Is there any way to define "no go areas" of a print bed?

deckingman

This is no big deal but I thought I'd ask the question......

The latest iteration of my printer design will have the ability for the nozzle to reach just outside the limits of the build plate. Which is nice because I'll be able to use the full 400mm x 400mm of surface area. BUT, I use a glass build plate (and no, I don't want to change that), which will be held down to the aluminium plate with clips in each corner. Which means that bad things would happen if I wanted to print something that had to extend completely into one or more corners. Or more likely, if I home X then try to home Y without first moving to (say) X+25.

So I just thought I'd ask if anyone knows of a way that these four "no-go" areas (about 20mm square in each corner) could be defined such that the firmware would treat them as hard limits, similar to axes minima and maxima. Of course, I still wouldn't be able print in these "no go" areas but at least it would stop the nozzle colliding with the plate clamps if when I do something stupid.

Edit I realise that this won't help with the start of homing where the initial axes positions are unknown.

droftarts

@deckingman There's the new M599 Define keepout zone? However, this is limited to 1 zone in 3.5b2. Maybe ask @dc42 if support for more is coming.

Ian

deckingman

@droftarts Thanks - that's the sort of thing I was thinking of. @dc42 four or more zones would be good. Also, maybe simply restrict movement similar to the way axis limits are treated, rather than abort the job (but with warning message) ?

o_lampe

@deckingman With the latest FW you should be able to define those clamps as (parked) tools and define a collision zone around them?
Just a wild guess...Not sure what the active nozzle would do when approaching one of the zones?

PS: Can't you define the bed shape in your slicer? It would only be an optical aid where NOT to place parts, though...

deckingman

@o_lampe Good thoughts. I'll look into the "parked tools" thing. I've just looked at my slicer and it seems that I can use a custom shape rather than a fixed rectangle, by defining it as an stl and uploading it. I'll add that to my seemingly ever growing "to-do" list.