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Strange tool path generation
« on: October 07, 2011, 06:30:28 AM »
Hi all,     The last few days i have been trying to learn Lazyturn. I read through the manual and all appendixes. Im up to the point were i have made a simple drawing in rhino CAD and inported it to lazyturn successfuly,created a tool and tried to create a rough tool path with it. The path it creates is a bit odd,im leaveing a 0.3mm clearance but the path cuts all the way up to the profile and even into the profile in some places,and on the fine finish pass it gos even deeper into the profile. on the finish path i was useing a clearance of 0. Im sure the problem is just something simple that i have overlooked but i cant figure out what.

any suggestions on what im doing wrong will be mutch appresiated

below is a pic of the tool path


regards
Simon

Offline RICH

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Re: Strange tool path generation
« Reply #1 on: October 07, 2011, 07:33:26 PM »
Simonc,
Please post the dxf file.
RICH
Re: Strange tool path generation
« Reply #2 on: October 08, 2011, 01:25:12 PM »
RICH,     Heres the DXF im useing.


The DXF was saved as a "R12" DXF as mentioned in the manual but in rhino there are 2 choices for R12, one is "natural" and the other is "lines and arcs". I saved as R12 natural, could this be my problem?


regards
Simon

Offline RICH

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Re: Strange tool path generation
« Reply #3 on: October 08, 2011, 02:46:45 PM »
Try  attached dxf ( imperial units) and word file.
I had trouble with your drawing and no time to fool with it so i redrew.
I don't know what the difference is between the two dxf's from Rhino since i don't use it.
Maybe try lines and arcs.

RICH
Re: Strange tool path generation
« Reply #4 on: October 08, 2011, 05:49:25 PM »
RICH,        Thanx for takeing the time to redraw it for me.

I tried saveing as lines and arcs and also found a problem in my original dxf were the radius didnt join to the line representing the OD,but it still gives the same tool path result. Think il try one of the CAD programs sugessted in your manual instead of rhino.

thanx again.


regards
Simon

Offline RICH

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Re: Strange tool path generation
« Reply #5 on: October 08, 2011, 06:41:23 PM »
I don't remember suggesting, nor would I suggest, a particular cad program to anyone.
This way if they don't like the program they won't be cursing me every time they draw a line...... ;)
RICH



Re: Strange tool path generation
« Reply #6 on: January 16, 2012, 10:41:55 PM »
Here is another strange tool path from someone learning LazyTurn: the drawing is of a collet for a clock wheel saved as DXF V12. Tool is a 35 degree diamond. Just the rough path is shown but the fine path is similar. The billet is .5 brass rod with an OD on the right hand side of the collet of 5/32. Disregard the left hand side - that's to come later. I'm being very conservative using 4 passes of .042. Also disregard the very slow feed rate.

Why doesn't the pathing go all the way to the drawing and what are those paths on the right side?
The drawing of the collet is 1/2 inch but LazyTurn shows the shaded portion as larger. Is this some sort of compensation for the tool bit radius?
Re: Strange tool path generation
« Reply #7 on: January 16, 2012, 10:44:31 PM »
The tif of the tool paths somehow got lost in translation.

Offline RICH

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Re: Strange tool path generation
« Reply #8 on: January 17, 2012, 06:35:03 AM »
Post screen shots of :
-the tool input dialog screen for your 35 diamond
-roughing parameters dialog screen
- The top side ruler ( green / yellow pentagon) how much of an offset are you using?
   Why are you doing that?
  
I have no problem with your drawing.

Have you had a look at the manual?

RICH

 
« Last Edit: January 17, 2012, 06:37:41 AM by RICH »
Re: Strange tool path generation
« Reply #9 on: January 17, 2012, 11:57:23 AM »
Thanks for the reply. Attached are screen shots for the roughing parameters and the tool input dialog. I was experimenting with a 45 degree angle left tool to see if the pathing would improve. There are no changes with 0 degrees and center tool.

The yellow pentagon is .0413 and the green one is .0313. I had assumed that I needed an offset so the tool would not be butted against the billet but making the offset zero shows there’s still space between the two.

I have gone through the manual several times (as well as the Mach Turn manual) and have absorbed most of it, except of course the part that would make the correct pathing. Clearance and tolerance are still a bit hazy. I find, oddly enough, that getting through a 2 axis manual is more difficult than getting my Tail mill up and running with Mach 3 Mill. I’ve cut a number of clock wheels out and need to produce identical parts on a lathe. I just finished retrofitting a manual Sherline lathe to CNC and it appears to be working.

What did you do to produce the pathing shown in the hcir.jpg? It looks like you have a large number of passes, both for rough and finishing.

I need a sharp corner on the left side of the collet as that is where the clock wheel fits. In fact, the ½ in. part should be undercut slightly. How is this done with the typical diamond insert tools? A friend who runs a CNC machine shop suggested a parting tool from the rear toolpost would do the trick but that’s too advanced for me as yet.