Alternate hinge designs

[MethylBromide]

I can't see using the Hinge object in many applications because I don't see how it would 3D print cleanly. It's mighty easy for the thing to stick together and be unusable. The main problem I see is the (potentially) long unsupported spans of pin. Aren't these likely to droop during printing and adhere to the barrel? Especially given this problem, the parameter for "Knuckles" seems like the wrong question. What we really want in this design is a maximum knuckle width, so the count can be calculated as a function of that and the width.

The sort of hinge I prefer to use in most cases, unless I add my own pin (as I see you allow) has cones on the alternate knuckles that nest into cone-shaped holes in the other ones. This has no bridges, so it can easily print in a horizontal orientation.

Could we not have an option for that sort of hinge?

[henmedia]

@MethylBromide for the record, there is a related request in #897: @NorthHighlander101 would like a flush hinge, with the knuckles inside the thickness of the leaves and a stop at about 90°. I will answer your idea here separately.

[NorthHighlander101]

Good afternoon....
Now here's a thing..
Re the 3mm thick knuckles and leafs......
On the Bambu A1 mini at 0.2mm nozzle, 0.1 layer height:
I reduced the clearance of the hinge in Layerling from 0.4mm to 0.2mm and here are the results:


Note that I stopped the job at 16 layers out of 30 to see if a narrow clearance would work.
But note especially that, without asking it to, Layerling has automatically increased the knuckle count! Just what I wanted!
I now have a hinge with a wonderfully stiff enough resistance, opens to 90 degrees and doesn't flop about!
Brilliant!

[henmedia]

@NorthHighlander101 thank you for the test and the photos, good to see it work with less play. The extra knuckles are no accident: when a knuckle width is set, layerling picks the count so that no knuckle gets wider than that. With 0.2 mm clearance the gaps take less room, so it adds two knuckles to stay within the width. If you ever want a fixed number instead, clear the knuckle width and set Knuckles yourself.

[NorthHighlander101]

Thank you, Stephan, a very interesting reply which I now understand.
I have tried experimenting with even closer clearances. I originally considered risking 0.15mm rather than going for broke at 0.1mm but I thought, what the heck, it's only filament and electricity!
As predicted, the hinge would not fold at 0.1mm clearance. So I tried again at 0.15mm. At first it would partly bend but a slight bit of force enabled "something" to break and the hinge, now acceptably stiff, bent to 90 degrees with no discernible damage to the cones. I tried pulling the leaves apart with a fair amount of force, but did not manage to separate the leaves.
I tried the same with the 0.1mm clearance model. This time I applied a very much greater amount of force, and the unit did break but not catastrophically. Again, I tried to separate the leaves but without managing to do so. At 0.1mm clearance, the movement is stiff but the leaf manages to stay in the 90 degrees position, something I can use in a future project.

[henmedia]

@NorthHighlander101 thank you for taking it that far, this is useful for anyone who wants a stiff hinge. What broke loose at 0.15 mm was most likely a very thin layer where the cone and its socket fused during printing; once that is free, the hinge moves on its own. At 0.1 mm the 90° hold comes from friction alone, so it may get a little looser with use. For a hinge that must hold its angle for a long time, 0.15 mm is probably the safer choice.

[NorthHighlander101]

"For a hinge that must hold its angle for a long time, 0.15 mm is probably the safer choice."
I agree, I am going to try a clearance of 0.12mm to see the result and I will report further.