Preparing for the Thread Milling Operation Calculation of Rotational Velocity and Feed at the Cutting Edge Rates at the Tool Center Line On most CNC machin

Preparing for the Thread Milling Operation Calculation of Rotational Velocity and Feed at the Cutting Edge Rates at the Tool Center Line On most CNC machin

Preparing for the Thread Milling Operation Calculation of Rotational Velocity and Feed at the Cutting Edge Rates at the Tool Center Line On most CNC machines, the feed rate required for programming is that of the center-line of the tool. When dealing with linear tool movement, the feed rate at the cutting edge and the center line are identical, but with circular tool movement this is not the case The equations define the relationship between feed rates at the cutting edge and at the tool center line Grades and Applications Internal Thread External Thread Grade Application PC9570T First Choice for steel and cast iron A tough sub-micron substrate with TiCN coating Provides good fracture toughness and excellent wear resistance PC9070T General grade Enhance wear Resisfomce with new-coating technology Multi layer film Superior performance for stainless steel and HSS n Trouble shooting Problem Possible Solution Cutting speed too high > Reduce cutting speed/use coated insert Chip is too thin Increase feed rate Insufficient coolant Increase coolant flow rate Chip is too thick Redyce feed rate / Use the tangential arc method Increase RPM Vibration Check stability Incorrect cutting speed .>- Change cutting speed Unsuitable carbide grade .> Use a coated carbide grade Feed rate is too high Reduce the feed. Profile is too deep > Execute two passes, each with increased cutting depth/ Execute two passes, each cutting only half the thread length Thread length is too long .> Execute two passes, each cutting only half the thread length Tool deflection > Reduce feed rate / Execute a “zero” cut Increased insert flank wear Chipping of cutting edge Material Built-up on the cutting edge Chatter / Vibartion JL Insyfficient thread accuracy Threading 42 D Technical Information for Thread Milling vc= vc x 1000 n x D2 n x n x D2 1000 F1 = n x z x fn n - Rotational Velocity R.P.M vc - Cutting Speed m/min D2 - Tool holder Cutting Dia. mm F1 - Real Feed rate at the Cutting edges mm/min z - No. of Cutting Edges fn - Feed per Rooth per Rotation mm/rev Calculation of Feed