Warped bottom question.

[cloakfiend 994]

Hi folks,

Im trying to print my first cut up object, as i usually just print one part pieces like head scans and such, and before I cant seem to remeber getting such big warping on the bottom, I've printed tiny and large? I tried a brim, but the warp just happened above the base just the same. Any ideas, if all my parts have this issue, it kind of defeats the point in cutting it up and i may as well just go stupid with my own supports instead and just print it in one. Warping kind of makes it impossible to accurately stick them together. Its tha weird inwards dip that annoys me. Printing more than one at a time is the only thing i can think of but i try to avoid retractions at all costs as it saves time and also as im still on my first PFTE after more than a year and a half of printing and dont want to have to swap it out! lol.

usual ref photo.

Model is hollow and printed at 189degrees with 0.4mm nozzle at 30mm/s. 0.06mm layer height.

Edited May 25, 2017 by Guest

[kmanstudios 1,120]

Type of material? What are you using for strickum to da buildplate?

I ask because I have been reticent to use rafts but have found they can be removed if taken off while still warm to hot.

But, I am speaking specifically about PC and CPE+ as I have not had this be an issue with PLA or other things so have not tried it with other materials. But, does work like a charm with the filaments I mentioned.

[cloakfiend 994]

I used to use rafts back in the day, but I only use PLA from Colorfabb now, and print with a skirt on prittstik power glue and no infill or support, to minimize waste, but have kind of been away from the printer for a while so am wandering why its doing this, but i saw it on a few of my letter prints too. Ill give the raft a go, i never really had trouble taking it of the raft, but only did it with ABS which i dont use anymore.

I havent applied glue or re-leveled in about 6-8 months but it does this even with brim selected and doubt the other stuff matters....This model is just for fun but was hoping to have it done in a day or so but it doesnt look like it.

I want to print without heat on the bed, neokto had a nice technique i must investigate and finally try somthing new out.

I feel its the heat of the bed combined with the nozzle temp, bummer.

[kmanstudios 1,120]

That is odd with the PLA materials. I have not used Colorfabb yet. Got a roll waiting for me to get to. But, PLA is so....well....bulletproof.

I do hope you follow up and present a solution if you find one. Adding to the data banks as we type

[cloakfiend 994]

Cheers mate, ill let you know what I've done if i got it to work. don't have time at the mo but maybe tomorrow. Lots of small pieces so if they warp they will be useless.

[kmanstudios 1,120]

When I replied earlier, I had awoken to the sounds of my printer making bad sounds because the CPE+ filament binded itself on the spool and had been air printing for a while. 3AM with only two hours of sleep.....

So, as a follow-up, I would ask a couple of noob questions that you can answer when you figure things out.

1. If you have not leveled or cleaned the plate in a while, nor used the machine in a while, would that not be step one? I mean clean it with degreasing dish soap, then very thorough washing followed by a solid alcohol wipe and mabe fresh glue. That stuff can get 'stale' and lose its 'ooomph' in a short time; at least here depending on humidity levels.

2. Printing PLA at the temp you describe, would that not create blobby bottoms? I think they are called elephant feet, or some such. I usually print PLA around 200°C or less, or just a bit more depending on brand and type.

3. Now, I did find on one piece that I had trouble with, I had to really kick the heat up on the buildplate to make the part stick and not warp with PLA. I mean I had to kick it up to 80°C and I usually do not have to do that at all. Especially with a shape as yours (Top cross section being rather boxy or radial in x and y) as my piece that gave me issues was a long, thin piece.

Just throwing spaghetti at the wall to see what may stick :)Look forward to the answers you find.

Edited May 25, 2017 by Guest

[cloakfiend 994]

Well, in my personal experience, once you have levelled the bed and dont use excessive force in ripping stuff off it when its finished in a way that ruins the leveling then then is no point in relevelling imo. And as for a dirty plate, well mine was real dusty, but I just wiped of the dust as my glue still holds pretty well even after 8 months or so. A brim sort out any plate warps, but the heat of the plate will warp the model itself above the plate up to 5mm from the base as the heat from the nozzle adds to the heat of the plate causing the model to shrink at the 3-5mm mark. The old cura didnt have a bottom layer mode and therefore made the base of the model 1.2mm thick as with all walls (which helped a lot with warping). Now I use only 2 layers for the bottom, BUT the problem is that it applies to ALL the damn bottom layers. Cura need to have an initial layers option that does not affect the rest of the model. It might do but I just cant see it. I print low temps, 0.06 at 189 degrees and cant go lower as the acetone will split the model if layers dont properly sit. You never need to heat theplate to 80 in my opinion, but maybe i just havent come across something that need it! I want to learn a way of printing on glass with/without glue without heat.

