Hello!
I tried your answer but that wasn't the solution. I appreciate the suggestion because it made me really look at the support options and I am happy to report that I found the answer to my first question during that deep dive:
Use Towers is the setting that controls those structures.
I am still curious about the second part, getting a clean and attractive interface surface between supports and parts.
"I am still curious about the second part, getting a clean and attractive interface surface between supports and parts."
It isn't easy. Sometimes it's a matter of the air gap you leave between the top of the support and the first layer of the print. Sometimes it's a matter of the Roof Interface Density. The problem is as @gr5 points out, if the support is the same material as the print then it wants to bond together. A sharp exacto knife is your friend as well as a set of pics to get the support out of tight places.
If you zoom in on the second photo you see that there are definite gaps between the lines of extrusion. You are under-extruding there and that will always leave a poor finish above the support (maybe gr5 can address that). There already isn't any "squish" for that first layer and shorting yourself on the amount of material extruded will make that first layer of Roof look very stringy.
For that part I would take a good close look at printing it with the "gear teeth" face on the build plate. Because the gear teeth have a piece that is discontinuous and starts all by its lonesome over the support it will be difficult to get a nice finish printing that portion vertically.
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For 99% of my prints I'm able to design them so that there is at least one orientation where I don't need any support. For most of the rest I use a dual head printer with water dissolvable PVA filament. Before I had dual head printers I would design the support in CAD right into the model so that it was functional, strong, and easy (as possible) to remove.
Or design it so that the "ugly" side isn't visible when the part is in use.
If you think of this part as a chair with very little back support, print it legs down. Then it can bridge across and connect the legs at the "seat" area, then change the design of the "back" to have a longer diagonal section so nothing needs support there either.
Now you don't need any support and the ugliest area (under the seat where it did bridging) is hopefully hidden with normal use of this part.
Unfortunately this is for an open lab setting, where I have no control over the parts design. I can only control the orientation of the parts to the build plate. This problem is only recently developed. My prints were better when I was using Cura 4.8. Currently we don't use the PVA support for a number of reasons, one being that we haven't gotten good results with it, but that is a separate post once I get our regular profiles solved.
It's interesting that you mentioned under extrusion as a possible cause. What would be the solution? I don't see a setting for extrusion after support material.
I have gone ahead and attached the 3MF file so you can look over it, I am using the default Cura settings (to the best of my knowledge).
Google won't let me download that file ("...is dangerous and Google Chrome has blocked it").
I don't know the Ultimaker printers so @gr5 or one of the others will address the under-extrusion.
Hum, I don't know what the download issue, I can download it between my work and personal laptop just fine.
I will wait for an answer while I tweak settings and press buttons.
Ok today it worked.
I looked at it. Since you have a dual extruder machine do you have PVA loaded in Extruder 2? That would make this pretty easy. Since I have a single extruder I went with gear teeth down on the plate and Tree supports. There is a bit of PLA left on a roll so I'm using it for a print of your part. We'll see. I'm a bit concerned about the radius on the top. It didn't seem to want any support.
If this were mine though I think I would have provided for a glue joint. A couple of locating holes suitable for filament to be glued in and it would locate the two pieces correctly. The "L" bracket nor the gear rack would require support.
Hi @UALib3D,
You've got lots of good advice here -from Greg and gr5..
So maybe this approach, thou different, could be considered.. 🙂
I've got an UM S3, so using this printers core 2 need to be considered to really be needed for "this" print.
If you can use the number one core for the hole print, it will print faster and be more efficient.
I'm using Cura 4.10.0.
I did a few changes to your project file, like this;
1) Orientation of the model on the print bed.
2) Deselected the core 2, in order to let core 1 also print the support (the core 2 shall stay in the in the printer).
3) Changed the combing from "all" to "not in skin". (Avoiding "visible" lines in print).
4) Support placement from "everywhere" to "only touching build plate".
5) Changed "build plate adhesion" from "brim" to "skirt". (I do not need brim, -and it create extra work to remove)
Nothing else changed in the project file.
Here is the changed file:
UM3_257876567_Supporttest_mod.3mf
Here's how it looks on the bed.:
Here it is, print time 1 hour and 27 minutes.
This is just the way I would do it, -but think Greg's way of doing this might be faster.
