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Messages - jtheath

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1
LazyTurn / Re: LazyTurn
« on: July 20, 2009, 10:22:29 PM »
Hi Rich,

Here are a couple DXFs from ACAD2002 saved as R12.  The cigarTop should have end diameters of 0.480 & 0.580.  The cigarBottom should have end diameters of 0.530 & 0.462.  I ran LT using the diamond35 bit and 0.002 depth cuts.  What I got as far as GCode was 0.531 & 0.626 for the top; 0.582 & 0.512 for the bottom.  Where's that extra 0.050 coming from?

These may still be more complex than ideal.  Used a spline to get the shape.

Thank you,   Joe


2
General Mach Discussion / Mach3Turn - dimension troubles
« on: July 18, 2009, 06:47:03 PM »
Good afternoon all!

I am having sizing difficulties with both the Turn Wizards output and LazyTurn output.  What settings within Mach3 can introduce consistent offset differences?  I'm getting parts that are about 0.080" larger in diameter than desired.  This appears to be constant across the length of the part.

I have run through the positioning tests, you know, 50-100 iterations of full length extension and return with a dial indicator in place and see no more than 0.0005" variance.

Any advice or direction would be appreciated.  I've been through the Mach3Turn mnual multiple times and nothing jumps out at me.

Thank you,   Joe

3
LazyTurn / Re: LazyTurn
« on: July 09, 2009, 10:49:42 AM »
Hi Rich,

I keep the manual handy and have read all the references.  As far as part positioning goes, I use the horizontal traingles to set the start point and tool offset in LTurn.  As far as design software goes, I'm the first to admit I know nothing about ACAD but I do have several years into CD and can knock things out quickly.  The ACAD manual is 2-3 inches thick and all I want is a nice, smooth curve.  It's not obvious how it's done in ACAD - sure simple radius-based arcs are easy but the ones I'm shooting for don't map into that.

As far as the multiple polylines - all I was putting together for that bushing profile are straight line segments.  Click the start point, double click the endpoint to terminate the segment.  I have no control over what CD generates.  Maybe this is something I could figure out in ACAD.

With regard to the finish pass - it isn't a problem for me right now.  All barrels have to go through an incremental sanding phase and finish application.  I'm shooting for 0.010-0.015 oversize coming out of the Mach3 run.

Thanks again for the advice/insight.  As I've said, I appreciate the efforts you all are putting on this.

Cheers,   Joe

4
LazyTurn / Re: LazyTurn
« on: July 09, 2009, 12:55:53 AM »
Hi Guys!

Rich, I'm still working on getting v12 DXFs.  I installed ACAD2002 and haven't yet figured out how to get the curves I want directly.  So I do my layout in CorelDRAW, export to v11 DXF, import into ACAD2002 then save out as v12.  Honestly, it doesn't seem to make much difference.  There's just something I'm not getting but I'm confident the lightbulb will eventually go on.  ;)  In the meantime, I'm loading my curves into LTurn and playing with the brown diameter value until I see the end diameters I'm looking for.

I just tried to create a simple stepped bushing profile and get something similar.  This bushing has a max diameter of 0.476" for 0.5" then drops down to 0.358".  The GCode appears to get within 0.001 of the desired max diameter but the small diameter is 0.050" too large.

Cheers,   Joe

5
LazyTurn / Re: LazyTurn
« on: July 08, 2009, 06:14:12 PM »
Hi Art,

Thank you for the quick response! 

Maybe there's a simpler way to ask the question.  On the display there are two triangles, a brown one and a blue one.  My understanding is the blue one sets the diameter of the stock and the brown one I understood to be the desired maximum diameter of the finished part.  For instance, I have a simple curve with left end diameter of 0.54" a maximum diameter about an inch to the right of that which is 0.595" and the rightmost diameter is 0.465".  I was defining the brown triangle value to be that 0.595" but that definitely didn't give me the desired left end/right end diameters.  The profile itself is simply a floating curve so those "end diameters" aren't specified in the drawing - it's a "floating" profile.  Defining those end radii in the drawing didn't seem to result in the desired diameters either.

I appreciate all the effort you're putting into this project!

All the best,   Joe

6
LazyTurn / Re: LazyTurn
« on: July 08, 2009, 05:17:09 PM »
Art, Rich - what's the trick in specifying the final part diameter correctly?  I'm still working with these relatively minor curves for turning pens barrels and it seems the diameter I specify turns out to be the diameter of the leftmost edge (nearest the headstock) rather than the maximum diameter of the turned part.  If that's the rule, great!  Nice and simple.  If not, how should it work and what should I specify?

Thank you,   Joe

7
LazyTurn / Re: LazyTurn
« on: May 26, 2009, 12:11:59 AM »
Hey Rich,

"... don't let you heart be troubled, for there will be a section in the LazyTurn manual ..."

That had me rolling!   ;D

Have a great week!   Joe

8
LazyTurn / Re: LazyTurn
« on: May 25, 2009, 07:01:41 PM »
No worries, Rich.  

I had meant to type, "What does one do when one hits a wall?  Take a detour."

There don't appear to be the necessary adjustment "knobs" for CDX4 to generate the desired dxf files.   Since LazyTurn will also import Corel Media Exchange (CMX) and HPGL2 (PLT) files among others, that solved my trouble.  Importing the CMX equivalent into LazyTurn produced what appears to be very good output and usable G-code.

I use CD as a vector generating app for other devices - laser and vinyl plotter - so am quite familiar with it.  I also could try Illustrator or install a copy of AutoCAD 2002 if it comes down to it.  For now though, I'm happy with what's working.

A question on the G-code generation - actually setting coordinates.  The Mach3Turn wizards allow setting the part X & Z zero points to the "front, rightmost" point on the stock to be machined resulting in moves that are in the negative direction for both axes.  LazyTurn, it seems, allows Z axis setting zero to the rightmost spot but X remains at the center of the piece.  Is it possible to shift the X origin (zero position) to the outer diameter of the starting stock so that setup operations whether using wizard or LazyTurn G-code are similar?

Best,   Joe

9
LazyTurn / Re: LazyTurn
« on: May 25, 2009, 10:59:57 AM »
Good morning Guys!

Thank you both for the guidance and response!  I've been working with CDX4 dxf generation options.  The options don't include version 12 - {2.5, 2.6, 9, 10, 11, 13,2000, 2002, 2004, 2005, 2006, 2007} - and all want to try some 2D projection of a 3D object (even though the drawing is a simple 2D line drawing - go figure).

So, what does when do when one hits a wall?  Take a detour.  Rich, thanks for mentioning 2D explicitly.  I exported using HPGL2 PLT format and LazyTurn ate it up just fine, producing a valid Cut.  Then I noticed the direct CMX file import option and tried that.  Even better!

All the best,   Joe

10
LazyTurn / Re: LazyTurn
« on: May 25, 2009, 12:57:58 AM »
Thank you Chip!  Thank you Art! 

Is there a "better" way to achieve the minor curvature?  There are a few profiles I'm working on.  Some more bulbous than others but since these are for pens, they'll never be significantly larger.

All the best,   Joe

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