Can't get heatbed calibrated  

Re: Can't get heatbed calibrated

Please take this input as what it is: the experiences of a total newbie. I only did my first prints yesterday evening (pictures to come in another thread).
Always take care when you try to lower the bed that you push down the corners (after turning the orange adjuster) since (like in my case) the screws are a very tight fit in the holes of the Y-carriage (when I move the adjuster 'up' the bed does not 'fall' by itself).
I also understand that the fact that there is a (small) height difference between the front and the back is not necessarily a problem, that's why you can adjust the height.
Also keep in mind that since a plane is really defined by 3 points in space that having 4 points/screws makes for some careful adjustments (provided your bed is flat). If the 4 points are not in a plane you will most probably have a 'floating' corner.

Re: Can't get heatbed calibrated

Hi Michael

Gerg is absolutely correct in everything he says.

There are a couple of things to add...

The glass and PCB (heater) are hardly ever going to be perfectly flat, due to manufacturing processes. Therefore we as end users, have to find our own workarounds for these issues.

The most common cause is the frame being twisted (you would have to remove the felt feet pads to confirm this).

Some people have used corner clips to hold the adjusters in place (there is a file for these on thingiverse and a thread about them on here). Others have been able to flex the PCB sufficiently to get a flat surface.

You can use the edge of a steel rule to see how flat the PCB is and where the high point is. You can do the same with the glass and match them up so that the two high-points face each other and when the glass is clipped down, the high points are cancelled out. You can lift the front and rear edges of the glass with tape to get a level.

You will find something that works. Keep trying and think laterally!

Peter

Re: Can't get heatbed calibrated

Hi Michael,

Have you seen my recent post?

http://shop.prusa3d.com/forum/prusa-i3-kit-building-calibrating-first-print-main-f6/simple-dial-gauge-bed-leveling-t652.html

I found this to be very useful. Of course you would need the bed level to make your first print but if you get it close it will work. The business card should just barely touch the nozzle for the best results.

Make sure that the hex head and locking nut are not tighted too much to the bed. That will stop you from using the thumb screws to level the bed

I can send a picture of you more help.

Godspeed!
Dale

Re: Can't get heatbed calibrated

I would agree with previous posters and also I want to add another perspective.

I got this printer about two months ago, and I still remember how frustrating it was to calibrate the Z axis. Sometimes I would get a "floating" corner, and usually the nozzle ended up too far away or too close resulting in either a print that didn't stick, or a smeared and rough surface that would make the nozzle grind on it.

But after many attempts you will get the hang of it, and I myself can nowadays fully recalibrate the Z axis even after my last maintenance where I changed the bearings on the Y carriage, and the calibration took less than half a minute followed by a perfect print (pre-heating time not counted). Just keep at it!

Re: Can't get heatbed calibrated

Before you clip the glass to the bed, check if the pcb alone will sit flat in all of the corners. If that does, then clip the glass to the pcb and check if the corners are still flat. If they aren't, then your glass is bent beyon what is tolerable,

For me, my glass was bent to the point that I could never get all 4 corners to stay in place. My solution was simply to replace the glass. Here in America, I was able to get 1/8" glass cut to size at Lowes for under $7. It doesn't matter if it's tempered, their basic glass works fine. Just make sure to bring your original glass to make sure they get the size right. Some people at these home improvement stores aren't familiar with metric to imperial conversions so it's easier if they just use your original glass as a template.

Re: Can't get heatbed calibrated

Thanks for all the tips guys! I'm gonna try it again this week, I'll let you know! 🙂

Re: Can't get heatbed calibrated

Hi guys,

Yesterday I did my first print, the little frog.
it came out pretty good!

Today I've tried another print with PLA/PLH from colorfabb, but that didn't came out successful. I printed on 210/50 (default PLA temp) after 30 minutes it came loose on one side..

Can someone tell me what I did wrong?

Images:
https://www.dropbox.com/sh/5vgvp43tru5zajb/AADXQUsW3x2BdwFmxAuqkEO-a?dl=0

Re: Can't get heatbed calibrated

Hi Michael

Either poor bed preparation or not enough heat. 50 degrees is OK for small objects, try 60 degrees after cleaning and re-preparing the glass.

Peter

Re: Can't get heatbed calibrated

Hi Michael

Either poor bed preparation or not enough heat. 50 degrees is OK for small objects, try 60 degrees after cleaning and re-preparing the glass.

Peter

Thanks Peter! I've cleaned the glass en prepared it again as in the video from Josef. I just printed a small model on 60 degrees and it came out perfect!

Now I've printed a larger print (70 degrees heatbed) but after 2 layers it came loose on the back side.. so I think I need to level the bed better on the back side?

Re: Can't get heatbed calibrated

Hi Michael

Be careful with the temps for PLA; 65 is about the max I usually print at; gets too soft if you go too hot.

Watch out for greasy fingerprints on the bed. Also you can calibrate slightly closer.

If you are slicing yourself, make sure the first layer is at least 0.25mm.

You can also try using a brim to assist adhesion.

Peter

Re: Can't get heatbed calibrated

Thanks Peter for the tips! I've printed ABS also, result is pretty good but can someone tell me why the back of the print (side of the heatbed ) looks this way? To high temp? It's also a little bit sticky.

I've used glue + juice.

?dl=0

Re: Can't get heatbed calibrated

Hi Michael

Was the bed warm/hot when you applied the juice?

That's what causes the white deposits.

Peter