If in a CNC operation there is more that one step drill of the same size then using a plain drill and chamfer drill gives significant benefit.
In the time a new step drill is called, one can call for a chamfer drill and get chamfers done at a substantially lower cost
We were using two step drills for machining cylinder block of our one ton vehicle called Ace on NTC machine.
The step lengths were different but the size of small diameter was same.
There were a couple of instances of breakage at the step (may be because speed/feed were not optimum for higher size but ok for smaller size) . Also manufacturing a step drill from higher size might induce stresses at the corner
Changing to a plain drill + Chamfer drill stopped the breakage and chamfer drill can also be without coolant hole (cutting down the cost further). here are the relevant photographs + PP slides. I must mention here that this tooling had come from NTC Japan.
By Surendra Datar
Tata Motors Limited
Pune
4 comments:
It was fine tip.Congratulations and regards to Mr. Datar. He is genious.
Thank you for the tip sir,
It is really very useful especially at a time when we are forced to cut costs and increase productivity.
Swamynathan R
Kaveri Precision Machining
Thanks Sir, I guess the tool in the linked website can be used to still optimize the cost of a Solid Carbide chamfering drill. This is a new indexible concept for chafering drilled holes on VMC / HMC. website : www.jic-tools.com.tw
It is good Idea. one of my customer was using various step drills. then he asked to give one drill and one C'sink tool but now he is again asking for the earlier step drills. He is telling that the step is helping to solve many quality issue and chamfer control
Yuvraj Rajguru
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