EDM, Laser Micromachining and More at GF Medical Demo Center

GF Machine opened its North American Medical Center of Competence in Lincolnshire, Illinois on April 19 with a wide variety of machines on display. Between a versatile automation cell, intuitive EDM features and powerful lasers for both marking and micromachining, the technology on offer could spark shifts in medical manufacturing and beyond.

The Automated Heart

At the heart of GF’s Medical Center of Competence is an automated cell bringing together several of the company’s machine lines. Both low-volume, high-mix and high-volume, low-mix applications are possible on this demonstration cell, which includes a Mikron Mill S 400 U milling machine, a Form P 350 die-sinker EDM, 3R workholding devices and cell management software, a FANUC robot and a CMM. The S 400 U also has a grinding option and a wet electrode cutting option, while all machines benefit from 3R’s one-minute setup times and repeatability within several microns.

GF positions itself as being able to make previously impossible parts, using this cell and the rest of the machines within the Center of Competence to demonstrate new design possibilities to shop owners and product design teams.

Killing the Right Sparks

Of note was GF’s wire EDM technology. This includes both the Cut F 600, a mid-range offering making its North American debut at the unveiling, and the Uniqua control technology on both this machine and a higher-end Cut P machine.

The Cut F features increased accuracy compared to the budget Cut E machines, with more durable ballscrews, a liquid-cooled Y-axis, and an X-axis repositioned to benefit from this cooling. Visitors to the unveiling also saw a demonstration of GF’s iWire technology, which senses height differences between sections of parts and automatically compensates, reducing wire consumption. Company representatives say this feature saves an average of 27% of wire — but the demo part on the Cut P boasted 60% savings. This technology works in conjunction with GF’s ISPS (Intelligent Spark Protection System) technology, which uses a sensor close to the cut zone to analyze Z-axis sparks along the wire.

As with the height differences iWire observes, the control uses this information to adjust cut parameters, reduce wire breakage and maximize operation speed. Erik Poulsen, GF’s medical marketing manager, says the technologies in the Uniqua control provide an unmatched level of fine control — even predicting the strength of individual sparks and killing single, overpowered sparks to maintain a smooth process.

GF’s also showcased an important update to its die-sinker EDM technology: iGap. This software ensures sparks only form on the front of the electrode, not the sides. By controlling the location of these sparks (and concentrating the machine’s power), electrode wear decreases and average cycle times are 30% faster.

Laser Focus

The company has also been quietly developing powerful laser technology to perform not just texturing operations, but full-on micromachining. Visitors to the Medical Center of Competence opening event glimpsed both applications.

Texturing is more than a simple finishing operation for medical applications, with Poulsen describing laser-created textures that assist in osseo-integration and friction reduction, as well as textures that are hydrophobic, hydrophilic or anti-bacterial. Users can create these textures with relative ease, as GF’s laser machines are accurate to within tens of microns — enough to eliminate the need for masking — and texture programming is streamlined through an ability to scan textures into the control system for replication.

While GF demonstrated its laser machines’ ability to perform laser texturing at the Medical Center of Confidence, it showcased laser micromachining at its nearby Microlution facility. The company pointed to three machine types for different applications: the MLTC for tube cutting, general purpose ML machines and MLDS machines that pair a laser with metrology or boring stations for a high-end multitasking solution.

These machines can use nanosecond and femtosecond lasers, with nanosecond pulses creating a heat-affected zone that adds variability and femtosecond pulses achieving low surface variability without a heat-affected zone. Control over the lasers is now so fine that the MLTC can create features that aren’t through-features, and both the MLTC and the ML5 can perform OD turning with lasers. Spot sizes average 20 microns, with one demo part pushing the MLTC to an 11-micron spot size.

The ML5 is climate-controlled, five-axis laser micromachining system. The company’s engineers say the laser uses prisms to strengthen the beam, ending up with hundreds of Megawatts of power for the tiny fractions of a second in which the laser is pulsing. Parts can have negative, positive or zero tapers, and parts-cleaning is all but eliminated.

GF mostly relied on demonstrating test parts on the Microlution floor, as many applications in the medical field and beyond are under strict NDAs. These test parts showcased the extremes these machines could meet, with the 11-micron part mentioned above being a stainless-steel pipe 0.012 inch in diameter with a 0.009-inch hole and tiny, non-through-part features. Other sample parts made with GF Microlution’s laser lineup included representatives of aerospace and electrical work that the company made available for inspection under microscopes.

Erik Poulsen is convinced that micro lasers will be increasingly vital to medical manufacturing. EDM and conventional machining can both currently create parts on a much larger scale, much faster for a fraction of the cost — but the precision and detail laser micromachining can offer (not to mention its current usefulness in texturing) enable product designers to explore new ideas and target new standards in the ever-growing medical market and beyond.