Seeking advice on print settings

[shurik 87]

Hi there,

While waiting for my UM2 to arrive, I'm trying to do the homework by following the forum.

Recently, some requests for prints started to pop up from my friends and colleagues, and this is where some guidance would be very helpful.

One of the examples, the most important for me so far:

The request is to print it at the maximium size. The quality should be pleasantly good to be presented to a class and the teacher, but there's probably no need to have it superbly fine.

There is the whole bunch of questions for me:

 

1. Is PLA sufficiently good for this?
   
2. How should the warping be prevented? It MUST be prevented here. Would brim do or there is a need for glue or something else?
   
3. How the overhang sections will be printed? Should some kind of support be added in every opening?
   
4. What software to use for all this? Ian kindly mentioned what he works with, but all these programs are horribly expensive. I set for Sketchup so far. What else?
   
5. In general, what settings would you recommend - temperature, bed, speed, layers, etc? Cura happily estimates the time for this to be at around 15 hours at the medium quality settings. How can this be reduced/fine-tuned without affecting the overall quality?
   

Hope, it's not too much of the noob questions. The advices here might help greatly by saving me a lot of time.

Many thanks,

Shurik

 

[SandervG 1,519]

Hi Shurik,

Allow me to answer your questions:

1: Yes. There is no reason why PLA would not be good for this purpose.

2. Since you are waiting your Ultimaker 2, heat your bed to 70/75°C and you should have zero warping.

To be sure you can add some glue that is being shipped with it, but I don't think that will be necessary.

3. The overhangs in this case are usually referred to as bridging. Considered they are relatively small you may need to use a small knife to remove 1 string, but that should be it probably.

4. Do you want to make it, or convert it in a printable file? For the latter, I would recommend Cura.

5. What colour do you want to print it in? My experience with PLA white is that it requires a slightly higher temp, so I would say Bed: 75°C , nozzle 220°, speed 50mm/s, resolution 100 micron

 

[das_enginer 2]

Hi Shurik,

If I were to try this print on my UM2;

1. PLA will work great for this.

2. I personally use Kapton tape on my bed, heated to 65 degC, and have not had any warp from any of my parts thus far; up to 150mm x 160mm footprint parts.

3. I would put support in the window openings, but I'm also fanatical about not having any sag. If the support is done right, there would only be a little sanding/filing at the top and bottom of each window.

4. For modeling software, I can't say too much as I have SolidWorks and ProEngineer availble, and use either of those. I'm not too "up" on the free CAD packages. For slicing (taking the part and turning it into code for the printer), Cura is great, but I've personally tuned my UM2 to run with KISSlicer so I have better settings control.

5. Settings for this will also depend on how you define "presentation quality". I'm quite particular, and would want a smooth surface finish, dimensional accuracy, no stringing, and minimal post-processing. To achieve this very reliably, and using the Ultimaker blue PLA that came with the machine;

- Nozzle = 225-230 degC, depending on ambient temps

- Bed = 65 degC

- Speed = 30 mm/s (50mm/s would probably work just fine too, but I haven't used it as much)

- Layers = 0.1mm

- Fan @ 95% speed at 0.6mm layer height (KISSlicer setting only)

- Retraction @ 40 mm/s, 5mm distance

Illuminarti also has a FANTASTIC writeup here: http://www.extrudable.me/2013/12/17/highqualityultimaker2/

 

[shurik 87]

Thanks a lot guys, these recommendations probably saved me a good few hours of potential frustration.

Yes, I made the thing in Sketchup, as this was the most accessible and convenient software I came across.

Sander - you say, the model is good as it is, no supports are required? It would be lovely, just wondering how the printer will print in the air <BTW - when I will be able to see this? :wink: > . I do not mind removing a string or two as long as it does not damage the overall look of the detail.

Herr Das_ENGINER - I'm just as obsessive with the overall desired quality. In this case, however, we need a compromise to achive some better printing speeds, if possible.

A question of impatience - is it possible to raise the printing speed from 50mm/s? What effect would it cause?

