Howto change wall thickness of support structure?

[klaus_kraemer 3]

I am so annoyed with the quality of the support structure!

 

After 4 of 6 total hours of printing the support structe has been broken off, short before the support had been needed. The dimensions of the support structure ahd been about 2 cm square. It happens so often, the the support structure breaks during a print. I cannot find a way to make the outer walls of the support structure thicker to get a more stable support tower. I'd so much to define wall thickness of the support structe the same way I can define it for the model itself.

 

Seething,

Klaus

 

 

Edited May 18, 2018 by klaus_kraemer
Picture added...

[XYZDesignPro 70]

In the Shell section of the settings you can set the wall thickness and line count of Extruder 2 to any count and thickness that you may need.  Also you might consider purchasing a 0.6 BB core for you support for thicker walls.

 

If this part is just a threaded nut, perhaps you should consider printing it laying flat?

[gr5 2,230]

I think you want to set "line width" for the second extruder.

 

Also note that PVA can absorb water and when it does it starts extruding lots of steam and the pva comes out snapping/hissing/popping and it doesn't work so well.  You can bake it back dry again on the heated bed under a towel for several hours - do a test sample fist to make sure you don't melt it and ruin it.

 

Also note that PVA sticks to glass and other PVA reasonably well but will not stick on top of PLA at all (well- it barely sometimes sticks).  So there is a feature called "horizontal expansion" that should be set to 3mm by default to help the PVA go "all the way down" to the glass.  In other words the support in this donut hole should be connected to side walls that go down to the glass.  So maybe you need to increase horizontal expansion.

[klaus_kraemer 3]

Thanks @XYZDesignPro and @gr5,

 

I'll try the possibilities in the Shell section first, before considering the 0.6 BB core.

 

Having it printed upright has been on purpose due to me wanting the surfaces of the up- and undersides being structured the same way...

Edited May 18, 2018 by klaus_kraemer

[klaus_kraemer 3]

2 hours ago, XYZDesignPro said:

In the Shell section of the settings you can set the wall thickness and line count of Extruder 2 to any count and thickness that you may need.  Also you might consider purchasing a 0.6 BB core for you support for thicker walls.

 

If this part is just a threaded nut, perhaps you should consider printing it laying flat?

 

I've been quite hopeful and even switched languages in CURA to be sure to use Shell section.

 

As you can see the modification of "Wall Thickness" / "Wall Line Count" does not affect the support structure. ?

The support structure remains only 2 lines wide, instead of 6...

Edited May 18, 2018 by klaus_kraemer
Orthography...

[klaus_kraemer 3]

1 hour ago, gr5 said:

I think you want to set "line width" for the second extruder.

 

Also note that PVA can absorb water and when it does it starts extruding lots of steam and the pva comes out snapping/hissing/popping and it doesn't work so well.  You can bake it back dry again on the heated bed under a towel for several hours - do a test sample fist to make sure you don't melt it and ruin it.

 

Also note that PVA sticks to glass and other PVA reasonably well but will not stick on top of PLA at all (well- it barely sometimes sticks).  So there is a feature called "horizontal expansion" that should be set to 3mm by default to help the PVA go "all the way down" to the glass.  In other words the support in this donut hole should be connected to side walls that go down to the glass.  So maybe you need to increase horizontal expansion.

 

As you can see in the thread's opening image, the PVA support structure broke away from itself. its base has been still well connected to the PLA...

[gr5 2,230]

Well to answer your original question:  "line width".  Select the second extruder near the top and change "line width".  0.5mm is pretty safe with a 0.4mm core.

[gr5 2,230]

Okay well, after reading what you posted over in the other topic and re-reading this you have lots of ways to strengthen the structure.

 

Line width and Horizontal expansion really will make the most difference but there are many other parameters to make it thicker/stronger.  To make something vertical more resistant to being bent and then breaking in half you only need to make it slightly wider to make it much stronger.

 

"support wall count" is probably what you have been asking about.  You can set this to 2 for example and you will have double walls around your support structure made from support.  For all of these make sure you select the second core in the top right corner of cura.

 

Look at all the other support features - you can change support density, support pattern and a few dozen other parameters.

 

The reason you probably did not get very good answers right away is that I've just never seen this particular problem - my pva support doesn't tend to break off like that.  Never seen that.  Not sure what's going on.

