Originally Published EMDM
October 2004
Equipment News
Recent developments in machining equipment |
High-precision machine generates elevated feed rates
A CNC precision micromilling and microdrilling machine is designed to carry machining of hardened steel into regions of very high speed without loss of high-precision capability. Provided by
Kern Micro- und Feinwerktechnik GmbH & Co. KG (Murnau-Westried, Germany), the machine is equipped with a spindle that turns at 300–20,000 rpm, and can optionally be fitted with spindles having maximum speeds of 40,000 to 160,000 rpm to suit individual requirements. A vector-controlled 500- to 40,000-rpm spindle that develops full power in its entire speed range can produce fine surface finishes when used with an infrared workpiece-measuring touch probe that has an accuracy of ±0.001 mm.
The machine features a C-form base frame made of vibration-dampening polymer concrete, a spindle mounted on the z-axis that moves only vertically, and a workpiece-bearing coordinate table that precisely positions the workpiece in the x- and y-axes by means of linear glass scales. This configuration allows the machine to generate high feed rates of 12 m/min and to accelerate to maximum speed after just 2 mm of travel. Because of the machine construction, such acceleration does not lead to vibration that diminishes milling performance.
The 2-tn milling and drilling machine occupies 2.5 m2 of floor space.
Laser system cuts tubular material
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A fully equipped laser system can cut stents and tubular material in almost any geometric pattern. The StarCut 18 laser from
Rofin Baasel Lasertech (Starnberg, Germany) can easily be changed from fundamental to low-order modes of operation at frequencies up to 3000 Hz. Kerf widths of less than 20 µm are routinely achieved.
The laser system is equipped with an automatic feeding unit that accepts tubing of any length. Easy-to-use software converts .dxf or .dwg files into the NC code. A graphical display of the cut geometry is displayed on the CNC monitor and allows process verification prior to cutting.
Laser cuts are done in dry mode without the use of fluid inside the tube material. The cutting nozzle in combination with a stereomicroscope and optional camera facilitates setup of the system to individual tubing diameters. Nearly any metal material can be cut.
Automated equipment is designed for the manufacture of guidewires
A range of automated equipment is designed for the manufacture of guidewires.
Guidewire Solutions (Lurgan, UK) offers a machine for microwelding guidewires, an automated mechanical J former, centreless grinders, wire feeders, and core-wire stamping machines.
Suited for distal welding applications, the microwelding machine can select a spring, place it into the weld head, and then remove and eject it. The process can be repeated without operator intervention. Mechanical J forming is carried out by a fully automated machine, in which the radius size and spring length can be adjusted in minutes. A constant and identical J radius can be repeatably produced.
The company also manufactures centreless grinders to exact customer specifications. The grinders are accurate to ±0.0001 in. diam and hold that tolerance reliably. A variety of grinders from manual feed to complex CNC and multiple-step models are available.
Machining systems combine Swiss-type and fixed turning
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Machining systems offer the advantage of fixed and sliding turning processes in the same machine design concept. The TNL and TNL-K systems, offered by
Traub Drehmaschinen GmbH (Reichenbach, Germany), feature both sliding headstock turning—known as Swiss-type turning—and short, fixed headstock screw-machine-type turning. The machines are available in two model sizes: the TNL12/TNL12K has a 16-mm bar capacity, and the TNL26/TNL26K has a 32-mm bar capacity. Both models are based on a building block concept, allowing the user to configure a machine to exact requirements.
The TNL12 model is available with two six-station turrets, a four-station end-working tool carrier, a heavy-duty counterspindle, and a four-station back-working tool carrier. The maximum number of fixed tools is 26, of which 18 can be live. The TNL26 model is available with two 12-station turrets, a five-station end-working tool carrier, a heavy-duty counterspindle, and a five-station back-working tool carrier. It accommodates a maximum of 58 fixed tools, 32 of which can be live.
The turret tool carrier concept increases machine capacity. A benefit of the high-speed indexing system is that chips are flung away from the tools. This is important when machining tough materials, and makes the machines well suited for materials used in devices that produce long stringy chips.
Turning centre machines implants and bone screws
A single-spindle automatic turning centre that accommodates part diameters from 13 mm is suited for machining complex small medical and dental implants and bone screws. The Deco 13a, supplied by
Tornos S.A. (Moutier, Switzerland), has 10 axes with a counterspindle and an interchangeable set of 20 tools, 15 of which can rotate. With one more spindle and an additional counterspindle, 12 axes are optionally available. The independent axes allow as many as four tools to cut simultaneously.
Patented control software designed for rapid programme generation and data transfer to the machine gives the centre the speed advantages of conventional cam control along with the flexibility of a CNC machine. The latest version of the software introduces automated tool collision checking and a geometry help screen, improving screen-to-screen and function-to-function navigation.
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