Help needed with support structures

I printed a Darth Vader model with generating support structures. As slicer, I usedSimplify3D. As there is a bunch of features concerning support structures I picked some which I thought would be fine. Unfortunately the support is so tight that there is no chance to get it away.

I give it another try with modified setting, basically less density of support. It seems that’s not much better.

Can anyone give me a hint how to get sufficient support which is easy to remove???

Whether in Luban, Cura or Simplify3D…

I know Cura has some support settings that let you tweak how close/attached the supports are. I don’t know much about Simplify3D.

That said, I generally use a pair of needle nose pliers to gently grab the support structure near the model, then roll the pliers to the side, with the pliers touching the model. It’s a twisting motion, relative to the model, so it does a good job pulling the supports away while still giving you very fine control. It takes forever though. :-/

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Hey @FlyByWire!
These are my support settings with PETG:

Most times i generate the support myself.

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I primarily use S3D, and I’ll second the other recommendations to check the horizontal offset. I believe the default in S3D is 0.3mm, if you’re closer than that you’ll have a bad time, in my experience.

Additionally, check out tree supports in the Cura experimental settings - I haven’t played around with them as I haven’t done anything that needs them, but I understand they are ideal for models like you’re printing.

Also, I know you said you sliced with S3D, but those support structures look foreign to me. Could you post the model and your gcode, I’d like to take a look.

Finally, there’s something up with the surface of your print, but I can’t tell if it’s over or under extruded. It looks like it could be improved. Any over-extrusion will cause the supports to fuse to the model, and under extrusion is also equally bad. Maybe double check your e-steps, and print some calibration cubes where you vary S3D’s infill overlap until you get a perfect surface. I believe the default is 15%, but I ultimately settled on 21%. By 25% I was getting overextruded skin layers, and at the default of 15% it was not fully filling the top layer.

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I’ve tried out a lot concerning that print and I guess this one has been sliced with cura. I can post the gcode later on.

That is my biggest problem. Every test print I perform I really can’t tell if Z is too high, correct or to low. I know all the pictures to compare but to me it’s difficult to say if there are rims within a pattern or if this is filament that’s not pressed down enough. Furthermore, it’s different from spot to spot so even if I have a pattern that looks very well, the next one is completely different…

I tweaked a lot of things over the last weeks. Including Extruder steps, linear advance, Slicer flow… Meanwhile, I got lost somehow as I don’t really know where to start and where to end. I’m not an engineer and I can understand all that cool stuff you guys are posting partly. I’m really thankful for that but without knowing much about all that it’s hard to get all that in line.

I even have the problem with bed leveling. I am using a 5 mm aluminum plate on which I glued a printsheet. Unfortunately the inductive sensor does not work with the printsheet on the plate, so I do have do do a manual leveling. To my experience this went a lot worse than auto leveling. Trying to print some test pattern yesterday I had the problem of Z being to high front left, and to low right back.
If I find the time for that I’ll try to perform an autoleveling with just putting a aluminum foil on the printsheet, maybe that works

Oh man that brings me back to my delta printer several years ago. I was just throwing stuff at the wall and seeing what stuck. There were so many variables it was overwhelming.

I’ll do what I can to help you through this, stick with it, and hopefully on the other side when we get it all working you can look back with your new experience and knowledge and go “that was pretty straightforward”.

Check out this thread I posted about getting the machine tuned up from scratch:

I’d recommend you go through the Teaching Tech calibration settings in order and start knocking out some of these variables.

On the first layer especially this is important, and you can gauge how it’s printing through the rest of the model as well:
image
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Here’s some of my calibration cubes, hopefully you can start to recognize the signs of being over or underextruded with these:

This is the bottom, so the first layer. This was a bit underextruded because the strings of filament are still rounded and not smushed together enough in the middle:

Here’s the bottom of a better print for comparison:

So that underextruded picture, here’s the top of that. Those gaps in the corners should not be there:

This specific print was after calibrating E-Steps and with an extrusion multiplier of 1.0, and it was putting down the correct amount of filament at the perimeters. The perimeters are nicely tied together like they are supposed to be. But the skin (surface) is thinning in the middle. The cause of that was S3D’s infill overlap was too low for me. If I raised the extrusion multiplier the perimeters would be too bulgy, because they weren’t over extruded, it was just the infill and skin that was slightly under.