[kmanstudios 1,120]

One thing I can tell you about the first pic with the wonky support printing and stringiness; it looks like a lot of moisture in it or sever underextrusion. A good support print using the UM PVA will look glascene. This pic shows what a pristine PVA should look like. The stringiness is because of printing an unfamiliar material without priming tower. Most of it gets trapped in the PVA and creates no issues with the removal process. UM PVA is also more brittle than other brands and can be easy to knock over if too long and thin. See right side of image. You can increase the support horizontal expansion (In support settings) you can use towers (In support structure) and you can also use Conical support (In experimental).

 

I also seem to have a completely different experience in how PVA sticks to PLA. I usually do not have issues. It is rare that I do. It is not perfect, but highly reliable in my experience. This goes for UM PVA and 3rd Party PVA. The support structure on the image is actually built on a PLA part of the lower print. This is UM PVA.

For this print (Below), I made a PLA structure to ease the use of expensive PVA. The scaffolding I built did not need to look good, just support a small distance from scaffold to model. You can also see the glascene appearance of the PVA. This is UM PVA and without priming tower,

Again, the scaffold did not need to look pretty. The model Printed sweet though...no clean up other than getting the PVA off. I call the UM PVA 'Alien Snot' when I am removing it.

This print (Below) is using Matterhackers PVA and a ton of PVA on PLA. Model is very concave as you will see in the picture after this. Even though not glascene, it is translucent and not all broken up and stringy like your first image. The strings are, again, because I do not use a print tower. This thing pretty much filled the build volume.

This is the finished model so that you can see how deep the concave area is where it had to print PVA on PLA.

And here, you can see the difference between humid PVA and fresh PVA. You can see how much more solid the fresh, no moisture, PVA looks while the humidity damaged PVA gets webby and not so solid. This will be for all PVA materials I have used.

Hope this helps. ?

 

Edited May 19, 2018 by kmanstudios

[klaus_kraemer 3]

Ok, I have to say my PVA is 5 months old now and probably has accumulated a good portion of moisture. I'am waiting for a dryer/suspender combo getting delivered sometime next week. Especially your new/old comparison is quite enlightening.

 

Still many of the problems you have mentioned could be mostly resolved by a sturdier support structure. What is wrong with thicker walls instead of expanding the structure horizontally to where is does not belong and takes lots of additional time and material? I have mostly successfull experimented with denser infills, but then removal and dissolving becomes tedious.

 

As an engineer I am looking to solve problems, not to look, how I can makeshift around them. So whats the real problem with a thicker wall? Why not use the wall thickness of the chosen extruder?

 

You mention PVA is quite expensive - all the more reason to look for a material saving solution Expanding horizontally is paid for in the third power as a product of X*Y*Z in the worst case. Not the kind of solution I'd look for. And sturdier walls would even improve the usage of older material. Another money saver.

 

I don't get why this problem is circled around and around but not uprooted.

[kmanstudios 1,120]

22 minutes ago, klaus_kraemer said:

all the more reason to look for a material saving solution

1. Have you tried to see the difference? Slice each way and see which uses more time and filament.

 

14 minutes ago, klaus_kraemer said:

Expanding horizontally is paid for in the third power as a product of X*Y*Z in the worst case

2. With Crapmandu filament, old and moisturized, the advantage of horizontal expansion is that it would bridge further out on the buildplate and not depend on skinny support on just PLA would be much stronger. Your example also misses the fact that your support is now spongy and stringy.

 

24 minutes ago, klaus_kraemer said:

So whats the real problem with a thicker wall?

 

3. Skinny is skinny where as a spread load (wide support) will be much stronger, otherwise the Eiffel Tower would be solid and not cross-sectioned as it is. Engineer or not, experience has taught me this. That is why I suggested playing with conical support or towers. You also have to consider that the support starts out spread and sparse and then gradually grows together as it gets to the support bed itself. Take a look at your slicing in the layers if you doubt this. As an engineer I am surprised that you do not connect the dots on solid can be more prone to failure than strands or cross support.

 

24 minutes ago, klaus_kraemer said:

Why not use the wall thickness of the chosen extruder?

4. You will run out of thickness on chosen nozzles sizes.

 

14 minutes ago, klaus_kraemer said:

all the more reason to look for a material saving solution

5. What part of me building a scaffold for the Dino so that I did not use so much PVA did you miss?

 

7 minutes ago, klaus_kraemer said:

As an engineer I am looking to solve problems, not to look, how I can makeshift around them.

