How to minimize overhangs when model has bridges?

[earaujo 0]

In this print of an e-NABLE Raptor Reloaded Hand, you can see overhangs in the gauntlet piece. Any comment on what can be changed on the CURA/Ultimaker2 settings we are using to improve this printout? Photos of the printout and the settings are shown below. Thank you very much.

[earaujo 0]

Now I know how to add photos to this forum. Sorry.

Edited December 4, 2015 by Guest

[gr5 2,170]

Now that you are activated you should be able to upload photos

[gr5 2,170]

Those bridging errors are very minor - I recommend not trying to print with perfect bridging as it involves unnecessary changes. e.g. printing slower at start of bridge so "thread" doesn't snap. Or thicker layers.

But those are normal - I would just cut them off with a razor or use a butane torch to make them shrink to invisibility with a quick pass over with flame. Or a candle. But razor is probably easiest into that tight area if you don't have a really nice butane torch.

Really those are fine for the raptor hand.

and the ones underneath - that would touch the back of your hand - those are fine also as they will be covered with velcro when it's all put together.

[neotko 1,417]

You could extrude the srf area to bridge and add it as a support. Don't know if I explain myself. But since beta cura allows setting for each object I would jusr make a separated underbridge object and set it 'with supports' (only that object). Don't know if cura beta don't mess with positioning but could work...

[earaujo 0]

Thank you gr5 and neotko for the fast reply. My son and I are e-NABLE volunteers and my son will start an e-NABLE club at his school as his 8th grade community service project. We are currently learning how to set the Ultimaker2 to print a "good" hand. I was in search of ways of improving the quality of the printout. With our current settings we are able to print a Raptor Reloaded, 105% scale, in ~17h. The model was split into 3 files (~6h, ~6h, ~4.5h), since schools don't like printouts to go overnight.

I understand your comments neotko, but I don't want to deal with a beta software version right now. I'll cut the extra threads and/or try to smooth the area with my soldering iron station, like gr5 suggested. Thank you again.

[gr5 2,170]

I have printed about 7 enable hands now.  I recommend brim feature to keep things sticking well to the bed while printing although then you have to cut it off after.  But it's worth it I think.

I recommend going .2mm layers as it still looks nice at .2mm layers and it prints faster but slowing down the head to about 40mm/sec.  You don't want to go over about 5 cubic mm/sec (you can see this number by hovering over the speed or hovering over the layer height).

The enable hand is close to the easiest model you will ever print.  The trickiest parts are the fingers if you include the fingernail option as the overhang is pretty severe.

For cleanup this is my favorite tool:

http://www.amazon.com/BBQbuy-Pencil-Welding-Soldering-Lighter/dp/B007A9YSPW/ref=sr_1_5?ie=UTF8&qid=1446666104&sr=8-5&keywords=butane+torch

But make sure you also buy this:

http://www.amazon.com/Zippo-Butane-Fuel-165gm/dp/B0176A4MKA/ref=pd_sim_469_3?ie=UTF8&dpID=31B-z13uNcL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=0HK207DWXQTXFV5YCHXK

Total cost < $20.

Edited November 4, 2015 by Guest

[earaujo 0]

Thank you very much gr5. We'll try the new settings. We are finishing hand number 6 right now. We have sent our first two hands to the "1000 Hands by October" program and now we are sending an assembled hand to e-NABLE for approval. The other hands will be used to start the school club and to engage other local schools to start their own clubs.

We have not tried the fingernail option yet, but we will, in case a child prefers a hand with fingernails. And the torch seems to be a nice tool to have. Thanks again.

[gr5 2,170]

I hope you are printing at different scalings and left and right hands. Typically they want from 100% to 140%.

[earaujo 0]

Yes, we are (two pairs of 120% right and left, and two pairs of 105% right and left so far). We have printed two hands with ColorFabb PLA magenta and intense green, but their gauntlets came out with under extrusion issues and one broke after I applied a small closing pressure. I'm back printing with Unimaker PLA white now. Let's see what happens. The nozzle seems not to be clogged. The filament seemed not to be tightly coiled or tangled. It may be the feeder or simply the ColorFabb PLA filament needs different settings.

[gr5 2,170]

White PLA is less viscous for some reason. This makes it tougher on overhangs but easier to print fast. You were probably just printing green and magenta too fast - those typically come out nicer than white. Also white is not the best color for fingers because it shows dirt well - gets into those layer-height-cracks after a month of use.

Anyway PLA is more viscous at lower temps and less viscous at higher temps - like toothpaste at 190C and like honey at 240C. If you print fast you need to print hot.

