Print issue with heated bed

[hreedijk 4]

Hello everyone,

I've got a question about printing with a heated bed.

On the photo's you can see that the print is not straight upwards.

No matter what I set on temp on the nozzle or bed, I'm keeping the same results.

If I set the bed lower than 60 C , the filement won't stick to the mirror anymore.

If I set the temp higher, the first layer will melt to much and having a sharp 0.1mm edge as result.

I also tried to print with the fan on, the result was even worse than on the photo's.

The print on the photo's was made with a nozzle temp of 210 C and with a bed temp of 62 C with filament of Faberdashery, color pearl white and printing with the fan off.

Has anyone any idea where to look to get the print straight?

Regards,

Harold

 

[baasb 6]

Yep, I would also wan't to know the answer to this question. I have the same thing, much less than on your pictures but still...

 

[owen 19]

When you are struggling to get your prints to stick on glass it's hard to make them stick without getting this 'Elephant's foot'. When you raise your nozzle slightly you avoid this but then you start to get lifting off the bed and/or the bottom surface not totally filled. Kapton sticks better than glass but isn't as nice to use so you can more easily avoid this but you have the other trade offs, takes longer to be able to remove your print, you have to replace your tape periodically, especially if your bed isn't perfectly level and the nozzle bights into it.

 

[hreedijk 4]

So if I understand it correctly, I need to to place kapton tape on the mirror glass.

I can perfectly level my bed, got a dial gauge for that.

I'll use kapton tape this evening, I'll post the results back here.

Thanx Owen!

Regards,

Harold

 

[owen 19]

Yep, I noticed it can stick easier and with less heat compared to glass.

 

[hreedijk 4]

What temp do you advise for PLA and ABS with a mirror and kapton tape?

Regards,

Harold

 

[owen 19]

Maybe not change your temp for PLA if it's at 70C but you will be able to start that tiny bit higher and still get it to stick well and thus avoid the Elephant's foot. I haven't printed with ABS but Joergen has if you look through his posts he has written much about it.

 

[hreedijk 4]

I've taken Owens advise to use kapton tape, I had a roll laying around of 200mm wide.

Last night I've made the same print, with heatbed at 70C, nozzle at 210C, fan at 25% and a speed of 60mm/s.

Result was even worse then before so I made a few tests with the temps and fan.

After those tests I can conclude that using the fan (in my case) is the main cause of the elephant foot.

Eventually I came close to the result I want to have.

In the pictures below I've used a heatbed temp of 54C, nozzle at 210C, no fan and a speed of 35mm/s.

Tonight I'll try not to set the first layer to be thicker that the other layers.

See how that will turn out.

Keep you posted.

Regards,

Harold

 

[owen 19]

Thanks for the update Harold.

That's a very nice print.

 

[hreedijk 4]

Well, It seems the elephant foot nearly has been gone....

I'll keep tweaking on it, but it's at a acceptable level now.

Thank you Owen for your time and patience!

Regards,

Harold

 

[barry-crump 0]

I have just installed a heated bed on my UM and just need to know how you control yours? do you do control the temp via an Ulticontroler? if so, what firmware are you running? (sorry to jump in on your topic but your heated bed looks like the same setup as mine).

 

[hreedijk 4]

No problem, hope I can help....

Yes, I'm using the Ulticontroller and a relay to control my HBP.

I'm running the latest firmware 1.5.7 and it's working fine.

I'm using a separate power supply for the HBP also.

Regards,

Harold

 

[gr5 2,189]

You will have to build your own copy of Marlin. There's tons of details on how to do this. Building your own Marlin is scary but not hard. It's pretty simple.

This was written very recently although the instructions are slightly more complicated than necessary:

http://www.extrudable.me/2013/05/03/building-marlin-from-scratch/

That's how to build from command line prompt. If you want to use the gui - the arduino IDE build environment it's simpler and fewer clicks but the above instructions are pretty good.

The hard part is editing the configuration.h file. Google "marlin heated bed configuration.h"

There are 2 ways for marlin to control the temp. PWM/PID or bang-bang. When your bed reaches the goal temperature PWM method turns the bed on and off 10 times per second. If you have a relay this is bad so don't use PWM/PID method. If your heated bed is low enough power that it takes many minutes to get up to temperature, again, PWM is not necessary. However if you have a really powerful heated bed (can get up to 70C in under a minute) and if it is controlled with solid state electronics, then PWM/PID mode is for you. Otherwise it will overshoot the temperature by too much e.g. 10C.