6. How is horizontal expansion the same as a makeshift? It works, your theories so far have not.

 

Sooooo......you came here for help, I offered my experience...Not a degree of theories. Take it, leave it, find a gazillion reasons to not do it. I really am not interested in anything but offering experience. And, by the way, I have a strange habit of getting things to work that others say 'nay' on. Why? Because I am not shackled. this has more to do with the Asperger's than anything. They say we think outside the box...well, actually, we do not know there is a box.

 

Sorry if this sounds harsh, but I have a real problem with people whipping their degrees around like it solves everything. It is a good thing to have, but it is not the end all and be all to everything. If it was, you would have this solved by now. I will be happy to help now and in the future, but not to argue these things based on that type of point of view, especially when you overlooked a few, very obvious points I did make prior or be looked down upon because you assume your degree answer's things that I did not. I am offering experience, nothing more.

 

And, by the way, I personally know a few of the incredibly bright people that have degrees here and none of them has ever whipped out the "I have a degree" argument on anybody.

 

[gr5 2,230]

14 hours ago, gr5 said:

"support wall count" is probably what you have been asking about.  You can set this to 2 for example and you will have double walls around your support structure made from support.  For all of these make sure you select the second core in the top right corner of cura.

Did you play with this?  Is this what you have been asking about all along?  Is this the exact feature you have been asking for?

[gr5 2,230]

You don't need a fancy drier to dry your filament as you can use your printer (if it's not busy of course - if it's busy then it's cheaper to buy a drier than to buy a second printer obviously).

 

I put filament on the glass and cover with a towel.  heat it up and leave it like that for many hours.  I have had to dry ninjaflex and nylon but not pva yet so I'm not sure what temperature pva gets soft at (I think maybe around 80C) so you would have to test a small piece first at a few temps to find the highest safe temp (it dries MUCH faster at 80C than 60C I'm sure but if you melt it all into one blob it's ruined).

[klaus_kraemer 3]

13 hours ago, kmanstudios said:

1. Have you tried to see the difference? Slice each way and see which uses more time and filament.

 

Oh yes, I did!

 

13 hours ago, kmanstudios said:

2. With Crapmandu filament, old and moisturized, the advantage of horizontal expansion is that it would bridge further out on the buildplate and not depend on skinny support on just PLA would be much stronger. Your example also misses the fact that your support is now spongy and stringy.

 

You are right, in this special case horizontal expansion should be helpful, but there are forms like cylinders where horizontal expansion simply leads to unnecessary support structures not even connected to the "useful" support structure.

 

13 hours ago, kmanstudios said:

3. Skinny is skinny where as a spread load (wide support) will be much stronger, otherwise the Eiffel Tower would be solid and not cross-sectioned as it is. Engineer or not, experience has taught me this. That is why I suggested playing with conical support or towers. You also have to consider that the support starts out spread and sparse and then gradually grows together as it gets to the support bed itself. Take a look at your slicing in the layers if you doubt this. As an engineer I am surprised that you do not connect the dots on solid can be more prone to failure than strands or cross support.

 

I dont know what you see in the original picture, but  won't you expect that an outer support wall wall built of 2 or 3 lines should increase the probability of layers still connecting, even with using Crapmandu (love this term!)? Btw. I sure know about mechanics but they fail if the struts are broken... 

 

I'm sure increasing Support Density, Support Line Distance is also a way to go... But there is still the fragile outer wall consisting of only one line...

 

Quote

 

4. You will run out of thickness on chosen nozzles sizes.

 

Maybe my english is poor, but I don't get the meaning here. I think that is what I ask for: Three lines with a 0.4 mm nozzle should add up to more wall thickness, shouldn't it?

 

Quote

 

5. What part of me building a scaffold for the Dino so that I did not use so much PVA did you miss?

 

I am not talking about building a scaffold (I appreciate, what you have achieved, anyway) - I am talking about CURA's support structures. I am well aware, that I could solve the prolem with a custom built support scaffold/structure.

 

Quote

 

6. How is horizontal expansion the same as a makeshift? It works, your theories so far have not.

 

Never mentioned horizontal expansion as a makeshift, but the line width parameter...

