S3D first layer issues?

[Chadd]

For those of you using S3D I was curious if you see odd first layer issues?

In my case I will print a part with say .2mm layer height and set the first layer to 50% layer and 130% extrusion with a brim. The brim will print flat as can be against the glass but as soon as it starts to print the actual part the first layer is no longer compressed on the glass and it has gaps between the extrusion. I have to manually increase the extrusion % through the control panel to around 140% for the first layer to get it to stick and then turn it back to 100% for the rest of the part.

I am confident this isn't a printer homing issue because the brim prints as expected and is stuck well and my Z home seems to be very repeatable.

I looked at the Gcode and it doesn't appear that the Z axis is being raised between the brim and the actual part first layer so I am at a loss here.

One thing I have noticed about S3D is that sometimes when you set the first layer extrusion width above 100% it will actually create gaps between the first layer extrusion instead of forcing the extra material into the same space. I have seen this by changing the setting then looking at the print preview. I would really like to get this solved as it is one of the very annoying things about S3D that drives me crazy.

About the only way I can consistently keep this from happening is to set a negative offset for the Z axis but that creates other issues and really compresses the brim making a mess out of it.

Any ideas?

Thanks,
Chadd

[CalifDan]

Chadd,

I use S3D and it took me awhile to figure it out also. I set the initial height to 80% or 90% and the width to 90 or 100%. Higher, I get space between the first layer lines. I also run the infill overlap pretty high (30%) as otherwise I don't get good overlap with the outer layers.

You might want to experiment. That is what I did. I just kept adjusting things doing the first layer or two until I started to understand how some of the settings were working. S3D is different coming from Slicr or Cura. I do like the ability to trouble shoot in the viewer.

[Chadd]

Thanks for the tips, I guess that I had forgotten about this because I had the same issue a while back with the first layer extrusion % setting. If you set it above 100% it doesn't force the extra material into the same space. It will actually change the spacing between the extrusions on the first layer and create gaps instead of filling it more densely. Like some other things with S3D it makes absolutely no sense, if I set the extrusion for my first layer to 130% I want 30% extra material to be laid down on the first layer and that isn't what happens with S3D.

That's the problem with 3d printing, you are always chasing your tail trying to figure out if you have a hardware or software issue. I was thinking that I had a Z axis hardware issue until I posted a thread with questions about bed mapping and got some feedback. Then I realized that my Z home and bed mapping were doing exactly what they were supposed to do and were in fact very repeatable and that the problem had to be software related.

I had even mentioned this issue with first layer extrusion in my S3D thread a week or to ago and had a brain fart and forgot about it. That is the problem with using multiple slicers, you forget the tricks of each one of them as you swap between them. I really hope that S3D comes out with an update soon to fix the issues that make me have to go back and forth between it and other slicers to print different parts.

So to answer my own question to get a good first layer in S3D the best way is to set your first layer height slightly lower and to leave the first layer extrusion set to 100%. As long as you have a good Z axis home and level/mapped bed you should get a good first layer. If you increase the first layer extrusion above 100% it will leave gaps between your extrusions on your first layer.

The only other option would be to set a negative offset for your Z axis in the gcode window but this will create issues with your brim so I don't recommend it unless you actually need the - offset due to a Z axis home issue.

Chadd,

I use S3D and it took me awhile to figure it out also. I set the initial height to 80% or 90% and the width to 90 or 100%. Higher, I get space between the first layer lines. I also run the infill overlap pretty high (30%) as otherwise I don't get good overlap with the outer layers.

You might want to experiment. That is what I did. I just kept adjusting things doing the first layer or two until I started to understand how some of the settings were working. S3D is different coming from Slicr or Cura. I do like the ability to trouble shoot in the viewer.

[jimc]

chadd, if you increase the first layer height above 100% it absolutely does increase the amount of filament being extruded. i can get my first layer to go down thick and crazy fat if i wanted to. with that said i rarely set my first layer height to anything except 100. i want my first layer to go down the same as all the others. i never go below 100. if i print at a low layer height like .1mm then i will bump the first layer to 125-150%. results are always as expected. there is an increased amt of filament extruded to make all the lines touch. now when you drop below 100% s3d will keep the extrusion amt the same so you can sort of squish the filament onto the build plate. could it be that you have your extrusion multiplier and everything calibrated for that first layer then when it jumps back up to full layer height its not extruding enough?

[Chadd]

chadd, if you increase the first layer height above 100% it absolutely does increase the amount of filament being extruded. i can get my first layer to go down thick and crazy fat if i wanted to. with that said i rarely set my first layer height to anything except 100. i want my first layer to go down the same as all the others. i never go below 100. if i print at a low layer height like .1mm then i will bump the first layer to 125-150%. results are always as expected. there is an increased amt of filament extruded to make all the lines touch. now when you drop below 100% s3d will keep the extrusion amt the same so you can sort of squish the filament onto the build plate. could it be that you have your extrusion multiplier and everything calibrated for that first layer then when it jumps back up to full layer height its not extruding enough?

As I mentioned I am talking about the layer width setting for the first layer under the "layer" tab. I promise you if you increase it to a number above 100% it will create gaps in your first layer and extrusion. Just as CalifDan and I have both seen, along with numerous others on the S3D forums.

If you read the tooltip for it it even says "The width of the first layer extrusion can be increased to help with adhesion". That is how it should work but it doesn't. Like I said you can reproduce it by changing the setting and then looking at the print previews.

