tips to get down to 185C?

[thedudevt 0]

First let me say thank you to everyone on the board, and to those who have contributed to the wiki. Your generosity is truly amazing.

I've read on the board here that you can print PLA as low as 185. I've been using 220 after getting some delamination at 200, but i'm getting alot of stringing, blobbing and warp and i think it can do better. I'm using BuildMeMarlin 1.0, NetFabb, and Printrun with Ultimaker grey PLA.

Does anyone have tips on tuning or modding to get the temps down? I've printed Owen's fan shroud and will install that tonight, and I've ordered ceramic tape and kapton to insulate the heater block.

I'm thinking part of the problem is you need smaller swings in temperature and faster response, hence the insulation. The warp may be material specific, I've got some spools from Ultimachine advertised as low warp but i haven't tried them yet.

Kyle

[Daid 306]

Your 200C might be someone elses 185. Because not all temperature sensors are giving off the correct values. My temperature is quite spot on, and I normally print at 210C, while I have printed at 190C, it caused more problems then it solved. I can remove filament at 170C, so that's about my melting temperature.

If you want to print low, you need to go slower. Also, different cooling can help.

[owen 19]

I've been using 220 after getting some delamination at 200

I can't imagine you could go much lower if you are getting delamination.

Like Daid said your actual temp might be lower than your reading.

I used to print at the lowest temps but have raised mine to 210 now with more consistent results and better prints.

I have found Marlin firmware seems to give a much steadier and smaller temperature range which helps too.

I get a lot of warping though and although I've tried a lot of the things to help, which haven't been helping, I think it might come down to the particular filament more than anything.

[thedudevt 0]

Thank you both for your advice. I'll add the fan shroud and insulation and see where I get with that.

Kyle

[codemaven 0]

I think I must be the odd one out.... I've never measured my actual temperature, but it must read low because I print at 175 and get fantastic results. I used to print at 190 and found that lowering it to 175 reduced stringing a little bit... But I still have really bad stringing. I think I might even be able to go a little lower on the temp.

Cheers,

Troy.

[hedis 0]

Something is strange here....

I'm printing on 245-250*c. And I have mounted a extra Type-K temp sensor on the heating block and my temperature readings are very accurate. (within 1*c)

Nothing rebuilt since we got the printer a week ago. (updated to Marlin, sliced with SkeinPyPy and printing with Printrun)

I get what I would say pretty good results on my prints.

I'll attach the only print I have pictures of right now.

This is a pretty bad print due to no infill and i forgot to make the walls thicker, so it's very fragile and not stable at all when it printed the head.

But look at the finish on the bottom part.

Ultimaker 2 Extended+ Press kit.zip

[thedudevt 0]

I think this calls for an experiment! I will slice (NetFabb) and print Yoda at 190, 200, 210, 220 to see for myself what the differences are in that range.I will then slice Yoda with SkeinPyPy and print at the best temp from the first experiment.

Kyle

[owen 19]

I think this calls for an experiment! I will slice (NetFabb) and print Yoda at 190, 200, 210, 220 to see for myself what the differences are in that range.I will then slice Yoda with SkeinPyPy and print at the best temp from the first experiment.

Kyle

Yes, your print looks good. It will be interesting to see how your experiments go.

[ddurant 0]

I think this calls for an experiment! I will slice (NetFabb) and print Yoda at 190, 200, 210, 220 to see for myself what the differences are in that range.I will then slice Yoda with SkeinPyPy and print at the best temp from the first experiment.

Kyle

You don't really need to reslice, though you can if you want.. Just edit the gcode file and look for M104 and M109 commands. Those ones set the temperature.

The prints look fine to me!

[hedis 0]

Yes, your print looks good. It will be interesting to see how your experiments go.

Did you mean my print, or did thedudevt post pics somewhere?

[owen 19]

Yes, your print looks good. It will be interesting to see how your experiments go.

Did you mean my print, or did thedudevt post pics somewhere?

