1 Topic by DLM

  • DLM
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Topic: Bed Temp, Leveling Issue, or filament tension?

Hi All,

Complete 3D printing newbie here.  Just set up my brand new Solidoodle 2.  Using Repetier Host with the built-in verion of Slic3r on a 32 bit XP machine with 4gigs of ram, Q6600 Intel CPU, and an old Nvidia 8800 graphics card with 1gig of ram (I realize that 32bit XP won't actually recognize all 4gigs of ram).  I also skimped on buying the enclosure--something I'm kind of kicking myself for now that I realize how important temp control is for this machine. 

Anyway, downloaded a few test STL files to check output.  Let the extruder hit 196 C and the bed about 91 C (wouldn't get any higher) before starting my print.  Imported a test STL file, sliced it for a .1 print, and all was going well.  I then set about printing.  First attempt just pushed around the first layer all around the bed.  I then realized that I was stupidly looking at the "set" temp for the bed, not the actual temp.  It was less than 80 C, so I gave it some more time.  On the third try the bed was about 91 C, it does stick, but it only sticks well on the far-right corner closest to the spool holder (when facing the machine).  When printing the first few layers of the medallion keychain I was printing, it would get octagonal on the opposite corner (near left corner).

I just let it attempt to finish to see what would happen.  About 30% through, the entire print slid off the bed and followed the extruder head.  I killed the print and took the resulting piece off the print bed.  The far right corner of the print was near flawless.  Layers lined up, particularly with a grid patter it was making, and the sidewall was completely perpendicular with the back face, as it should be.  The near left corner, or just about the remaining 75% of the medallion was very flawed.  Layers didn't match up and the edge/sidewall was very slanted as if it was progressively widened instead of printed on top of itself.

I'm wondering if this is a leveling issue, a Z-tab issue, an uneven bed temp issue, or a filament tension issue.  I understand that this might not be enough info to diagnose, but some general direction would be helpful.  I'm thinking it is a leveling and filament tension issue.  I noticed that the near left corner was the furthest away from the spool, so it put some tension on the extruder head when stretching the filament.  I also noticed that when the bed wasn't hot enough, it seemed to stick to the corner closest to the spool, which probable had the least amount of tension and/or was level or hotter than the rest of the bed. 

I'm going to try to mess around with the Z tab later today and check into leveling, but any comments would be appreciated.

2 Reply by highc7691

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Re: Bed Temp, Leveling Issue, or filament tension?

leveling and z tab seem like the most likely to me. I just figured out all of those on my machine, and before that uneven prints were really common. Try adjusting the z screw closer if the print isn't being picked up by extruder. Also make sure to check out bed leveling, as that seems like a bad level. If that doesn't work then you might have to do a bit more serious work.

3 Reply by westin.williams

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Re: Bed Temp, Leveling Issue, or filament tension?

Just did the leveling and z height adjustment on mine today. I printed the file attached (scale it as need in R.H.), it allowed me to calibrate all four corners of the plate with the three leveling screws for the bed, you can see them under the kapton tape fairly easily. After that, I slowly adjusted the z height until it matched what my commanded height was, I'd use a business card or something of similar thickness if you don't have a feeler gauge to measure the distance very accurately. If you are still not getting it to stick, I did some slight firmware adjustments on extruder temp since ABS melts better around 225C but if you are afraid to go that far aqua hair spray works wonders. Just BARELY spray the bed (when it's warm, helps it evaporate more cleanly)  and you will get it to stick just be very careful not to put too much or you will be prying your print off with a crowbar. Acetone will clean it off real well anytime you want to remove the residual spray. If you use the solidoodle profiles for slic3r you should be fairly good to go. I'm dealing with my own communication issue at the moment but I have gotten extremely good quality prints after I made a few of these simple adjustments. Goodluck!

