consistent issues with first layer only

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Farr0wn3d
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consistent issues with first layer only

Post by Farr0wn3d » Thu Apr 02, 2015 1:57 am

Hey guys, I'm new to the forum and I just got my kit assembled last week and have been printing and calibrating since then. While I'm quite new to 3d printing I do have a fairly considerable mechanical background.

My issue is this, I was able to set up my .2mm settings fairly well, to the point where my first layer was only slightly wider (.55mm) than the successive layers (.42mm) by upping my first layer height to 210% and width to 45%. However, when I'm trying to print at 100 microns, it smushes the hell out of the first layer, letting filament pressure build up in the nozzle and when it lifts for the next layer it unleashes it in a smear for the whole next layer sometimes lol after that its smooth sailing and my prints turn out great.

Is this just something I have to learn to love about the M2? poor first layer and as a result sometimes poor finish on the layers above it, or can this be addressed? any help would be greatly appreciated!

Jeremy in Calgary alberta canada

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jimc
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Re: consistent issues with first layer only

Post by jimc » Thu Apr 02, 2015 2:35 am

ok first thing. if your calibrating and getting your z height set correctly then set everything back to 100%. your height and width. a 45% width is going to throw everything out of whack. with everything set at 100 your first layer should extrude evenly. if its too tight it will smear like you are saying. if its too far away then the extrusion will be very narrow, round and probably not stick. your first layer should go down just as clean as all the others....assuming your build plate is completely flat. there can be slight variances in that.

jsc
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Re: consistent issues with first layer only

Post by jsc » Thu Apr 02, 2015 2:38 am

You shouldn't rely on slicer tricks to compensate for mechanical set up issues. You need to set your z end-stop height so that your first layer comes out the same as all the other layers when printed with first layer at 100% layer height and 100% extrusion width.

viewtopic.php?f=3&t=1964 details how to use a thin wall cube to adjust your extrusion multiplier, and simultaneously find out how far off you are on the end stop adjustment. Once that object comes out with the walls at your extrusion width and exactly 2mm tall, you shouldn't have any issues at any layer height.

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Farr0wn3d
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Re: consistent issues with first layer only

Post by Farr0wn3d » Thu Apr 02, 2015 3:28 am

First off, thanks for the replies!

I cant say with absolute certainty that my build plate is irregular but when I use the bed level wizard and get 100 microns at the edges and then bring the nozzle to the center of the build plate its touching the glass. Are the stock settings in Simplify3D for the v3b 24v M2 accurate or will they require more than minor tweaks?

I did that calibration test and I got my wall thickness to match the auto setting of .42 with the multiplier set to .80 I will have to go back and pay more attention when doing this again, because the best I got for the prints without top or bottom was 1.8mm

Jeremy

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jimc
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Re: consistent issues with first layer only

Post by jimc » Thu Apr 02, 2015 4:08 am

80 seems low if you have your filament dia set correctly. measure your filament and be sure that is entered in the s3d other tab. that value and the multiplier effect flow rate. its not uncommon for glass to be out .1mm. get the bed gap set correctly with the extruder centered on bed. like both me and jin said though you need to set the first layer width and heigh back to 100 to do any of these calibration settings.

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Farr0wn3d
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Re: consistent issues with first layer only

Post by Farr0wn3d » Thu Apr 02, 2015 4:39 am

Thanks jimc, I've set everything back to 100's and did a bed level and the glass is definitely higher in the center. I'm heading to bed right away, but tomorrow I'll get to work on straightening out my z axis issues. I'll post what I come up with

Jeremy

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Re: consistent issues with first layer only

Post by over-$-pent » Thu Apr 02, 2015 6:23 am

Flip your glass over so the high spot is down and use the bed clips to pull the glass flat on the ends. I had this happen to me and it worked well. I'm within about .002 side to side and end to end now. Give it a try.

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Re: consistent issues with first layer only

Post by TSC » Fri Apr 03, 2015 2:34 pm

I have the same crown issue with my new M2. Mine isn't the glass though it is the metal plate that has M2 engraved on it. The clips actually bend the glass to the metal plate. I used the same procedure with the bed leveling wizard in Simplify3D as you described earlier. Normally I never checked the middle until I tried to get things a little closer to the nozzle to avoid having to always print a raft, and I found the nozzle scraping my tape off in the middle. I then checked the metal bed on a machinists table and can easily see/measure a relatively large crown. I was wondering if this was typical for an M2 as well. I have difficulties with the first layer due to this crown. It would be interesting to hear from others if this is a common problem and how they deal with it.

jsc
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Re: consistent issues with first layer only

Post by jsc » Fri Apr 03, 2015 11:23 pm

You can optimize the height for the middle, because that is where most prints will happen, or optimize for an average between the center and the edges to better use the whole bed. It's not an issue except for at low layer heights, and you can always print the first layer at a larger layer height to get around that.

If you check out the recent MIC6 plate thread, that gives a link to get a machined aluminum bed replacement which is dead flat across the entire bed, which is quite nice.

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Farr0wn3d
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Re: consistent issues with first layer only

Post by Farr0wn3d » Sat Apr 04, 2015 6:35 am

Well guys I appreciate the help and I feel a little foolish..

when I was leveling the bed I was doing it cold and with a piece of paper, and my nozzle might have had a bit of a clog from all the crammed up attempts leading up until now. I decided to swap on my spare v3b, heat up the nozzle and bed to operating temp, swing the fan out of the way and just do a fine visual alignment ensuring that the z stop light would illuminate the instant I couldnt see light between the nozzle and bed, I did this in the center to get the height, and then max/mix X, then max/min Y. once I was confident I was at perfect zero with my z stop. I did a the calibration print and what do you know... it came out perfect. 2.02mm tall, .41mm layer width, with my layer height and width in simplify back at 100%.

Needless to say I'm thrilled, and excited to go from here. Just gotta clean the first nozzle now.

Thanks again fellas!

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