I have a model that I would like to print with a tpu pad on the bottom, PETG on top. I know that I can glue them together, but I would like to try printing it as one since PETG can bond to tpu.
I think it may be possible to slice it with my tpu in the external spool, PETG loaded in ams slot 1, set a pause at the changeover point, and manually retract the tpu. Un-pause and I would imagine it will load the PETG from the AMS, and thus use the assigned filament profile I have tuned for the PETG. The tpu tuning and PETG tuning I use are very different.
I attempted it tonight though, and I can’t get external spool printing to work at all unless I unplug the ams. I load the tpu manually before starting the print, but if I leave the ams plugged in it will cut the filament and then I get an error. I attempted to assign the tpu to external spool but something is amiss.
Is what I want to do possible with my p1s and first gen ams unit, or no?
Can you “lie” to the slicer, etc. saying you have both of the same materials? I don’t have an AMS so I do not know all of the functions. I due know they read the RFID tags in the spools so you may have to do something to fool the system.
I have printed TPU and PLA with my P1S by saying they were both TPU and adjusting the nozzle temp to be in the overlap range. I had to switch filaments manually due to no AMS.
I could certainly put a pause in and just load any filament I like, the printer wouldn’t know any different. I could manually change the nozzle temp, but between my tpu and this PETG, nozzle temp, pressure advance, volumetric flow, cooling, everything is entirely different.
Is there a way to slice it with a pause, and actually have a separate filament with the filament profile assigned after the pause and just do it all with the external spool? I think not but perhaps I just don’t know how.
I don’t typically use bambu filaments and don’t need to worry about rfid tags interfering.
I have not tried this but I did an experiment in Studio with a simple cube. I placed a primitive cube on the build plate and sliced it with TPU selected as the filament. I used the vertical slider on the right and went to layer #5. I right-clicked and selected ‘change filament’. I selected a filament in the project that was PETG and sliced again. It appears when looking at the gcode, it knows it changed to PETG. I verified it changed the temperature for layer #5 and beyond. I cannot tell if it changed the PA, etc.
It would be easy to do a quick experiment like this and see how it works.
This might be worth a look.
While PETG and TPU do fuse together well, the issue is automating the swap, otherwise you are left to handle everything manually.
Unfortunately, the automation options are limited. Dual or multi nozzle printers have this ability, single nozzle variants require significantly more fiddling.
Have you considered ways to join the parts where they interlock after each has been printed separately?
This would be very model specific and the geometry (mostly thickness) would play a part in any success.
You could use the flexibility of the TPU to let you push, squeeze and otherwise manipulate it into locking parts in the PETG part. This could also benefit from hardware like screws, but this again is design dependent as they may detract from the overall design aesthetic.
When I mean locking, I mean things as simple as a twist lock (think about how the Bambu Lab spools lock into place) and without significant effort and a choice by the person unlocking the parts, they remain locked.
Other locking techniques exist for none cylindrical connections.
The other main benefits include the speed of printing and reach, as if this is meant fir others as well as yourself, the solution requires no special techniques, knowledge, patience or risks associated with the single nozzle solution.