Yep, your Yoda print in this thread.

[thedudevt 0]

First print at 220C - Marlin + NetFabb Ultra Profile with .1" support grid, through printrun, about 7 hours - some of the stringing in the shirt is from a G00 rapid between the support grid pass and the next layer shell pass. Lots of stringing to the right ear, and the top of the head has a hole from too much heat, too little cooling, or too much dwell time. Also, the low overhangs at the chin, and ears tips show a bit of sag to the strings, as well as the material that doesn't stick, gets wiped off at the begining of the next shell pass.

I have not installed Owen's fan yet, so my UM is stock except for a Z height fine adjust thing (no more grabbing the Z screw on the first layer).

Kyle

Ultimaker 2 Go Press kit.zip

[hedis 0]

Nice! It will be really interesting to see your other results. Probably better sticking between the layers with higher temp.

I printed and mounted this fanduct earlier today (

http://www.thingiverse.com/thing:17768

), but haven't really tested it since then. I started to correct our belt tension problem. (all adjustments bottomed out, and still much slack on the belts)

You really get 360* coverage of the airflow with that one, but it's harder to see the printhead.

Why isn't there a adjustment for the filament amount in Printrun? It was very good for testing purpose in RepG. (I suppose it's possible to tune by sending the commands manually from the terminal)

Or is it related to the 5D extrusion calculation? (or removed due to it to be more exact)

I also need to print the better Z home adjustment tool.

I have to fine tune it by turning Z axle every print now...

thedudevt> Is that the big 100mm Yoda? (

http://www.thingiverse.com/thing:16309

)

Thats the one I printed.

[thedudevt 0]

I'm printing the 190C yoda head now, I'm up to the chin overhang and so far it looks the same. I'm priting the first yoda-lite http://www.thingiverse.com/thing:10752 which is about 65mm tall. It takes about 7 hours to complete.

I'm not so comfortable letting it print while I sleep yet. The paranoid me wants to build something to catch the flames when/if something fails. I'm sure the odds are tiny, but then that's why they call it paranoia.

Hedis, this is the Z adjuster I printed, http://www.thingiverse.com/thing:11033 I really like it so far. I haven't applied the fan shroud yet, and I won't till I've finished printing at least three temp runs. I should have bumped my speeds up to 300 as well but I don't want to change too many variables at once.

I like that fan shroud (it's swoopy), but I'm not sure the little axial fan can generate the pressure to really take advantage of the shape. I guess I'll just have to print that now too.

I've been looking into a faster way to run this temp test, and I came across this thing -

http://www.thingiverse.com/thing:9804 . It looks perfect for testing stringing and bridging. I'm thinking of manually adding an M109 temp change between each step. I bet you could test 10 settings in an hour or two. Much faster than one setting per day.

I talked about reslicing in SkeinPyPy, partially to teach myself, but also I was thinking I might gain something from trying out retraction. But then, that's another variable...

The good news is of course that the 220C yoda head cleaned up fine. Looks great except for the holes in the head, which might just require better cooling.

Kyle

[alaris2 1]

what was the conclusion here?

I'm down to 180C but experiencing some problems with parts curling and lifting off the bed which might be temperature related, I need to run more tests.

I also have the 'swoopy' fan. you're right, it looks great, but the fan isn't capable of generating the pressure and most of the air blows back out the fan side instead of at the head side.

it's also extremely difficult to access the head for cleaning and there's several design faults (walls too thin to print reliably, curvature of working end doesn't deflect the air correctly..)

it looks great, but I can't recommend it. I'm going to redesign the fan shroud myself.

[thedudevt 0]

Sorry, I never updated this thread. I got sidetracked with extruder problems, followed by a quixote-like quest for a better extruder, only to find three weeks later that I just needed to clean out the hobbed bolt once in a while... The original extruder is still the best one i've tried so far. The only change I made is adding an M3 nut on the thumb screw to act as a jam nut.

