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alnavasa

Warping over heated Bed

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So, thats pretty much it, I am getting a lot of warping on the Ultimaker Original prints,

I need to always use Brim (which I don't like)

Someone told me to print in 100ºC but i think 70ºC sticks better, but I am sure that there is an optimum temp for it.

It's a PCB MK2 Heated bed, pasted with kapton to an aluminum plate (4mm), that has another shell of Kapton on top where I print.

So what should be the temp for printing PLA? so that it sticks perfectly with no brim needed. And what about ABS i tried once to do it, but it took the heated bed 30 min to reach 120ºC (it takes 11 to reach 100ºC, and 5-6 to reach 70ºC)

 

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For PLA I use 50°C on glass covered with a dried solution of water and PVA (wood glue). Works very good most of the times.

For your setting I don´t know the optimum teperature, but if it is too hot your first layer does not look that good. And waiting half an hour until your HB has reached the temperature is way to long. You can speed that up with a heat gun.

For finding the optimum temperature I would start with a temperature which works well for you, print a small object, lower the temperature 5 degrees, print again and so on. Until you found the temperature at which the object does not stick well anymore. Increase the temperature 5 or maximum 10°C and you have your optimum temperature.

 

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I only tried printing PLA on Kapton once - it did not stick at all.

Try not using Kapton tape, you should get better results. I'd try printing on just the bare platform - you might need to play around with both bed and nozzle temperatures until it works.

 

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PLA I use 65deg and blue painters tape. Sticks great, rarely need to use a brim.

 

I may try that, I thought that by having the heated bed i didn't need that any more.

 

For PLA I use 50°C on glass covered with a dried solution of water and PVA (wood glue). Works very good most of the times.

For finding the optimum temperature I would start with a temperature which works well for you, print a small object, lower the temperature 5 degrees, print again and so on. Until you found the temperature at which the object does not stick well anymore. Increase the temperature 5 or maximum 10°C and you have your optimum temperature.

 

I'll give that a try, I thought that I could print over kapton tape easily

 

I only tried printing PLA on Kapton once - it did not stick at all.

Try not using Kapton tape, you should get better results. I'd try printing on just the bare platform - you might need to play around with both bed and nozzle temperatures until it works.

 

For me it sticks, but later it warps, so, yo mean over the aluminum? Is it Better to use cristal or aluminum ?

Thanks to all you

 

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If the part has a nice flat bottom which you " think " would support the upper layers, then I use nothing.. just 60-64 degrees and nothing else... I do often use brim though, just to get the material flowing nicely. At first I was printing everything with 75 degrees and glue and bla bla bla... but nah, keep it simples :p

 

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If the part has a nice flat bottom which you " think " would support the upper layers, then I use nothing.. just 60-64 degrees and nothing else... I do often use brim though, just to get the material flowing nicely. At first I was printing everything with 75 degrees and glue and bla bla bla... but nah, keep it simples :p

 

I like that, I'll give it a try, I don't like the fact of changing bluetape or messing to un stick the prints

 

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I have never tried printing directly on Aluminum. But printing directly on glass without any glue or hairspray should work well, as many people have reported so.

I print directly on a Basalt bed which is not exactly the same as glass, but should be very similar.

Definetly try abandoning the use of any kind of tape. Maybe you need gluestick or hairspray for some prints, but I believe you should get good results even without them - if you take your time and fine-tune your temperatures.

I usually make parts with large flat bottoms. If you have a very small bottom area, then you might need something to stick the print down. I noticed that the first few lines usually don't stick well, but they start sticking better after 2 or 3 lines are next to each other.

 

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Printing on aluminum is fine but you will scratch it up pretty quickly. I prefer glass or kapton tape.

For Kapton tape you have to clean it occasionally to get finger oils off of it. Soap and water or alcohol work well or "glass plus".

You need 40C to 70C for the PLA to stick well to Kapton. Temperatures higher than 70C may cause the bottom of the print to shrink a bit (not a temperature thing - it's a PLA-taking-too-long-to-cool thing).

It's very important that you have leveling perfect - you want the PLA squished into the tape - no gaps between the lines where air can get in. I'm going to guess this is your main issue. Also lay the first layer down hot to let it flow nicely so 240C for the first layer and print slow, say 30mm/sec. Then you can lower the temp to 210C or whatever you prefer and speed up to 50 or 70mm/sec or whatever. No fan on first layer also.

I don't know why you hate brim. It just peels right off and leaves nice bottom edges. If you really hate brim then it will help if your part has rounded corners. With sharp corners, all that lifting force is applied to a tiny spot at the corner. With rounded corners the forces are spread out.

Any bed temp from 30C to 70C will provide approximately the same stickiness but when you get above around 75C you start to get above the glass temp of PLA such that it never quite solidifies - more like clay - it will not move for days but it isn't quite solid either. At those temps IT WILL NOT WARP/LIFT. Instead it will just kind of flow and settle and look great. But you get other issues - layers take longer to cool and the part doesn't come out quite as nice - it's pretty good but not as nice.

Also the warmer the bed is, then the warmer the air 20mm off the bed are which reduces the shrinking and reduces lifting of corners.

Printing on glass is so much easier. You can use glue stick or you can use wood glue mixed with water and those parts will stick so well you will be posting questions about how the hell to get your parts off.

 

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So right now I am printing over cristal (just placed over the aluminum) prints got way better, I think its due to what you say, the bed leveling, I think that the aluminum was not completely flat, cristal should be completely flat, and has a very difficult chance to be deformed.

I didn't have time to check thing, and try other, just printing over cristal heated to 65ºC sprayed with hairspray, It sticks perfect, and its a little bit triky to get it out, but I didn't have time to make a 9 hour print and have that risk, so thats what I did.

I'll try printing bare on the cristal next time, also printing first layer warmer, thats a good idea,

Thanks gr5 for all the support given!

 

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Sorry I am new to this and just trying to catch up on techniques and terminology. Please bare with me.

What is Brim?

What is Cristal and where did you get it?

Is the glue stick that was sent with the U2 not the best method and should it be cleaned off and reapplied with each print.

Sorry for the basic questions. I have only had it for 2 days now.

 

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Brim is an option that you can select in Cura. Brim will add some lines of material to the first layer, in order to make it larger and therefore make it stick better to the platform.

It's easiest to just see it for yourself in Cura's "layer view". The brim will be colored differently from the rest of the model (is it still light blue? I didn't like the new layer view so I switched back to 14.01).

Cristal is the spanish word for glass ;)

I never had any success with gluestick - someone else should answer that...

/sidenote:

Does anyone have experience with Polyetherimide (PEI) plates? I've read that it works like a charm, makes both PLA and ABS stick when heated, but the parts pop right off when cooled down. No tapes, no Kapton, no glue.

But the stuff is really expensive so I'd like to hear something from more experienced users...

 

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Thanks for the feedback and great information Jonny. Is there a way to create more support in specific areas? My current build does fine with support in 80% but there is a sphere that always breaks loose and eventually comes off the build plate while printing. Maybe I should put a sacrificial block on the bottom of the sphere to cut off later? Any help would be greatly appreciated.

 

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