Last week I was contacted by a local machining company who was stamping oil pans for a large automotive manufacturer. Stamping, also referred to as pressing, is an industrial machining process where a flat material, like sheet metal, is placed into the stamping press and a press die stamps down to form a specific shape or mold.
As the oil pan exits the stamping press the parts are sent through a water rinse to remove any particulate and then hung from a drying rack. After the parts are dry they are sent to a paint booth then an oven for the paint to cure. They were beginning to see reject parts after the curing process due to residual water droplets being present which caused the paint to bubble or streak in this particular area. As a quick fix, on each side of the drying rack they ran compressed air to long lengths of 1″ PVC pipe with approximately (21) 1/8″ drilled holes spaced about every 4 inches to try and dry the parts more efficiently. While this did improve the dry cycle time, they were still seeing the rejects due to gaps in the airflow continuing to leave water drops. Another concern was their compressed air usage as they have a large number of rotary presses requiring compressed air so this particular application was, as the customer stated – “getting whatever air is left”, and potentially starving other processes of required air.
Once again EXAIR had the perfect solution, the Super Air Knife. The Super Air Knife produces an even, high velocity curtain of air across the entire length of the knife. Extremely efficient, the unit uses only 1 part of compressed air while entraining 40 parts of surrounding, ambient air. In this particular application, I recommended the customer mount one 84″ knife on the front and another 84″ unit on the back of the rack, allowing the parts to pass through the laminar airflow removing the excess water from both sides of the part.
Addressing the compressed air usage – each 1/8″ drilled hole is going to consume roughly 21.4 SCFM @ 80 PSIG, so for a quantity of (21) drilled holes, the total would be 449 SCFM per PVC pipe. In contrast, an 84″ Super Air Knife is going to consume only 243.6 SCFM @ 80 PSIG, or just a little over half of what they are currently using!
Metal Stamping Machines image courtesy of Sam Beebe – Creative Commons License