I also learned that running the head too fast during traverses (or fill) kicks up previous fill which leads to collisions which leads to skipped steps which leads to disappointing mornings. I was setting my max speed to X300 Y300 in the header, but it's much happier at the build-me-marlin default.

I did notice that lower temps generally lead to:

1. Parts detaching from the bed mid-print- I've got a pile of yoda shoulders. This may get better soon, Daid's been talking about seperate temps for the first layer in Cura.

2. A 'furry' overhang surface finish which is really difficult to clean up compared to strings.

3. At really low temps, poor adhesion between layers making parts really fragile. This also happens with too much speed or too little material.

So, there are a lot of interconnected variables. I've learned that focusing on one parameter has unintended consequences and is not necessarily productive. But then you won't really understand the system until you've figured out what all the knobs do.

Going forward, I'd like to focus instead on figuring out retraction. Then you can get low stringing AND a good surface finish. I'm slightly jealous of the guys that can lay out whole trays of parts and churn out 36 hours worth of usable pieces. Retraction is I think also necessary for dual extrusion. I've printed a few parts with support so far, and the overhang surfaces just can't be cleaned up.

Meanwhile, I've finally got back to where I was three weeks ago, my little robot chugging away making nice clean parts (20x20x210 T Slot right now), only now I have a better idea of what not to do.

Kyle

[Daid 306]

Going forward, I'd like to focus instead on figuring out retraction. Then you can get low stringing AND a good surface finish. I'm slightly jealous of the guys that can lay out whole trays of parts and churn out 36 hours worth of usable pieces. Retraction is I think also necessary for dual extrusion. I've printed a few parts with support so far, and the overhang surfaces just can't be cleaned up.

Retraction with 50mm/s, 2mm retraction, at 200C, in Cura gives pretty good results. Not perfect yet. But pretty good.

Note: Cura will give better retraction results then Skeinforge, as it will only retract if Comb couldn't avoid holes. I want to change it so it retract before or during the move, which should give even better results. But I haven't got around to figuring that out yet.

[thedudevt 0]

Thanks for the tip, I'm eager to try it.

Kyle

[alaris2 1]

great tip Daid. tried that last night and the stringing is reduced to mere whiskers.

also tried your suggestions for changes to the first layer (as per another post) at the same time and they work well too.

it seems that whilst I/we can print at 180C - 230C the low temperature prints are not as strong structurally and tend to have adhesion problems (with the bed and with other layers) - hot prints tend to burn the PLA a bit but otherwise are OK.

it seems 200C is a good place to be.

remind me - why were we trying to get down to 185C again?

[Daid 306]

Pretty nice right I've been printing at 220C, but 200C seems to be the sweet spot for string reduction (with retraction) and strong parts.

If you are looking for a new challenge, get some flexible PLA. I got some yesterday, and that stuff is weird. It feels odd, and it's not easy to print with it. I've only done a single print with it and it had trouble with the infill. I'm not sure how to describe it, as it's not soft like rubber. But it's also not rigid like normal PLA. It flexes quite easy, but it does not compress I think. I should do some larger prints to see how this stuff acts.

[somerwil 0]

I didn't see anything about different print temperatures for different PLA's in this topic. Do you guys print all your PLAs at the same temperature?

I change print temperature in the gcode since I feel the 'solid' colors need a higher temperature than the (semi) transparent colors. This means going to lower temps also depends on the material you're about to print. My Ultimaker white and silver for example needed some 20 degrees more than my light blue PLA to get a good extrusion.

Nevertheless I also feel getting the temperature as low as possible is not the best way to reduce stringing because it also results in other problems like a lack of adhesion. I personally try to get to the 'just cool enough' temp for my material and add some 5 degrees to it so the layers stick better.

With the Ultipanel I have now attached to my UM, I manually bring temp up a little to make the first layers stick to the platform better. After the first layers are printed correctly I bring the temperature down again, even though it's just for about 5-10 degrees. Controlling the temperature on the go is really a nice feature of the panel!