Print Multiple Solids from one extruder (inc. on the single material machines)

[Russell Bates @russb My Robox is a Green Kickstarter Beta United Kingdom]

I want to be able to print two different solids from the same extruder with different infill parameters.

My main use for this would be to create 100% infill areas inside parts with say 20% infill. This would enable me to print solid stiffeners inside hollow or low infill parts, and it would allow me to add solid areas for machining allowances on prototype parts which are post processed (ie, thread or gear cutting, general milling, turning/boring). This saves me wasting plastic printing an entire object solid or adding many perimeters to a part just so I can tap threads in one small hole.

[Mike @17bt CHORLEY, Lancashire]

@russb Forget about doing this in Automaker as you describe, but you might need to go in Advanced mode, but I found by adding more perimeters, when doing threaded parts, was a fair compromise, so that way I had somewhere to bite into post print. I am fortunate my CAD software allows me to create threaded forms, that translate into STLs, so can print the 3D threadforms and clean them up if needed. I do find that sometimes it’s better to do this with the actual screw, as it gets more of a bite.

I should add this is doable in other slicers by assigning a different process to the areas when using Simplify3D for example, but these are usually added at layer intervals. Cura does some natty things with support that block areas, not seen any that do that with material in a print.

[Russell Bates @russb My Robox is a Green Kickstarter Beta United Kingdom]

Mike,

I do print my threads, and if they above a certain size (say 10+TPI/>2mm pitch then they need no tweaks ie. they are near enough perfectly formed unless using a fine layer height which reduces overhang ability and causes a bit of a curl to the thread.

However, I have a part now for example that has threaded ports both horizontal and vertical, printed solid its over 250grams so around 1/3rd of a roll (£££!) and a heck’ov’o’lot of time to print. Also the horizontal holes will never have a nice finish around the top (actually its a bore straight through the part with various diameters) and as it’s a large part printing 5+ perimiters over the whole part just to have enough material to tap in 5 small areas is time consuming. For the top of the horizontal bore, I like to use internal supports and print slightly undersize and then clean up on the lathe - being a able to combine two solids in a similar way to printing dual material parts but with one being solid infill and one being 20%, but both from the same extruder would be really nice.

My current work around is create a hairline gap (or gaps. for thicker solid areas), big enough for the slicer to recognise but small enough that in reality, it prints as one solid part. I position this hairline gap exactly “No.of.Perimeters” multiplied by “perimeter extrusion width” away from the edge to be machined/tapped, and add second gap if needed the appropriate distance away from the first. This then creates solid areas around holes, or even inside parts. This is ok for simply lining holes, but if your looking to create more advanced internal stiffeners for example, this can become challenging.

I’d like to see this feature, if CEL are promoting this is as research and development tool, then why not? I hope that with the software already able to create instructions for two separate materials and extruders, it should be a simple tweak have it create two (or more!) separate “materials” but reference the same extruder for each - allowing parts to be created from a single material but with differing properties. Trying to explain my work around method to some (most) of the other engineers is surprisingly difficult as they don’t understand how a slicer creates the instructions, its all just jargon to them, they just want to press go and wait for their part…….

[Enginwiz @enginwiz My Robox is a Blue Commercial Version Germany]

You can edit the sliced toolpath in Stratasys Insight and add cad geometry as additional toolhead path inside the printed objects. Insight is the slicer for the Fortus line of industrial printers. You have to spend more than € 50000 for these printers and the chip coded filament will cost around € 200 per kg.

Maybe someday the open source and low cost slicers will progress into editing the interior structure of the printed parts. The processes of Simplify3D could be a workaround, but currently not on a Robox.

Your way of forcing the old Cura based slicer in Automaker to create additional perimeters is a clever workaround for threaded areas. Another solution could be to glue solid printed threaded bushings into the side holes of your low infill base part. You could even go further and glue metal threaded bushings into your printed parts to have the same fitting strength as industrial piping.

 

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