Nozzle rubbing/touching object

Hello. I'm new to 3d printing and purchased two CR-10s (one for home and one for work).

The printer at work is just fine and have several nice prints. 

The printer at home is having problems and I'm hoping someone can help me out. The print starts fine but after about 1" high the nozzle starts rubbing against the newest layer (top) of the object being printed. After a few passes it just knocks the object off the bed and messes it all up.

I tried lowering the bed, then readjusted the bed height to recommended settings. I also slowed the feed rate and set Z Hop to .1mm (I think that's what I set it to).

I was noticing that the first layer (adhesion layer) was fine around the edge but right in the center I noticed that a line was slightly above the bed and was not sticking. I raised nozzle temp to 210 and the bed to 67 and everything started to look fine(clean adhesion layer)....but then I noticed the rubbing after about an inch in height. I never noticed the rubbing before because the print never made it past the first layer. I'm not printing a large object either. I tried two different objects and it does the same thing.

I'm using 1.75mm blue PLA filament. I used this filament at work and had no issues (didn't adjust anything at work....straight out of the box)

Any help is appreciated!

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Hi @FDDRAGON is the part still properly attached to the bed before the problem occurs?  Some nozzle fouling problems can be simply where the part has warped away from the bed and curled up so that it's in the path of the nozzle.  Does the problem happen suddenly, or can you see the nozzle beginning to drag into the surface slowly over many layers?  Does it happen all across the top surface or only at one point, and if at one point, is it the same point every time?

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It seems to happen suddenly and I will do another print to see if it does it at the same point.

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It's a good idea to make yourself a simple test cube or cylinder say 20mm on a side/diameter and 40mm high, rather than using a large, slow print.  Try printing this piece at various locations on the bed. 

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I am going to agree with cobnut.  The number of folks we see on here testing with large, slow prints is amazing.

 

Print a small test cube (20mm x20mm) at 100% infill.  If you do, I bet you will see a hump on it.  This means that you are overextruding, and at some point the material builds upward, until your nozzle hits it.

 

The same file on 2 same printers print the same.  Is that what you are doing?

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Yes, I am printing the same file, no adjustments to the file. And both printers are CR-10.
I've already printed 5 items on the printer at work and had no issue.....I still haven't had one successful print at home

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