<h2>Problem</h2>

<p>My CR-10 printer seems to be trying to print the model 4 or 5 layers too low. This means that for the first few layers, the printing nozzle is forced against the bed, preventing extrusion until the print reaches higher layers.</p>

<h2>Outcome</h2>

<p>This results in the bottom part of the print having the internal structure visible and the printing head deteriorating. I had to remove the old nozzle because it was clogged up with what I believe to be some residue that was picked up during preceding prints.</p>

<p><a href="https://i.stack.imgur.com/mUfsT.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/mUfsT.jpg" alt="A print showing the structure inside the model because of missing layers"></a>
<em>note: On this print, the top part is almost-well printed. It cannot be seen in pictures, but I say "almost" because the well-printed part is still much thinner than expected. This is the result of my purposeful mis-leveling the bed so that the part where the printer "homes" is higher than the lower part. I did this to see if there was any obvious bending of the printing bed. Doesn't look like there is.</em></p>

<h2>Fix attempts</h2>

<ul>
<li>I have tried to re-level the bed multiple times, but it doesn't matter as the "too low" effect is independent from the location on the bed.</li>
<li>I have tried using the printer's built-in Z-offset but to no avail. This might be due to the fact that I control the print through Ultimaker Cura 4, so I tried looking for the Z-offset property in Ultimaker Cura and even though internet says it exists, I failed to find it.</li>
</ul>

<h2>History</h2>

<p>The printer used to work perfectly well and I do not remember having changed anything before the problem arose. I recently changed the nozzle and made sure to tighten it as high as possible but the Z-offset problem still persists.</p>

[{'answer_id': 10800, 'author': 'Stefan', 'author_id': 14693, 'author_profile': 'https://3dprinting.stackexchange.com/users/14693', 'pm_score': 1, 'selected': False, 'text': "<p>Did you verify the Cura z-offset actually changed the corresponding G-Codes? </p>\n\n<p>I had the opposite problem on my RF1000. To fix the problem I added the following 2 lines to my start G-Codes:</p>\n\n<pre><code>M3001 ; Activate Z-Compensation \nM206 Z-0.3 ; Set z offset 0.3mm closer to the nozzle\n</code></pre>\n\n<p>The first line was default in some example prints and is (as far as I know) only used by Renkforce printers. The second line moves the nozzle closer to the bed. In your case you'd have to move it further away and would need a positive Z value.</p>\n"}, {'answer_id': 10801, 'author': 'Mathieu VIALES', 'author_id': 12378, 'author_profile': 'https://3dprinting.stackexchange.com/users/12378', 'pm_score': 1, 'selected': True, 'text': '<p>TLDR; Make sure the bed isn\'t too high, the z-axis should reach the end-of-rail indicator without forcing against the bed</p>\n\n<hr>\n\n<p>So it appears I simply misunderstood (or mis-assumed) the way my printer works.</p>\n\n<p>For some reason I believed that it was the printing head, while auto-homeing, that was defining the "point zero" for the z axis. Didn\'t realize, even after disassembled the whole head block, that there was no such mechanism built in.</p>\n\n<p>While zeroing it before starting my on-going print I noticed the "click" of the end-of-rail switch for the z-axis while the head was forcing against the bed, desperately trying to reach that damn switch. Then it all clicked together ...</p>\n\n<h2>What happened:</h2>\n\n<p>For some reason a few weeks ago I decided to level the bed by raising the z-axis by spinning the its driving wheel <em>by hand</em>, taking it very far from the end-of-rail stopper. Ever since then I\'ve been leveling the bed this way, not realizing I was preventing the head from reaching end-of-rail without having to force against the bed.</p>\n\n<p>So yeah, just took the bed as far down as possible, made the printer auto-home and leveled the bed from there, as it should be done, and my print is now going very well.</p>\n'}]
['https://3dprinting.stackexchange.com/questions/10798', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/12378/']