Just built, calibration errors with microswitch  

Re: Just built, calibration errors with microswitch

Photo?

Re: Just built, calibration errors with microswitch

sorry, I've been out of town. no need for photos. I'll describe what the problem was, and how I got myself into it.

The cable wrap behind the extruder assembly was causing the interference. When I was assembling the printer I was sure I was closing the switch. When I finished assembly I had that large gap. I've unwrapped the cable wrap from the area that interferes with the chassis.

However, I now have another problem which should probably go in it's own thread. I was able to print while I had the printer in my work area, but now that I've moved it to it's final location, I can do a self test and pass, a Z axis calibration and it does perfect, but when I do an XYZ calibration, the extruder is mashed down hard onto the bed. I've moved the sensor WAY down below the nozzle to prevent damage to the bed. I'll do another Z axis calibrate, and then the XYZ again, and it ALWAYS mashes down hard on the platform. What's happened?

Re: Just built, calibration errors with microswitch

sorry, I've been out of town. no need for photos. I'll describe what the problem was, and how I got myself into it.

The cable wrap behind the extruder assembly was causing the interference. When I was assembling the printer I was sure I was closing the switch. When I finished assembly I had that large gap. I've unwrapped the cable wrap from the area that interferes with the chassis.

However, I now have another problem which should probably go in it's own thread. I was able to print while I had the printer in my work area, but now that I've moved it to it's final location, I can do a self test and pass, a Z axis calibration and it does perfect, but when I do an XYZ calibration, the extruder is mashed down hard onto the bed. I've moved the sensor WAY down below the nozzle to prevent damage to the bed. I'll do another Z axis calibrate, and then the XYZ again, and it ALWAYS mashes down hard on the platform. What's happened?

People who have had XYZ Cal smash down like that have reported success by doing a factory reset, then reinstalling the latest firmware.

I am assuming it is not SEEKING down into the bed, but smashing down right away.

The other possible cause is that the printer is not seeking where then little plugs are on the bed (1 has a circle around it), due to bad belts or steps on the X or Y gantry.

Re: Just built, calibration errors with microswitch

That is good advice, and i did just that. My problems are a bit more complicated.
Do a self test, everything passes. Do a Z axis calibration, and it stops at the correct distance from the plate about half the time. If it does fine, I'll move on to the XYZ calibration, and when the RAMBO sensor/nozzle come down from highest position, it goes down hard on the plate. Power off, start over, and I'm stuck in this circle.
I've checked the end stops, and when I put a metal object under the RAMBO sensor it always changes from Z0 to Z1.

I've gone to factory reset. I've reflashed the firmware. I've double checked that I have good connections between the cables and the control board. At this point I'm stumped, and scared to keep trying, as I am digging a little hole in the print platform with the nozzle.

Re: Just built, calibration errors with microswitch

Please post a photo of the TOP of your printer. Where you drive the gantry to the top when you do a Z Cal. The part that hold the Z axis screw and rod.

Re: Just built, calibration errors with microswitch

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I have more here, including a video where i fail a z calibration but autohome just fine. Also some pictures of the tip with extruder at bottom and top positions.

https://www.dropbox.com/sh/5dmn57uh9eg0f4w/AACdlqDir-1xlQvg1J3npZjXa?dl=0

I'm quite discouraged as i see no reason for this to happen.

Re: Just built, calibration errors with microswitch

It is hard to tell from your photos, but based on 20171023_201524.jpg it looks like you might not have the extruder seated properly and it is hanging down too low. (Very hard to tell from that perspective.)

The XYZ Calibration routine is written differently than I would expect. It does NOT use the PINDA probe at all. It steps down a certain number of steps from the "hard stop" at the top, and then begins to search for the PINDA trigger points by moving back and forth, then slowly stepping down, to find them. The result is that if something on your machine is incorrect (e.g. the distance from the top of the Z gantry to the bed) it has no way to know that. Some people have installed the Z end stops incorrectly which changes that distance, which is why I wanted to see a photo of the top. (Yours look okay).

The heat block should not hang down below the fan funnel. See photos on steps 7 and 17 here:
http://manual.prusa3d.com/Guide/5.+Extruder+Assembly/295

If you could take a photo like the third photo on Step 1 and the first photo of Step 2 here:
http://manual.prusa3d.com/Guide/9.+Preflight+check/302

(Note the heat block is up higher than the fan shroud, and the PINDA does not protrude as far as yours does.)

(Yours might be okay, I just can't tell from your photo.) Additional photos of your extruder and how it is mounted might help us identify an issue. The bottom line is something in your assembly has changed that distance, and the head is crashing because of it.

Re: Just built, calibration errors with microswitch

More images have been added to dropbox link above. I see what you mean. Ill adjust that tomorrow and see what happens. Thanks!!

Re: Just built, calibration errors with microswitch

More images have been added to dropbox link above. I see what you mean. Ill adjust that tomorrow and see what happens. Thanks!!

Yup. That is the issue. The extruder is not installed correctly.

Once you have that fixed, please use these steps to get going:

http://shop.prusa3d.com/forum/prusa-i3-kit-building-calibrating-first-print-main-f6/-before-you-ask-troubleshooting-video-updated--t472.html#p39190

Re: Just built, calibration errors with microswitch

Thank you so much. It's working perfectly after playing with the LiveZ Adjust for a half hour or so.

Is there a way to replace my gouged print bed?

Re: Just built, calibration errors with microswitch

Thank you for taking the time to look at and solve my problem. After about a half hour of LiveZ Adjust it's printing like a champ.

Re: Just built, calibration errors with microswitch

First you need to figure out if the bed itself is damaged, or just the PEI sheet. The PEI sheet is readily replaceable and inexpensive.

The bed is more expensive. Prusa sells one, but shipping is high. There is a third party one which is also not cheap. If you can live with it for a while (e.g. you can move prints out of the way) do so, and then do the upgrade to the magnetic bed when it comes out (Dec or Jan?). I think that will be a very nice upgrade.