EQUIPMENT NEWS
Water-guided laser beam cuts stents without damage
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A cleanroom-compatible machine especially adapted for the cutting of sensitive medical devices such as stents uses a pulsed laser beam guided by a water jet to produce clean cuts free of remelt effects. The LCS 300 laser cutting system from Synova S.A. (Ecublens, Switzerland) comes with optimum cutting parameters preloaded. It has a processing precision of ±3 µm, working area of 300 × 300 mm, and maximum axis velocity of 1000 mm/sec. The charge-coupled-device camera and fast image-processing software with which the machine is equipped allow alignment and inspection to be performed automatically. Employing Laser-Microjet technology, the laser machine offers remelt-free cutting owing to the short-duration pulsing of the infrared laser and produces no thermal damage to the component, or oxidation of stent struts, because the water jet keeps its surface cool.
Benefits of this technology include high cutting speeds, very good tolerances and surface finishes, the ability to make narrow and parallel cuts of 28 to 60 µm, minimization of postprocessing requirements, consistent results, and the accommodation of any cutting geometry. The laser machining process involves no tool wear and low running costs.
The machine features a 15-in. flat colour screen with touch panel as the user interface, and operates with software based on Windows NT. It can be connected to a local-area network for data transmission. An integrated modem allows for remote diagnostic servicing. Available options include a chiller, alternative laser sources, a water treatment system, two-dimensional reference scales, and transformers.
Actuators provide fine positioning resolution
Size 8 hybrid linear actuators are available with encoder feedback that is cost-effective in high- as well as low-volume motion control applications. Haydon Motion Europe (Coueron, France) has included a lensed light-emitting diode as a light source in the units, which additionally include a monolithic photodetector array with signal-shaping electronics to produce two-channel bounceless transistor-transistor logic (TTL) outputs. The internal monolithic electronic module converts real-time position, speed, and direction into TTL-compatible outputs. Requiring only 21 mm2 of space, the stepper motor–based actuators come with numerous patented features that enable such small packages to offer high performance and durability.
Encoders with resolutions of 120–330 cycles per revolution or 480–1200 pulses per revolution can be supplied with the actuators. The optical incremental encoder design features two-channel quadrature TTL square-wave outputs. The actuators themselves come in a range of resolutions that extend from 0.0015 to 0.04 mm per step, and deliver as much as 4.5 kg of thrust without compromising their potentially long operating lifetime or entailing high costs. All models can be microstepped for finer resolution.
The devices are well suited for applications requiring precise positioning and rapid motion. They can be incorporated into new equipment designs or used as drop-in replacements to enhance the performance or life cycle of existing equipment. Standard and custom configurations can be supplied.
Tiny hone enables machine to produce very fine part finishes
A fully automated high-precision production honing system employs a micrometric expanding blind-bore hone that the manufacturer says is the world’s smallest. Pemamo-Honing Phosa S.A. (Le Landeron, Switzerland) constructed the system on the foundation of its MVR 060EH vertical honing machine, which accommodates alloy steel components ranging in diameter from 0.6 to 2.5 mm and uses micrometric expandable superabrasive hones that ensure absolutely regular and parallel expansion of the hone on the total component circumference. Originally built in order to meet the specifications of a medical device manufacturer, the honing system has proved it can achieve a repeatability within 1 µm, a surface finish of 0.015 µm Ra or better while holding a size tolerance of ±1.5 µm, a roundness of 1 µm, and a cylindricity of 2.5 µm.
Loading and unloading processes, in-line premachining gauging, cleaning and in-line measurement of every honed part, and quality monitoring and control are all completely automated. Loaded, oriented, and fixtured parts are honed automatically by a 1.5-mm blind-bore hone. After honing is completed, the worktable indexes to a measuring station for part cleaning and measuring. Measurement results for all parts are displayed on a numerically controlled touch screen control panel and recorded, which also allows tool wear to be monitored. The full cycle takes 20 seconds.
