one print starts off bed

Hi all,
I got my Ormerod to print!
Still making a few test pieces.

Two issues:
One drawing refuses to start on the bed.
The Z home is good and the setup just finished a different print successfully.
Each time I try to print one particular object it starts about 1mm above the bed.
Made with sketchup and slic3r.
Did I do something to the object in sketchup?

second question is there a way to compensate for small holes?
The drawing has 8.2mm holes on the flat horizontal axis,
but the print comes out 7.4mm.

Thanks for the help earlier,
Kimon

seems maybe there was a reversed face?
Couldn't get the drawing to load clean into kisslicer,
rebuilt it and reversed the faces a few times until they were all aligned.
Successfully printing now.
Still not sure what was wrong though...

Slic3r will put the object on the XY-plane, no matter what is the "lowest Z" in the model. That does mean though that if there is some tiny little bit sticking down under what is supposed to be the bottom, the actual model can start "above Z=0", which will of course ruin it.

As for the holes, they often come out a bit smaller than what is in the model, and how much depends a lot on your printer and print settings. I usually enlarge the diameter 0.3-0.5mm which seems to be enough. As long as the holes are round, that is usually the easiest way to solve it. Problem then is when you have non-parametric designs (which is most of them) and the compensation differs between printers, but the difference is usually small enough that I can just file or drill out the holes to fit.

Getting holes to print to the exact dimensions specified by a design has been a long discussed subject on the 3D print forums, most printers make holes using short straight lines not arcs. That's the nature of the software. These lines either have to criss cross the required arc leaving part of the line outside the arc and part inside the arc, or the algorithm pushes the whole line outside. So unfortunately, you need to know your printer, how it prints different hole sizes and experiment with sizes. Once printed a little reworking as mentioned above using a drill of the correct size is usually required.
Hope that brief explanation helps you not chase the perfectly printed hole for to long.

thanks all.
I see the horizontal holes are a old issue.
Slightly small is ok, and it is consistent, so thats good.

The models that printed off the board all had errors flagged in Kisslicer

I've had trouble printing files that slic3r claims to have auto repaired, including large parts missing from the first layer. I find it safer to run the stl files through the Microsoft/Netfabb online repair facility before slicing them.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Hi Amsterdamman!

I didn't realise this was why you were asking about Kisslicer on IRC. If you're modelling in Sketchup (and, to be fair, other CAD programs, but Sketchup is quite bad for it), be aware it doesn't always produce very good stl files; it is quite easy to have intersecting faces and/or holes in the exported mesh. Then the slicing software has difficulty understanding what is the inside and outside of the model. The best thing to do is to use Netfabb Basic (free - [www.netfabb.com] ) or upload it so the netfabb cloud service ( [netfabb.azurewebsites.net] ) which generally can fix these kind of problems.

Ian
RepRapPro tech support

Another great program for fixing issues is Autodesk Meshmixer: [www.meshmixer.com] I've found that it's resolved some issues for me without having the resort to the Netfab cloud service.
It's also got an interesting system for supports, gives you a great view that shows you where support is required and allows you to add pillars.
The pillars work well when using Cura, but Kisslicer doesn't really like them however .