Splitting a toolpath?

[Ms Wolffie]

I have a piece that will take a very very long time to carve.
In order not to get problems with the neighbours, I cannot run the machine after dark.
Is it possible to split the toolpath into manageable chunks? That would also give the router time to cool down.
I am thinking of either putting stop/restart lines into the toolpath or simply cutting/pasting some of the lines and make them into individual toolpaths.
I will make sure the beginning/end lines will be in each toolpath.

I know Mach has that feature but the Shark doesn't.

Cheers
Wolffie

[Markm]

hello
there is a tile toolpath option in the software that should do it.

Mark

[Ms Wolffie]

Isn't tiling for material that is larger than the bed?
I just want to split the carving time into smaller chunks.

Cheers
Wolffie

[metalworkz]

Hello Wolffie,
Yes, tiling is basically to break the job down to fit within the travels of the machine, but I think it will also accomplish what you want to do. If you are doing 3D toolpaths and just wanted to split the time for the 3D maybe do the whole piece complete with the roughing toolpaths and just tile the 3D toolpaths? You could use the estimated time and break that into intervals that fit your schedule. Can preview it and see if that will work for you? Might not be exactly how you want to do it, but may be a way to get it done.

[cac67]

Toolpath tiling will not work. You would have to accurately locate x0 y0 in the correct spot on the job for each toolpath to start from. It's designed for you to move the material to a new position so you can carve larger pieces than your table can support.

What you need is tape splitting. You'll have to edit a post processor to do it, but the way it works is to save the toolpath in parts of however many lines you set it up for. I used this to carve a job that took 44 hours, and I spread it out over 5 days.

See this post for a link to the guide: http://www.vectric.com/forum/viewtopic.php?f=4&t=6213

[Ms Wolffie]

Thanks Adrian
That's the word I couldn't remember.

I just couldn't imagine my router running over 40 hours in one go.
Not only would it probably break down but I would have the police here with a noise complaint

I don't think it was the Post Processor Guide I needed?

Cheers
Wolffie

[rscrawford]

The problem with tape splitting on a Shark machine is maintaining your home position after things are shut down. The Shark does not have a machine home position, and no way to accurately save a home position (no limit switches to calibrate from).

So if you shut the machine off and something moves, you've just ruined a long cut job unless you can figure out a way to rezero the home position in a repeatable manner.

[Ms Wolffie]

When I stop the machine for the day and I have more to do on the same project, I put the router down to the surface on XYZ0 before I shut down.
That way it is there the next day.
If I cant do that, I make a mark where XYZ0 is.
Fortunately we do not have large temperature changes here, it is either hot and wet or cooler and dry but the changes are gradual.
Pity you cant fit limiter switches to the Shark, I hate the way it bangs into the ends of travel if I jog too fast
Cheers
Wolffie

[tmerrill]

Toolpath tiling will not work. You would have to accurately locate x0 y0 in the correct spot on the job for each toolpath to start from. It's designed for you to move the material to a new position so you can carve larger pieces than your table can support.

Sure it will work! You simply do what you say, accurately locate the new X0,Y0 for the next tile and then run the tile. While the Tile Toolpath may not have been developed with this in mind, it was actually tested in this manner to verify toolpath alignment between tiles without introducing any possible misalignment while physically moving the material.

The problem with tape splitting on a Shark machine is maintaining your home position after things are shut down. The Shark does not have a machine home position, and no way to accurately save a home position (no limit switches to calibrate from).

Interesting, I don't have limit switches and it works fine with my machine. Are you saying if you return a Shark to X0,Y0 and shut it off, when you restart it X0,Y0 will no longer exist? If it does restart with both X and Y at that zero location, then Tape Splitting will work fine from a machine and control system point of view - possible issues with material movement are external to this.

Tape Splitting simply breaks a long toolpath into shorter individual toolpaths, with each one being a complete toolpath (has a header and footer). Just like any other toolpath, the router will return to the Home position at completion and be ready to run the next toolpath. It makes no difference that the toolpaths were originally made up from one longer one or were created individually as we normally do.

Tim

[Ms Wolffie]

Thanks Tim, I remember reading something about it but I couldn't find it again.
I couldn't remember how to do it

Cheers
Wolffie

[fixtureman]

There may be a way to use tiling by readjusting the XOYO over the size of the first tile

[cac67]

I stand corrected, tiling can work. I still recommend tape splitting though. Once you've edited the post processor (not as hard as you may think) you just end up with a bunch of toolpaths that you run from the same zero.

I actually copied my standard pp twice and made a separate one for roughing since they weren't going to have the same number of lines. To determine that number I saved the tp with the standard pp then loaded it into notepad. At the bottom of the window it shows how many lines in the file and I just divided that number by the number of tp sections I wanted, then set that in my modified pp. It won't give you even times since it's based on number of lines in the tp but it's not too bad.

As far as zero goes, when I was ready to go home for the day I would click "go to z" on mach 3 to move the bit to x0y0z0 then just shut down. The next day when I fired back up I would just hit the xyz zero buttons on mach before moving the machine. I also had no limit or home switches on my machine.

[Ms Wolffie]

As far as zero goes, when I was ready to go home for the day I would click "go to z" on mach 3 to move the bit to x0y0z0 then just shut down. The next day when I fired back up I would just hit the xyz zero buttons on mach before moving the machine. I also had no limit or home switches on my machine.

Same as the Shark, you just click go XYZ0 and it is the when you fire up again.

I only wish for limit switches to avoid the slamming into the end of travel, sometimes I go too far when I move the router forward and up to change bits, that can throw the XYZ0 out.

I believe you just have to make sure there are some top and bottom lines that have to be on every part of the split?

Cheers
Wolffie

[cac67]

I believe you just have to make sure there are some top and bottom lines that have to be on every part of the split?

Cheers
Wolffie

Nope, that's automatically generated. You're really only adding 1 line to the pp to tell it how many sections to cut it into. Each section is a self contained toolpath with the appropriate header and footer section. So when each toolpath is done it's going to return to xy0 anyway, you just have to take z to zero.

You'll also need to change the name of the post processor in the header section, not just the file name. The name in the header section is what shows up in the pp list. That's of course assuming you're working from a copy of your original pp, which I highly recommend.

[Ms Wolffie]

Thanks Chris

I don't think I am at the stage as yet where I would dare change the original toolpath.
Very pleased though, this is going to be much easier than I expected.

Actually read the complete Post Processor Guide today, I would never have believed it would be anything I would understand but I did though

Thanks again to all for your good advice.

Cheers
Wolffie