Springs are found in innumerable applications in the medical sector, from insulin delivery through to surgical tools, equipment and wheelchairs. Compression springs are the most common type used in medical and surgical equipment for fluid and motion control. Lee Spring has over 3,500 Type 316 stainless steel stock compression springs in its portfolio of 15,500-plus different products. Its stainless steel compression springs, passivated and ultrasonically cleaned instrument springs, 'Lite Pressure' and standard compression springs have been used by leading international medical companies.
Alongside its stock range Lee Spring also designs and produces a huge variety of custom springs, including wire forms, washers, stampings and assemblies, many for the medical market. These 'specials' embrace every aspect of spring construction and performance and call upon the unique experience of spring engineers and technicians. When specifying springs for these applications, precision and performance are paramount but many other factors are critical too; for example, material choice, finishing and especially cleaning.
"We work closely with our customers to develop design specifications and products that meet or exceed their requirements. We pride ourselves on the systems that we have implemented to ensure that we will achieve and maintain superior quality levels on all the products we provide," says Sanjeev Rivera, director of sales and engineering at Lee Spring Company's main manufacturing centre in Brooklyn, USA. Here, springs are produced at state-of-the-art manufacturing facilities that implement lean manufacturing techniques - an essential approach that maintains both quality and competitive edge.
Lee Spring's production capability can handle wire diameters from 0.127 to 15.88mm and includes in-house plating, ultrasonic cleaning, passivation, powder coating, heat treatment, polishing and assembly. Material options include music wire and a range of alloys, including stainless steel 316 and 17-7, Inconel 600, phosphor bronze, beryllium copper and Hastelloy. Spring types include compression, die, extension, torsion, continuous length, belleville, battery, swivel hook, conical, drawbar, wave and constant force - excluding custom forms. The company has ISO 9001 2000 recognition and is committed to RoHS standards at its seven plants in the Europe, Asia, North & South America.
In Europe, Lee Spring's torsion and extension springs are used in fluid control valves that deliver intravenous fluids, while standard compression springs find use in insulin dispensing, automatic injection pens. The company's Lite Pressure compression springs are used in pre-loaded syringes for the delivery of medication and in anaesthetic equipment where low pressure is required. Custom compression springs have also been designed to aid the dispensing of pills for a proprietary birth control pill compact.
In medical equipment, compression springs are used in endoscopic biopsy devices for accurate tissue sampling. Surgical tools - staple guns, for example - utilise many types of compression springs, while surgical equipment applications include suction lines for body fluid recovery. Other examples of spring fluid control applications include pneumatic and solenoid product lines for critical applications, including peritoneal and kidney dialysis machines, blood analysers, arterial catheterisation, multi-fluid drug delivery systems and peristaltic pumps.