Getting started with automation made easy

Manufacturing high-precision mechanical parts automatically and reproducibly proves to be very demanding in practice. However, for Sistro Precision Mechanics, it is the right step to continue meeting the high demands of customers. Together with GF Machining Solutions, this project was successfully completed in surprisingly short time.

Highest accuracy and precise surfaces are requirements that Sistro Precision Mechanics GmbH deals with daily. As a supplier in four industries – aerospace, precision engineering, sealing technology, and medical technology – the company has developed excellently over recent years despite the global economic crisis. "We specialize in the development and manufacture of mechatronic system assemblies and precision parts. It is essential to perfectly combine techniques from fine mechanics, electronics, and assembly. Thanks to our many years of experience in precision parts manufacturing, we can offer complex solutions in prototype, single-piece, and small-series production, as well as in assembly integration," explains DI Günter Höfert, who has been co-owner and managing director of Sistro for seven years.

Since 2007, the company's turnover has doubled to over seven million euros. With 62 employees on a 3,000 m² operational area, the Tyrolean company offers milling, turning, grinding, eroding, and surface finishing. Its highly qualified staff are mainly trained in-house by the "excellent Tyrolean training company."

Precision is everything

"Having previously only operated prototype manufacturing, our current focus is on small-series production of precision parts with batch sizes of 100 to 500 pieces per year. Most parts undergo complex manufacturing processes, including surface treatment," describes the managing director the scope of his company's services. In addition to milling, turning, grinding, eroding, and surface finishing, Sistro also offers value-added services specifically for medical technology, such as cleaning, sterilizing, and packaging.

The main added value of his company, Gunter Höfert sees in the complexity and precision of the manufactured parts: "A tolerance of 3 to 5 microns is quite common. Besides machines and tools, know-how about the manufacturing process plays a major role in this area."

Automation of milling processes

Seven years ago, Sistro operated with single-shift production and one operator per machine. Gradually, Gunter Höfert switched to two-shift operation and multi-machine handling. Significant investments in new milling and eroding machines have also been made since 2007. To better meet customer requirements, the company also faced the challenge of partially automating production. Maintaining consistent high quality was a top priority. "We wanted to grow into automation technology slowly and steadily," Höfert continues.

Therefore, they deliberately decided not to invest in a linked system. "For us, it was the logical step to acquire a very good 5-axis machine that meets our high precision requirements and equip it with a simple pallet changer," he explains. He also emphasizes that involving employees in automation investments is very important.

Quick to become productive

Sistro was looking for a solution that would enable quick productivity gains while building internal automation expertise. The goal was to increase the weekly cycle time from 72 hours to at least 120 hours with the new system in a short period.

Since the company processes a wide variety of materials with the highest precision (from titanium and aluminum to plastics and special steels), Gunter Höfert and his team placed particular importance on partnering with a company for whom precision is a matter of course.

Micron HPM 450U as the basis

Günter Höfert wanted to leave nothing to chance for this project and examined several suitable concepts closely. Ultimately, he chose the Mikron HPM 450U from GF Machining Solutions, a 5-axis milling machine that allows lateral automation and provides optimal access to the machine chamber. Combined with the very compact WPC 10 multi-pallet changer and an ATC tool magazine with 220 tool stations, this package exactly meets Sistro’s requirements: "The compactness and the particularly attractive price-performance ratio of the entire solution convinced us."

The Mikron HPM 450U is a 5-axis machine for versatile, automated production that combines dynamic capabilities with stability. "Our Mikron HPM 450U offers machining options from simple drilling to complex 5-sided and 5-axis simultaneous machining," says Robin Manigatterer, sales engineer at GF Machining Solutions. The lateral loading allows free access from the front, enabling unobstructed, clear work. The system was intentionally designed as a standalone solution to clearly separate workflows and to familiarize users with automation processes.

Parts with high requirements

To test the new automation solution, Sistro selected a very complex component consisting of two mold halves that must geometrically fit perfectly. The mating surface has very high surface quality requirements. The results of the test machining were convincing.

Through the special cycle ITC 5x (intelligent thermal compensation), the machine's thermal behavior could also be monitored. "With ITC 5x, we guarantee reproducible accuracy," says Robin Manigatterer. Although the cycle takes about 20 seconds, for Gunter Höfert, quality takes precedence over cycle time: "Thanks to the high accuracy we now achieve with the Mikron HPM 450U, manual lapping and polishing work can be reduced by around 50 percent." This results in significantly higher process stability and reproducibility.

Partnership as a concept

Sistro has been working closely with GF Machining Solutions for a long time. Over the past two years, they have acquired almost exclusively milling and eroding machines from the Swiss manufacturer. "The machine concept precisely meets our requirements and fits very well with our parts spectrum – that’s a prerequisite for high productivity. And ultimately, personal contact is also crucial," says Gunter Höfert. "Both the machines and the service and support from GF Machining Solutions deliver on their promises." A partner that Sistro Precision Mechanics GmbH plans to continue relying on in the future. And the target of a weekly cycle time of 120 hours was already achieved after just two months of operation.