Adding connections.

[ukracer]

I need to made a printed surround for a perforated steel bed.
Approx 2mm thick.
Obviously my 3D printers are not big enough for 400mm in one print but I can print a few lengths that fit the bed.

I have never added connections to parts. Is this done in Fusion or Cura.
I.e design stage or Slicer stage.
I can print 4 corners and a number of straights. As long as it raises the steel perforated plate up by 25mm it will do the job.

 

[Dr.Al]

Definitely design stage. I've done quite a few things with connected parts and I tend to use dovetails as it's fairly easy and they're robust. I just draw a dovetail shape across the face of the part, extrude the line through the part and then use the resulting surface to split the part in two. With my printer, I don't have to add any extra clearance (although I sometimes fillet the outside corners to be sure), but you might need to depending on how things fit. After printing, they slide together with firm pressure and stay together very rigidly (depending on thickness).

 

[Screwdriver]

Orientation is everything. Any type of plug and socket join will work but it is vitally important to design in the orientation of your print right at the start. I typically design a part knowing which side is flat on the bed (always trying to avoid supports) that will also tell you which direction your print layers will be on any dovetail or plug. That in turn allows you to avoid layers being perpendicular to the axis of strength required iysiwm.

Exactly like the grain in wood, you orient your material to have strength in a given direction and never at random, same with FDM.

<edit> PS I have had tremendous success by using micro screws in tiny printed holes. Even my venerable Ender3 will print a 1mm hole! It will be a bit rough but it doesn't matter, it can be chased out with a drill bit and the added bonus is it gives you near perfect alignment and as strong a joint as you like. At that scale, you don't need threads, the micro screws will cut their own thread easily and that part of the print is typically stronger than an unscrewed part.

 

[Agroshield]

...I tend to use dovetails...

Would there be any advantage from a stress perspective of using something that looks more like a jigsaw puzzle joint than a sharp-cornered thing?

Something from here might go well with a 3DP: https://openbuilds.com/projectresources/50-digital-wood-joints.229/

 

[ukracer]

This is almost what I need https://www.thingiverse.com/thing:1007544

If I can rework the stl to stick a 2mm groove 5mm deep all around the inside and make it bigger and split it into section short enough to print it might just work.

 

[Dr.Al]

Would there be any advantage from a stress perspective of using something that looks more like a jigsaw puzzle joint than a sharp-cornered thing?

Something from here might go well with a 3DP: https://openbuilds.com/projectresources/50-digital-wood-joints.229/

I'm not sure to be honest. I use the dovetails as they're super easy to draw and they've always worked for me.

 

[Bladevane]

Definitely design stage. I've done quite a few things with connected parts and I tend to use dovetails as it's fairly easy and they're robust. I just draw a dovetail shape across the face of the part, extrude the line through the part and then use the resulting surface to split the part in two. With my printer, I don't have to add any extra clearance (although I sometimes fillet the outside corners to be sure), but you might need to depending on how things fit. After printing, they slide together with firm pressure and stay together very rigidly (depending on thickness).

I tried this method with a 2mm thick dovetailed corner/edge and it worked a treat. The parts pushed together firmly straight off the printer bed. Maybe a thicker printed piece would need some clearance but so far I'm impressed. Thank you @Dr.Al for suggesting this method.