Perfect in PLA layer shift and steps in ABS
Hello,
When I print this 100 mm aerofoil in PLA it is usable. In ABS, which I prefer due to better toughness than PLA, the part has stepping and layer shifts. See photos. PLA part is shown in top two photos and is silver, ABS parts are white and in bottom photo. Sorry about the busy background, I was looking for a dark surface so I used the magazine.
The white ABS wing on the bottom is printed using Prusa Slic3r's "Optimum" setting as is the silver PLA part in the separate photo. The center ABS wing is "Optimum" setting with the infill speed reduced to 50 mm/s from 200 mm/s. The ABS part on the top is printed with the "Ultradetail" setting for an 8+ hour print time.
I have printed many mechanical objects on my i3MK3 in PLA, ABS, CPE and PTEG that had some problems I was able to resolve, but nothing like this aerofoil. Specifically, tall narrow thin wall parts in ABS seems to print pretty well for me, until now.
Stepping is present on both the Optimum ABS parts but not the Ultradetail one but the layer shifts are worse on the Ultradetail.
Question one - what is your analysis?
Question two - I am not able to open G-code files sliced in and exported from my one personal copy of Slic3r. How is a previously exported G-code file brought back into and opened using Slic3r? I figure that if I can re open the PLA G-code file and simply increase the heated bed and extruder temperatures then I can get ABS to print as well as PLA.
Thanks in advance,
Mike
Re: Perfect in PLA layer shift and steps in ABS
To answer your second question first, you can open a g-code file in any text editor. If you want to try that and simply change bed and nozzle temperatures without changing anything else, open the file and search for all instances of M104 (set extruder temperature), M109 (set extruder temperature and wait), M140 (set bed temperature), and M190 (set bed temperature and wait).
To answer your first question, I highly doubt that the slicer is creating the artifacts you see. In other words, taking "known-good" G-code and changing the temperature won't necessarily fix the problem. If it does, then basically it means there are some other settings in the ABS or PETG profile that need to be corrected.
Your structure is extremely tall and thin, which means that as the vane is built up from the bottom, it may be getting deflected side-to-side a bit by forces from the print head. So check the first layer adhesion to make sure it's extremely well stuck on the bed when printing in ABS or PETG. It might help to add a brim around the object to help anchor it firmly. That said, I recently printed a PETG object 18mm in diameter and 160mm tall without a brim, and it did fine with no layer shifting.
It probably would not help to use a raft, because rafts tend to be fairly frail and may be flexible.
Another alternative would be to re-orient the print so it mainly lies flat on the bed, although this will only work if the vane has a flat surface to put on the bed; if it's curved then you'd have to print it with support and it will be messy on one side. But even then, you can sand that side of it and get a better vane than what you're getting now.
Re: Perfect in PLA layer shift and steps in ABS
Thank you for your thoughful reply, when i get back i will try that. I did use a 3 layer, 3 and 5 mm wide brim on ABS parts. The part had a "crisp" break when i removed from the bed and the brim was challenging to scrape off so i don't think adhesion was the problem. I do agree that it looks like the part is getting pushed around by the extruder. Since the defects are up high away from the bed, that tells me that the part is flexing. But why is it so much worse in ABS than PLA?
Grrr....
Mike
Re: Perfect in PLA layer shift and steps in ABS
Hello,
I should change the title of this post to "How do you make cylindrical tower supports?"
Can support towers adjacent to my aerofoil be added to the STL file before slicing and printed as shown in this picture from an Ultimaker forum - https://www.3dhubs.com/talk/t/printing-tall-narrow-objects-challenge-like-with-a-stylus/7940
I am using a STL file obtained from Github. Alibre is my only CAD program and it will not import STL files.
Many thanks,
Mike
Re: Perfect in PLA layer shift and steps in ABS
Maybe try Windows 10 3DBuilder. I think it lets you import .stl and change to .obj then you can add pillar supports.
Hope that works,
Neal
Re: Perfect in PLA layer shift and steps in ABS
Google "Convert STL to STEP" and you'll see several instructions involving the use of FreeCAD. I won't say that FreeCAD is intuitively obvious, and it's definitely not a replacement for your Alibre, but it might work for you to create a file that Alibre can use.
Even though FreeCAD doesn't list "STL" as one of its supported Import formats, it actually does import an STL file.
I just followed the procedure to create a STP file of the cable-holder.stl (part of the MK3 printable parts) - and it worked. There were a couple of minor points where the instructions I was following were evidently for a different version of FreeCAD - but I was successful following the general guidance of this site: https://all3dp.com/1/7-free-stl-editors-edit-repair-stl-files/