MACHINING OF BLOW FORMED PRODUCT

PURPOSE:To prevent chips from staying in a cavity by sending compressed air from a hole formed before machining the opening section thereof to a cavity section and discharging chips outside from said opening section simultaneously with machining. CONSTITUTION:A small hole 3 is made by a drill or the like after a body 1 is formed by blow forming. In the next step, a pipe 6 is connected to the hole 3 in the step of forming an opening section 2, and the opening section 2 is machined by a milling machine or the like. And compressed air is sent to the cavity 5 through the pipe 6 from the small hole 3 simultaneously with the start of machining by the milling machine or the like. This discharges chips B producted in machining the opening section 2 outside the body 1 at the same time of the production of chips by the pressure of the compressed air flowed and prevents the chips from entering the cavity 5. Therefore, this leads to the elimination of such state that the chips B stay in the cavity 5 after the completion of products and prevent blowed products from reducing in the price due to the staying of the chips B.