next pass to start from the last pass position

This forum is for general discussion about Aspire
Post Reply
alex pavel
Posts: 26
Joined: Mon Nov 26, 2018 6:52 pm
Model of CNC Machine: General Numeric

next pass to start from the last pass position

Post by alex pavel »

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.

User avatar
FixitMike
Vectric Wizard
Posts: 2176
Joined: Sun Apr 17, 2011 5:21 am
Model of CNC Machine: Shark Pro Plus (retired)
Location: Burien, WA USA

Re: next pass to start from the last pass position

Post by FixitMike »

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.
Good judgement comes from experience.
Experience comes from bad judgement.

alex pavel
Posts: 26
Joined: Mon Nov 26, 2018 6:52 pm
Model of CNC Machine: General Numeric

Re: next pass to start from the last pass position

Post by alex pavel »

Thank you!

User avatar
Jim_in_PA
Vectric Craftsman
Posts: 278
Joined: Wed Jan 10, 2018 3:24 am
Model of CNC Machine: Camaster Stinger II SR-44 (MacOS user)

Re: next pass to start from the last pass position

Post by Jim_in_PA »

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. :)

alex pavel
Posts: 26
Joined: Mon Nov 26, 2018 6:52 pm
Model of CNC Machine: General Numeric

Re: next pass to start from the last pass position

Post by alex pavel »

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.

User avatar
Adrian
Vectric Archimage
Posts: 14655
Joined: Thu Nov 23, 2006 2:19 pm
Model of CNC Machine: ShopBot PRS Alpha 96x48
Location: Surrey, UK

Re: next pass to start from the last pass position

Post by Adrian »

What type of toolpath is it you're using?

User avatar
Jim_in_PA
Vectric Craftsman
Posts: 278
Joined: Wed Jan 10, 2018 3:24 am
Model of CNC Machine: Camaster Stinger II SR-44 (MacOS user)

Re: next pass to start from the last pass position

Post by Jim_in_PA »

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.

alex pavel
Posts: 26
Joined: Mon Nov 26, 2018 6:52 pm
Model of CNC Machine: General Numeric

Re: next pass to start from the last pass position

Post by alex pavel »

Adrian, i am using profile toolpaths at the moment.

alex pavel
Posts: 26
Joined: Mon Nov 26, 2018 6:52 pm
Model of CNC Machine: General Numeric

Re: next pass to start from the last pass position

Post by alex pavel »

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?

User avatar
mtylerfl
Vectric Archimage
Posts: 5892
Joined: Thu Jan 29, 2009 3:54 am
Model of CNC Machine: -CarveWright CNC -ShopBot Buddy PRSAlpha
Location: Brunswick, GA

Re: next pass to start from the last pass position

Post by mtylerfl »

alex pavel wrote:Adrian, i am using profile toolpaths at the moment.
Why not just assign the Spiral Ramp to your Profile Toolpaths?
Michael Tyler

facebook.com/carvebuddy

-CarveWright CNC
-ShopBot Buddy PRSAlpha CNC

User avatar
adze_cnc
Vectric Wizard
Posts: 4371
Joined: Sat Jul 27, 2013 10:08 pm
Model of CNC Machine: AXYZ 4008
Location: Vancouver, BC, Canada

Re: next pass to start from the last pass position

Post by adze_cnc »

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.

Steven

User avatar
mtylerfl
Vectric Archimage
Posts: 5892
Joined: Thu Jan 29, 2009 3:54 am
Model of CNC Machine: -CarveWright CNC -ShopBot Buddy PRSAlpha
Location: Brunswick, GA

Re: next pass to start from the last pass position

Post by mtylerfl »

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!
Michael Tyler

facebook.com/carvebuddy

-CarveWright CNC
-ShopBot Buddy PRSAlpha CNC

Post Reply