Successful search for the missing micron

‘To be more innovative than others’ is a mantra that Hannes Fuchshofer adopted during his apprenticeship in the 1980s, and as an independent entrepreneur, he has been living by this philosophy for more than 25 years. Today he runs a highly successful business, underpinned by regular investment in the latest technology – a case in point being a recently purchased ultra high accuracy Kern Micro HD 5-axis machine. PES reports.

Hannes Fuchshofer’s professional career has been rich and varied: vocational training in 1987; master craftsman in 1991, then production manager in a mechanical engineering company until 1994. Then he found a new challenge in self-employment and started a one-man business in his parents’ garage in Eibiswald, Austria.

“In the beginning I wanted to keep investment as manageable as possible because I saw other small businesses that went bankrupt in the first few years due to high running costs," he recalls.

Through a combination of hard work and support from his family, Mr Fuchshofer developed his own skills and grew the company, building a reputation for high quality and reliability – values that remain a cornerstone of the business today. Today Fuchshofer Präzisionstechnik GmbH employs around 100 members of staff and makes effective use of 33 CNC machining centres.

But this alone doesn’t make Fuchshofer stand out from the competition: “I see these as base requirements for any company,” Mr Fuchshofer emphasises. “What differentiates us is our ability to innovate and explore different technologies and markets. This is the secret of our success.”

What Mr Fuchshofer means by this becomes clear after a closer look at the company. The business has invested in a number of machines for ultrasonic processing and has expanded its bread and butter service offering to include optics, watchmaking, medical technology and additive manufacturing which offers completely new possibilities, especially for the prototype production.

Pinnacle of high precision

Fuchshofer’s machining capabilities have been enhanced significantly with the purchase of the Micro HD from Kern Microtechnik based in Eschenlohe, Bavaria, Germany. The machine occupies a prominent position in the company’s new production facility built a few years ago. Technically, it represents the pinnacle of the high-precision 5-axis milling of small parts.

The Austrian contract manufacturer has offered simultaneous 5-axis milling as part of its service portfolio for more than 15 years so working to accuracies in the hundredths (mm) range is all in a day’s work. According to Mr Fuchshofer however, some customers, especially from the optics and semiconductor industries, expressed their desire for even higher precision: “There was talk of a permanent accuracy of 2 to 4µm. This simply couldn’t be achieved with our existing machines so we approached Kern, whose machines are renowned for their high levels of accuracy and repeatability, for a much more precise milling solution.”

He continues: “We performed machining trials in Eschenlohe, Germany and quickly decided the Kern Micro HD was perfect for our needs. The data is impressive: the HD achieves seamless accuracies of less than 1µm on circular features and surface quality of Ra 0.05µm, which can usually only be achieved through grinding.”

According to Mr Fuchshofer, the new addition is living up to expectations in everyday production: “With the HD, we manufacture various ceramic and titanium parts, and some of these are being produced 12 times faster than before,” he enthuses.

“A compensation plate made of invar and titanium for camera sensor applications is currently proving particularly tricky. With small batch sizes of around 80 pieces, we make elongated holes and drilled holes where we have to guarantee an accuracy of ±2µm.

“In the past, the job required extensive preparation and various additional measurements; my calculations also included around 20% rejects. With the Micro HD, we manage the job much faster and in terms of repeatability every part was spot on so zero rejects.“

Several technical highlights are key to the Micro HD’s precision and performance. For example its micro-gap (<10µm) hydrostatics (patent pending) improve the rigidity and damping properties of the machine. This, in combination with a rapid 42,000rpm spindle and high quality tools ensures high surface quality and accuracy on the part. In addition, the design of the integrated micro-gap hydrostatic and large linear motors in all axes enables high rapid traverse speeds of 60m/minute and acceleration up to 2g.

Another highlight of the HD is its temperature management as Peter Schöps, Kern sales manager for Austria explains: “Our engineers have taken this aspect to a different level,” he says. “This is important because, according to a number of different studies, temperature fluctuations are responsible for around 70% of all accuracy errors in the high-precision range.

“Because of this, coolant is managed very precisely in the Kern machine. Cutting fluids run with a volume flow rate of 200 l/minute through the machine base, rotary/swivel axes, linear axes and spindle. In addition, the linear motors are actively tempered. The result: in thermal stress tests, the temperature fluctuations in the machining chamber remain at just ±0.05° Kelvin.

Integrated automation

For Hannes Fuchshofer the business is all about repeatable accuracy and productivity time after time: “We’re not a large-scale manufacturer – most customers expect between 10 and 100 parts, sometimes a few hundred. This has to run fully automated and with guaranteed quality. I get all this and more with the HD.”

Mr Fuchshofer has his Micro HD currently equipped with an internal workpiece and toolchanger and an interface for an external Erowa automation system. With this, he can adapt the machine to growing needs. He is convinced that with the new machining centre, he will continue to win new business from customers that were previously out of reach.

Whilst the performance of the Micro HD was a prominent factor in Mr Fuchshofer’s purchasing decision, he is also keen to emphasise the excellent levels of support from Kern – from first contact all the way through to consultation, installation and process integration.

"Kern thinks like us and I have an extremely good relationship with all of the Kern employees I have met so far. First and foremost, of course, there’s our personal sales manager Peter Schöps, but the same is true for the service crew and Kern management. We became a member of the Kern family. If there is any kind of question, we will receive qualified support that will help us immediately. These are not just empty words, this is reality."

In the UK, Kern machines are sold and supported by Middlewich, Cheshire-based Rainford Precision.

Rainford Precision www.rainfordprecision.com/kern-micro/

Kern www.kern-microtechnik.com