After changing the infill overlap, up from 15% default, to 30% (I just doubled it as a guess) this happened:

You can see the top surface of this is clearly overextruded because the nozzle is dragging through plastic where the filament had no where to go and was shoved upwards. Again, the perimeter outlines are all good, so this is just infill and skin issue, so I dropped it to 23% (I picked a number halfway between 15 and 30, so 22.5, rounded to 23) and got this:

This looks pretty good to me. After more test prints with other models I ended up settling on 21%. Clearly 15% to 21% seems like a small change, but it has big consequences.

The test cube here: XYZ 20mm Calibration Cube by iDig3Dprinting - Thingiverse. The picture shows clear underextrusion of the top layer because you can see through it.

This is the test cube I was using later on to fine tune things. It’s a fairly difficult cube to print perfectly, which is why I like it later in the process, early on I just used the Teach Tech models with simple cubes. Small, fast, uses minimal filament, and can test many things simultaneously, but on separate parts so it’s easy enough to keep all the variables separate.

Many MANY times this happened, and I’m sure it will to you too if you print this:

What ended up being the cause here is insufficient cooling, and putting a desk fan next to the printer helps. What happens is the thin wall can’t take much force (by design, it’s a test cube) and there’s overhang as the layers go up and the circle top is closing up. Without enough cooling the PLA curls up, and then the nozzle hits it on the next layer, breaking it.

OK on to bed levelling. That’s great, I’m actually shopping for an aluminum plate right now. I tested the inductive sensor with a small piece of aluminum foil and it picked it up, so thanks for the heads up. I was looking at gluing a PEI sheet also. How thick is the sheet you’re using? If it’s more than 1mm or so you could try adjusting the height of the sensor, there’s a slot and a screw on the back of the module. Just make sure there’s clearance that it doesn’t hit the bed while printing.

I’ve coated a bed in aluminum foil for levelling, that’s actually how I level my delta - I clip onto the nozzle and foil and use the nozzle’s electrical contact with the foil as a probe. Personally for this printer I was really hoping to now have to do that, which is what the aluminum buildplate is supposed to be for…

If you are going to do manual levelling, in my opinion you must have backlash compensation enabled because otherwise it’s incredibly frustrating, and also use the Luban machine control panel with a custom step size of 0.01mm. The smallest on the controller is 0.05mm which is too big in my opinion. I believe the touchscreen isn’t doing anything for calibration except sending commands to the main controller that you would talk to directly with a serial cable, so moving the Z height up and down with gcode or the control panel is Kosher as far as I know.

Something I’m working towards is using shims to flatten the plate as perfectly as possible. Hopefully auto bed levelling will become redundant at that point, and you only need the Z height offset, which there’s a firmware command to update that (M206 Z__)

Best of luck, hope you can make some more progress. Let me know how it’s going.

Brent

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Dear Brent,
thank you so much for all you help! I really appreciate that!
Coming to the extrusion multiplicator I’m stuck. I use the 25mm test cube from the teaching tech page. I measure the walls with a digital caliper. No matter what value I choose, wall thickness is always 0.45mm, it should be 0.4. I double checked to have the right settings in Simplify3D?!
E-Step calibration worked very well and is reproduceable.

The sheet I‘m using is 0.95mm. Together with the duct tape (0.013mm) close to 1 mm.
http://www.mtplus.de/Dauerdruckplatte0.html

Without the sheet the aluminum plate has been mostly recognized, with the sheet, no way. I tried to set the sensor down but then I had collisions with the build. BTW I think it‘s needed to say that it it impossible to lower the probe without unmount the cover on the right of the printhead to get access to the air Channel as this is connected with the probe.
Next thing I will try is just put a piece of aluminum foil on the sheet for autoleveling. Maybe that works?!

Backlash compensation is maybe the next thing I will have to do. The idea of using the jog in luban is great. I agree that the 0.05 mm on the controller is to rough. I didn‘t notice that there is a way over luban with better stepping.

