A customer manufactures a medical flow-through valve which contains a pump that regulates the flow rate of fluid drip on an intravenous line. Inside the valve, a metal disc makes contact with the pump, which is part of an adjustable-speed pulsating mechanism. The entire valve unit must be disposable, as every fluid change would require a new valve for sanitary and infection control reasons.
The precision stamping challenge
Blanks made of 1008 cold rolled steel 0.040” thick were used to stamp 0.60” diameter discs. The stamping challenge was to reduce thickness of the steel disc to 0.020”, leaving an inner circle of 0.50” in diameter.
In addition, an electro deposited 0.0001” – 0.0002” as per MIL-T10727A Type 1 tin plating was specified, with no discoloration and no distortion on the final component.
Finally, meeting the required flatness tolerance of 0.0001” resulted in the plated discs sticking to each other.