next pass to start from the last pass position

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next pass to start from the last pass position

Postby alex pavel » Sat Feb 09, 2019 10:52 pm

At the moment if i have a toolpath that requires 4 passes, every pass the tool will go at the tp start location and mill from there. Is there any way to tell it to start the next toolpath from where it is? It's a waste of time to go all the way at the start location when it could just continue from there with the next pass.
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Re: next pass to start from the last pass position

Postby FixitMike » Sun Feb 10, 2019 12:02 am

Yes, there is a way. If it takes 4 passes, use 4 separate toolpaths, adjusting the start depths accordingly and use the Start At option to suit. If you are cutting Inside or Outside of a vector, you will have to also alternate the Climb and Conventional Direction selection.
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Experience comes from bad judgement.
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Re: next pass to start from the last pass position

Postby alex pavel » Sun Feb 10, 2019 1:04 am

Thank you!
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Re: next pass to start from the last pass position

Postby Jim_in_PA » Mon Feb 11, 2019 3:58 pm

Mke's answer is absolutely valid, but I'll play devil's advocate on this... yes, it's not the most efficient to go back to the original start point, but machine rapids are generally reasonably fast. You have to weigh the slight machining efficiency gain from splitting things up into multiple tool paths vs the risk of mistakes with resetting all the start heights, start points and machining direction. You only get to screw it up once with the original method vs, say...four times with the alternative method. :)
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Re: next pass to start from the last pass position

Postby alex pavel » Tue Feb 12, 2019 11:34 am

I'm not going to make a new toolpath for each pass. I would end up with about 30 toolpaths. I just can't believe there is no option for this! If you have a 2000mm long pass even if machine rapid is fast, i still lose a few seconds on each pass, and that means a few minutes on my current project. I think this should really be implemented in the software, the option to start the next pass from the end of the current pass.
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Re: next pass to start from the last pass position

Postby Adrian » Tue Feb 12, 2019 1:11 pm

What type of toolpath is it you're using?
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Re: next pass to start from the last pass position

Postby Jim_in_PA » Tue Feb 12, 2019 7:52 pm

In order for the software to do what you want, it would have to generate four separate toolpaths itself to complete the task with the start points flipping to the previous end-point. The way it works now (a very general statement here...) is it generates the code for a single pass and repeats that code after adjusting the Z-height for the next pass. That's more efficient from a code perspective, but yes, it does burn a little time moving from finish back to start. I can't think of any logic reason that the software couldn't support what you want outside of making it more slightly complex by automagically changing the start points for the affected vectors for each pass, which in turn opens up more opportunity for Mr Murphy. Put in the suggestion...

Oh, an I can commiserate right now with the job I'm running for a client that already has a 7 hour cut time and multiple passes for the rough 3D toolpath.
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Re: next pass to start from the last pass position

Postby alex pavel » Thu Feb 14, 2019 9:24 pm

Adrian, i am using profile toolpaths at the moment.
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Re: next pass to start from the last pass position

Postby alex pavel » Thu Feb 14, 2019 9:29 pm

Thanks for making things more clear Jim! Well i wish they will add this feature soon. How would i make this suggestion to the developers?
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Re: next pass to start from the last pass position

Postby mtylerfl » Fri Feb 15, 2019 1:02 am

alex pavel wrote:Adrian, i am using profile toolpaths at the moment.


Why not just assign the Spiral Ramp to your Profile Toolpaths?
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Re: next pass to start from the last pass position

Postby adze_cnc » Fri Feb 15, 2019 1:30 am

alex: These profile toolpaths: are they using open vectors? If closed vectors are you using lead-ins? These are the only two ways that I foresee the motion from the "end point" to the "start point" that you describe. (The only other way I see this movement happening would be using a closed vector with a last pass offset.)

In these cases, Michael, would the spiral ramp be of use?

For normal profile toolpaths (with closed vectors, no leads, no last pass, etc.,) the post-processor I use doesn't do any lifting when executing the 2nd to nth passes.

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Re: next pass to start from the last pass position

Postby mtylerfl » Fri Feb 15, 2019 1:45 am

Steven,

We are forced to make guesses and assumptions, as Alex has not posted a file example of exactly what “kind” of Profile he is doing.

How about it Alex? An example file trumps a description attempt every time!
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