Proper lubricant selection is not only crucial to part production and tool life extension, but it can dramatically impact pretreatment and finishing processes as well. For this reason, “cleanability” studies are recommended prior to making major changes in process chemistries. One of the many ways to gauge ease of removability of a lubricant is the “copper displacement” or “copper strike” test.
In this test, individual lubricants are applied to standardized metal coupons and allowed to dry on the surface. Typically, two coupons will be tested for each respective lubricant: one coupon will be dried in “room temperature” conditions (~70°F) and the other in a laboratory oven at 180°F for one hour each.
After drying, each coupon is then rinsed for thirty seconds in agitated/mixing tap water. This should rinse the majority of the water soluble materials from the coupon surface and yield a surface for the next step of the test. After the thirty seconds of water rinsing, the test coupon is partially immersed in a 4% copper sulfate solution at room temperature.
After thirty seconds, the test coupon is removed from the copper sulfate solution and allowed to air dry. The copper sulfate solution should selectively bind to clean areas of the test coupon and deposit a thin copper film. If the lubricant is not entirely removed from the coupon surface, the deposited copper film will not be uniform or will be incomplete.
IRMCO FLUIDS are oil-free stamping lubricants that form true solutions in water. They are typically cleaned in neutral to mildly alkaline cleaning solutions (pH typically 7.0-10.0) and at temperatures from 110°F-140°F –depending upon cleaning method (i.e. immersion, spray, ultrasonic, etc) and dwell time in the cleaning stage(s) and yield a water-break-free surface.