Crimping equipment affixes electrodes with precision
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Automated equipment is available for the precise crimping of small electrodes onto a wide range of interventional devices, such as the cortical stimulation leads for which it was originally developed. The EC500 electrode crimper from Machine Solutions Inc. (Flagstaff, AZ, USA) creates uniform cylindrical crimps at multiple points along the electrode, effecting all of these crimps simultaneously and with repeatable force and geometry. The segmental compression technology produces retention forces sufficient to affix the electrode to the lead body while also generating only low connection impedance.
Designed for crimping numerous types of idiosyncratically shaped contact tubes onto the wires of the cortical stimulation device, the crimper uses terminals whose geometry requires that the several zones adjacent to tabs used for laser soldering onto the electrode be crimped. It employs channel-shaped, or U-shaped, terminals into which the wire is placed. The crimping machine closes the terminals over the wire, changing the U shape into an O that secures the electrode.
Power amplifiers control piezo drive voltage, current
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A line of high-voltage power amplifiers is designed to provide the precise control of output voltages and output current needed to drive piezos for precise positioning, vibration damping, and surface morphing in the precision machining of small medical devices. The PZD series of amplifiers offered by Trek Inc. (Medina, NY, USA) consists of the PZD2000A, PZD700, PZD350, and PZD50, which cover a broad range of voltage and current options. Other applications for which these amplifiers are suitable include electro-optic modulation, microplasma research, and ion-beam control.
At the high end of the line, the PZD2000A offers a voltage range of 0 to ±2 kV and a current range of 0 to ±400 mA. The Model PZD50, by contrast, provides a configurable voltage range of 0 to ±50 V, 0 to +100 V, or 0 to –100 V and a current range of 0 to ±8 A peak. Some of the amplifiers are available as single-channel, dual-channel, and high-current units. The manufacturer’s amplifier technology features a four-quadrant output stage that sinks or sources current into reactive or resistive loads throughout the output voltage range, making possible the accurate output responses and high slew rates reactive loads demand.
Flexible micromachining workstation can be operated around the clock
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An excimer-laser workstation designed for medical device micromachining is suitable for processing such components as stents, catheters, microfluidic components, sensors, nozzles, microscreens, microelectromechanical systems, biosensors, microvias, and many other small precision parts. The IX-4000 ChromAblate from J P Sercel Associates (Manchester, NH, USA) can machine parts in materials such as plastic, polymer, ceramic, glass, and metal to submicron tolerances and produce micron-scale features. Whether configured for large-scale processing of micron-scale feature arrays or micromachining tiny features, the machine is engineered to operate around the clock in industrial environments. It is highly flexible and configurable.
The high-performance system is available with production-grade robotics, part prealigners, and machine vision, all of which are integrated in a user-friendly Class I laser system. Its large workspace enables parts with dimensions up to 300 mm to be processed when the appropriate stages are fitted. Alternatively, the machine can be used for reel-to-reel applications. It provides a uniform beam profile, and offers various imaging and nonimaging homogenizers for demanding large-area projects. An optional 193-nm beam-delivery package can be supplied for use with materials that do not couple well with the longer ultraviolet wavelength and for optically more transparent materials.
Precision special-purpose machinery built under high security
A specialist builder of precision machinery for manufacturing companies in numerous industries counts among its customers medical and pharmaceutical device makers whose production facilities must conform to good manufacturing and good automated manufacturing practices. Lambert Engineering Ltd. (Tadcaster, N Yorks, UK) has been supplying its expertise in and innovative approach to machine building to a global clientele for nearly 35 years. Its service goes beyond simply delivering what the customer requests by including consultation with the company in order to develop solutions that will achieve the best possible results in application.
Most of the work carried out in its 70,000-sq ft factory is treated with the highest confidentiality. Each machine is constructed in a secure production area, access to which is restricted to personnel associated with the project and who possess the access code that is necessary for them to gain entry.
An example of the company’s work is a precision drilling machine it developed to enable a customer to drill holes in PVC tubing for medical devices. While the rotary table presents one set of tooling for drilling tubes of various sizes and in different positions, a second set is loaded by a human operator. The machine uses a six-axis robot, incorporates a digital colour camera to check quality, and employs a laser sensor to check drill bit diameter.
