<p>I have a Monoprice Select v2 that I just bought less than 2 months ago. I've manually leveled it on several prints prior.</p>

<p>I noticed a couple of holes in my print bed after my last print, like the extruder pushed into the sheet really hard. They're both on the same side.</p>

<p>I then noticed that the extruder's horizontal bar wasn't leveled so I leveled it. I did this by unplugging the wire to one motor and modified the z-position so that the other connected side would go up. (Is this the proper way of adjusting the horizontal bar?)</p>

<p>And then I moved the extruder back into its Home position at z-position 0.
That's when I noticed that it seems my extruder barely reaches my print bed even though I have the screws almost loosened to the point of detaching from the thread.</p>

<p>The extruder z-limit-switch (I think that's what it's called) seems to be pressed so the extruder is as far down as it can go. The controls also show that the z-position is at 0.</p>

<p>So I'm guessing my print bed somehow lowered. But I don't see how that could possibly be.</p>

<p>Any ideas?</p>

<p>Here are some photos but I'm not even sure what to show really</p>

<p>you can see the z-limit-switch in the right of this pic next to the letter A's
<a href="https://i.stack.imgur.com/jj6hS.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jj6hS.jpg" alt="pic1"></a>
you can see my extruder still has some distance to go before reaching my print bed but you can also see that my screws are loosened as much as possible
<a href="https://i.stack.imgur.com/NUOdX.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NUOdX.jpg" alt="pic2"></a>
showing the horizontal extruder bar is now leveled
<a href="https://i.stack.imgur.com/RyK5o.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/RyK5o.jpg" alt="pic3"></a></p>