Edited May 26, 2017 by Guest

[neotko 1,417]

If you want to print pla without heat the fast solution is to use the old bluetape. Ofc that will need a relevel to compensate the thickness. The only downside is, bluetape can break and can last 2-8 prints and you loose the ahiny bottom layer, but for your stuff you don't need that maybe?

[cloakfiend 994]

I dont care bout the shiny layer, I dont know why anyone cares to be honest? Im doing a test print today so will let you know how it goes!

[kmanstudios 1,120]

I dont care bout the shiny layer, I dont know why anyone cares to be honest? Im doing a test print today so will let you know how it goes!

 

I look forward to seeing what you find as a solution. I am doing my first print with ColorFabb while the Supersized Enterprise is setting its final epoxy gluing.

I am using the translucent orange, Seems to be printing ok. Will know when I get the print off.

But, most definitely looking to see what you come up with

Edited May 28, 2017 by Guest

[geert_2 556]

Have you tried printing this with the build-plate temp 5°C or 10°C lower? Or have you measured that build-plate temp? If you could get the temp just below where the PLA starts to get flexible, but still has enough bonding, it might work.

For a stable bottom layer, I think it needs to be at least 0.5mm to 1mm thick. If you only make it 0.2mm or so, it will not have enough rigidity to keep the walls upright, I think.

[cloakfiend 994]

I got home late and fell asleep lol. Ill try printing with lower build plate temp and a brim. Perhaps I'll do a few more bottom layers as well just to see, but could somone let me know if there is a way of only setting the initial amount of layers without affecting bottom layers further up the model? Thinking about the warping issue more, I think the bottom thickness might have something to do with it, but on a large model, just filling in the large area takes aaaaaages which is why I have resorted to doing just two layers from the bottom. Printing all at once will also reduce the heat per object but increase print times a bit but not so much due to the arms. Then comes the sticking parts together, filler and sanding fun! lol. should have pics by tomorrow if i dont fall asleep again. I find the translucent Colorfabb more rigid than the other colours, the lighter the colour, the more runny the filament. Yellow and dutch orange print well but are more runny than say blue, red or green. Also going to switch back to the original 0.4 nozzle to lower the heat as the OB is much larger and produces more heat than the original non replacable nozzle.

Edited May 29, 2017 by Guest

[cloakfiend 994]

Well just got round to doing it now all in one mode rather than one by one, but the problem seems to still be there plus an annoying moment of under extrusion due to being towards the end of the roll (bummer). In my honest opinion, the only way to avoid it is to have a much thicker bottom layer, which means more print time unfortunately. I may as well just use the old ancient cura that I downloaded back in 2014. There are zero benefits for me now with the new one, just more problems. Brim only kept the edges in place, did not help with the latter stage of warping 5mm higher up. Im pretty sure its to do with the heat from the head and plate which are strongest at the start of the print.

And... the pics as promised, it will take a lot of filler and post work though though which I hate doing but you can't avoid it with multipart stick jobs I guess.

Edited June 2, 2017 by Guest

[kmanstudios 1,120]

I have never seen anything like that before. That is odd. I would be interested to see if it is a Cura version difference.

[neotko 1,417]

@cloakfiend I think your issue is:

a) Printing on the material limit. Explanation:

PLA (colorfabb, faber) goes matte when it reaches the lowest extrusion temperature (the temperature vs the speed that is ok).

Please check the nozzle temperature when printing one, I think your fan is affecting the nozzle temperature, so it changes the pla expansion when being printed.

Please try this:

a) Use bluetape

b) Disable bed temperature (set to 0)

c) Relevel

d) Set fan to 100% at layer 2 (or the height when the layer 2 starts)

e) Set the print temperature +5 degrees

[neotko 1,417]

Also you have a mark from underextrusion on the moment with more retractions. Check if the coupler is near its end of life.

You really should think of upgrading your machine to the um2+ feeder and hotend. It will make your life much easier.

Or even better, just get a bondtech feeder and change the couplers to the new TFM that do last muuch longer (dunno if you upgraded this?)

[cloakfiend 994]

Thanks for the info, Ill give it a whirl, I haven't changed my coupler since i bought the machine, and whats the difference in nozzles from the ob to the um2+, Ill give the blue tape a miss as I hate messing around with the plate my glue on it is about a year old, and I don't even take it off anymore, lol. I find that towards the end of the colorfabb rolls, i always get under extrusion, so i should really already crank up the demos, plus with retractions you need to print slightly hotter due to the momentary pauses. Oh well, I'll try printing hotter, but doubt that will help as my old models with thicker bases print find. You need to remember that i have not changed my way of printing in about 2 years, so when i get different results i get confused as to why. But unfortunately I have used three machines over the past few years and only one of them (my one) has the OB installed.

Here is my botch job, I'll see how good he comes out after all my hard work. I could have re-printed it, but if you know me then you know I won't do that. Its for fun anyway!

Pre acetone just glued...

