Medical Instrument Arm
- mechanical design
- DFM
- component engineering
- cost reduction
Product Spotlight
3M Health Care, CDI Products had a functional mock -up of a mounting arm assembly when Piton was asked to provide design enhancements, redesign for manufacturability, and incorporate industrial design styling elements. The arm assy supports the System 500 Blood Gas Monitor which is used to sense blood gas parameters during open heart surgery. The arm attaches to a vertical pole, integral with the heart-lung machine. It allows the perfusionist to adjust the viewing angle of the Monitor for ease of use while seated at the heart-lung machine.
After a review of aluminum casting technologies, it was decided that a sand casting approach was the best choice for the main arm piece. This process was cost effective for the production plan of 2000 assemblies, would provide sufficient dimensional accuracy, and would allow for the incorporation of complex surfaces suggested by the client's industrial designer. Piton created a cast part design that required minimal secondary machining and could be sanded and painted to a level consistant with surgery center equipment.
The three knobs, key appearance features, were redesigned to be made from a single custom extrusion. The clamp pad was also redesigned as an extruded part. The upper and lower acetal cylinders were turned into a single part, used twice. The Monitor tray was resized to be made from stock sheetmetal. A lead-in cone, needed to guide the Monitor onto the tray, was kept as a lathed part, but was converted from a press-in part to a bonded part, reducing assembly costs. A heavy duty compression spring, hidden in the tilt/swivel knob, was replaced with a flat wire spring. This provided the desired friction in the adjustment system but allowed the use of a lower profile knob.
The successful enhancement of the arm design, both for ease of manufacture, and aesthetics, led to a finished product that was up to the standard of the state- of-the-art Blood Gas Monitor.