Bernhard Fischbacher, Tobias Telser and Paul Heilmann were visiting a fair to catch up on laser marking systems when the staff at ROFIN made a surprising offer. The managing directors of DHF Precision Mechanics GmbH were invited to take a seat in front of the manual laser welding system Performance and weld some parts by themselves; an experience, which caused the three DHF managers to re-think their investment agenda.
Today, two years later, DHF uses laser material processing to manufacture Brainlab's DASH, among others; an intra-surgical navigation system for knee endoprothesis, which relies on an iPod touch for analysis, planning and exact positioning of cutting tools.
CNC specialist from Ostermünchen (Munich)
Headquartered in Ostermünchen near Munich, DHF Precision Mechanics counts well-known medical device, electronics and aerospace engineering companies among its customers. The company specialized in high-precision CNC-milled parts and assemblies. After 15 years of virtually continuous growth, the company now operates 18 CNC machining centers and offers a service portfolio ranging from prototype manufacturing to bulk production of several 10.000 parts/year.
With utmost precision and fast and flexible reaction to customer requirements DHL established a very good reputation in the market. When needed DHF pushes the technical limits of CNC milling, like series production of parts for electrical motors, which must be produced with tolerances down to some microns on a lathe. The parts feature bearing seats where ball bearings have to be glued in place.
Outsourcing laser material processing so far
With quick reaction to customer requirements as a major objective, DHF established high in-house production depth. From CAD/CAM construction to preparing wrought material (various steel and aluminum alloys and titanium), to CNC-milling, to surface finishing, assembly and quality assurance.
Production processes at DHF frequently comprise welding, engraving and marking. Techniques for marking and joining on high-precision workpieces call for the laser. Welded parts have to feature perfect, pore and crack-free weld seams. Especially medical device manufacturers, which have to provide sterile hardware, call for immaculate surface quality to eliminate any chance of bacterial colonization. The same goes for all deep engravings and markings. Contours have to be free from burrs and ditches. The marking process must not induce any material changes which might promote surface corrosive action.
Up to 2012, DHF had been outsourcing laser material processing jobs completely. However, outsourcing significantly reduced production flexibility and speed for certain parts, but increased complexity of logistics. More than that, the annual outsourcing business volume had been reaching the six-digit range; reason enough to think about establishing an in-house laser material processing center. Being laser-rookies, Fischbacher, Telser und Heilmann initially focus on laser marking because they expect laser welding to be much more difficult to control - at least up to their first personal laser welding experience.
Complete solution from ROFIN
Now going for the real deal, the DHF managers incorporate a laser welding system in their investment planning. That means sending samples to various laser manufacturers and asking for a live presentation of the laser welding process - not an easy task, considering the required acuteness and surface quality, namely for medical devices. Andreas Schöllhorn, responsible sales manager at ROFIN-BAASEL Lasertech Starnberg, knows about the importance of an optimum presentation in the application lab. Consequently he strives to achieve the best possible performance there - and convinces the DHF managers.
But Schöllhorn also knows that's just the beginning: "Medium-sized companies expect way more from us than just selling suitable laser systems. We take care of the employee's training, help setting up the first applications and our application support provides unbureaucratic assist during the first months. If required, we even design the production room according to laser safety standards, like we did for DHF".
Establishing an in-house laser processing center
Not more than 6 months after their first contact at the fair, ROFIN installs a laser processing center at DHF GmbH, comprised of the integrated CNC and manual laser welding system Intergral and the marking system CombiLine Advanced. The laser welding workstation seamlessly integrates manual or joystick-controlled deposition welding with CNC operation. It offers a cross table for workpieces of up to 500 kg weight and an additional rotary axis. The Integral was chosen because of its large working chamber, which is spacious enough to freely rotate parts of up to 400 mm in diameter.
For the CNC-experts Fischbacher, Telser and Heilmann planning of optimum production workflows and manufacturing the required components is an essential part of day-to-day operations. They quickly design large breadboard, work holding devices and laser programs for various parts; a modular system together with systematic documentation, which allows setup of any welding or marking application within minutes.
Even today when looking back Paul Heilmann still expresses his surprise. "We had been planning to ramp up things slowly and to back source the laser jobs one by one. In fact external laser processing was gone within a few weeks! Today we have ready-to-use setups for some 100 marking and welding applications right at our hands."
Laser processing for high-tech medical devices
The enduring cooperation with Brainlab, a worldwide market leader for image-guided surgery and radiotherapy, benefitted from laser technology as well. Bernd Fischbacher: "Frequently, we are already cooperating in early product design stages. It is a big advantage to know exactly not only the possibilities of CNC milling but also of joining technology and marking not to mention the faster manufacturing of prototypes."
For Brainlab's DASH, DHF Precision Mechanics GmbH manufactures and assembles the iPod holder with all fixed or detachable 3D position markers and cutting devices. All pieces have to meet the sophisticated quality standards for medical devices. The entire parts set comprises 14 weld joints of precision milled part, even of different stainless steel alloys. The mostly circular weld seams feature a width of only some 100 μm and must not show any pores or micro cracks.
DHF deep engraves the plastic iPod holder with the laser to form cavities which will be filled with a special paint. Thus the marking is still visible when the paint slowly vanishes after numerous sterilizations.
A smart business decision
Bernhard Fischbacher, Tobias Telser and Paul Heilmann are more than satisfied with their decision for an in-house laser processing center. After 2 years, the generated turnover outweighs the investment of about 150.000 € and the regular costs of operation. More than that, DHF managed to add new, frequently demanded material processing skills to its key competences. Fast and flexible reaction to customer requirements is a critical factor of success, not only for DHF GmbH but for many medium-sized companies.