[cloakfiend 994]

Here is a face made with old cure (no glass plate warping deformation) and a pillar with new cure (bottom touching plate is warped inwards). Pillar even has 10 % infill to support the top. The face is totally hollow.

The face has no ground warping, the pillar does.

Edited June 4, 2017 by Guest

[neotko 1,417]

Well good things of the um2+

Much more torque feeder, enough so you don't need to worry about the end of the filaments (the extra friction that they cause). Anyhow I'm not a fan at all of the um2+ feeder (and much less of the old um2 black feeder).

It uses a TFM coupler instead of the milkwhite PTFE. The difference is that instead of 100-200 print hours, it can go to 1000-2000h (specially at PLA temperature) without affecting the extrusion.

Since you print with the filament without spool you have as little as possible friction from the spool, that's why (I think) your coupler has last this long.

I know that's a pain to change stuff, but sincerely that underextrusion line for me is clearly the first symptom of the coupler about to die.

When the coupler dies, it goes brown and compress into itself, making the hole where the filament goes through tinner, and that adds a lot of friction to the extruder.

That's why I also recommend you the um2+ kit and not just the parts separated, because is much more 'plug & use' instead of disassemble & reassemble the head.

Ofc, changing just the coupler is WAY cheaper. Is around 20€ on 3dsolex (don't buy the I2K since you really don't need that) and ofc you would need to change the spring to a fixed size spacer (any UM reseller can sell you the aluminum spacer for like 3€ + a TFM coupler for 20€ or so).

Seeing that your PTFE coupler lasted this long, the TFM might last for you longer than the machine belts

Edited June 3, 2017 by Guest

[cloakfiend 994]

Thanks for the advice!

Ill most likely switch back to the old nozzle due to improved print quality and when i do that i'll change the to the TFM coupler.

I am well aware that I print on the limits of the material as i specifically spent much time investigating what the lowest temp i can get away with is. Which is why i can't print on the roll, (especially with the old black feeder)

The limit is where i find quality to be best, which is where i was testing the ruby nozzle as well. I know the best I can achieve now, and I also feel that I know when the coupler is dying and I feel not quite yet! lol. you tend to get more surface instability with a dying coupler, and from personal experience not printing on the roll simply means when the coupler does die, I'll know about it.

The more retractions you do especially on small models, the more temp you need to combat the cooling of the filament after constant heating and cooling, which leads to an overall drop in working temp. I printed at 190, but should have gone to 192 or 193 to be safe, I saw the temps fluctuating on the LCD, but ill just need to change a few things, as the last time i changed to the OB i ruined the casing of the heater which is still the old one so takes even longer to heat the nozzle with the ob as it was not designed for that.

BTW.....how long do the belts last? and the motors?

Edited June 4, 2017 by Guest

[geert_2 556]

If the filament is near the end of the spool, thus if it has a very narrow bending radius, try stretching it manually (if you haven't done that already). Wind it bit by bit in the opposite direction around a 7cm diameter skater wheel, or something similar. So it has a bending radius of about 50cm, almost equal to that of the bowden tube. This will greatly reduce friction in the bowden tube and in the nozzle.

Further, if you remove the bowden tube and manually put a piece of filament in the nozzle, you can often feel if the coupler is getting worn out: this often causes a higher friction at some points. So I think Neotko is right that you should have a look at the teflon coupler.

These two things will probably solve the underextrusion part.

The bending problem I guess is going to require thicker walls, especially at the bottom, and indeed switching on the fans early, after the first or second layer, so it gets good cooling as soon as the first layers are put down.

[neotko 1,417]

BTW.....how long do the belts last? and the motors?

 

The motors I don't know, I have a box with some extra just for a rainy day, but 2 years, 3 machines, not used one yet, so I think maybe more than 2 years? XD

The belts, that I had to change on 2 machines, the first sign of belt about to die (or close to) is that they start to do some oldmattress-sex-noise that is quite disturbing since at first you think something is being scratched. So if your belts start to sound like that, it could be a nice idea to buy new ones and replace them. But the noise doesn't affect quality to a visible point (ofc you and I could actually see the problem since we are really mad about proper good quality).

[cloakfiend 994]

Ah, fair enough! its coming up to two years now so i may get some spares!

[neotko 1,417]

Ah, fair enough! its coming up to two years now so i may get some spares!

About the belt noise. @IRobertI told me to use a brush to clean all pulleys and today did it with a nylon small one) and brushed all pulleys (even motor ones) and the squeaky noise has banished. But also when I changed belts I saw some tooths that where actually very damaged.

So kudos to @IRobertI that guy rocks

[cloakfiend 994]

Damaged teeth!!! ahh I hate the dentist and I had a terrible belt incident ages ago when i changed the fan shroud and when i put the original one back i forgot to bend the back with the heater back and as i was going home, it smashed against the top left motor and the belt was grinding against the teeth because it was jammed. I knew something was going to be damaged.