I follow the posts of illuminarti, he gives a lot of inspiration to try and follow his steps. Using my location, the hope is one day to be able to present mr. dizingof a fine printed result of his creations.

My deepest appreciation for the helpful advices.

 

[SandervG 1,519]

Do you mean you want to raise the temperature from 50mm/s to.. ?

During the print or while preparing in Cura?

During a print you can increase the speed if you go to Tune > Speed (100%).

It is available at the home menu when you are in the middle of a print.

100% means only what speed you set in Cura, it can be 30mm/s, 50mm/s or anything else.

If you increase it with approx 20% (80-120%) you don't really need to change anything else.

Of course it depends on the complexity of the model if increasing the speed would be wise.

If you want to increase or decrease it more, you probably also want to change the print temperature, as you want those two to be in balance. As a rule of thumb:

200°C - 30mm/s

210°C - 50mm/s

230°C - 80mm/s

 

[das_enginer 2]

Das_ENGINER - I'm just as obsessive with the overall desired quality. In this case, however, we need a compromise to achive some better printing speeds, if possible.

A question of impatience - is it possible to raise the printing speed from 50mm/s? What effect would it cause?

I follow the posts of illuminarti, he gives a lot of inspiration to try and follow his steps. Using my location, the hope is one day to be able to present mr. dizingof a fine printed result of his creations.

 

Higher speeds I've found to present 2 problems at the moment. The first is worry of under-extrusion, and the second is surface "smoothness".

I'm guessing you know this, but just in case; under-extrusion is where the printer nozzle is unable to push out the volume of plastic that the print needs fast enough. Eg. the speed of the nozzle and layer height dictates mathematically a set mm^3/sec of plastic, and if something keeps the plastic from actually coming out that fast, you'll see missed lines in the part and it may be weaker / unusable. As Sander pointed out, the easiest way to fix this is to increase the temperature of the nozzle. A hotter nozzle will allow the plastic to melt faster, and flow better. The concern with higher temperatures is that if the print head slows down significantly for smaller details vs. a fast long wall, the plastic is now too "runny" and may sag / droop / warp. Really high temperatures can degrade the plastic itself. Ideally you would print at only ~5 degC above what you absolutely need to prevent under-extrusion at a given speed, but this takes trial and error to determine which is very time consuming.

If you want a "fast" print with "decent" quality, the best I've tested thus far is:

- Nozzle = 240-245 degC, depending on ambient temps

- Bed = 65 degC

- Speed = 50 mm/s

- Layers = 0.2mm

- Fan @ 85% speed at 0.6mm layer height (KISSlicer setting only)

- Retraction @ 40 mm/s, 5mm distance

Keep in mind this isn't a guaranteed setting list. Because of the faster head speed and the double layer height, the nozzle is extruding at over 300% faster than my "high quality" settings, so there may be slight under-extrusion here and there depending on how much the fan is cooling the nozzle, how the PLA is reacting, and ambient temps. I've had ~85% success rate with these settings. Technically the Ultimakers are capable of moving the head around at much faster speeds than the 50 mm/s, but I haven't played around with it yet, and feel strongly that the UM2 is most limited by it's nozzle design such that the same extrusion speeds as seen on the UM1 will be difficult if not impossible to achieve (but that's a different discussion I'm still exploring).

The second trade-off for speed is the "smoothness" of the walls. On a 30 mm/s print, a straight wall generally looks straight and lines up with the other layers very well. The faster you go, the more likely there is some induced "wavy-ness" or "ringing" in the lines, but this is usually very minor and probably not a concern for your part.

Sorry for the novel!

 

[gr5 2,069]

The most difficult thing of this print will be warping/shrinking which can lift the corners. If you get 20mm up and the part hasn't lifted off the bed you should be good.

Sketchup is fine (I use it). You will need the STL exporter plugin - there are a few. Export in mm. You can scale the part in Cura. The worst thing about sketchup is it often gives you missing spots/holes or inner walls. Cura hates this. Look at the part today (don't wait for you UM2) in Cura. look at the part in XRAY view (icon top right corner). If there is any red these are potential problem spots. Then look at it in slice view and drag the layer up and down looking for problems particularly in the red areas. If there are problems, fix them in sketchup or you can play with the 4 checkboxes under "fix horrible" but much easier to fix a model as simple as this in sketchup.