Here are my recommended top speeds for .2mm layers (twice as fast for .1mm layers):

20mm/sec at 200C

30mm/sec at 210C

40mm/sec at 225C

50mm/sec at 240C

The printer can do double these speeds but with huge difficulty and usually with a loss in part quality due to underextrusion. Different colors print best at quite different temperatures and due to imperfect temp sensors, some printers print 10C cool so use these values as an initial starting guideline and if you are still underextruding try raising the temp. But don't go over 240C with PLA.

[earaujo 0]

Thank you gr5 for all the info. We have not changed the settings yet. It is still the settings I have initially posted in this thread. I do hear the feeder clicking from time to time and sometimes I do see less material coming out of the nozzle after hearing a click. So, I'll check

the feeder only to be sure. I'm adding some photos here.

The objective is to get experience with 3D printing and come up with an initial settings for the several combinations filament-Ultimaker2 that we may use for the Raptor Reloaded Hand. I have searched the web and several forums, but I was unable to get this information clearly stated. The info is in pieces here and there with no photos to really compare the settings. Initially we will be experimenting with PLA filament only, but later on I'd like to try ABS.

We only got white PLA because of the Star Wars fever.

The settings are as before, and these are the results of several prints/hands:

Thank you again.

Edited December 4, 2015 by Guest

[earaujo 0]

The settings are as before:

Edited December 4, 2015 by Guest

[fergazz 60]

For cleanup this is my favorite tool:

http://www.amazon.com/BBQbuy-Pencil-Welding-Soldering-Lighter/dp/B007A9YSPW/ref=sr_1_5?ie=UTF8&qid=1446666104&sr=8-5&keywords=butane+torch

Hi gr5! What kind of cleanup you can do with this... It`s like a heat gun? Have you ever post anything explaining it? Cheers and peace out V

[fergazz 60]

I will try as soon as possible a friction welding technique with my Dremel rotary tool, that`s what I have in hands right now, but I`m very curious about this tool above.

[gr5 2,170]

Hi gr5! What kind of cleanup you can do with this... It`s like a heat gun? Have you ever post anything explaining it? Cheers and peace out V

 

If you have some threading or stringing you can aim the torch at that and they shrivel up and shrink and mostly disappear.

If you print for example a horse and the belly was printed "in mid air" with no support and is all spaghetti ugly and sagging too much - you run it back and forth over that spot for a few seconds and then push up with your thumb and it is still ugly but now in the correct shape.

That's about it - the thing I like about the tool is that it is so fast! I wish it could do everything - it just does a few things. But when you print say the eiffel tower with 500 strings it can clean those all up in seconds.

You still need other tools like a sharp razor/knife and some small metal files to enlarge holes that aren't big enough for screws or parts that aren't quite sliding together.

[gr5 2,170]

These photos are great earaujo! I wish you posted those initially. Several comments:

Your settings look fine - I would change the "bottom layer height" from .25 back to .3 as that is a better choice as you want this pretty thick to compensate for imperfect leveling and imperfect flatness of the glass and gantry structure that moves the head. But .25 is okay.

also the fan comes on at full speed by 5mm but that's a little late for many parts (such as the fingers). I think I have mine set to 1mm which seems slow enough. If the fan comes on too fast the nozzle cools too much too fast and you get underextrusion for maybe 40 seconds on the layer where the fan comes on. But anyway these settings are not your problem.

Also I noticed you are doing .15mm layers and 40mm/sec which works out to 2.4 cubic mm/sec. The printer (some printers anyway) can handle up to 10 mm^3/sec at 230C. The printers are all tested at 8 mm^3/sec in the factory. I try to stay under 5mm^3/sec so 2.4mm^3/sec should be no problem.

Anyway you have intermittent underextrusion issues. I'm going to guess you have filament tangles or some issue with the filament feeding. I strongly recommend you put the filament on the floor - also check for where the end of the filament may have gotten tucked under another loop. If this is the case remove the filament from the printer and unwind enough until you can fix it and re-wind it back up - never let go of the end of the filament even if the house is on fire! Anyway also put the filament on the floor - this helps a lot:

If putting the filament on the floor doesn't work the next thing is to check your temperature. Here are my recommended temperatures. Oh by the way - if you are hearing the "click" followed by underextrusion then: SLOW IT DOWN. Look for problems. Raise the temp maybe. At 190C PLA is like toothpaste and at 240C it is like honey. You get more control and better looking prints at the cooler temps but then you also have to slow it down.

