EQUIPMENT NEWS
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Thermal shrinking systems provide uniform heat application during catheter processing
A company that has dedicated itself to developing automated and semiautomated systems for catheter fabrication has announced the formation of a tube-processing product group. One of the premier products from the Machine Solutions Inc. group, which is headquartered in Flagstaff, AZ, USA, is the MSI VS1100 vertical shrinker.
Thermal shrinking systems are used to process a range of medical products including stent-delivery systems; guiding, diagnostic, and urinary catheters; and other braided and coiled catheter products.
The PC-controlled VS1100 features a nozzle that provides 360° heating. This design prevents the formation of hot or cold spots during the shrinking process. The four-station system allows operators to accurately program processing speeds for each product. Multiple heat zones can also be programmed to tolerances of less than 1 mm. Profiles can be saved and recalled as needed.
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Dispenser’s vibratory feature results in more-efficient solvent application
A dispenser of cyclohexanone and similar solvents includes a proprietary rotation and vibration feature that optimizes operation. Offered by Tecna S.r.l. (Mirandola, MO, Italy), the system typically is used to manually bond medical-grade PVC tubing to connectors.
The process works as follows. The operator places the tubing in the dispensing station. A photocell recognizes the hand movement and the dispensing wheel begins to vibrate. The vibration reportedly compensates for varying tolerances in tubing diameters, thus improving operational efficiency. Easy-to-replace adapters that accommodate various tubing sizes are installed on the unit’s dispensing wheel. The adapters are immersed in the solvent; this technique prevents occlusion and facilitates maintenance compared with traditional dispensing methods, according to the manufacturer.
Rotary blade cutter processes 12.7- to 28.5-mm-diam flexible tubing
Materials such as flexible polyurethane, flexible PVC, and nylon-reinforced and rubber hose from 12.7 to 28.5 mm diam can be cut to very tight specifications using a rotary blade cutter. The WC601D tubing cutter, supplied by The Eraser Company, Inc. (Syracuse, NY, USA), features five variable feed rates to provide the operator with the flexibility to choose the most appropriate setting for the task at hand.
The belt feed is designed to prevent material from being crushed along its length and on its cut ends. To allow programmable batching, 99 programs can be stored in memory for frequently run jobs. The rotary cutting head consistently produces clean, square cuts.
The company offers a range of wire, cable, and tubing cutters; wire and cable strippers; wire twisters; and related equipment. Interested customers are invited to send a 10- to 20-ft sample of material, and the company will recommend the optimal processing solution from its line of equipment. Custom designs are also available.
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Sizing trough accurately calibrates small-diameter tubing
A proprietary sizing trough helps manufacturers to accurately and reliably extrude tubing in diameters up to 20 mm. A unique feature of the modular product, developed by Dexsen (Comblain-au-Pont, Belgium), is the sizing die mounted on an articulated system. The die is positioned in front of the straight or cross head unit by means of micrometric tuning. Because only the sizing die moves, the cooling trough remains precisely aligned with the extrusion line.
The trough’s venturi system provides a stable vacuum and ensures silent operation. The cooling and sizing sections of the machine are designed in a monoblock configuration to prevent water leakage, and a water collector placed in front of the trough catches any water runoff when the extrusion line stops and starts. The water collector’s design allows the sizing die to operate in close proximity to the extrusion head.
The system’s modular design enables easy integration of peripheral devices such as wall-thickness and diameter controllers. The entire machine is reversible and can be mounted right-to-left or left-to-right using the same components.
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Microbore machines achieve fine surface finishes
Exceptionally smooth bores in diameters from 0.015 to 1.5 mm can be achieved using a company’s range of microbore sizing (MBS) machines. Developed by Microcut Ltd. (Lengnau, Switzerland), the systems can work to very tight tolerances and are suited for processing stainless steel and nitinol, as well as hard materials.
The machining is done by means of an abrasive process that involves a microdiamond tool and carrier wire with conical and cylindrical parts. The conical element expands the bore while the cylindrical part maintains a consistent diameter. Repeatability can be ensured for a large number of pieces. Tolerances of <1 µm are routinely achieved.
MBS equipment is advantageous for producing bores in medical-grade stainless steel and nitinol because it results in a very smooth surface finish. For example, 0.16-µm Rz surface roughness can be achieved in 55-mm-long stainless-steel tubing with a 0.4 mm ID. Tubes longer than 55 mm also can be processed.
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Machine forms range of catheter tips
A catheter-tip-forming machine with integrated punching tools can produce closed, open, whistle, and Tiemann tips. In addition to forming tips, the TF-05 unit from Soebygaard Machine Design (Naestved, Denmark) can punch one or two side-cut lateral eyes.
The forming takes place when the catheter tubes are placed in glass or nickel moulds. The tooling is heated, which causes the thermoplastic material to melt. By pressing the tubing into the mould, the desired tip shape is obtained. Punching takes place during the tip-forming process and does not require additional time.
Four tubes can be handled simultaneously. While two tubes are being heated and punched, two others are being cooled. Between 500 and 800 tubes per hour can be processed.
The machine is controlled via a touch screen, and as many as 20 settings can be stored in memory.