The bridging over doors and windows don't need any support but you will wan't to lower the temperature possibly for those areas - I mean you were talking about speeding up the print which can be done by raising the temp to 240 and printing much higher speeds but 240C is bad for bridging so you can lower the speed and temp when you get near the tops of the windows/doors:

See post #17:

http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/?p=25304

 

[gr5 2,069]

Oh - and to keep the corners from lifting use the "brim" feature in cura (try it today!) and keep your bed hot 60-70C and use the glue stick that comes with your printer - at least in the corners of your model.

 

[gr5 2,069]

Also I don't recommend a > 4 hour print as your very first print with so many things that can go wrong or be loose on your printer - I would do a small version first.

 

[shurik 87]

Das_ENGINER, your "novel" is most educating, you should be proud, not sorry.

gr5 - well, you have quite a bit of the advices, exactly what I could hope to get on this forum. Of course, a small test model is waiting to start with and to play with speed/temperature settings. What do you think about the blue tape vs. glue on a full-scale? What is preferable?

Another potential problem I spotted is the floor - there is one, I see it in Cura, but not in the slicer mode where the printing animation sequence is shown like there is no floor. Why? What should be done?

On the other note, it looks like most of my dumb concerns will disappear when the printer will <ever> arrive.

 

[shurik 87]

OK, will illustrate the problem.

This is how the object is being shown:

And this is how it's being sliced:

Seems like the floor isn't going to be printed. How to get it printed?

 

[dgsharp 0]

OK, will illustrate the problem.

This is how the object is being shown:

 

And this is how it's being sliced:

 

Seems like the floor isn't going to be printed. How to get it printed?

 

I'm certainly not an expert but can you verify that on the Advanced tab under Quality / "Cut off object bottom" that the number in the box is 0? If it's a larger number than 0 then it will trim off that much from your model (useful when your model doesn't have a flat enough bottom surface to secure it to the build platform). Sorry if you looked at this already.

The only other thing I can think of is if the model were slightly canted relative to the platform -- if it were tipped up at a fraction of a degree, Cura will place it so that the lowest area (which could be a single edge or point) is touching the build platform and the rest is floating. Try enabling brim and looking at the slices for the bottom, and if it doesn't draw a brim around the whole model then this could be it. I saw this yesterday with a model someone sent me that was tilted up ever so slightly on one side. I was able to use the "Lay flat" command, it took a few seconds to process but it did the trick.

Good luck!

-Dave

 

[gr5 2,069]

Seems like the floor isn't going to be printed

 

So who needs a floor? Gosh you guys want everything

Just kidding.

It's most likely the model. Cura doesn't like internal edges. One thing you can try is when in cura instead of looking at layer view, try xray view. Anything red is a "problem".

Your model should be "manifold" (I think that is the right word). It should have no holes and no internal walls. It should be obvious what is inside and what is outside. So for example did you put a bottom on your floor if you look at it in sketchup from below?

Anyway if you don't want to fix it in sketchup you can try the various "fix horrible" settings. Usually 1 or 2 of the first 3 checkboxes fixes it. Never check both A and B. This means there are 11 different combinations. I know it's a lot to check so probably easier to fix the model in sketchup.

If after reading this and looking at it in xray view and checking the bottom you are still stumped, post the sketchup file somewhere and I'll look at it.

 

[gr5 2,069]

Another possibility: your floor is thinner than your layer height.

 

[shurik 87]

Thanks a lot guys! Although there are some red lines in X-Ray view, the "Extensive stitching" did the trick:

Hope, this will be tested anywhere soon.

 

[shurik 87]

Just thought here - we do have a pretty warm weather in general and even now in particular. These PLA things do not like the warmth, as it's mentioned in several topics.

So, what settings should be tried for ABS? Shall I opt for ABS at all? What would be the ramifications?