Hey guys, On a CNC lathe, I just want to know how you guys do a job when there is facing and turning. Do you actually use a left hand tool for facing and a right hand for turning or do you use the same tool for both. I use a right hand tool to do both but what I am asking is, is this harder on the tool doing a face cut over a turn cut? I typically take .100 depth of cut when turning and .05 when facing, however in conversational mode, this requires me to program 2 different paths because of the different depth(no I can't enter 2 depths in the same cycle:/) So I do 1 of 2 things, either enter in a .05 doc and let it turn at .05 or program 2 cycles. Is .100 depth of cut too much for a right hand turning tool to cut or is it fine?
While I'm here I'll ask this as well. I always dictated a tool hand by turning the tool facing me and whichever way the insert is pointing determines left or right. Is this correct?
While I'm here I'll ask this as well. I always dictated a tool hand by turning the tool facing me and whichever way the insert is pointing determines left or right. Is this correct?
Depends upon which side of the part the tool is on. If it's on the opposite side of the part (as in most slant bed, turret type CNC's), you're basically correct. If the insert is facing you (up), and the tip is facing left, it's left hand. Have to run CCW spindle direction. If insert is facing down and tip is left, it's right hand. Run CW spindle. Of course, if you're talking engine lathe, then tool will likely be on operator side of part with insert facing up and tip left. this will also be right hand. Same tool, just right side up instead of upside down. Confused yet?
Some say on a slant bed, turret type CNC that running left hand tools to rough turn is more rigid, since rotation of spindle will transfer force into the ways, instead of trying to lift. I suppose if you're really pushing it that it's true, but in normal situations I haven't noticed any discernible difference.
Ya our CNC lathe I'm talking about has the tool in front of the part. Not like a slant bed so the tool is basically positioned like an engine lathe except on a turret instead of a toolpost. But my question is, does taking .100 depth on the face hurt the tool at all? I do notice it doesn't chip as nice as when turning. Keep in mind when I program with my Mastercam, this scenario is not an issue as I can tell it different depths in Mastercam. Its only when I program at the machine where it doesn't let me have different depths, in turn is what leads me to ask if its ok to face .100 at a time with a right hand tool.
It is a CNMG 432 by the way the tool in question.
Some tools geometry does not work well for facing as well as others. My last job on my mazak I had 13 tools in 12 tool stations. No room for finishing and roughing tools for any operation. CNMG tools will work great for facing and turning. I was facing .150 of uneven bar ends today. 3 inch crs I was facing the sheared end to a smoth face in one pass. With a left hand tool.
Mostly use right hand tools but either one works. Most tools on the main spindel side are left hand tools, as they go in with the insert faceing down in the machine. Pending on the job if i have a heavy roughing part I will use the left hand tool because it puts cutting preasure down on the turret, most times all the preasure pushes up on the turret. I do this to even out the cutting forces on the turret, keeping it from walking up out of Y zero from lots of heavy cutting.
Also if you look at you tools they are labeled rather they are left or right handed. For instance your cnmg holder if it is a seco tool will read either DCLNR or DCLNL the last letter meaning R= right or L= left. No guessing required.
Why are you removing .1 of the face of the part? That seems overly excessice, my rule of thumb is to add .01 to the radius of the tool. And secondly conversational at the control for ROUGH facing and turning?
Wha
t type of geometry are you trying to turn?
No, you are reading into it too much. I do not face .100 off a saw cut edge. I was simply asking if the tool can take .100. I'll tell you why I would cut .100 off the face. I get stock that is a lot of times 1/4" oversize on the length. First side I skim it to clean up. Most times I have at least .200 to remove off of the second side, hence why I would be cutting .100. As for conversational at the control, it doesn't matter what geometry I'm cutting. The fact is we do some simple turning at the control for one off's and small qty's. Believe it or not, its quite fast to use the conversational programming, I mean c'mon its a lathe, how hard is the geometry going to be? Take for example a pin that has say 3 diameters with a few rads and a thread. Very simple part, why would I waste time drawing it and adding a toolpath when I can simply use the conversational control to make it? Never said I was "only" roughing at the control. I may be going out on a limb here but have you any "conversational" control machines? If you did, you would know exactly what I am talking about.
Mrainey, thank you for the illustration.
All Comments ( 0 )