Toolpath outside print area  

RE: Toolpath outside print area

Looks like you are in Simple mode.  Change to Expert mode and MANY more settings become available.  

For a full size print you would need to start off with turning any skirt off.  Make sure there is no brim, change the support expansion from the default 3mm to 0.  Thats at a minimum.  You still might have trouble though as support even with zero expansion still has a tiny bit outside usually.

You would need to attach a zipped up copy of your Prusa Slicer project for us to be able to tell you more.  File>Save Project As and then take the saved 3mf file and ZIP it up and attach it.  Must be zipped or the forum wont do it.

RE:

Thank you, I appreciate you taking the time to help this noob out. Hoping to learn how to maximize my build volume in general in addition to fixing this particular simple project. I did take a look at both the expert mode as well the middle one and got overwhelmed and went back to basic 😀 

If it isn't practical to build 250x210 with support, that's fine. It would be great to hear recommendation as to what the actual practical max is.

I've attached my project as per your instructions. Thank you again for taking the time to help me.

RE: Toolpath outside print area

Here you go.  Several things in the interest of learning 🙂

With a object like this then a layer height of 0.15 is pointless.  Its just adding to the print time.  Its all stright up and down with no details.  I've changed it to 0.2 but you could go 0.3 and not really see a difference.  Except to make it quicker tot print.
The support settings are the default and definitely suboptimal.  A 0.1 contact z distance will result in difficult to remove support.  The part of pretty thin so Id be worried about it breaking at the top section when trying to remove support.  I've changed to a contact distance of 0.2 which should make them easier to remove.  I also changed the expansion etc that I mentioned so that it will print without exceeding the plater size.  Other support changes made, top interface layers increased to 4 (will help with removal), Bottom interface layers set to 0 as they aren't needed or wanted, XY separation increased slightly to move support a bit further away from the part.

At the layer height you had selected you had a single layer of infill.  That's also pointless and could possibly result in the top surface being wavy/depressed in spots as it would sag into the gaps in the infill.  With large area flat tops like these you really need to up the infill % to much more, say 40%.  With a single layer though its just easier to increase the top or bottom layers and get rid of infill and just do another solid layer.  The time difference will be minimal, especially with the savings of going from 0.15mm layer height.

Are the holes in the Object supposed to be octagons ?  Normally that would indicate low resolution export to stl settings in the CAD software.  Also 90 degree transitions on those edges are stress hotspots.  Normally you would add a chamfer to them to reduce stress in a small area.  Its quite a thin part and I don't know what sort of structural load it is supposed to take.   

RE: Toolpath outside print area

Like I said before I'm a noob, so assuming I did any of this on purpose is a bad assumption 😀 I'm mostly just fumbling about using all defaults trying to learn along the way, so I truly appreciate all the pointers. No the holes are actually supposed to be circles but they came out as octagons, like due to export setting issue as you suggested. It isn't critical to the design whether it is circles or octagons, it's just screw holes. I'm using OpenSCAD as my CAD software. Sounds like I need learn what a chamfer is and how to add that to the print, been wondering how I design it so that bend is stronger. The thickness of that model isn't something I put a lot of thought into, just picked some thickness that seemed reasonable, maybe I should make it a little thicker.

It is intended to be bolted to a keyboard drawer via those holes and serve as a place to have my mouse. So it doesn't need to support a huge load, but needs to be strong enough for me to rest my hand on and navigate a mouse around on. I'm estimating this might be around 1.5kg of weight.

Again, thank you so much for your help.

RE: Toolpath outside print area

I guessed that 🙂

I would be making it much thicker overall, particularly the vertical section, its almost certain to break along the layer lines.  That vertical section is very very thin and all it has is layer adhesion keeping it together with not a lot of surface area.  You are probably going to need much more than a chamfer, like support ribs that extend along the right angle joins both top and bottom.  The design you have would be great if it was made out of steel or another metal (although even in steel it would flex as you move the mouse around) but for plastic, well even if it was injection moulded it would still break I think after even limited use.

RE: Toolpath outside print area

. I'm using OpenSCAD as my CAD software

It's important to increase $fn from its ridiculous default value to get rounded circles. I usually just set 

$fn = 64;

at the beginning of the script.

Any decent computer should handle this just fine. 

But in case previews get bogged down, you can also use two different values for preview and render:

$fn= $preview ? 32 : 64;

See https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Other_Language_Features#.24fa.2C_.24fs_and_.24fn

RE: Toolpath outside print area

And as Neophyl pointed out, you're not going to have much joy with this unless you significantly increase the strengths of both the vertical part and the large surface. The way it is now, it'll break just by staring at it too hard.

RE:

You might gain some strength by printing that part on its side, then the filament would be laid around the corners and you are no longer relying on layer adhesion, also no support needed - it will still break but not quite so quickly.  Make it thicker and add some ribs.

Re octagonal circles:

You can set $fn globally globally as @fuchsr suggests but you can override it if you like.

// Example

$fn=120;

difference(){
    cylinder(r=20, h=10);  //  uses global $fn
    cylinder(r=10, h=10, $fn=5);  // overrides global $fn
}

This cuts a pentagonal hole from a cylinder.

Cheerio,

RE: Toolpath outside print area

Thank you.

RE: Toolpath outside print area

Great idea, thanks.