Retract only when crossing open space?

[nerys]

I thought I understood how this works but I am not so sure now.

I had a print come out horrible. nasty stringing to the point it was pulling filament from the nozzle and causing in effect and result an underextrusion once it started printing again as it thought their was x filament in the nozzle and there was not because the oozing/stringing had pulled it out.

bad

anyway I figured maybe temps were too high or something. turns out retraction was straight up simply not happening. at all.

the drive gear did not even attempt to reverse (to retract) well duh that is the problem.

but I have it set to retract only when crossing open spaces or over 3mm of movement.

what gives? why was it not retracting?

the only thing I thought of at the time was maybe it does not recognize an open space if that open space is not in the same process?

ie I am printing 4 components simultaneously. each has its own set of processes. is it possible because of this it does not recognize going from one discrete object to another discrete object as an "open space" because each is its own process?

suggestions?

I turned on force retraction between layers and turned off retract only over open spaces and this seemed to fix it but now it constantly retracts for any movement (which can create its own problems in some prints)

what am I doing wrong? is there some other setting that will interfere with the only retract when crossing open spaces and stop that from working properly?

[dkightley]

If you have multiple components with their own processes then there one simple way to reduce the extruder movement between components....use sequential printing.

First, work out how how much clearance you have under your extruder to allow one part to be partially printed and another be printed at bed level. Then select Sequential Printing in the Process Selection box that pops up when you select printing. Enter the max clearance...and you'll only get movement in between parts when the clearance height is reached.

[nerys]

I love sequential printing sadly this won't work as these components are 165mm tall and too large volumetriclaly.

with the new sanded PEI there is no way the printer will "knock" components off the bed without knocking it out of register.

I have done that before. sequential and just let the arm knock the first component right off the bed.

I can't do that with these components.

it appears to be a flaw. I could be wrong when time permits I have a test. I will print 2 cylinders in a single process and 2 cylinders in their own process same settings and see if it retracts between objects. its a very odd problem.

I was just stunned when I started the print and watched it and no retraction??? I was like WTF? why is it not retracting IT IS set to retract :-)

[andrewk72]

Mine retracts fine between parts. Are you sure you have "retract between layers" enabled?

[nerys]

Ok this is now legitimately a bug in my eyes.

First. the setting retract every layer and retract open space "conflict" with each other (one disables the other)

Second the real problem. Only retract when crossing open spaces is broken with multiple objects in separate processes.

I just tried it (zip attached 2 factory files inside)

they are identical except in one I have a single process for both tubes and in the second I have each tube as its own otherwise identical process.

the one process file has retraction when open spaces are crossed the two process file has ZERO retraction at all anywhere (except when it completes the entire print) even though retract when crossing open spaces is selected.

IE retract when crossing open spaces is broken in muti process prints and worse there is no work around I am aware of.

I can set retract every layer and this works but it only works for ONE PART of the print. the part just prior to the layer change.

when it goes from part one to part two there is no layer change so there is no RETRACTION between the parts and I see no way to force it to do this. IE I see no way to make it retract AT ALL when going from part one to part two in a multi process environment. it simply refuses to retract.

I never noticed this bug before because I never had to use processes so extensively before.

one possible work around (not sure if this will work in an actual print without the oozing that will result screwing up the print) is to print a 1mm tower for EACH and every part in a process and add that tower to "each" process segment so it will recognize an "open space" or maybe Two towers one entry tower and one exit tower.

but that will only work if I can control the ORDER it tries to print the parts. IE I would need it to always print the entry tower in a process and then the part in that process and then the exit tower in that process. this would relegate the oozing to the entry and exit towers but I don't see that kind of fine process control in the software.

I did find one work around.

instead of print the 4 parts of the rocket

I print 4 of the SAME part and make 3 other files to do the same.

this way there is only ONE set of processes and it recognizes and executes the retract only when crossing open spaces command.

not ideal. it is a bug that needs fixing but at least there is "some" way to work around this but only if you have enough TIME.

part of the reason I want to do all 4 parts is it takes 19 hours. so I can do one rocket "per day" essentially.

if I only needed one I would have to do each part alone and that woudl take 2 days instead of 1 days because I would do one part goto bed then do second part and goto work. 3rd part goto bed 4th part goto work.

2 days. while doing all 4 parts at once I can do the same in 19 hours since I won't have to be at the printer to start the next part.

[nerys]

retract between layers works fine but does not fix this problem.

when I print layer x on part 1 and then move to layer 2 to print layer x the layer has no changed so no retraction occurs.

this is where retract when crossing open spaces is supposed to come into effect but it does NOT if the two parts are in separate processes.

SO in prints part 1 then moves to part 2 and prints then retracts then prints part 2 again then moves to part 1 then retracts.

what is SHOULD be doing is print part one retract then move to part 2 and print then retract then print part 2 again then retract then move to part one print it and retract.

it skips the retract "between parts" (not layers) when those parts are in there own processes. if both parts are in the SAME process it honors the open space retract.

sorry for posting so late we had rain last night and well my internet pretty much does not work if its raining. :-)

[andrewk72]

You are only printing a single outline, so there isn't even an interior of the print to cross over! When you print parts with multiple outlines or with infill, then you can be moving inside that layer without crossing the outline. That's what the "only retract when crossing open spaces" setting is intended to control - it will only use retractions when you leave the interior of the layer. But if you are only printing a single outline (which you are), then there's no concept of an interior at all, so there's no way to cross anything.

You have "only retract when crossing" enabled, which means it won't retract at all. So just disable that setting for both your processes and it will work fine. I just tested it and it retracts between both parts perfectly when you turn that off.

[nerys]

I wonder what would happen if I simply turned off all "retract behavior" options all together as you suggest.

the problem is I really do not want it retracting UNLESS its crossing open space.

retracts always introduce the chance of error. the fewer the retractions you can do the better by far.

so while your solution works it creates artifacts elsewhere because the printer is retracting all over the place (one of the objects has lots of "island" printing in different spots where retraction is really not needed or desired)

only retract when crossing open spaces combined with do not leave the outline for movements SHOULD give me exactly the result I want.

never retract unless your jumping from one part to another (open space)

I think the software only considers open space IN the process and since I have a separate process for each part it sees "no" open space at all. because none of the actual open space is "encompassed" in any of the processes since I have one or more for each object but none for "more" than one object.

that is something they need to fix.

this is not a single perimeter issue. the full place has 1 single perimeter object 2 double perimeter objects and a triple perimeter object with 25% infill.

the behavior is identical across all 4 objects.

[2012bencormier]

Hello, I got the same probleme between printing support and the main part, it doesn't retract. It will retract between every support tower and then goes strait to the main part without retracting. If there is more than one island in the main part, it retract normally, then goes to the support and still retract between the tower support and when it goes back to the main part it doesn't retract.

For sure there is a problem...

(still this is on the same process)

[CompoundCarl]

It's working fine for me. Can you post your factory file (File > Save Factory File)?