Hello all,
I have printed a bunch of ‘print-in-place’ models with hinges, etc.
Then I thought, OK, I’ve got the hang of it now (pun intended). Let’s just try printing a simple thing ‘in-place’ and see how badly I fail.
I failed hard, probably due to a lack of knowledge or naivety.
I found that a good tolerance for my H2D is 0.15 mm, as demonstrated by various readily available test models I printed.
So, how can I print these two barrels in place without using a ridiculous amount of special support material that dissolves in water (PVA)?
Is this possible after all? Any hints are welcome!
If not, never mind — I was just too naive! 
The files and print profiles can be found below.
How-to-print-in-place.3mf (75.6 KB)
Link to the folder containing all files:
Thanks for any suggestions — cheers!
You can’t. The design is too tight.
As you have noted, the only way would be to use dissolvable filament. However, only a tiny amount.
You would create a “washer” shape and place it under the outer spinning tube. Just that, none anywhere else, one or two layers max.
If you wanted this entirely printed without support, you need to tweak the design.
The inner spinning tube would need to be changed so its outer due touches the build plate and the slowly moving backwards and getting taller.
Essentially an angled shape top and bottom.
Let me know if that doesn’t make sense and I will mock up a visual for you. It will maintain the spin and be entirely printable without supports.
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I have not opened your files.
a trick to print in place is modeling the support. it is a way to specify exactly how to do the support.
Or you could use the manual support to only support the overhang.
Add support to the outside parameter of the overhang. allowing it to bridge.
surface finish might be an problem.
Can you change the geometry?
If so, change the overhang to a cone shape.
Good luck.
Another solution is to split the part. That is the best surface finish on the overhang.
I am thinking an L shape that is revolved, and a flat washer. Maybe with an interface shapes.
Performs the same job, and each part is printable without support, prints together as a single print, with no other parts required.
That inner cut can be a smooth curve if you prefer.
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Thanks for all the suggestions — they all make perfect sense!
I created this model as a simple object for my actual problem H2D vent bayonet mount v2 suction dial & 90° mount (which I solved differently, as you can see).
@Robert_ONeill:
I like your idea of modelling ‘breakaway’ or ‘sacrificial structures’ into the model. If you have PVA, it should even work in tight spaces, as with this object. On the other hand, how many people do have PVA to hand for printing? I wonder how you could print those ‘sacrificial structures’ in the same material so that they can be removed from this tiny space.
@MalcTheOracle:
I tried leaving more space between the inner and outer objects vertically, but they always stuck together at the horizontal top and bottom interfaces. If I made the top and bottom gaps larger, the result was pretty ugly, but as I said, I don’t know if there are clever settings for “self-supporting” printing. Your suggestion in the picture you posted might be doable in my other design, for which this was a practice run. I used this method in a couple of places, but I’m not sure why it didn’t occur to me in this situation.
I thought there might be a clever setting in the slicer that would prevent the bottom and top horizontal interfaces from sticking together (where the outer ring supports the inner ring and vice versa).
Thanks again for all your suggestions — I’ll experiment with them and see what works best.
Your problem is different to your original suggested solution.
It is a rotational locking join. Essentially, one that can be achieve by turning an outer against an inner where the inner is a socket design and the outer is the plug.
If you have an empty (reusable) Bambu Lab filament spool, you can see this type of joint used to lock the two sides together. Your solution would do this across a wider portion if the initial tubing (in your model photo vs the simple and narrow one in the spool example), but the principle is the same.
Unlike a traditional screw, it is designed to lock two things together, providing a uniform direction that doesn’t rise or fall (like a screw), but can spin a ore-determined way around the circumference.
Thanks for the quick reply!
I should have been more precise!
I don’t mean the bayonet lock. That is working perfectly fine and I don’t want to print this in place - I meant the “dial ring”.
I designed the “dial ring” so that it can be broken open at a seam and then slipped over the hose connection:
This is what I would like to print-in-place and this is what this simplified model was supposed to represent.
I was talking about that as well, you were clear enough, maybe I wasn’t.
At first glance, the locking mechanism of the spool reminded me of the bayonet lock I used, hence my reply. My engineering English is a bit weak on the weak side.
Let me have another look at the filament spool and digest your comment a bit 
I am talking about a twist rotation restriction with a hodge at the start and end so the rotation can be left open or closed rather than a full on hard lock.
Malc’s saying that if you abandon your rigid squares for a more printable 45degree angle, you wont need support at all, (or at least, not in the intricate thin bits) and as long as you still leave a reasonable clearance gap, it will be freespinning, captive, and not fused together.
Or maybe he’s sayin somethin else. I dunno. <3 But his idea’s good.
lots of good suggestions. A couple of thoughts.
The main problem with generic print in place is supporting the first layer above the gap. This can be done with the support that needs to be removed or with angled layer. Support that needs to be removed is an option. You may have noticed that on the image MalcTheOracle sent had an angle interface. This can go back to vertical after it reaches the right diameter.
My attempts at PVA support have been marginal. It was a long time ago and I found better ways.
Another way is pause the print and put something in. In a case like this is print a thin washer. when the print is paused, insert the washer. The next layer will stick well to the printed washer. But under the washer remains separate. You might use a pva glue (glue stick) to keep it from moving during the print. Then soak out the glue. Just leave room for the inserted washer.
To take this concept up a notch. insert some bearing that is friendly to soaking. print the “washer” insert the bearing, then insert the printed washer. Maybe the bearing is something thick like a ball bearing. Maybe it is something thin like a ring of nylon.
I was not clear that the “washer” is printed before the main print.
Thanks for the suggestions!
It all sounds pretty complicated for someone who just wants to print a tool without investing too much time.
Since the dial ring cannot be printed with the print bed as the base and must be supported by the ‘inner’ ring, I suppose there is no straightforward, easy way to do this. Lesson learned
Alternatively, You could just treat the ring like a “Support” and model it 0.20 away from the bottom, it will be crunchy and need to be snapped free like normal supports. Some of the popular print in place stuff does this (infinity cube hinges, etc)
I can show you how to do it your original way and using dissolvable support in two places if you have it.
No design changes from your earlier model.
Or if you have support for PLA, in the same two places.
Support for PLA came with the P & X series. I do nit know if it comes with the H2 series (not checked).
I tried to do that, but I never managed to get a print where I could loosen it and if the gaps got to large, it ended up pretty ugly 
But I will give it another go and make the vertical distance between the two object way larger to ensure the spinning axis is 100% not interfering.
Yeah, I have been working on that issue for a while now, some people know me from my Fidget Gyros and spinner fame.
https://makerworld.com/en/collections/1848447-the-gyro-and-spinner-family
This one turned out popular.
Let me mock you up a model with the logic in-place and I will share the 3MF.
You can choose if you do something with the principle or not within your own work.
Theoretically I think I got the idea. I modeled - as suggested - a one layer sacrificial structure between the two objects to print this in PVA. But I don’t think this is suitable for publishing a model - not everyone has PVA at hand just for this.
It becomes even less practical because the actual model should be printed in ASA-CF (or other more heat resistant material), so you can’t use anything dissolvable. 
How-to-print-in-place-sacrificial.3mf (103.4 KB)
Waiting for the print now - lets see if it works in general.
