Application technology becoming a project in its own rightIn the course of testing, it became obvious that PVAL processing required significantly more expert knowledge than could be expected from a newcomer to injection molding production such as the chemical company which had made the enquiry. Consequently, Andreas Huber decided jointly with another former Battenfeld colleague by the name of Günter Buzek, who had been operating an injection molding plant of his own since 1999, to present their offer to the chemical company for handling the production as a sub supplier. They still maintained this offer, even when the negotiations were no longer about delivering supplies from Austria, but about the construction of an “in-house production facility” at the company’s Polish filling plant, and they established Buzek Plastic Poland Sp.z.o.o. in May 2005. Using three hydraulic HM 270/1330 machines from Battenfeld with rechargeable injection batteries, the leap from a 12-cavity test mold to 32-cavity hot-runner molds was made, and series production was started. In spite of numerous “outliers” among material data and consequently high reject rates, the production got under way. The key factor was a situation-related production method, which consisted of manual parameter adjustment based on continuous observation of the material’s behavior and included 100 per cent visual inspection of the finished parts by operating staff on every machine.
2005: evolutionary stage II, 32- and 64-cavity production cells become standardAfter about another year, the process technology and composition of the material compound had been stabilized to the point where a further increase in production capacity could be considered. As the product design was not altered for the time being, the cycle time remained unchanged at 28 seconds, with a scrap rate of about 15 per cent. What had to be further improved though, was the method of visual parts inspection. Instead of separate inspection on every machine, a multi-track parts transfer system was installed, to which several machines were connected, and which transported the parts to a central inspection station where every single part was still inspected by human staff.
In 2008, the production routine of the Buzek team had been stabilized to the extent that the number of cavities could be doubled once more, this time from 32 to 64. However, the aim was not only to double the number of cavities, but also to combine this with a reduction in cycle time. To provide the necessary prerequisites, the molded part was re-designed in close cooperation with the customer’s engineers, with a selective reduction of wall thicknesses which led to a 15 % decrease in both part weight and cycle time. But this required larger and faster machines. Because of positive past experience, Battenfeld was again selected as equipment supplier, and the hydraulic models chosen were HM 400 / 2250 machines, again with rechargeable injection batteries, including Battenfeld robots and parts transfer systems. The result of this evolutionary stage was impressive: within only three years from production start-up, the company had increased production output by 300% and simultaneously reduced the scrap rate from 15 to 9 per cent. The high output volume forced the company to create a new concept for quality inspection of the finished parts. This was no longer feasible using human staff, neither economically nor in terms of available human resources. To solve this problem, the Buzek team installed a supporting visual inspection system with automatic separation of rejects. A mere supporting system, because it was able to recognize only the parts’ general completeness, but not every defect in minor details.