Nothing sticking to be after 1.75mm upgrade  

Re: Nothing sticking to be after 1.75mm upgrade

Hi David

Sounds to me as though the nozzle is too far away from the bed. Have you re-calibrated the bed height?

What first layer thickness are you trying to print? There was a post which recently mentioned the Z_MIN_POS set in firmware to be 0.23mm.

If your calibration is correct, then your first layer may have to be set to greater than 0.23mm.

If you have a set of feeler gauges, you could start off the print and turn off power during hte first layer and measure the gap between the nozzle and the bed to check whether the above is the case.

Peter

Re: Nothing sticking to be after 1.75mm upgrade

Hey David,

I had the same problem, the issue is to do with the distance the nozzle is from the bed and in my view, the 0.23 minimum height set in the firmware. effectively when you zero the z-axis you are actually setting it to 0.23 because of the 0.23 minimum override. it doesn't make sense to me why they have done that but then again its not my printer or name applied to the thing. For me, zeroing the z axis should zero the z axis and you setup things from there. At least that is what their documentation says should happen, for some reason the firmware doesn't reflect that.

Anyway, I had heaps of issues like you, virtually nothing would print. I adjusted the firmware to set the z-axis minimum value to 0 instead of the 0.23 and now no issues with prints sticking to the bed. I have just have other issues as noted in my other posts. My 3mm version worked great really enjoyed printing with it, the 1.75mm version not so. I wish I hadn't upgraded at the moment.

Angus

Re: Nothing sticking to be after 1.75mm upgrade

Hi Angus/David

I have a Chinese clone running 1.75mm which sets the Z axis to zero. I really don't understand the 0.23mm offset and I have queried this with support via e-mail, but have had no response to date.

Calibration with the clone is done cold, with Z @ 0; the nozzle gap is approximately 0.1mm, or if calibration is done hot, then the gap is as small as possible (for me, that's 0.02mm).

With the Prusa original, I note that calibration is done hot to 0.23mm, hence the z axis offset,

If you don't want to amend the firmware, then I guess there are a couple of options:

Make all layer heights 0.25mm
Print on a raft with the first raft layer > 0.23mm

Some things print better with a raft anyway; with Cura, I have had so many failed prints that I use a raft for almost everything now with that slicer.

Peter.

P.S. My clone has the bed sitting on springs, so if the nozzle gets too close the bed is pushed down. The Prusa is different in that the bed cannot move down and a collision could possibly damage the nozzle/hot end (especially previous versions).

Re: Nothing sticking to be after 1.75mm upgrade

How do I set my z axis to 0?

Re: Nothing sticking to be after 1.75mm upgrade

Jacob

There are a couple of ways of doing this, one easy and one more complex, the latter involves amending and re-compiling the firmware and should only be used if you absolutely know what you are doing.

The easy way is to print with first layer height of 0.25mm ot to print on a raft with the first layer of that raft set to 0.25mm layer height.

The harder way is to download the firmware source code, download and install the Arduino compiler and install the RAMBo as an output device, make a change to MIN_Z_POS (I think that's the one, but I can check it for you if you decide to go this route) to Zero (was 0.23), compile the firmware and upload it to the RAMBo.

If you do want to take this further, and I would advise again that you only do so if you are confident in what you are about to do, then please let us know.

Peter