Looking for Ideas to Improve the 3D Printed Enclosure Mounting

[keenanjohnson]

As I've started to put together more than a few of the 3D printed enclosures, I've become aware that tightening the bolts attaching the main box enclosure to the top sensor shroud and head is a bit tedious. See images below.

I think there are two things making this hard:

• You have to exert a bit of force into the bolt to get it to "bite" into the 3D Printed Hole on the other side.
• There isn't much room to turn a standard hex wrench inside the enclosure. At best you can probably get just over a quarter turn which means a lot of turning motion haha.

Ideas for Solution
I have a few ideas for how to improve this, but I would love to hear other opinions!

• Add a heat insert into the tapped hole - I've thought about adding something like this into the hole.
  . This adds a new part to the BOM which isn't ideal, but it would significantly decrease the force needed on the bolt to get it to thread properly
• Replace bolt with Clips - The previous off-the-shelf enclosure we used to use is held together entirely by plastic clips molded into the shroud layers. Perhaps we could switch the bolts to 3D printed clips? This might make the shroud harder to disasemble, but doesn't add any parts needed to build a frog

[keenanjohnson]

@eaudiffred perhaps you might have opinions here?

[eaudiffred]

@keenanjohnson Two very good points.

1. For some reason OnShape does not model the threads. It's currently just modeling a tap hole for the bolt size that we select. With some other CAD programs I've been able to print the threads. Works pretty good down to M4 size. I'll see if there is an option in OnShape to actually model the threads so that they get printed.
   a. The threaded insert is a good idea, but I agree more parts is a pain and the negative out weights the positive.
   b. I've been tapping the holes for the couple of enclosures I've made and its significantly easier to get the bolts in. They just spin right into place. Can't assume that everyone has an M4 tap laying around though, so we will figure out a way around that.

2. For this I would recommend installing the board after the screws. Without the board in there, you can use the long side of the hex wrench and just spin the bolt into place (if the threads are already cut).
   a. We could angle the bolts slightly more toward the center to get the wrench away from the wall. I could also try and get a compound angle on the bolts so that the end of the wrench also sticks up away from the enclosure.
   b. I like the clip idea too. Just have to think about it a little more and figure out a design that is printable. I'll check out the Acurite design. Maybe we can copy it. We might be able to print a clip piece that pops into the body and the two shrouds.

[eaudiffred]

Instead of the threaded insert, we could make a slot to slide in a nut. Still adds parts, but the nuts will be cheaper than the insert. I don't love that idea because it makes assembly just a little harder, but it can be added to the potential solution list.

[keenanjohnson]

Yeah the captive nut is another good idea!

Here's what the Accuweather Injection-molded clips look like. I'm not sure if this geometry is feasible to 3D print or not.

[eaudiffred]

What do you think about this? Only thing I'm worried about is how securely it holds together.

I think I'd want to test the fit and function of this first. If successful, then figure out how to design a clip between the lower shroud and head piece.

[keenanjohnson]

Oh this looks promising to me! The PETG plastic is quite springy, so I'm not worried about it breaking down over time I think.

Have you already started a test print?

[keenanjohnson]

I can if you have not :)

[eaudiffred]

I have not started one. Wont be able to until I get back in town on the 30th.

[eaudiffred]

I just finished printing a test. Works great!! Much better than I hoped it would. Its snug, so not supper easy to snap into place, but it fits tight and feels rigid. I'll start thinking of a way to incorporate the head. (Ignore the poor print quality. I tried to print it fast and had bad bed adhesion and lots of warping)

[keenanjohnson]

Wow this is great! This will be really helpful I think for easing the assembly for say a student and reduces our parts required! Wins all around!

[eaudiffred]

Are all of the electronics on the top of the housing up-to-date?

[eaudiffred]

Depending on the available space, I'm thinking this might be a solution:

[keenanjohnson]

Oh good call! The electronics are not. I've made the final decision today to switch to a different GPS part that doesn't include the incredibly huge USB cable. #91.

We'll need to update the CAD, but the GPS unit will become much smaller and has a very smaller connector. (Product Dimensions: 25.5mm x 25.4mm x 8.2mm). https://www.adafruit.com/product/4415

[keenanjohnson]

I can update that cad today @eaudiffred

[eaudiffred]

Ok, cool. I think I'll have to claim some of that space for the frog head clips, but it looks like with the smaller GPS there will still be plenty of space available.