4 Reply by DLM

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Re: Bed Temp, Leveling Issue, or filament tension?

westin.williams wrote:

Just did the leveling and z height adjustment on mine today. I printed the file attached (scale it as need in R.H.), it allowed me to calibrate all four corners of the plate with the three leveling screws for the bed, you can see them under the kapton tape fairly easily. After that, I slowly adjusted the z height until it matched what my commanded height was, I'd use a business card or something of similar thickness if you don't have a feeler gauge to measure the distance very accurately. If you are still not getting it to stick, I did some slight firmware adjustments on extruder temp since ABS melts better around 225C but if you are afraid to go that far aqua hair spray works wonders. Just BARELY spray the bed (when it's warm, helps it evaporate more cleanly)  and you will get it to stick just be very careful not to put too much or you will be prying your print off with a crowbar. Acetone will clean it off real well anytime you want to remove the residual spray. If you use the solidoodle profiles for slic3r you should be fairly good to go. I'm dealing with my own communication issue at the moment but I have gotten extremely good quality prints after I made a few of these simple adjustments. Goodluck!

I ended up trying some bed leveling last night.  Kind of sucks that I had to poke through the kapton tape, but oh well.  Fiddled with those three hex screws and my disposable subway pass.  All seemed level and tight, and then I went for a test print at 196C and 90C, and it still picked up the first layer when trying to make the second pass.  I looked at the Z tab, but quite honestly, that screw feels like it isn't even attached to anything.  It is kind of frictionless when turning it.  I couldn't seem to get any different results from it.  Finally, I thought to trouble shoot using deductive reasoning.  I'll squish the first layer, then slowly ease the distance away instead of the other way around.  I leveled the print bed fairly flush to the extruder nozzle.  One would think this would produce a wide smear of a first layer.  However, upon printing, I still got these rounded first layer lines that barely stuck to the print bed.  It was as if the Z height reset someone between leveling and pressing print. 

I'll go back again and try to mess with the Z tab again.  May also try another suggestion of slowing down the pace of the first layer.

5 Reply by westin.williams

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Re: Bed Temp, Leveling Issue, or filament tension?

When you run your print, do you have it put down a skirt around the print job? It's in the slic3r print settings. I have mine do 2 passes or 10mm extrusion whichever is greater and that helps get the plastic flowing. It will pull up for part of the pass and then it reaches it's flow point and adheres to the bed. It is also possible your flow rate is low. If you don't extrude enough plastic to match the speed at which you are moving the nozzle will begin putting tension on the laid down plastic and this also makes it harder to stick. Again the settings are in the filament setting in slic3r and all you do is increase the flow rate factor. This will increase the number of steps per mm on the extruder motor to give you more flow. You can also try and adjust this in the R.H. manual settings for percentage of flow without have to reslice your project everytime until you figure out exactly what's causing it.

6 Reply by IanJohnson

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Re: Bed Temp, Leveling Issue, or filament tension?

The Z tab doesn't attach to anything.  The limit switch for the bed bumps into the bottom of the screw, so where you set the screw controls how close the the nozzle the bed homes-

http://wiki.solidoodle.com/first-layers … e-z-offset

7 Reply by DLM

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Re: Bed Temp, Leveling Issue, or filament tension?

westin.williams wrote:

When you run your print, do you have it put down a skirt around the print job? It's in the slic3r print settings. I have mine do 2 passes or 10mm extrusion whichever is greater and that helps get the plastic flowing. It will pull up for part of the pass and then it reaches it's flow point and adheres to the bed. It is also possible your flow rate is low. If you don't extrude enough plastic to match the speed at which you are moving the nozzle will begin putting tension on the laid down plastic and this also makes it harder to stick. Again the settings are in the filament setting in slic3r and all you do is increase the flow rate factor. This will increase the number of steps per mm on the extruder motor to give you more flow. You can also try and adjust this in the R.H. manual settings for percentage of flow without have to reslice your project everytime until you figure out exactly what's causing it.


Thanks for the suggestion.  I do have a skirt, and flow doesn't seem to be a problem in that the machine almost drips a bit when I hit anything higher than 190c at the extruder.  Well, on second thought, maybe the pre-flow doesn't really tell me anything.  I'll check the flow rate once I get my machine running again.  It decided to not run yesterday.