I started a new print where the previous print used the same colors already loaded in the nozzles on the rack. Still, it purges every nozzles even assigning different colors for each nozzle.
I must be doing something wrong, how can the H2C not remember the previously assigned color? Is there a setting I overlooked or is this normal behaviour?
It may not be purging for color, but to clean out the old filament that had previously been heated up? As filament is heated and cooled in the nozzle it can lose some of its integrity and not print very well. I don’t know if this is because it is prone to picking up more moisture as it is heated and cooled or if there are other reasons, but I do know that if you print with filament in that state, it does not look good.
Try printing without the prime tower to remove the old filament and you will see why they do it. The old filament will have defects and not print well.
I am not saying that this is the reason for it, this is just my own guess as to why it might be done. But I am sure that it is done to ensure the highest quality for your print.
I have an X1C and recently got the H2C. I can say the amount of purge for the H2C is nearly nonexistent by comparison. Yes, it does still create small amounts of purge, but nothing compared to the X1C!
I agree with Bill, it still has to get rid of any filament in the nozzles that sits around more than a couple minutes (or less). That filament basically breaks down once heated and sitting around unused in a nozzle for any appreciable length of time after that is undesired, as Bill said you don’t want to use it. That includes nozzles sitting around waiting for another layer/color to print.
As for nozzle assignment, that’s really up to you (us, H2C users) to verify at this point. The software and printer try to do a reasonable job, in my experience, though for ultimate control there’s manual assignment. There are pending feature requests around assignment, for example to make it easier to identify which actual filament was used in which nozzle (color is almost useless… I have black in at least 6 different materials, not to mention other dark colors which look nigh indistinguishable). So far in my use it seems to remember choices between one print and the next, but I’m usually not printing with a lot of colors/materials at once so maybe I just haven’t run into it. If you could describe your process more specifically, that may help others make suggestions or troubleshoot further.
Cheers,
-Max
That makes sense. So I get that your H2C is doing the same.
I was printing a 5-color model that used orange, blue, green and black on the right nozzle (white on the left).
I then printed an other model (a different one) that used exactly the same color assignment. Black was the last color used so it was in the installed right nozzle and white was the first color to be printed so it did so with the left nozzle (which was flushed but that one does not have a chip so it’s normal). When the first color on the right (red) was to be printed, instead of picking up the red nozzle, it flushed the black and loaded the red filament from the AMS, when the blue was to be printed, it went to the rack and chose the previous red nozzle and flushed it for blue. It was the same for the remaining colors.
I can understand the flush for new clean filament but why stagger the nozzle, I think it should be better to keep same color to avoid cross bleed or even just to reduce purge time (a change in color especially from dark to light generally requires a long time which could be saved when using same color).
When I look at the nozzles in the menu after a print I can clearly see the color in each nozzle (not so clearly as it’s just the inside of the nozzle that is colored) so why not use that as a starting point for the next print?
EDIT: I moved the model a bit on the plate in BS forcing a re-slice and hit print. The nozzle colors are now assigned to the right nozzles on the rack in BS so don’t know what happened before. I have changed some of my spools in the AMS and printer was powered off between the 2 prints, don’t know if that has affected the color assignment for the print (it shouldn’t have but?).
Ah, I see what you mean now, thanks. I’m not sure I’ve compared the nozzle assignments between different models (slicer files) or that I’ve had models with the same material combos. But I agree it would be helpful and logical to re-use the same nozzles for the same colors/material as used last time, at least by default, regardless of model/file. I’m not sure it matters in terms of purging out the old material, but if I want to use a specific nozzle for a certain material, would be nice if the printer (and/or Studio) remembered that. Especially since I can’t tell which material was used per nozzle, besides by color (and I’m not disciplined enough to track that myself).
-Max
Just re-launched my print and it works as intended, selecting the right color nozzle and in the process just performed a minimal purge. All is good but don’t know why it did not work the first time. Thanks for your help.