Hi, we are running a production machining job on a injection molded hard plastic part (urethane). The holes have to be done after molding to hold a very tight spacing. We are drilling a .272 hole .500 deep going thru the part. The problem is the chip will wrap around the drill causing a birds nest that gets bigger and bigger until it melts the tops of the last few holes. We have to run this job dry and we are running air blast.Due to the fixturing we cannot get the blast too close to the drill. So we have been running this job pecking about .025 to keep the chip short. This adds to our cycle time and is tough on the Z axis ball screw. We have used a straight flute and carbide coated drills to just drill thru with no success and all kinds of feed and speed combinations. Now we are running a carbide tipped drill pecking and it makes good parts I would like to just drill thru with no pecking. This is run on a Mazak 510 with a 12000 rpm spindle.
Thanks
Thanks