If I wanted to change the color of a printed item at a certain point and decided to use the feature in Simplify3D that allows for those setting what would the start height be for the second portion of the print?
Example:
1. import model that I want to be multicolored
2. Change settings to this;
Start Printing at Height; 0.00mm
Stop Printing at Height; 4.00mm
3. change spool
Modify settings to this;
Start Printing Height; 4.00mm Is this correct or should it be 1 layer higher or?
Stop Printing Height; leave unchecked so it will just quite when model is fully printed.
Will this work?
I was going to just pause the print and try to change the spool quickly but thought this might work. Any suggestions are appreciated.
Thanks,
KeithA
Start/Stop printing at Height
Re: Start/Stop printing at Height
There are a number of issues in doing it this way that you will have to be aware of.
First, at the start of every print, if you have turned off the motors since the last job, it must home all axes before the next job. When it goes to home the Z axis, you must make sure that the first part of the last job will not crash into the gantry, which it will do if it is tall enough, and it is in the middle of the bed.
Secondly, when you start the second print, you must be sure to turn off skirt/brim, and that your startup sequence does not intersect any part of the lower part. If you use the somewhat standard sequence of drooling off the right side and then start the print, it will move diagonally from the drool zone to the next layer start, which will probably happen to cut right through your existing object. You must raise the head above the current layer height before moving to layer start. One way to do this is to insert a G1 Z move right after the drool sequence manually into the gcode.
I just checked the semantics of "stop at height" and "start at height." Somewhat surprisingly, it appears that "stop at height" means print that height, then stop, but "start at height" means "start at specified height + one layer". So "stop at 5" with .1mm layer heights will print 50 layers, and "start at 5" will start at height 5.1mm.
You should also make sure your ending gcode for the first print does not turn off the heated bed or extruder heat.
First, at the start of every print, if you have turned off the motors since the last job, it must home all axes before the next job. When it goes to home the Z axis, you must make sure that the first part of the last job will not crash into the gantry, which it will do if it is tall enough, and it is in the middle of the bed.
Secondly, when you start the second print, you must be sure to turn off skirt/brim, and that your startup sequence does not intersect any part of the lower part. If you use the somewhat standard sequence of drooling off the right side and then start the print, it will move diagonally from the drool zone to the next layer start, which will probably happen to cut right through your existing object. You must raise the head above the current layer height before moving to layer start. One way to do this is to insert a G1 Z move right after the drool sequence manually into the gcode.
I just checked the semantics of "stop at height" and "start at height." Somewhat surprisingly, it appears that "stop at height" means print that height, then stop, but "start at height" means "start at specified height + one layer". So "stop at 5" with .1mm layer heights will print 50 layers, and "start at 5" will start at height 5.1mm.
You should also make sure your ending gcode for the first print does not turn off the heated bed or extruder heat.
Re: Start/Stop printing at Height
Maybe pausing the print is a better option? I have read somewhere that there is some sort of time out that needs to be dealt with after 2 minutes if I remember right. Do you think that may work better?
Re: Start/Stop printing at Height
Pausing the print has other issues. There is no good way to specify the pause point in Simplify3D other than manually. In other hosts, you can use special gcode to pause, then resume manually. I asked Clayton from S3D and he said they do not have such a feature yet, but he would pass it along to the engineers. Also, I am not sure if Simplify3D properly tracks/ignores extrusions when paused, so if you manually extrude a few hundred mm when switching spools, does it ignore that when you resume? I don't know, you will have to experiment.
There is also the motor timeout, which you mentioned: if the motors are idle for ~2 minutes, they disable. You can turn this off or lengthen it through M codes, I believe.
You would want to pause then retract immediately, to avoid a melted spot on your print.
One suggestion would be to try using a different host, like Repetier Host or OctoPrint, which does support a pause syntax. Repetier Host uses @pause, Octoprint uses M0 I believe. You can also insert some gcode to lower the bed, maybe do some priming moves on restart, etc. I haven't tried any of this myself yet, so if you succeed please let us know.
There is also the motor timeout, which you mentioned: if the motors are idle for ~2 minutes, they disable. You can turn this off or lengthen it through M codes, I believe.
You would want to pause then retract immediately, to avoid a melted spot on your print.
One suggestion would be to try using a different host, like Repetier Host or OctoPrint, which does support a pause syntax. Repetier Host uses @pause, Octoprint uses M0 I believe. You can also insert some gcode to lower the bed, maybe do some priming moves on restart, etc. I haven't tried any of this myself yet, so if you succeed please let us know.
Re: Start/Stop printing at Height
By coincidence I just happened to have a situation where I needed to do this. I started a print and after the initial solid layers realized I had the wrong infill. I stopped the print just when it finished the solid layers, went back into S3D and resliced with the correct infill, set the start height to the exact top of the solid layers (.5mm in my case), removed the skirt, and started a new print with that g-code.
Bingo! it worked. But like jin pointed out there are gotchas- you have to make sure the model won't collide with the gantry when it homes, and there's a good chance the nozzle will collide with the part on the way to the start of the second print. You could fix that in the gcode if you want to brave it, and maybe even in the start gcode just by dropping the bed way down at the end of the wipe and figuring the main gcode will recover from that and won't hit the models in the process.
The reason I went to all the trouble was because I had just freshly prepared the bed with elmers/hairspray and didn't want the mess of removing the layers I had printed on there already.
Bingo! it worked. But like jin pointed out there are gotchas- you have to make sure the model won't collide with the gantry when it homes, and there's a good chance the nozzle will collide with the part on the way to the start of the second print. You could fix that in the gcode if you want to brave it, and maybe even in the start gcode just by dropping the bed way down at the end of the wipe and figuring the main gcode will recover from that and won't hit the models in the process.
The reason I went to all the trouble was because I had just freshly prepared the bed with elmers/hairspray and didn't want the mess of removing the layers I had printed on there already.
Re: Start/Stop printing at Height
Well I tried to do it just by pausing it and entering the codes to keep from timing out and lowering the platform. I was able to get the filament swapped out and restart the print. It repositioned itself to where it left off without issue and is still currently printing. It did however do something unusual, it printed a blob of filament when it resumed. The blob is bigger than a pea but it seemed to fall into a location where there was a hole so I am hoping I can salvage it. I dont know what caused it but the printer made an unusual noise while it was creating the blob. It happened fast enough that I couldn't identify the cause. I will take a closer look when it completes in a few minutes.
Keith
Keith
Re: Start/Stop printing at Height
Could it have been trying to retract a whole bunch to get back to where it was? And the blob was formed from heating/ooze? I'm dubious about whether S3D handles extruder repositioning properly during a pause (it should ignore all extrusions/retractions while paused by resetting the extrusion dimension).
Re: Start/Stop printing at Height
I guess you could zero the extruder yourself while in pause (G92 E0). If I tried that I'd probably have my finger on the abort though, not knowing what state S3D is expecting the extruder to be in when it restarts.
Re: Start/Stop printing at Height
The gcode that S3D puts out zeros the extruder between layers, so if you caught the pause anywhere other than the start/end of a layer, you would get some extra filament.