[{'answer_id': 7882, 'author': '0scar', 'author_id': 5740, 'author_profile': 'https://3dprinting.stackexchange.com/users/5740', 'pm_score': 2, 'selected': False, 'text': '<p>You decide which layer height you want based on the quality you desire, but never go over about 75&nbsp;% of your nozzle diameter, so with your 0.4&nbsp;mm nozzle never choose layer heights larger than 0.3&nbsp;mm. The rationale of this rule of thumb is that the filament leaves the nozzle as a tube and needs to be flattened to make it adhere to the previous layer.</p>\n'}, {'answer_id': 7883, 'author': 'Trish', 'author_id': 8884, 'author_profile': 'https://3dprinting.stackexchange.com/users/8884', 'pm_score': 2, 'selected': False, 'text': '<p>Layer hight can be theoretically <em>anything</em> as long as it fits into these ranges:</p>\n\n<ul>\n<li>it needs to be at least one step for the Z-Axis motor to be physically possible</li>\n<li>it should be at max 3/4th of your nozzle diameter to create an adhesion surface</li>\n</ul>\n\n<p>In praxis, the lowest setting for layer height due to physical limitations of the extrusion systems is around 0.05\xa0mm. </p>\n\n<p>Also, not <em>any</em> number is possible, it is dependant on the Z-axis system: since one or one-half step is the smallest rotation that the stepper can achieve, the raise that belongs to this partial rotation is how much one and the next layer height can be together. The step limitation usually is of no concern though, unless one has a very steep lead screw.</p>\n\n<p>As a rule of thumb: doubling layer thickness results in <em>almost</em> half the print time. 0.1, 0.2 and 0.3\xa0mm are common because they allow easy checking the printed accuracy in Z-axis with calipers.</p>\n'}, {'answer_id': 7886, 'author': 'Dmitry Kasatsky', 'author_id': 14121, 'author_profile': 'https://3dprinting.stackexchange.com/users/14121', 'pm_score': 2, 'selected': False, 'text': '<ol>\n<li>The thicker the layer, the smaller the number of interlayer contact zones (this is a weak point), the higher the strength of the part.</li>\n<li>For good interlayer adhesion, the thickness of the layer should not exceed half the diameter of the nozzle (this is pure geometry). The recommended value is 0.8 * 0.5 * D.</li>\n<li>There is an opinion that the thickness of the layer should be a multiple of the height of the Z climb to one full engine step (in order to avoid accumulation of error).</li>\n</ol>\n\n<p>Thus, for an engine with a step of 1.8 degrees and a screw with a step of 8 mm per revolution (most common configuration of Z-axis), the layer thickness must be a multiple of 0.04 mm. For a nozzle with a diameter of 0.4 mm, the recommended layer thickness is 0.16 mm, maximum valid is 0.2 mm.</p>\n'}, {'answer_id': 9828, 'author': 'Joel Coehoorn', 'author_id': 12562, 'author_profile': 'https://3dprinting.stackexchange.com/users/12562', 'pm_score': 2, 'selected': False, 'text': '<p>Let\'s start with the stepper motors used to move the z-axis. Most printers use a Nema-17 motor, and <a href="https://reprap.org/wiki/NEMA_17_Stepper_motor" rel="nofollow noreferrer">most Nema-17 motors turn 1.8° per step</a>. For the motors that don\'t use 1.8°, almost all of them are .9°, such that assuming 1.8° is pretty safe for most us (if you have a .9° motor and wrongly assume 1.8°, the motor will just take two steps instead of one). </p>\n\n<p>But these motors don\'t move the print head or bed directly. Rather, they will turn a threaded rod to lift or lower the necessary part. We need to figure out the linear distance traveled along the rod per step. </p>\n\n<p>There are two ways to determine this. First, we can look at the threads on the rod, and think about the linear distance traveled if the rod turns one complete revolution. Use a sharpie marker to trace a thread, and then measure the distance. </p>\n\n<p>Alternatively, if we check the specs for the rod in terms of threads and pitch. Most 3D printers use 8 mm rods, but looking at my own printer these aren\'t standard metric threads. Indeed, <a href="https://reprap.org/wiki/Threaded_rod" rel="nofollow noreferrer">the pitch can vary quite a bit from printer to printer.</a> Both 2 mm and 3 mm pitch is common, with the number of threads on the rod varying from 1 to 4. To find the linear distance of a revolution, you multiply the threads by the pitch. A 3 mm pitch with 1 thread has a linear distance of 3 mm. A 2 mm pitch with 4 threads has a linear distance of 8 mm.</p>\n\n<p>With either method, we know the linear distance for one complete revolution (360°). But a single step only moves a small portion of that: 1.8°. Thankfully, this works out to an even number: 360/1.8 = 200. There are 200 steps per revolution.</p>\n\n<p>Now we know enough to figure out the step distance. The math looks like this:</p>\n\n<pre><code>StepDistance = (RodPitch*RodThreads) / 200 \n</code></pre>\n\n<p>As an example 2 mm pitch and 4 threads produces this expression:</p>\n\n<pre><code>(2 * 4) / 200\n</code></pre>\n\n<p>and the final result is:</p>\n\n<pre><code>.04 mm per step\n</code></pre>\n\n<p>Those values are common, but not universal, so you need to know what numbers to plug in for your printer. </p>\n\n<p>You should also be aware that many stepper motors can <a href="https://www.rs-online.com/designspark/stepper-motors-and-drives-what-is-full-step-half-step-and-microstepping" rel="nofollow noreferrer">take half steps or even divide a single step up to 256 times</a>. If you can watch your printer smoothly move from very low to very high, or vice versa, without jerking for each step, this is what it\'s doing. That means your printer may be able to make adjustments as fine as .00015625mm. At this point, we\'re down in nano-meter territory. I think it\'s probably best to assume your printer wants to take at least a half step when moving from layer to layer.</p>\n\n<p>Now lets look at applying this <code>.04 mm per step</code> value to a real printer. Please remember: this is just an example, where the .04 mm number is based off a specific rod type. <em>You need to know the values for your specific z-axis rods</em>.</p>\n\n<p>Let\'s say you have a printer that advertises a .1 mm minimum layer height and a .4 mm nozzle. Given the .04 mm steps, you <em>might</em> do much better actually using .12 mm layers, which is an exact multiple of .04 mm. But then, if we consider half steps, .1 mm could be just fine. On the other end of the range, we don\'t really want to go above 75% of our nozzle width. That\'s .3 mm. Given a .04 mm step height, a better max is really .28 mm... but, again, considering half steps, we could in theory choose to do the exact .3 mm height. </p>\n\n<p>The main thing I want to take away here is for when you\'re looking for an in-between layer height: .1 mm is too slow, but .2 mm is too course. It\'s probably best to bump up the layer in exact half-steps. For this example, that\'s .02 mm increments. So after .1 mm we try .12 mm, then .14 mm, and so on. Finer adjustments may be possible, but there\'s a power of two law at play here, so keep dividing things in half, rather than by 10ths. If you don\'t get good results this way, try assuming full steps, and start at .12 mm for the layer height, then go to .16 mm, and so on.</p>\n'}]
['https://3dprinting.stackexchange.com/questions/7881', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/13712/']