Get involved early in design
By getting involved much earlier at the R&D stage, a fastener supplier has helped a manufacturer of car pistons and filters cut costs and improve quality
By switching from conventional screws to self-tapping screws, German engine component manufacturer Mahle says it has made significant cost savings of up to 80% in preparing screw locations in its production process.
“According to our findings, when inserted into pre-cast holes, self-tapping fasteners reduce processing costs by around 0.25 euros per piece – without affecting quality in any way,” explained Otto Mehrer, production manager at Mahle’s filter plant in Ohringen, Germany. “The screws provide process reliability and the number of separate process steps is significantly reduced.”
Cost analyses carried out by Mahle showed that a self-tapping screw, which is only around a third more expensive than a conventional screw, ultimately reduces manufacturing costs by up to 80%.
The self-tapping screws are Taptite 2000 fasteners supplied by Arnold Umformtechnik, who told Eureka that different levels of savings can be made depending on whether the fasteners are used in manual, semi-automated or automated screw fastenings. The savings range from 65% for manual screw fastenings to 80% for automated assembly lines.
Another crucial factor is the much lower investment required with self-tapping screws, compared to conventional fasteners and the effect on upstream and downstream production costs. Mehrer explained: “Direct fastening solutions reduce management costs too. These involve pre-production costs such as development, logistics, buying and warehousing costs, as well as keeping costs down in our quality department.”
Where fastenings can be made into pre-cast holes, no drilling or thread cutting is required. So there is no need for the relevant tools, such as the processing centre and washing unit required for the screw locations where metric threads are used. The same applies to pumps and to the disposal systems required for cutting emulsions and the measuring instruments needed to check the gauge size of metric threads. Therefore, the use of self-tapping screws, especially on new production lines, can lead to significant savings in mechanical processing station costs.
“In all, we are noting a proportion of around 40 per cent of metal direct screw fastenings – and it is rising,” stated Mehrer. “We still have to break down some of the prejudices held by our customers. Ultimately, it is our clients who, on the whole, specify the type of fastening technology they want. So that makes it even more important to ensure that specialists such as the project managers at Arnold are included into the development process for new modules.
“Because it is only by taking such far-sighted decisions at the early stage of engineering design, that the full cost saving potential can be realised,” he concluded.