I have been trying to print a part with S3D now for the last 2 hours and have had to stop the print and peel off the build plate because the first layer is not laying down like it should. The issue is that I can slice two different parts with it using the exact same settings and it won't slice them the same. One part I can slice and it prints a very good first layer, the next part I slice without changing anything and the first layer is crap.

Just when I think I get it figured out the very next part I slice I get poor results and have to spend time and resources to get that particular part to slice and print correctly. I guess I am just one of the numerous people who can't figure out how to consistently get S3D to produce good prints.

[jimc]

oh yes you did say width. well what you are seeing i have never seen before. i can set that width whatever i want and the flow increases to make the line that width. i also dont see the inconsistency issues either. in the past 4 days i have printed 120 of these parts. 6 on the bed at a time. im running 2 printers, same make and model. i have sliced each time i do a bed full of them and they print exactly the same every time. im not sure why you are seeing such different results. if you just leave the first layer width and height at 100%, set your bed gap correctly you shouldnt need different settings for the first layer really. as long as you have 100% contact thats all you need. it cant get any better than that. with everything set at 100% and the gap set on your printer it just makes everything easier and doesnt leaver room for any weird crap to happen. i pretty much set it and forget it.

[Chadd]

oh yes you did say width. well what you are seeing i have never seen before. i can set that width whatever i want and the flow increases to make the line that width. i also dont see the inconsistency issues either. in the past 4 days i have printed 120 of these parts. 6 on the bed at a time. im running 2 printers, same make and model. i have sliced each time i do a bed full of them and they print exactly the same every time. im not sure why you are seeing such different results. if you just leave the first layer width and height at 100%, set your bed gap correctly you shouldnt need different settings for the first layer really. as long as you have 100% contact thats all you need. it cant get any better than that. with everything set at 100% and the gap set on your printer it just makes everything easier and doesnt leaver room for any weird crap to happen. i pretty much set it and forget it.

I really wish that were the case for me, it looks like I finally have a successful print on the part I have been trying to print. I ended up just increasing the extrusion to 150% through the machine control panel for the first layer then turning it back down to 100%. The only reason I battled this part for so long is that I needed the supports that S3D generates for this one, it does such a good job with supports.

If you take a look at this thread over on S3D forums it is the exact same issues that I have with the first layer in S3D.

https://forum.simplify3d.com/viewtopic.php?f=9&t=2292

[jimc]

yes i posted in that thread. ok there arent that many things that cause that. #1 cause is the bed gap isnt set correctly. the width of the lines being printed is controlled by your bed gap. now there are a couple things that control the bed gap. #1 is your mechanical setting on the printer. #2 gcode tab you can have some z-offset entered there (should be zero). there is also something else i want you to check. go in the scripts tab and look at your start script. look at the last line. do you see a command that looks like this "G1 X180 Z0.25 ; lift"? not sure what printer you are using but the x value in that line is not important but i want you to remove the z part so the line should just read G1 X(xxx). xxx leave the value thats originally there. if you have that bit of code for the "z" then its dropping your bed .25mm before it starts printing making the bed gap for the first layer too big.

[Chadd]

yes i posted in that thread. ok there arent that many things that cause that. #1 cause is the bed gap isnt set correctly. the width of the lines being printed is controlled by your bed gap. now there are a couple things that control the bed gap. #1 is your mechanical setting on the printer. #2 gcode tab you can have some z-offset entered there (should be zero). there is also something else i want you to check. go in the scripts tab and look at your start script. look at the last line. do you see a command that looks like this "G1 X180 Z0.25 ; lift"? not sure what printer you are using but the x value in that line is not important but i want you to remove the z part so the line should just read G1 X(xxx). xxx leave the value thats originally there. if you have that bit of code for the "z" then its dropping your bed .25mm before it starts printing making the bed gap for the first layer too big.

I appreciate your suggestions and your willingness to help but I really don't think you understand the issue. I agree that most first layer issues are due to Z height problems but in this case it isn't. If it were a Z height issue both the brim/outline and the part would exhibit the same under extrusion and they don't. You can increase the gaps in the parts first layer by increasing the "first layer width" above 100% the more you increase it the larger the gaps get. Try it out for yourself and I think you will see.

The issue is that when you use the control within S3D to increase the extrusion on the first layer it doesn't work, it does the exact opposite.

The brim will print perfectly but once it goes to the actual part first layer where it uses the extrusion width that you have set in the layers tab it leaves gaps between the extrusions just as show in the pictures from that thread. If you notice his brim outline is printed perfectly but the layer of the part isn't. That rules out any issues with Z height otherwise both the brim and the part first layer would be printing the same and they don't, again the brim prints as it should.

I have parsed my Gcode generated by S3d to verify that there are't any changes to the Z height between the brim and the part and there aren't. So the only thing that can be different between the Brim and the actual part is the width of the extrusion and the difference in tool paths for the extrusion width.

I did receive an email back from S3D support and he said that instead of using the setting for "first layer width" that is in the layers tab that I should set up a separate process for the first layer if I want to more than 100% material extrusion on the first layer. So they must know that sometime is up with the "first layer width" setting.

[jimc]

Hmmm i see. I wish i had something useful i could tell you but im just no seeing that happen here on my end. My brim prints the same and i can make my first layer width super fat with no problems.....weird