Another thing I was wondering over today is the Z offset on the controller. Last times I used that it kept the last Input. Now it‘s on + 0.05 mm. Even when I change it before starting to print (adjust settings) or if I change it during print, next print is 0.05 mm again?!

thanks again,
Holger

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EDIT see the next post…
Here’s mine, 0.48. If you’ve set the filament diameter and you’re getting .45, that seems perfect, don’t go chasing that last .03mm, that’s so tiny.
image

I wonder if the Snapmaker buildplate itself can trigger the sensor, and that’s why it works. Interesting, I’m going to think on this.

To lower the probe within the designed limits there’s a slot on the rear of the toolhead, you don’t need to do any disassembly. See the picture just above step 3.

Yea, I keep the Z offset at 0.00, unless mid print I need to make an adjustment (has only ever happened once) and then yea, you have to manually set it back.

Take care,
Brent

Oh I just remembered something from the process, when I used his pre-sliced g-code I also got like 0.45 I think you’re fine. when it was all said and done I circled back around and sliced my own and it was much closer. I think running the pre-sliced g-code has to be taken with a grain of salt and when it comes to chasing hundredths of millimeter it’s fine. His does say it’s supposed to be 0.4 but I think it’s generally recommended that your extrusion width be slightly larger than the nozzle and I don’t really get why he says it should be 0.4 because it should smush out a bit.

I should add that linear advance has its fingers in all of these settings and after getting the basic settings close enough to have a meaningful linear advance calibration you should double check the rest of the calibrations again because it can affect them particularly extrusion width.

I’d also like to recommend that you keep a document of the settings that you choose and I also chose to keep the g code necessary to set them. I fat fingered the m503 command enough that I typed m502 on five separate occasions and factory reset all the settings.

I initially tried it that way. For me, after loosening the screw, I could hardly move up or down. Giving more force the probe suddenly tilt facing towards the nozzle. After unmount the cover I found out that this is due to the air channel is very tight connected to the ventilator. Maybe there is some tolerance in production, and in my case was more tight than it should be…?!

Now that you mention how tight that fit is I also noticed that when I disassembled my head. It’s like it’s in need of some lubrication. Maybe a tiny tiny amount of a dry lubricant would fix that but it would require disassembly unfortunately. Don’t really have any easy suggestions for that one, sorry

I set it to 0.4 manually as supposed in the manual. But you‘re right. This might be a minor issue

Finally I printed the cube with 0.75 extrusion multiplicator. No the walls are exactly 0.40-0.41 mm.
The Thing I’m wondering avout is, that first I calibrated the E steps (in my case from 221 to 249 which is about 21%) and then I reduce the flow by 25%?! On the first view this doesn’t make any sense eo me?!

Hey, i havent read all in this topic but, why did you reduce your flow at the testcube?
Did you set your extrusion width to manual 0,4 or 0,48mm?
I guess if you let it automatic in S3D it could slightly change because of different walls, infills, etc.

Hi Chris,
this was part of the “teaching tech” optimization. I set the extrusion manually to 0.4 and finaly got 0.45. With teh flow I came to 0.40-0.41.

What happens if you set your extrusion width to manually 0.5?-Do you even have to decrease your extrusion multiplier?

Haven’t tried that. To my understanding it was that if the nozzle is 0.4mm, ideally the extrusion width should be 0.4 mm although?!

For best print results, it is often recommended that your extrusion width be at least 1.2 times your nozzle width.

More reading:


The 0.4 mm is just for callibration purposes. I was thinking that if the nozzle is 0.4 mm and you set the extrusion wide to 0.4 mm on printing a single layer wall the thickness of the wall should be 0.4 mm?! If not, you adjust the multiplicator to come to the 0.4mm?!
Maybe I missinterpreted the Manual???

Sure, in theory that’s right, if the extrusion cross section was a rectangle.

It might be helpful to remember that the proper extrusion cross sectional shape is obround which can be difficult to achieve if the extrusion width is not slightly wider than the nozzle.
image

With a smaller width the extrusion will take on a more circular shape, which can disproportionately affect the calculated extrusion volume the slicer puts out, resulting in wall thickness dimensional inaccuracy.

That’s why I suggested putting this on hold once you’re within 0.03 to 0.05mm of the target value, moving on with the rest of the calibrations, and at the end when you’re quite sure the machine is well tuned up doing one last pass through with a 0.48mm extrusion width. It should be tighter than 0.03mm tolerance at that point.