One process with raft, one without, wrong first layer height

[TopJimmyCooks]

Set up a two process print, one model with raft and one straight on the bed. it tries to print the entire raft first and then drop Z back down to the bed to start the first layer of the non-raft model. Not sure why it wouldn't alternate layers as with the rest of the print. but anyway, that will work as I oriented the parts so the nozzles wouldn't hit.

The raft and skirt for the raft print fine at the expected first layer height. However, the non raft part the Z height is wrong and the first layer tries to start at about 0.00Z.

I suspect its just a bad idea to have raft and non raft parts together but interested to see if anything can be adjusted or if it's just an issue. factory file attached. Thanks.

[JoeJ]

That looks 100% correct to me. Both parts are printed correctly on the bed, even though only one of them has a raft. The small gap you are seeing between the female buckle and the raft is due to your raft separation distance setting (currently set to 0.1mm). That greatly helps the raft separate easier from the part, so you probably don't want that to be set to zero. I usually use around 0.15mm.

Again, looks 100% correct to me.

[TopJimmyCooks]

The issue is not the raft which looks perfect but rather the first layer on the non-raft model. I will try a G-code z offset on the no raft process and see if I can get the nozzle off the bed. the printer is behaving as it does when I try to extrude with the nozzle touching the glass - the hobbed bolt slips on the filament and very little comes out.

[JoeJ]

The "first layer of the non-raft model" is elevated above the raft because you have a positive raft separation distance of 0.1mm in your settings. That setting determines the air gap between the raft and the first layer of the model (there is a good diagram here: https://www.simplify3d.com/support/tuto ... and-brims/)

A gcode z-offset will shift the entire print (raft included!) down by the entered amount, so that's not what you want.

[TopJimmyCooks]

So gcode Z-offset is per factory file rather than per process. Is there any good documentation about what settings in the process edit dialog affect the entire print? Shouldn't they be in a different dialog rather than the "process edit" dialog if they're global rather than per process? Perhaps some labeling or different tab setups or background colors or something to identify global settings are in order.

By the way my mistake was that the non raft process had a layer height of 0.1mm and In the past I have always set a default .35 mm first layer regardless of subsequent layer height in Slic3r. My Z offset from abl probe to nozzle in firmware was too small to handle such a short tolerance/was tuned for .35mm. Changed the layer height on that process to 0.2mm and it worked.

In the future if I have raft and non raft processes on in the same factory, probably need to make a 3rd process to get better control of the first layer of the non raft part if/when it prints after the raft.

There's a lot of capability here and I'm digging it, but it is not as easy as it could be to get there.

[TopJimmyCooks]

Gcode Z offset can be either positive or negative. Not trying to troll at all, just want to be clear for posterity.

The raft/part separation was ok but I need to play with it. looks like S3d doesn't default to laying a solid layer down for the first part layer above the raft. Need to look into that -that's odd. What if it was a flat bottomed vase or something?

[dkightley]

Not 100% sure I'm talking sense here....but here goes!

From what you're saying, the first layer is printing with the nozzle too close to the bed. You have your right extruder first layer settings at height 90% and width 100%. If you believe the first layer is printing with the nozzle too low, perhaps increasing the first layer thickness up to someting like 150% (or greater) will lift the nozzle up. To compensate for the amount of filament that it would want to extrude, reducing the first layer width down to something like 50% may be what is then needed.

[TopJimmyCooks]

That would be another viable solution if it was the first layer in question. However, I don't think S3D considers it to be the first layer. It prints the raft for the vertical part completely first- layers one through five, then moves and lowers Z and says it's on layer 6 for the first layer of the 2nd (non-raft) horizontal part process. so to really control that layer separately you would need to introduce a 3rd process that is only for layer 6 and apply it to that model only.

[dkightley]

I downloaded your factory file and upped the first layer thickness on the right extruder settings to 150% ....and the simulation showed the first layer to be thicker. So I think the layer is being treated as a first layer.

Just another thought.....have you got the right extruder nozzle at the correct height for correctly printing a thin layer? If you've been printing at 0.2mm layer thickness and thinking the z positioning is okay when its actually a tad low.....and then switch to 0.1mm layer thickness and find the nozzle is almost touching the bed.

[TopJimmyCooks]

I saw the same difference in graphical representation of layer 6/layer 1 but it is not the case in printing. the first plastic to hit the bed (skirt on the raft) shows effects of layer 1 changes, but layer 6 is a .20mm layer.

You did nail it though, I have always made my first layer .35mm with slic3r regardless of subsequent layer height. then I tuned my z probe offset to bring it down about .2mm, so when it hit a .2mm first layer height with this factory file, it was tight to the glass.