[CNCnUtZ]

I am interested in also converting my lathe to CNC and wanted to get a feel for creating Gcode for lathe operations first to get an idea of what Im up against.
Ive fumbled with MC lathe but cant seem to get the toolpaths to cut the directions that I want .

Im so used to creating toolpaths the way you would with a mill ...I cant seem to grasp the method needed to cut a part on a lathe.

I was wondering if someone could give me a basic description of creating toolpaths for a lathe in MC...
Or send me a small part file with a description of the steps taken to achieve the end result.

Thanks in advance

[HuFlungDung]

Hi CncNutz,

I can't help you with Mastercam, but generally speaking, lathe paths are simple 2d chains. Once you figure out how the screen coordinates jive with the real world setup of your lathe's axis, it is simply a matter of drawing in the correct quadrant.

For a slant bed lathe, with tool approach from the rear, it seems logical to draw the path in the Z-X+ quadrant. For a conventional lathe, you still have to draw in this quadrant, but most likely, this will seem opposite to the layout of your machine.

The part's outermost face is usually drawn to coincide with the X axis, at Z0 in other words. All cutting takes place in the Z- or X-direction (typically). Of course, the part's axis of rotation coincides with the Z screen axis, or X0.

It is not necessary to draw a complete "double-sided" cross-section of your part, since you only need to construct a 2d toolpath along one side of it.

Is that of any assistance?

[CNCnUtZ]

Hu...
Although Ive been using a lathe for some time ..I have no idea which is Z and X! Up until recently Ive been quite content with being a "manual" machinist when concerning turning operations.

But since Ive gotten the CNC bug that we all eventually end up getting...Ive been getting closer and closer to taking the plunge(plunder would be a better term) in converting my lathe to CNC also .

Im going to go out on a limb here and assume that Z is cross feed..correct?

Could you possibly give me a description of which axis is goes with what direction/movement on a lathe?

Ive never even used a coordinate system other than default in MC mill and it never dawned on me that I needed to use a different coordinate system when creating toolpaths for a lathe in MC lathe.
I dont even know how to model in MC design...I usually model my parts in SW and then import 2d dxf's or dwg's into MC for toolpath creation since I know SW fairly well and MC has such a non windows compliant UI....its easier for me this way.

It seem I really need to delve into MC and learn all aspects of the software to get a better understanding of how it all works in unison.
Or maybe I need to look into another CAM package thats more "userfriendly"...Can you suggest anything by chance?

Thanks for the eyeopener BTW

[CNCnUtZ]

Originally posted by HuFlungDung
Hi CncNutz,

I can't help you with Mastercam, but generally speaking, lathe paths are simple 2d chains. Once you figure out how the screen coordinates jive with the real world setup of your lathe's axis, it is simply a matter of drawing in the correct quadrant.

For a slant bed lathe, with tool approach from the rear, it seems logical to draw the path in the Z-X+ quadrant. For a conventional lathe, you still have to draw in this quadrant, but most likely, this will seem opposite to the layout of your machine.

The part's outermost face is usually drawn to coincide with the X axis, at Z0 in other words. All cutting takes place in the Z- or X-direction (typically). Of course, the part's axis of rotation coincides with the Z screen axis, or X0.

It is not necessary to draw a complete "double-sided" cross-section of your part, since you only need to construct a 2d toolpath along one side of it.

Is that of any assistance?

Yep.....I going to be fairly busy tonight to see if I make any progress with this...

I really dont need to CNC my lathe , but it sure would be nice.

One more thing...
When using a CNC lathe in a hobbiest fashion (generally) do you still use the toolpost as is or do you fashion a stationary toolpost with the required tools on it for all operations?

This is really unclear to me. Ive tried to google to find a better explaination of how the tooling is setup on a CNC lathe...

but it doesnt seem to be out there to read of (My googling skills are rather lacking maybe?)

Thanks for the replies

[HuFlungDung]

CncNutz,

I can say for sure, you are going to want to spend money on a very good manual quick-change toolpost. There is a 40 position toolpost made by Klopfer, and various clones of it out there, that is excellent for repeatability. Lots of shops use these on cnc lathes, including me. I use two of these posts (front and rear) on a small cnc lathe retro.

These are expensive, but at least you won't be discouraged from inaccurate tool placement. These toolposts come in a variety of sizes to match your machine swing.

I do not know for certain how repeatable those cheap 4 way quick change toolposts are. They might be all right, too.

[cadcam]

CNCnUtZ, to set the View look in the lower left hand corner of the screen were it shows (Cplan) this were you want in most cases a D+ or D- by the upper turret or muns being a lower turret thoghts.

Now when you say create a line horz give it the Dia value and it will place it by half the dia in the D+ being Y+ on the screen or the oppist.

this just a start. I will be back.

[CNCnUtZ]

Thanks. Ive actually made some progress with it.
Just need more practice.
\
One more question...how do I create my own tool and also have the preview show the shape as its designed?
I make a custom tool and save it but when I backplot the operation I get an error stating a colision or the cutter is out of the bounding area even though the cutter is listed in operations>parameters>tool as the smaller diameter cutter i created by changing the default parameters from the tool I clicked on to begin with

Im thinking that I have to actually create the tool profile too in order for it to verify and backplot right...correct? can anyone run me through this??

thanks again for the time and suggestions........