Z-Axis grinding on Print Start. Home's All Axis Perfectly?

[waxtronaut]

Ok, so I've attached a video. To date, although new at this, have printed about 30 or so good prints on this machine. Today, when switching filaments, I went to start a new print off and SD Card like I usually do, when at the beginning of the new print, the extruder zero's in perfectly on all axis as you can see in the video, but then once it clears the initial homing process, and begins to move to the right of the print bed and lower itself back down on the z-axis before extruding some filament off the side of the bed. I hear a terrible grinding sound now and the z-offset is about 1/4 inch higher than the print bed. I dont' know whats going on because the initial homing on all axis is perfect as always, but then this happens.

I haven't changed anything physically, but did change profiles inside of Simplify, from the semi-flex back to the standard high quality 1mm PLA pre-set I've had good luck with prior. I can't physically see any obstructions that would cause this stopping of the z-axis before it returns to the proper zero position on z-axis. I have unplugged the z-motor, and the motor that moves laterally, I didn't mess w/ the one connected to the extruder as it was too tight to mess with, and also unplugged, and replugged in the main power cable. I've reset the power and still have same issue.

Any guesses as to whats causing this?

Other than this new issue, for being a newb, i've had a blast printing things from hatchbox wood fill, semi-flex, glow in the dark, and all kinds of awesome filaments. This is THE printer I knew I'd waited years to buy... I have zero buyers remorse. I'm using Simplify3D and its equally as fun to use and the prints I show my friends blow them away. the finish on my prints are like glass, unbelievable how good... I love this machine so far.

https://drive.google.com/file/d/0B9_kEj ... sp=sharing

[Jules]

Is the problem just happening with one specific file? Maybe the factory file that came on the SD card?

We saw something like that happen when the V4 nozzles first came out, because the file on the SD card for the vase was initially set up using the V3B nozzles. (The V3B sits a lot lower than the V4.)

I'd try the file over USB instead of using the SD card, to see if it makes a difference. Or maybe try a different file and see if it still happens. (Make sure you're using V4 profiles.)

(Or maybe the guys know of something else it might be.)

And it looks to me like your Z-Knob is set a little too closely to the frame - there is supposed to be a filament width's worth of space between the bottom of the knob and the frame, to keep that squeaky grinding from happening when it drops the bed down. There's a little set screw in there, and you would need to raise the knob a little, then tighten the screw. (They come loose with a lot of machine vibration - just tighten it up.)



(If you're just getting started, you might want to take a look at the new Beginner's Guide we just posted yesterday. Lot of handy stuff in there.)

Beginner's Guide viewtopic.php?f=3&t=3342

[Slipshine]

Check in your profile to see if the code it adds to the beginning of the print has been changed.

it sounds like it is going over to purge the nozzle and the the z axis is commanded to go down . The table cant go any higher so the stepper skips (the grinding sound) throwing out your z-position until you home the machine.