how to control engraving order?

[dwneumann]

I often engrave words into my workpiece. I create a text object using a single-stroke font, grouping the letters together into one group object, then use 2D Along Curve profiling to create the toolpath.
This works well, and conveniently only requires creating one toolpath for the whole group, but the order in which the letters are engraved appears random. Images 1 and 2 below show this. This random ordering causes the rapids to increase the cutting time 10-fold (my little machine only has 30ipm rapids).

If I ungroup the letters and create a separate toolpath for each letter in left-to-right order, I end up with many many toolpaths (inconvenient) but then far far less time is spent on useless rapids. Image 3 shows this.

Is there a way, either via Rhino or MadCam, to control the cutting order of objects in a group, so that I can have the convenience of only creating one toolpath as well as the speed of machining them in left-to-right order?

p.s. I am using MadCam v4.3 with Rhino v4 (as a hobbyist I can't justify rebuying Rhino 5 to upgrade MadCam).
Thanks.
Dean




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[Dan B]

I think what needs to happen here is that the curves that you are engraving need to be ordered in Rhino. I have a macro that does that, but it doesn't work very well. I plan to write a Python script that should work better. Can you post your example file for me to test with? I might be able to do this today.

Thanks,

Dan

[dwneumann]

thank you Dan. Much appreciated.
Here is the rhino file...
Regards,
Dean

[Dan B]

Hi Dean,

I just wanted you to see this, before I do any work on a script. I brought your file into Rhino 5 and madCAM 5 and it's pretty organized right out of the gate.



I noticed that your font is pretty clean (no duplicate curves or tiny closed areas). Is this a font you created? I have a single line engraving font that I made about 12 years ago. It has some irregularities that I don't see in yours.

Thanks,

Dan

[svenakela]

I cut quite a lot of graphics for bike frames that are going through the repair workshop. The cutter will jump around a bit and does the same thing on a dedicated vinyl plotter cutter too. I cut all the graphics in a router as I often use special vinyl that doesn't work in a plotter cutter and I always create the layout in Rhino.
There's no need to group the text and let MadCAM choose the cut order instead of using the Rhino curve order. I tried your text and got not more than a handful of jumps. I also prefer using Project Curves instead of Along Curves. The cut depth is then simply a matter of setting a Stock To Leave. You can also have the text polylines way above your model and out of the way.

[dwneumann]

Dan, your toolpath does look much nicer than the Rhino4+MadCam4 toolpath. Unfortunately the $1700 upgrade cost is prohibitive.
The font is MECSOFT-FONT1.
http://wiki.mcneel.com/rhino/engravingfonts
Rgds
Dean

[dwneumann]

svenlaka, I like your idea but I don't think I have the Project Curves strategy available to me in MadCamv4.3. if so where would i find it?
thanks,
Dean

[Dan B]

I cut quite a lot of graphics for bike frames that are going through the repair workshop. The cutter will jump around a bit and does the same thing on a dedicated vinyl plotter cutter too. I cut all the graphics in a router as I often use special vinyl that doesn't work in a plotter cutter and I always create the layout in Rhino.
There's no need to group the text and let MadCAM choose the cut order instead of using the Rhino curve order. I tried your text and got not more than a handful of jumps. I also prefer using Project Curves instead of Along Curves. The cut depth is then simply a matter of setting a Stock To Leave. You can also have the text polylines way above your model and out of the way.

Sven, take another look at along curves in the next SR. you can now put in a negative value to cut below the curves.

[svenakela]

svenlaka, I like your idea but I don't think I have the Project Curves strategy available to me in MadCamv4.3. if so where would i find it?
thanks,
Dean

Hmmm... It should be in the same cluster as Along Curves, I don't remember if it was/is present in version 4. The cutting shouldn't jump around too much in the old version anyway even if you use Along Curves.

[Mauri R]

Dean,
I performed the Fonts Engraving in the following manner.
I used single line fonts using a another software package.
I exported the Fonts to a DXF file.
Imported the DXF file into Rhino 5/MadCAM 5.
I used a 20D .1mm Tip in this example.
I lowered the fonts by the depth I wanted to cut .1mm
I used Along_Curve and Project_Curve.
On all 4 examples there is no extra movement of cutter, two I started from the 1st letter and the other 2 I start from the last letter.
I thought that MadCAM 4.3 had Along_Curve and Project_Curve cutting?
Hope this helps.
Regards,
Mauri.

[Mauri R]

Dean,
MadCAM 4.3 does have Along and Project Curves.
Refer pictures below.
Regards,
Mauri.

[svenakela]

Dean,
MadCAM 4.3 does have Along and Project Curves.
Refer pictures below.
Regards,
Mauri.

Yes, that's also how I thought it was.
Thanks for the snapshots.

[JOM]

Hi Dean,

I just wanted to let you know that the upgrade cost is only $ 295 if you upgrade to the corresponding version of madCAM 5 as you have for madCAM 4.3.
For example: Entry-level to 3X, Fouraxis to 4X or Expert to 5X. There are also special prices when upgrading from educational to commercial.
Here is the price list: madCAM - Compare Prices

Thanks,

Joakim

[dwneumann]

thank you everyone. i will try Project Curve engraving to see if it engraves in a different order than 2D profiling, and thank you Joakim I will consider upgrading to rhino5 and madcam5. it certainly would be nice to have all the new features of both.
Regards
Dean

[dwneumann]

Thanks everyone for your help. Project Curves with the "optimize curve order" option selected does the trick perfectly.
Cheers,
Dean

[Dan B]

You won't regret upgrading. Both Rhino 5 and madCAM 5 are huge advancements compared to what you have now. You will wonder why you didn't do it sooner!

Dan