Grinding
Grinding
With a pedigree unsurpassed in cutting tool production, the latest VOLLMER VGrind 340S is the machine of choice for the medical industry. Here, Rotary Tooling Application Engineer and VOLLMER of Americas resident medical expert, Carlos Becerra explains why. Whilst many industry segments utilise tools manufactured from materials like HSS, carbide and PCD; tools for surgical applications and orthopaedics are often manufactured from stainless steel. The main reason is that when surgeons are undertaking procedures like bone and cartilage drilling, grinding or shaving; carbide tools have the propensity to break or create excessive heat during operations. The ultra-hard characteristics that make carbide perfect for many manufacturing processes – are also the same attributes that make them unsuitable for invasive procedures. Surgical tools are generally manufactured from 17-4PH, 420, 440A, 455 or M2 tool steel with lengths from 50 to 250mm and diameters from 0.3 to 12mm. And here lies the challenge… With small diameters and a stainless grade with a likelihood to deflect during machining, precision production can be a challenge. The Steady Rest & ‘Run-Out’ The steady rest is the single most critical factor in producing cutting tools to a standard beyond that made on rival machines. The innovative steady rest on the VGrind 340S supports the tool and prevents tool deflection during grinding. Any tool deflection will have an adverse impact on not just the precision of the tool, but also the ‘run-out’. Surgeons’ hand tools typically operate at high speeds, exacerbating the ‘run-out’ impact of cutting tools. Run-out can result in reduced accuracy and even excess heat generation if a tool is rubbing against a bone instead of cutting. This can adversely affect the well-being of the patient. Run-out of up to 5mm is common in
tools that are not precisely manufactured with a supporting steady rest to prevent deflection. Not only can excessive run-out generate excessive heat, but it can also diminish precision where and when we need it most. Furthermore, excessive vibration in the surgeon’s hand tool can lead to….well let’s not think about those consequences. To categorically eliminate this obstacle, the steady rest on the VGrind 340S provides support under the tool to prevent deflection – but it also provides a supporting finger over the tool body support to eliminate movement. However, VOLLMER has taken this innovation a step further, providing two steady rest points, and not just one. The steady rest system supports the cutting flutes of the tool as well as the cutting tip of the tool. With typical tool shank diameters for hand tools being 4.5mm and the cutting flutes often much smaller, the potential for deflection grows with decreasing tool diameters. As you would expect from VOLLMER, we have doubled down on eliminating deflection, such is its importance and potential
A PERFECT MATCH FOR MEDICAL
As one of the world’s most heavily regulated industries, the medical sector and the manufacture of everything from pharmaceuticals and healthcare aids to surgical instruments, implants and prosthetics to dentistry – everything has to adhere to the most stringent of standards. So, when it comes to surgical cutting tools for the industry, the leading OEMs and their supply chain rely upon production machines from VOLLMER.
Machinery & Manufacturing 35
Machinery & Manufacturing 34
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