[keenanjohnson]

Yes here you can see how it looks in the built assembly, so this is a great space saver

Should I modify this in your clip assembly branch and then we can merge everything in together later?

[eaudiffred]

Sure, that sounds like a good plan.

[keenanjohnson]

Done!

[eaudiffred]

I made some progress on design yesterday.

One thing I'm worried about with this design is disassembly. Once the head is on, it seems like it'll be difficult to remove. One way to fix that would be to modify the clips to slip in and out both directions. That might make it little less secure/rigid. Any thoughts?

[keenanjohnson]

It makes a lot of sense to me that making it easy to disassemble would be important! So I would say let's try it!

[keenanjohnson]

Ok @eaudiffred ! I'm back with my printers now, is this ready for another test print on my side you think?

[eaudiffred]

Yes! I think it's ready to go. I was planning to do a test this week too.

[keenanjohnson]

Awesome! I can start one today if that's helpful.

[eaudiffred]

Defiantly!

[keenanjohnson]

How did you handle the supports for the head top piece now that there are clips coming down?

[eaudiffred]

Good Question! I have not dumped it into Cura to experiment yet. I'm thinking that the Tree supports will work similar to how the last version was printed. The clips hang down further, so less support underneath them. The top/underside of the head will need plenty of support though. That's where it might get tricky.

I'll have some time this evening, I think, to mess around with it. If you start one today, let me know what you try.

[keenanjohnson]

Sounds good! I started a print yesterday, but it failed due to a poor bed leveling on my part I think. I realized after it failed that I probably didn't think about the supports enough. I had it set on the tree supports, but I want to take another look at it today and try again.

[keenanjohnson]

I decided actually to try out a different slicer program called PrusaSlicer, which is another open source slicer I've heard can work better for Ender printers on forums.

I'm trying the print with this kind of support which seems pretty minimum! We'll see if it works haha

[eaudiffred]

Cool! How did it turn out?

This is the first option I'd like to try in Cura. Its the option requiring the least amount of time and material, so it may fail miserably, but I can add material and structure from here.

I need to level my printer again and re-zero the head. Hopefully I can get a print started tomorrow.

[keenanjohnson]

Wow my print turned out great. I was unsure if the petg could bridge that full gap but it seemed to do fine!

[eaudiffred]

Wow! I'm really surprised it could bridge that gap too! Can you post a screen shot of the settings you used?

Is it snug/secure when clipped together?

[keenanjohnson]

My settings were these:

• Bed Temp: 85 C
• Nozzle Temp: 250
• Layer Height: .2 mm
• Infill 15%
• Default supports, build plate only

I used the default Ender 3 V2 Profile in Prusa Slicer.

It feels fairly snug when I clipped it together. I've found that I can definitely pull it apart, but the force required feels about right to me that it's not loose, but also not too hard to separate.

[keenanjohnson]

[eaudiffred]

I printed off a lower shroud and a head over the weekend. Seems like I need to slightly widen the slot in the lower shroud so that the clips fit in a little easier. Other than that it seems to fit well.

Any other thoughts or changes?

[eaudiffred]

Changes are made. Made it 1mm wider so that there is 0.5mm clearance on either side.

[eaudiffred]

I right clicked the hollow blue circle while the latest (purple) version was highlighted. Is selecting "Merge into current workspace" the correct way to do this? Just want to make sure before I screw something up, lol.

[keenanjohnson]

Yes! That's correct if you are currently viewing the Main branch, then clicking that will merge it into main :)

[eaudiffred]

Ok, will you double check me on that. Nothing seemed to happen, but it did add the merge in the change history.

[keenanjohnson]

Yeah that looks good to me! I can see your changes in the main branch with the clearance. You can delete the old branch once you are ready to eliminate confusion in the userinterface as well.

[eaudiffred]

@keenanjohnson, How is the clips design holding up? Is it working out ok during printing and assembly? I still need to print an entire assembly. I'll give it a shot with PrusaSlicer

[keenanjohnson]

Things seem to be doing great so far! I have put together 4 with this design with no real issues!