Here are my recommended top speeds for .2mm layers (twice as fast for .1mm layers):

20mm/sec at 200C

30mm/sec at 210C

40mm/sec at 225C

50mm/sec at 240C

The printer can do double these speeds but with huge difficulty and usually with a loss in part quality due to underextrusion. Different colors print best at quite different temperatures and due to imperfect temp sensors, some printers print 10C cool so use these values as an initial starting guideline and if you are still underextruding try raising the temp. But don't go over 240C with PLA.

[gr5 2,170]

Here it is adjusted for .15mm layers (I just multiplied byt .2/.15 or 1.33330:

26mm/sec at 200C

40mm/sec at 210C

53mm/sec at 225C

66mm/sec at 240C

So it's important to be at 210C minimum. Colorfab tends to be less viscous and you can often print colorfab at lower temps. Or higher speeds.

[gr5 2,170]

Oh - a few more things - I strongly dont' recommend you go to ABS without first getting really good at PLA. PLA is much easier to print and once you get 100 prints under your belt you will probably be getting "perfect" prints every time. You will see then how frustrating switching to ABS is.

And the reason settings aren't posted much in e-nable is because every printer type is different. 210C for the UM2 doesn't translate to 210C for a typical reprap. Plus 10 other details. Even on this forum people get a certain set of settings that work great for them and then they stick with it. Also even among um2 printers the temp sensors can vary by +/- 10C so 2 users might be 20C different (very rare - would be 1% chance but still). I know because I sell those temp sensors and I test every one at 260C and about 10% are off by 10C.

And there are non-temp related issues as well - some UM2 printers inexplicably need 120% flow to print well and some don't. Etc.

[earaujo 0]

Thank you gr5. I understand all your comments, I'm an electrical engineer with a MS in robotics, but new to 3D printing. This tells me that it will be a little harder than I expected. My son's school also has an Ultimaker2, so to start we have "similar" printers, but it will not save us from experimenting there too. Later on, we are planning to help other local schools with probably other printer models.

I see the interesting spool holder that you have in the floor. I went to the web in search of a 3D printer model of a spool holder and I found tons of ideas. Do you have any comments or do you know of a better option? Or, I can simply try to replicate what you did.

http://www.thingiverse.com/thing:1001312

http://www.thingiverse.com/thing:46016

About ABS, I live in northern CA, but I'm from Rio de Janeiro, Brazil. It is not hard to find children in need of a hand there and also Rio temperatures in summer can easily exceed 40C. I have seen street thermometers showing 50C plus. So this is my motivation to learn to print using ABS. I'll only try ABS when I'm comfortable with PLA, and I'm not planning to do it at schools.

[LePaul 321]

Thank you gr5 for all the info. We have not changed the settings yet. It is still the settings I have initially posted in this thread. I do hear the feeder clicking from time to time and sometimes I do see less material coming out of the nozzle after hearing a click. So, I'll check

the feeder only to be sure. I'm adding some photos here.

The objective is to get experience with 3D printing and come up with an initial settings for the several combinations filament-Ultimaker2 that we may use for the Raptor Reloaded Hand. I have searched the web and several forums, but I was unable to get this information clearly stated. The info is in pieces here and there with no photos to really compare the settings. Initially we will be experimenting with PLA filament only, but later on I'd like to try ABS.

We only got white PLA because of the Star Wars fever.

The settings are as before:

And these are the results of several prints/hands:

https://www.dropbox.com/sc/y5hzmvc3z4llxcg/AADwhei64MFdBLbSG3qlCkbfa

Thank you again.

 

My ColorFabb Standard White PLA/PHA prints came out like that too.  I refined every setting I could and still had those problems.  When I went to another color of ColorFabb Filament, it printed perfectly!  

I like the Stormtrooper-ish look to those gauntlets!

Edited November 9, 2015 by Guest

[fergazz 60]

Hey earaujo! I'm from Rio too... check out our group in Facebook and stay tunned with brazilians ultimakers owners... seach for: Ultimaker Brasil

Aquele abraço! Fernando Gazzola

[gr5 2,170]

earaujo! You deleted your photos from drop box and so now they don't show up here! Next time please upload them to ultimaker so you can delete them off your drop box account without messing up your posts.

[earaujo 0]

Hi gr5. I simply don't know why they are not shared anymore. The photos are in Dropbox and I don't recollect touch them. But I agree with you, the best is to download them to Ultimaker. I only used my dropbox because I was unable to download them. I have updated the posts. Sorry.

Edited December 4, 2015 by Guest