Machinable plastic for a electronic module with wireless?

WobblyHand

WobblyHand

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Have a small electronic board with display that needs a housing. The housing needs to protect the backside of the unit and to be able to pass wifi signals. I think that the housing could be milled out of some 1/2" or 5/8" thick white acetal. (If I had a 3D printer, I'd probably use that. That's yet a different rabbit hole to fall into!) Would need a block about 3" x 4" x 1/2". Is acetal an ok choice for this? Concerned about milling out a pocket and having the block distort or fold up on me. The block would have walls about 0.30" thick and the base about 0.25-0.30" thick. The pocket would be about half the depth of the block. Assuming that's ok, how would one go about doing this? How do you clamp the acetal enough to work on yet not distort this stuff? As a beginner, one hasn't got much experience to draw on, so sometimes these "simple" things seem difficult. Suggestions or alternate ideas welcomed.
 
You will have no problems making a shallow box with quarter inch thick walls out of delrin. Just mount the block in your vise.
You don't have to clamp the vise as tight as steel because the cutting loads are so much lower in plastic. Delrin machines a dream, once you do you won't want to go back to mild steel.
 
markba633csi said:
How about just buying a little plastic box? Aliexpress has lots
Click to expand...
Little boxes with dimensions, stand offs and features in the right place are rare. Nonetheless, that's a pretty good idea to have some of them on hand for these sorts of projects. I'll take a look and see if I can snag a few for future endeavors.
 
If you can, a "project box" from one of the many manufacturers would be a lot cheaper than a block of delrin that you turn 90% of into chips. There's nothing wrong with cutting one though, and I can't see any reason it wouldn't work.

Depending on the electronics, you might also be able to use an external antenna. I've got a wifi connected device outside now in an aluminum box with an external antenna that works great.
 
Asm109 said:
You will have no problems making a shallow box with quarter inch thick walls out of delrin. Just mount the block in your vise.
You don't have to clamp the vise as tight as steel because the cutting loads are so much lower in plastic. Delrin machines a dream, once you do you won't want to go back to mild steel.
Click to expand...
Thanks. Guess I'll source some delrin.
 
Polycase has many options from pocket remote size to NEMA 12 cabinets. I use them quite a bit.
 
ttabbal said:
If you can, a "project box" from one of the many manufacturers would be a lot cheaper than a block of delrin that you turn 90% of into chips. There's nothing wrong with cutting one though, and I can't see any reason it wouldn't work.

Depending on the electronics, you might also be able to use an external antenna. I've got a wifi connected device outside now in an aluminum box with an external antenna that works great.
Click to expand...
I hear you. It does seem a waste, but using a "standard" plastic box means there's additional fab work like making stand offs, adapting to the internal features of the box, all on a box that may not have square parallel sides. (So they can get it out of the mold.)

The board I have uses a soldered on module with an integral PCB antenna, so no option for an external antenna.

A quick check on Newark and Aliexpress show some boxes that have interfering features where I don't want them, or they are not the right size. The Polycase look interesting, but the standoffs are in a place that would require making an adapter plate. Fortunately that isn't hard. If I am understanding the drawing for SN27C-01 correctly, the locking tabs are all on the long side, which is good. The price is right, which makes it worth thinking about a little further. It wasn't what I was envisioning, but maybe there's need to envision something different. I would have to mill out a slot for the power cord and some connectors on the short ends. The 3 degree mold release angle of the cover will make it hard to hold. Since I'd be cutting out the cover for the display, I guess I could screw down the cover to a plate and machine the cover slots on the mill table. After that, I'm not sure how I'd mill out a rectangular hole in the cover. Might have to make little hold downs as I go, without losing the position.

By milling it out of the block, the standoffs are integral to the design and are not wobbly nor questionably anchored nor are there holes through the box. There would be some meat in the cover to attach a bezel, if I designed it correctly.

I've not had the best experience adapting some boxes, but to be fair, those experiences were before having a mill and precise positioning ability. That should make things a lot easier. It can be hard to adapt something that just wasn't designed with your needs in mind. Other times you get lucky. It isn't really luck, but simply one's experience base was larger, or you simply have practiced more...
 
Another option is to pop a post up asking someone to 3D print one for you. I'd be happy to, but we're on opposite sides of the pond! This is a perfect use case for 3D printing :)
 
I have custom made various boxes using 3mm (1/8") PVC sheet. It can be welded together into any shape you want with gutter/down pipe cement and can be drilled and tapped with ease
 
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