3D printing a port adapter/extension ring?

[Barmaglot]

First draft of the extension/adapter, with the Tokina 10-17mm inside:

 

 

Got the dimensions a bit wrong - the port side is a little too snug, not leaving space for a o-ring, while the camera side is too loose, not getting any friction. The zoom gear worked on first try but is also a bit too small - the teeth are barely catching. Altered the design, sent it to the print shop for another draft run - fortunately it's quite cheap here in Thailand, less than $20 for both parts. 

[Barmaglot]

@Isaac Szabo, a question if you don't mind - how repeatable are parts dimensions across different 3d printers? I just got my second draft of the extension, and now the housing bayonet is perfect, with just the right amount of snugness to rotate with a bit of effort, but the port side is a little bit loose. I have reduced the internal diameter of the opening from 92mm to 91.3mm which, hopefully, will get it exactly right, but I'm a bit worried that when we're talking sub-millimeter tolerances, a different printer, different material and different settings can put it out of alignment. 

[Isaac Szabo]

You're right that sub-millimeter tolerances are not guaranteed to be maintained across different printers, materials, and settings. As an example, I was recently testing the accuracy of my two printers using a 100mm diameter test print. My main printer had a maximum error of 0.22mm, which I decreased to 0.09mm after some adjustments. However, my newer printer (different brand, different slicer) had a maximum error of 0.51mm, which was larger than I expected. I'll also note that one of the aspects of my waterproof print settings is around 20% overextrusion, which leads to slightly swollen dimensions compared to normal settings. 

Edited March 23 by Isaac Szabo

[Dave_Hicks]

2 hours ago, Barmaglot said:

@Isaac Szabo, a question if you don't mind - how repeatable are parts dimensions across different 3d printers? I just got my second draft of the extension, and now the housing bayonet is perfect, with just the right amount of snugness to rotate with a bit of effort, but the port side is a little bit loose. I have reduced the internal diameter of the opening from 92mm to 91.3mm which, hopefully, will get it exactly right, but I'm a bit worried that when we're talking sub-millimeter tolerances, a different printer, different material and different settings can put it out of alignment. 

For sure there are going to be individual variations, but if you are using a print shop they likely have a fleet of identical printers. These would be likely to be consistent.

 

Settings in the Slicer (Cura, Prusa, etc) have a big impact on the structure of the print. Printing with .1mm or .2mm layer height, or the line width can have an impact on sub-mm dimension. Most printers use a .4 mm wide nozzle, but .2 and .6 used in some situations. This and other slicer settings can create some variation if not carefully controlled. I suppose this is the downside of using a print shop, you don't have quite as much control.

 

It may be better to aim your print at being snug, and then use sandpaper and blades to touch up any fine fit issues. 

[Dave_Hicks]

BTW, I am very curious about the settings you are using to print your port. (Wall perimeters, layer height, material) I am working on some camera floats right now and balancing weight & bouyancy while remaining watertight. I'm willing to work closer to the edge of failure as it's not part of a housing, but still want it to be durable. 

[Barmaglot]

57 minutes ago, Dave_Hicks said:

For sure there are going to be individual variations, but if you are using a print shop they likely have a fleet of identical printers. These would be likely to be consistent.

Right, but I'm using a local print shop here in Bangkok to print non-waterproof drafts so that I can dial in my design, with the intent to send the final version to @Isaac Szabo to print it using his tested method. I'm somewhat worried that the design that produces an exact fit using the local shop's printer and settings will produce something else when Isaac runs it through his process.

[Dave_Hicks]

40 minutes ago, Barmaglot said:

Right, but I'm using a local print shop here in Bangkok to print non-waterproof drafts so that I can dial in my design, with the intent to send the final version to @Isaac Szabo to print it using his tested method. I'm somewhat worried that the design that produces an exact fit using the local shop's printer and settings will produce something else when Isaac runs it through his process.

Yes, that may happen. Iteration and evaluation are part of 3d printing of custom fine tolerance parts like this.

[Isaac Szabo]

4 hours ago, Barmaglot said:

Right, but I'm using a local print shop here in Bangkok to print non-waterproof drafts so that I can dial in my design, with the intent to send the final version to @Isaac Szabo to print it using his tested method. I'm somewhat worried that the design that produces an exact fit using the local shop's printer and settings will produce something else when Isaac runs it through his process.

 

Yeah, I'm not sure there's a way to ensure a good fit on the first try without me putting in more work than I have time for right now. But with your local printer it might be a good idea to try for a fit that's 0.1-0.2mm looser than you want to try to account for the slight bulge from my waterproof settings.

Edited March 23 by Isaac Szabo

[Barmaglot]

I guess I'll have to take my chances and most likely iterate once.

[Barmaglot]

Looks like third time was indeed the charm - now both ends appear to have a snug but not overly tight fit.

 

As an added bonus, it turns out that if I use my old short macro port (originally meant for 16-50mm kit lens or 30mm macro) instead of the 4-inch dome, I get an absolutely perfect fit with the Canon EF-S 60mm macro lens:

 

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This opens up the possibility of using the 60mm with wet lenses, such as attaching the UWL-09F to widen its field of view a bit for larger subjects on blackwater dives.

 

Time to progress to the waterproof print iteration.