the crystalline injection point that has to be covered on both sides by amorphous material. Mahir sells the system as a package. The ROI is less than six months. Licences are not due. In comparison to the “pre-blow” pro- cess also offered by Netstal, Mint-Tec can distribute the PET material in the base area in a targeted way. Making “pre-blow” suitable for water bottles and Mint-Tec ideal for water and CSD bottles. The inner minting tools are situ- ated on the bottom of the transfer plate, the outer shaping part are the cooling sleeves: The Mint-Tec Unit moves into the preform, without touching the neck or preform body and presses the origi- nal preform end cap into the desired new geometry. Material steps in the base area can be achieved for the first time technology. The idea is to use the preform’s residual heat to improve the base design of the preform. The transfer plate and the take out device are locked against each other and the preform base design will be optimised in a mechanical way. The preform base area is now per- fectly prepared for the following blow moulding process thanks to the minting device. This results in a saving of 3 to 4% of the material compared to the normal preform and still 2% compared to preforms that have, for example Advanced preform base geometry to improve the blow moulding process Injection moulding with preforms – does it always have to be this way? by Alexander Büchler Mahir Aktas, CEO Crea- tive Packag- ing Solutions (CPS), Turkey