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Vertical LSR Molder Eliminates Flash Trimming

Originally Published January/February 2001

EQUIPMENT NEWS: Molding Equipment

Vertical LSR Molder Eliminates Flash Trimming

Machine to debut at MD&M West

As the market for medical disposables continues to grow, so does demand for molding equipment and tooling suited for the efficient, cost-effective production of compliant parts. In this section, equipment manufacturers describe recent additions to their product lines, such as a molding machine designed for the manufacture of intraocular lenses that is being introduced for other device applications. A briefcase-sized system for tipping and welding thermoplastics into finished catheters, a rotary table injection press suited for the assembly of IV components, and highly precise core pins used in the manufacture of syringes and related products are also featured.

A liquid-silicone injection molding machine originally developed for the manufacture of intraocular lenses will be introduced to industry for other applications at the MD&M West 2001 show in Anaheim, CA. Created by Kuntz Mfg. Co., Inc., the LSR 2010 meets the unique requirements of liquid silicone rubber (LSR) micromolding applications by accomodating mold materials of varied viscosity levels. "Having manufactured liquid injection molding equipment for more than 10 years and listening closely to our clients, we feel the LSR 2010 taps into the best concepts for a very versatile machine," says Axel Kuntz, vice president of operations. The molding machine offers dependable shot size, repeatability and accuracy, and flash-limited molding when using precision molds.

Designed by Kuntz Mfg. Co., Inc., a vertical molding machine is suited for the production of miniature to medium-sized products in clean environments.

The LSR 2010 features microinjection technology that was developed for intraocular lens manufacturing, which does not allow flash trimming. Using precision molds, each part is formed accurately, with no spillover or other irregularities, removing the need for operators to touch the finished product. Because there is no barrel screw, the injection design minimizes the amount of material waste. The machine is nonhydraulic and thus is less unlikely to cause contamination in cleanrooms.

Other enhancements to the LSR 2010 include a vertical layout with a 47 x 48-in. footprint and compatibility with standard molds measuring up to 8 x 8 in. The model also offers standard platen mounting hole patterns, adjustable daylight settings in 1-in. increments, and up to a 10-tn clamp force.

The machine was designed for miniature to medium-sized, single- or multicavity parts, and for insert molding applications. Automatic door opening provides easy part removal. Material can be fed from cooled, prefilled disposable cartridges or from in-line mix and metering equipment.

The LSR 2010 is suited for the production of implantables and other medical applications, as well as insert and overmolding operations. The unit is small enough for R&D setups and durable enough for nonstop 7-day production runs.

Press assembles medical consumables

A rotary table injection press from C. A. Lawton can be automated to load inserts such as needles and lances.

A 10-tn rotary table injection press is available to device OEMs for the assembly of tubes, IV manifolds, and related consumable medical devices. Designed and built by C. A. Lawton Co., the press can also be automated to load inserts such as needles or lances, or to remove finished devices. Presses can be custom built in 10- to 30-tn sizes, or in any size necessary to suit a requested application. Allen Bradley Pro-Set injection controls can be integrated into the presses to provide adaptive tuning and consistent shot sizes regardless of environmental conditions.

Compact molder suited for cleanroom production

A compact injection molding machine with a 2100 x 800-mm footprint incorporates an injection unit that meets the same quality criteria as much larger units. Developed by Arburg Gmbh + Co., the unit is designed for the molding of small technical parts and can be easily adapted to cleanroom use. "The combination of small floor space, low purchase cost, highly flexible production capabilities, and the quality of the molded parts makes this a very interesting machine for manufacturers of medical parts," says director of corporate communications Christoph Schumacher.

An Arburg press combines a small footprint with features typically found in larger units.

To achieve a small footprint while maintaining acceptable performance levels, Arburg placed the control cabinets underneath the injection unit. Likewise, the water manifold has been integrated into the machine base behind the control cabinets. The plasticizing unit has been optimized for the production of very small parts: the screw has a 15-mm diameter and an L/D ratio of approximately 18:1.

The pivotable injection unit is designed as a modular assembly for easy removal, and the plasticizing cylinder incorporates a coupling that snaps into a central socket. The two-stage programmable injection speed profile includes adaptive temperature regulation, and back pressure can be programmed to positive and negative values.

Unit designed for prototyping, small parts

The AB-300-4 from A.B. Machinery comes with a foot-operated hopper.
Also suited for cleanroom production, an ergonomical plastic injector incorporates "no-lube" pneumatic components and a stainless-steel injection chamber and piston. The unit was designed for insert molding, prototyping, and production of small parts. The AB-300-4, available from A.B. Machinery, features a foot air-operated material hopper that frees the operator's hands for faster handling of molds. The mold stop and clamp are adjustable to accommodate various mold thicknesses. The AB-300-4 features a 4000-lb clamp force, 0.25-oz shot capacity, and 6333-psi injection pressure.

Catheter-forming system in a "briefcase"

A briefcase-sized molding machine is capable of forming and welding thermoplastics such as polyethylene, fluoropolymers, polyvinyl chloride, polypropylene, and polyurethane. The PIRF system from SEBRA measures 3 x 7 x 10 in. and molds at up to 400°C. It can be used to produce 0.5–13 mm diameters for single- or multilumen catheters measuring 1–19 mm. The molding machine includes a solid-state RF generator, a flexible computer controller, and a compact power supply. Now CE marked, the PIRF system provides fast, precise, and repeatable control of heat time, cool time, and insertion pressure.

Company offers core-pin expertise

Core pins that feature multiple complex steps, counterbore-style heads, end detailing, and flat work can be custom manufactured for medical molding operations. Available from Ross Tool Corp., the core pins are precision ground from M-2 and 300- or 400-series stainless steel. They can be made as small as 0.01-in. diam and in lengths ranging from 0.5 to 8 in. Used for manufacturing syringes, tapered luer components, catheters, and related medical products, core pins provide 0.0001-in. tolerances for diameter and 0.001-in. tolerances for length. Styles include shoulder-type, bottom, and beveled, or a combination with 0.005-in. steps.

Stainless-steel molds

High-tolerance molds are designed and built by Mold Craft Inc. using state-of-the-art CNC coordinate-measuring equipment and machining centers.
High-volume, multicavity, and multimold projects are a specialty of Mold Craft Inc., which designs and builds injection molds. Using a CNC coordinate-measuring machine, Mold Craft can provide dimensional certification of the mold steel and first-article inspection of the plastic parts. Leader pin and bushing holes are precision bored, and parting-line locator technology provides exact pocket sizing and location. The company can process 24 x 48-in. molds that weigh up to 8000 lb; they can be fabricated from full and prehardened 420 stainless steels, precipitation hardening stainless steel, H-13, and standard P-20 mold base steels. —Katherine Sweeny

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Copyright ©2001 Medical Product Manufacturing News
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