First Layer Settings
June 25, 2017 03:54AM
I'm really getting into fine tuning my printer, which is a Duet wifi converted Zortrax M200, with a Printbite surface on the build plate.

This thread is not about surface adhesion, I'm not having a problem there at all.

My problem is that I just can't quite nail down the right level of solid infill on the first layer.

I don't claim to be the guru, but I am not a beginner and have gone through all the practical steps methodically....leveled bed thoroughly at operating temp with a feeler gauge, set nozzle height, run bed compensation, extrusion test/set esteps every new roll of material and then checked extrusion further by printing double thin walled squares and measuring the thickness. I tend to then take that extrusion multiplier up just a tad so if anything I'm extruding slightly over rather than under.

The problem I'm having is that the first layer lines are open as if under extruded, but if I up the extrusion it stuffs the hell out of the top layers.

This is worst with ABS, slightly evident with PLA and not happening with PETG. All at 0.2mm layer height, 90% first layer height and 100% first layer width.

I'm new to S3D, but again have tried to be methodical.

I started by increasing the layer width, which a reasonable person would assume would "increase the layer width" and therefore fix the problem. But no, it also increases the gap between the lines and therefore doesn't help, at least not by itself. I actually think this is a really dumb feature, as if it just affected the width and not the gap between the lines it would be so easy to dial it in to perfection. Of course I could be missing something, I'm not perfect.

I've tried dropping the first layer height down to 50%, also not really seeing an obvious change.

I've tried slowing it right down, which doesn't hurt but adhesion wasn't the issue.

I haven't tried any Z offset yet, as it seems that it would have the same affect as lowering the first layer height.

I find the S3D troubleshooting page and forums only good for issues I had right in the start of printing, but really would like to see some advanced "dial it in to perfection guides".

Could anyone share their step by step procedure that uses the 3 settings (height/width/offset) in the correct order for a correct resuly in closing up the lines in the first layer.

I've even considered running 2 process's in the slicer, with 0-0.2mm being run at a higher extrusion mulitplier to close it all up, but I'm hoping to avoid elephants foot in my prints.

Would really appreciate some tips from the supercoaches.
Re: First Layer Settings
June 25, 2017 09:33AM
Can't help you a lot, sorry, but:
Quote
hobbymods
I haven't tried any Z offset yet, as it seems that it would have the same affect as lowering the first layer height.
This you got wrong, AFAIK. Z offset affects the height of the nozzle ONLY. Modifying the first layer height affects the height AND the amount of filament extruded.
Re: First Layer Settings
June 25, 2017 12:04PM
When i print at a layer height of 0.2, i set the initial layer height at 0.35 with 120-150% extrusion. this should fill in your gaps in the bottom layer.

When you set your 1st layer height down to 90% i think you are moving the nozzle too close to the bed and restriction the extrusion,
Re: First Layer Settings
June 25, 2017 03:42PM
Quote
obewan
When i print at a layer height of 0.2, i set the initial layer height at 0.35 with 120-150% extrusion. this should fill in your gaps in the bottom layer.

When you set your 1st layer height down to 90% i think you are moving the nozzle too close to the bed and restriction the extrusion,

I'll try that, but I'd have thought that the S3D default of 90% layer height and 100% extrusion width would be reasonably close to the mark?
Re: First Layer Settings
June 26, 2017 06:39AM
I would agree with Obewan


_______________________________________
Waitaki 3D Printer
Re: First Layer Settings
June 26, 2017 08:55AM
Quote

I haven't tried any Z offset yet, as it seems that it would have the same affect as lowering the first layer height
Very different things. What did you set the bed gap to? If you set it with a feeler gauge you must have a gap and that should be your Z offset.
If your feeler gauge is 0.15, your first layer height is (0.2 x 0.9) = 0.18 and you have 0 Z offset the nozzle will be at Z = 0.18 but the gap will be 0.15+0.18=0.33 so it will look like under extrusion.
You should set the feeler gauge width as the Z offset (negative as its bellow the nozzle).
Increasing the extrusion width should help so its odd that it doesn't but im not familiar with your software. Infact it seems to be acting like increasing the nozzle width.
I would be setting my first layer about 0.25 to ensure I have some chance of coping with errors in the initial Z gap and setting the first layer multiplier at 120% to ensure I have some pressure.
Re: First Layer Settings
June 27, 2017 09:57PM
After extensive messing around wit this, I've found the sweet spot for my machine printing ABS in 0.2mm layers.

I've found that a first layer height of 150%, width of 120% and Z offset of -0.2% works beautifully for me.

I didn't like going too high on the width, as the lines were a bit fat for my liking and some detail was lost in tight and tricky corners.

My machine runs a Duet Wifi board with an IR Z probe, and a Printbite surface.

Zero nozzle height is set by raising the bed until the nozzle pins a sheet of paper (as per the manufacturers procedure), then entering a G code that sets that height as absolute zero, so I'm guessing theres about a 0.1mm positive offset there already.

I'm knocking out "Warpinator 5000's" in ABS that are dead flat and staying stuck to the bed, so I'm guessing I'm on the right track.

I'm not at all new to printing, and my machines are adjusted/leveled very finely mechanically with feeler guages mostly (with the exception of the sheet of paper for nozzle height before someone picks that one), I just needed to get my head around S3D and the way these 3 settings that can be used for the first layer relate to each other.

Much happier now!
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