printing individual objects  

RE: printing individual objects

I am not sure if I understand you correctly. You mean to print one object completely and then print another one in one print job? Or you just want that each layer starts with the object in front?

You can (should) sure print all at once, what is a reason for separating them?

Separating object too far from each other is maybe not such a good idea, by the long moves you waste your time and also small amount of filament is usually extracted (or better flows down from the nozzle) and it is then left on the object.

Milos

RE: printing individual objects

I have three objects on the print bed.  I want to print one at a time completely, then move on to the next one.  The command is under the Print Settings: Output Options/Complete Individual Objects.  This saves time (30min out of 300) and the long jumps between objects, not counting the filament retractions and stringing.

One has to be careful that the extruder doesn't hit one object while printing another.  That is why I separate them to the corners.  However, the height is a problem if the bearing rods sit down on a finished object.

If you print the objects from front of the bed to the back, that can be avoided.

PruserSlicer has the command to print objects individually, but no help seeing they are arranged properly.

RE: printing individual objects

Try loading the gcode into pronterface (should also be installed with Prusa's official "software & drivers" package, at least it is on Winblows). As I recall, pronterface has a gcode preview feature.

RE: printing individual objects

OK, I got the point. Still I think that printing more objects in parallel has its benefit especially in extra time to cool down. Stringing can be avoided with print settings and the risk of hiting the printed object is quite big. 

However, it seems that PrusaSlicer does not allow to choose the printing sequence, it just checks if there is enough space between to safely print. If not, you will get the error message until you arrange it correctly. So most probably it will choose itself the sequence.

RE: printing individual objects

Milo, 

It is true that PrusaSlicer allows you to set the extruder clearance, however, you can set it at anything, so the software will let you crash objects. I note that the Y rods come to within ~25mm of the bed on the first layer.  You can set the Height to 45mm and still crash the rods.  Likewise for the XY spacing.  

I understand you have to manage possible crashes yourself, I just wish there was a way to properly preview the process before starting the printer.

RE: printing individual objects

PrusaSlicer seems to print in the order you add the objects.  Theres an existing github request to allow users to specify print order but its unknown when (or even if) that will be added.

RE: printing individual objects

Pronterface was not included in my Prusa's "software & drivers” package.  I found a Mac version and downloaded it, but can't get it to run.  When I load a .stl file it just sits there saying “slicing” an d never shows th object.  I guess I need to learn how to use it.

RE: printing individual objects

Posted by: ben.g16

Pronterface was not included in my Prusa's "software & drivers” package.  I found a Mac version and downloaded it, but can't get it to run.  When I load a .stl file it just sits there saying “slicing” an d never shows th object.  I guess I need to learn how to use it.

I was suggesting loading a gcode into pronterface, not a stl.

RE: printing individual objects

OK, it seems there are two mindsets for printing multiple objects.  One is to print them together and the other is to print them separately.  

Printing them separately brings up the problems of this thread, namely, crashing the extruder into a finished object, and the lack of information from PruserSlicer about print order.

So, I decided to look into the question a little closer and decided both views are right, but occupy different design spaces.

The argument against printing them all at once is excessive jumping back and forth between objects, possibly causing some stringing and offset alignment problems.  Jumping back and forth between scattered objects can also waste a lot of time.  Printing individual objects seems to eliminate this, but brings its own problem outlined above.

The revelation is both schemes have their place, and they don’t seem to overlap.

If the objects are small - say thumb screws, then printing them individually is best because the small structures don’t fare very well with the extruder jumping back and forth on tight dimensions.  Small things like thumb screws also don’t cause much problem with extruder collisions.

Larger objects that have significant layer print times, such as 20 seconds or greater per object, lend themselves to being printed together.  AND, packing them tightly together minimizes the wasted jumping times.  I use 2mm between boundaries.

As a test, I printed three objects with volumes approximately 20 x 30 x 30mm using both methods.  In the individual print method, I spaced them about 75mm apart going from front to back on the bed and diagonally to maximize extruder clearance.  I spent a while trying determine the print order so I could get them to print from front to back.  The print time was about 5 hrs.

Then I arranged the same objects together (2mm spacing) and printed them all at once.  Since the layer time per object was pretty long, the cool down going from one layer to the next was long, regardless of method.  

The surprise was when I eliminated the long jumps between the scattered objects in the “individual" print to the short jumps in the “together” print, the total print time actually went down to 4 1/2hrs.

So, in the future, when I print small objects (<20 sec/layer) I will use the individual method and when printing larger objects (>20 sec/layer) I will use the together method.

BTW, 20sec is not verified as the best dividing point.  That is still up for grabs.  And volume, or area footprint, may be a better measure since layer time is invisible in the design stage.

RE: printing individual objects

Did you use PrusaSlicer to print multiple as individual objects? 

I have enabled "Complete individual objects" with 2 objects at opposite corners of the bed.  No error but after slicing the preview (in PrusaSlicer and Octoprint) shows all objects printing layer by layer, instead of finishing one object and then starting the 2nd object.  Tried various things and even reverted to original settings for Print, Filament and Printer.

Do you have any advice ?

RE: printing individual objects

Actually, I have just checked how it is actually printing and individual objects are being completed first.  The preview is not showing individual completion as it's showing extrusion per layer across all sequenced objects.

RE: printing individual objects

For anyone still looking to determine print order, if you have the output option to complete individual objects turned on, you can turn on travel visibility.  There will be a thin blue line going from object to object, and the last object printed will be the one where the tool pulls up and to the left.

RE: printing individual objects

@erik-b16

How do you turn on travel visibility? I don't see the option. If it's supposed to be in the same area as turning on the option to print one object at a time, it's not there.

RE: printing individual objects

No it’s on the preview of the slice. There’s a tick box to show travel. The colour key shows the lines in thin blue. 
However if you are using 2.2.0 then you can just hit the E key on the 3D model plater view and it will bring up the labelling of the objects. They have numbers on them so you can see the order. The order is still determined by the list on the right hand tree view but you can now drag them to reorder them. 

RE: printing individual objects

@neophyl

I have three objects to print individually.  The reason is they are TPU and jumping between them is not going to work with all the stringing.

Hitting the E key shows the print order and I can arrange diagonally across the bed from corner to corner.  This ought to print since the order would be from front to back and there should be no collision with the X gantry.

However, I get the collision warning no matter what I do.  So, I deleted the center object.  Now there is one at the opposite far corners.  Still get the collision warning.  There is no way to see the travel indicator because it will not slice.

RE: printing individual objects

Can you attach your project with the 3 parts .  Save project as and then zip up the .3mf file. Need to zip it or the forum won’t accept the file. 

RE: printing individual objects

Posted by: @ben-g16

[...]  Still get the collision warning.  There is no way to see the travel indicator because it will not slice.

What is the exact warning? XY distance should be fine, but those parts look tall enough that the gantry won't clear, so it won't try to honor sequential printing.

RE: printing individual objects

@neophyl

Unfortunately, they are proprietary, so let me give simple dimensions that anyone can duplicate for testing.

#1 is 48mmØ x 47mm tall, tapering to 7mmØ at the top.

#2 is 39mmØ x 43mm tall, tapering to 7mmØ at the top.

#3 is 35mmØ x 41mm tall, tapering to 7mmØ at the top.

RE: printing individual objects

The gantry height limits what you can print sequentially. Looks like 20mm is max.