Newbie trouble: Brand new assembled mk3 doesn't configure
 
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BernieC
(@berniec)
Trusted Member
Newbie trouble: Brand new assembled mk3 doesn't configure

I just received an assembled MK3. Every time I power it on it tells me I should run configuration on it, so today I did. And it failed. It says if the XYZ calibration catches the paper I should power it off and do some adjustment I don't think I'm capable of doing properly. It was on the right side [that is, the calibrations did fine on the near-left-side calibration point, but when it slued to the right to do the second one it caught the paper. Is there some simple way to describe what needs to be done? I have no idea where the "M3 screw" is nor am i familiar with the assembly of the probe holder. There's a diagram in the manual [6.3.10.2] but no scale or what the black line is actually indicating. Sorry to be so helpless, but this might also affect another problem I've been trying to cope with [prints never stick; I've IPAed, acetoned and dishwahed the plate to no avail and the nozzle running too low could account for that].

Thanks /Bernie\

Posted : 15/11/2018 5:29 pm
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Illustrious Member
Re: Newbie trouble: Brand new assembled mk3 doesn't configure

M3 means metric 3 mm ... but the instructions are talking about the screw that retains the pinda probe.
https://manual.prusa3d.com/Guide/9.+Preflight+check/514?lang=en

This procedure sets the mechanical height of the pinda probe - the distance between the nozzle tip and the pinda.

Adjusting the vertical Z axis lead screws to level the X axis is a pretty simple task, then you adjust the pinda height.

While power is off, and remove the metal sheet ...

Move the extruder to the far left, adjust the left vertical lead screw until the nozzle just touches the heat bed.

As you manually move the extruder from left to right, use your finger to turn only the right vertical lead screw a bit to prevent nozzle dragging.

Once the extruder is on the right side, adjust the right lead screw so the nozzle just touches the heat bed.

If you need to turn the vertical lead screws after this step - you must turn both screws an equal amount so the X axis stays level !!!

Now, move the extruder to the center of the bed. Use a shim (I used a a cable tie as my shim) and place it under the pinda probe, between the probe tip and bed. Loosen the pinda screw, and slide the pinda probe down until it touched the shim. Tighten the screw so it holds the probe in place.

If this sort of adjustment bothers you - you are going to hate 3D printing. Fine adjustments are a requirement for most every new print. And the Prusa Mk3 is more automatic than most 3D printers, including expensive ones.

The second manual adjustment you must do manually is First Layer Calibration. This is the part that determines if prints are going to work; whether the first layer sticks to the PEI bed. Essentially, you are doing a software calibration for pinda height (telling the software how high the pinda is off the bed). The idea is to get an accurate 0.2 mm first layer. You will be doing this a lot - learn the procedure well.

If you did the mechanical pinda height adjust correctly, the Z offset value should be somewhere between -500 and -1500. Personally, I've used values between -650 to -850 as the nozzle wears.

Another bit of advice, never touch the surface of the PEI sheet with your fingers. A finger print will destroy a print. Handle the PEI sheet only by the edges.

Here's photos of my latest First Layer adjustment: I prefer the large circle because I can see how well the material is sticking and have lots of time to make live adjustments.

Posted : 15/11/2018 7:24 pm
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Illustrious Member
Re: Newbie trouble: Brand new assembled mk3 doesn't configure

ps: The XYZ failing - dragging against the paper - is probably due to the X-Axis not being level.

Lots of reasons shipping could have tweaked the frame a bit causing the problem.

The X-Axis must be level to the heat bed. Just run through the PINDA adjustment making sure you can manually move the extruder side to side without scraping the nozzle. Start with the nozzle close to touching on the left, and turn the right lead screw as needed while moving the extruder right.

The right Motor shaft is the right lead screw I am talking about. The shaft turns freely when power is off.

If the subsequent xyz check still fails, you'll probably need to adjust the First Layer / Live-Z setting to a more positive number (e.g., -800 towards -600).

Here's a link to the official Prusa build instructions for this step:
https://manual.prusa3d.com/Guide/9.+Preflight+check/514?lang=en

If it continues to fail, then you should contact Prusa customer support.

Posted : 15/11/2018 7:56 pm
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