 

Quote

Sorry if this sounds harsh, but I have a real problem with people whipping their degrees around like it solves everything. It is a good thing to have, but it is not the end all and be all to everything. If it was, you would have this solved by now. I will be happy to help now and in the future, but not to argue these things based on that type of point of view, especially when you overlooked a few, very obvious points I did make prior or be looked down upon because you assume your degree answer's things that I did not. I am offering experience, nothing more.

 

And, by the way, I personally know a few of the incredibly bright people that have degrees here and none of them has ever whipped out the "I have a degree" argument on anybody.

 

 

I mostly concur with your opinion, I simply intended to convey I'm not unfamiliar with mechanics. And even Msr. Gustave Eiffel had to use sturdier struts for the corner supports of his ingenious tower...

 

Hope we are good again! ?

 

Edited May 20, 2018 by klaus_kraemer

[klaus_kraemer 3]

3 hours ago, gr5 said:

You don't need a fancy drier to dry your filament as you can use your printer (if it's not busy of course - if it's busy then it's cheaper to buy a drier than to buy a second printer obviously).

 

I put filament on the glass and cover with a towel.  heat it up and leave it like that for many hours.  I have had to dry ninjaflex and nylon but not pva yet so I'm not sure what temperature pva gets soft at (I think maybe around 80C) so you would have to test a small piece first at a few temps to find the highest safe temp (it dries MUCH faster at 80C than 60C I'm sure but if you melt it all into one blob it's ruined).

 

Thanks for the money saving advice. I'm kind of a tool freak, so I've decided on purchasing such a thing. In comparison to the price of an UM3 the costs are quite reasonable...

[klaus_kraemer 3]

4 hours ago, gr5 said:

"support wall count" is probably what you have been asking about.  You can set this to 2 for example and you will have double walls around your support structure made from support.  For all of these make sure you select the second core in the top right corner of cura.

 

Did you play with this?  Is this what you have been asking about all along?  Is this the exact feature you have been asking for?

 

Are you referring to the parameter in the EXPERIMENTAL section under "Tree Support": "Tree Suport Wall Line Count"?  Couldn't find a "Support Wall Count" parameter...

Edited May 20, 2018 by klaus_kraemer

[kmanstudios 1,120]

5 minutes ago, klaus_kraemer said:

Three lines with a 0.4 mm nozzle should add up to more wall thickness, shouldn't it?

I had read that as taking a nozzle with say, 0.4 width and telling the line width to be 0.8 or some other larger number.

 

6 minutes ago, klaus_kraemer said:

Never mentioned horizontal expansion as a makeshift, but the line width parameter

Now I am confused (Not hard to do) But no worries on this, I think you are beginning to suss this out a bit.

 

7 minutes ago, klaus_kraemer said:

I am not talking about building a scaffold (I appreciate, what you have achieved, anyway) - I am talking about CURA's support structures.

I think something is missing here.....If I printed the dino with no scaffolding (PLA) it would have taken about 2 inches of PLA to reach the buildplate. With the PLA scaffold, it only had to go about half an inch. That is a lot of PVA saved.

 

I have played with the support structures a lot. I mean twiddled just about every setting available. I rarely use more than 20% - 25% support. Layer adhesion is your biggest issue with your current PVA as I see it.

 

Something went wonky in the sentence below as it would not let me type after the tag......I hope that does not make it difficult to understand.

 

Which makes me glad  has replied with his temps and heating method. @gr5

 

12 minutes ago, klaus_kraemer said:

Hope we are good again! ?

 

Of course. As I said, I will always help. This is odd stuff. And it is more than just structure. And, while Eiffel had to use thicker supports at the base, my point was that nobody thought his thin, triangulated structures would be possible at such huge heights and loads. All thoughts up to that time were about solid walls and making them thicker and thicker and thicker for taller buildings.

 

 

[peggyb 171]

Support Wall Count does not exist, only in the tree support, but that is probably not what you are looking for.

Don't think that it will make it into the support settings because the it normally works with one wall... if not, the problem lies elsewhere...

and if the layers don't connect now, they probably will not connect with multiple walls as well...

I hope that drying the filament or try some fresh solves your problem.

[kmanstudios 1,120]

26 minutes ago, peggyb said:

I hope that drying the filament or try some fresh solves your problem.

I think that is the biggest issue all around.