[Mr.Chips]

I have a project to cut into a wood slab a sculpture of a group of running horses, the cut area will be approximately 12" x 40", the system says it will take approximately 48 hours of run time. Needless to say I don't want to do that in one sitting.

I want to break it down into about four hour segments. My thought is to install X Y and Z limit switches and home them and always start and stop with all the axis homed, how does this sound?

Or is there a better way?

Thanks
HH

[ger21]

One thing that may be an issue is the wood moving overnight. If you remove a lot of material from one side, it's possible that the board could warp over night, and the next days cutting might not line up exactly.

Can you program it to run faster? Or is your machine at it's limit? It shouldn't take 48 hours to cut something that size.

[Mr.Chips]

Running at 80 IPM and the 2.5 D and depth is aprox 5/8". There is a lot of detail on this piece of art.

I did take out one horse of the group and made a 8" x 11" using 0.011" stepover and it too in excess of 6 hours, and the detail was excellent and didn't require any sanding of cleanup. I really don't want to sacrifice the quality that is possible just to speed the time up.

I just want an accurate way to stop and be able to restart without an obvious flaw there, or am I dreaming?

Thanks
HH

[ger21]

Does that include roughing and finishing? If you have to, I'd break up the roughing, as that doesn't really matter, but I'd try to do the finishing in one non stop run.
What kind of tool are you using for finishing? And what kind if wood?

I'd probably run at 200ipm with about 8% stepover, if your machine can do it. Depending on how fast your Z axis is, though, it probably won't ever see 200ipm.

In theory, yes, you should be able to home the machine and resume where you left off. Provided nothings moved, and you can reset Z zero exactly the same each time. In reality, I think there's a good chance you'll see a slight difference between sections. But you never know until you try.

[Mr.Chips]

Yes that included both the rough and finish cuts.
Just did a simulate of the finish and it was 3 hours and 9 min using a 0.125" bull nose bit at 80 IPM

I don't remember what the step over was on the original run.

I just did an air cut at 200 ipm and it didn't stall but the actual ipm was looking like 122

Thanks for your comments
HH

The wood is a walnut slab about 2.75" thick

[FoxCNC1]

please let us know how it goes... and post pictures if you can.

I am going to piggie back here and ask a question about IPM. What is a "normal" speed for general cutting. Let's say 1/2 MDF to a depth of 1/4"
I have a Freud 76-100 but I can't find any chip load information. How would you typically asses how fast to run it without this information.

[Mr.Chips]

Here's the beg of file not sure if it would be of any help.


( Horse 3D Finish 1 )
( File created: Tuesday, September 10, 2013 - 08:58 AM)
( for Mach2/3 from Vectric )
( Material Size)
( X= 10.250, Y= 12.000, Z= 0.750)
()
(Toolpaths used in this file
(3D Finish 1)
(Tools used in this file: )
(2 = Ball Nose {0.125 inch})
M03
N100G00G20G17G90G40G49G80
N110G70G91.1
N120T2M06
N130 (Tool: Ball Nose {0.125 inch})
N140G00G43Z1.0000H2
N150S1000M03
N160(Toolpath:- 3D Finish 1)

[ger21]

Yes that included both the rough and finish cuts.
Just did a simulate of the finish and it was 3 hours and 9 min using a 0.125" bull nose bit at 80 IPM

I don't remember what the step over was on the original run.

I just did an air cut at 200 ipm and it didn't stall but the actual ipm was looking like 122

Thanks for your comments
HH

The wood is a walnut slab about 2.75" thick

In that case, just do the roughing in multiple steps, and do the finish all at once.