I'll think you have some options now..
Good luck.
Thanks
Torgeir
1
Since we are beating this poor model to death...this would be my preference. The PLA I have left is old, brittle, silky, and the layer adhesion is poor. My first attempt fell apart when I removed the support. It looked good though! Print time for this one is 45 minutes and the L bracket won't suffer from delamination of the layers.
Between the 4 of us we have considerably more time into it than it would take to print. I won't bother to include a part file since the holes are 2.2mm for 1.75 filament and you have an Ultimaker so you would need 3mm holes which won't fit.
And here it is. Locating pins installed and then the final assembly.
Edited by GregValiant
1
This is all very helpful information, and I really appreciate taking the time to even print a sample!
Unfortunately I don't have any say over the model and can't make modification to it. My job is just to slice jobs and press buttons. We currently don't use PVA supports because of various reasons, so it's all single extruder work for this piece. Plus we get a lot of requests for ABS, and you can't use PVA with that, so if I can find the general recipe for settings for clean supports that would be a boon.
Torgeir:
1) Initially I had it supported that way Greg did, but without the tree supports. The issue is that I know I was have ugly layer lines and say trying to minimize them by putting them on the thin edges. I am printing a test print right now with Greg's orientation and we'll check it's surface finish.
2) I have support material as extruder 1, so no need to disable the second print core
3) Great tip about the combing, I will have to look into that for future prints.
4) I have used that feature in the past but couldn't on this print with the orientation I selected. I think you can see the results of not using supports in the gear teeth.
5) I also use skirt most of the time, but brim is the default and I didn't want to mess with too much for my sample. We also have ambient temperature issue where I work.
Do you have any problems with your default surface finish on your supports on your UM3? I would love to see some of your prints to compare and contrast!
Greg:
My kingdom for the ability to modify the files. Unfortunately we don't have the bandwidth to do those corrections, design via email is a nightmare if you've never tried it. I tried my hand at a redesign, just to practice, and I did a similar split but I chose a half lap joint.
My service is concerned with speed of print and easy of customer interaction, they want folks to be excited to 3D print stuff. We do have a separate department that I can refer folks to but if I can dial in our settings, that would go a long way. Especially since the other department refers back to us for print profiles.
I deeply appreciate the work you've put into brain storming solutions, none the less.
Here is the last piece I printed, using Torgeir's suggestions, it's pretty good and I wonder how it compares to your own prints.
@Torgeir and @gr5 are the Ultimaker gurus. I'm more of a "quick and dirty" sorta guy. I think all of us learn by taking cracks at other peoples printing issues.
I can understand the customer wanting to go with ABS (or PETG?). On that part though, I guess it would depend on how it is being stressed. One thing I liked about the "L" bracket idea is that it minimizes layer failure. It's only a 3mm cross section and I broke two of them getting the support off (admittedly the PLA was not good). The designer was concerned as well as evidenced by the outside fillet on the 90° bend of the "L". That inner sharp corner still looks like a problem.
Good Luck.
58 minutes ago, UALib3D said:Plus we get a lot of requests for ABS,
Consider using Ultimaker's "breakaway" material. It works great with ABS and leaves a nice surface behind.
I really hate ABS. It's weaker. It's harder to print. It looks worse. And it stinks. It really stinks bad. The only thing where ABS beats PLA is that it is a higher temp material but... there are so many other choices of materials! If all you care about is higher temp, well it depends what the working temp will be, but perhaps PETG or nGen can handle the temps your customers need and those are stronger and come out better.
I am actually most comfortable with ABS, before we got Ultimakers we only used ABS. Historically PETG has been one of the worst materials for us to use. It strings terribly and the supports are worse, being very difficult to remove. I almost have a phobia of it at this point.
I will look into the breakaway material.
And I will keep practicing for good support interface.
31 minutes ago, UALib3D said:I almost have a phobia of it at this point.
I feel the same way, I have no luck with PETG, but I get great results with ABS, especially with UM ABS which prints great without any problems.
On 7/9/2021 at 3:50 AM, UALib3D said:Torgeir:
1) Initially I had it supported that way Greg did, but without the tree supports. The issue is that I know I was have ugly layer lines and say trying to minimize them by putting them on the thin edges. I am printing a test print right now with Greg's orientation and we'll check it's surface finish.
2) I have support material as extruder 1, so no need to disable the second print core
3) Great tip about the combing, I will have to look into that for future prints.
4) I have used that feature in the past but couldn't on this print with the orientation I selected. I think you can see the results of not using supports in the gear teeth.
5) I also use skirt most of the time, but brim is the default and I didn't want to mess with too much for my sample. We also have ambient temperature issue where I work.
Do you have any problems with your default surface finish on your supports on your UM3? I would love to see some of your prints to compare and contrast!
Greg:
My kingdom for the ability to modify the files. Unfortunately we don't have the bandwidth to do those corrections, design via email is a nightmare if you've never tried it. I tried my hand at a redesign, just to practice, and I did a similar split but I chose a half lap joint.
My service is concerned with speed of print and easy of customer interaction, they want folks to be excited to 3D print stuff. We do have a separate department that I can refer folks to but if I can dial in our settings, that would go a long way. Especially since the other department refers back to us for print profiles.
I deeply appreciate the work you've put into brain storming solutions, none the less.
Here is the last piece I printed, using Torgeir's suggestions, it's pretty good and I wonder how it compares to your own prints.
Hi @UALib3D,
I've just printed your model using Cura 4.10.0 and Arachne engine beta.
Printed it with black TPLA as it (black color) have better emission than any other color.
As I've an UMS3, I used same print quality profile (corrected with your setting and those I've added).
Made some pictures of the two prints in daylight for better details..
The first two pictures is just finished printing with Cura 4.10.0 :
In this two pictures above you can see the boundary between the support and the model.
The support just snap easily off by using hand, so no tools needed.
Here you'll see the acceleration/deceleration by changing the object angle in this daylight, quite as normal, but you cannot feel this with your finger nail..
Yet another angle to see the upper surface.
Here you see that the support side could be better by reducing the distance say -from 0.3 to 0.25 mm, however this can often led to some extra job to remove a little support remains. So a little testing may pay off.
(As you see, it looks rough, but nothing is loose or protruding from this surface.)
In the next pictures there is the used support filament on the weight, -this as I've reduced the support in Arachne Beta just to show how this can reduce printing time for any slicer.
Note that the "Preview function" in Cura is a real good tool for checking the support pattern, -if that the support of critical parts in the object have the needed support.
Also reduced the "initial layer horizontal expansion" by "-0.4 mm" in order to avoid "the elephant feet".
Arachne Beta is much more accurate and better handling the infill due to much better line width control.
So it's much better in so many ways, -but it's still an experimental slicer as we often hear.
You mentioned problem with the ambient temperature, how(?) -to high to low, or variation?
Thanks
Torgeir
3
Torgeir,
That is some very thorough documentation! I am using Ulti Cura 4.10 for my slicing and it looks like you and I are getting very similar results on our finish. So, aside from the few parameters you mentioned to tweak, that seems to be about that I should be expecting from same filament supports. Break away filament was mentioned, I might get a mini spool and experiment with that.
The ambient temperature variance is, predictably, variable. I work in a storage room in the build of the building and the HVAC for my space is directly effected by the demands of the building. Being that this is a library they often keep it aimed at the high 70s, it's not a joke that female office workers often bring sweaters in during the middle of our very hot summer due to the AC in the building. I was lucky enough to be able to move the printing racks out of the way of the vents. We have a new dedicated space for the printers, with the intent to show them off to the public, so I will have to run new tests since their new location invalidated my old results. I will let you know when they are done later this week. I have a big project planned to gather a lot of data, it'll be fun!
Hi @UALib3D,
Thanks for the feedback.
"It's not a joke",.. -I can testify this is so true.. 🙂
I'm using a transparent light plastic box when i order to avoid cold draft going into the printer.
It's not an elegant solution, but it's very practical.
One of my son's made four support holders to keep the edges of the box on the outside of the printers top.
Here is a picture of this setup, installed on my UM2E+:
Good luck.
Torgeir
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gr5 2,170
If you have a dual printer, that feature is very useful but if your supports are the same material you are printing - not so much. I'm guessing it's this one: support horizontal expansion. Set that to zero. If not then maybe post your project file here so we can look at all your settings. Do "file" "save project...". It will include your model in the project file and your printer and your profile and your overrides.
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