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I was tasked with refreshing an existing product line. We wanted to add a number of features to our basic [radio] monitor-receiver. Things like adjustable digital audio levels, a different L/R filter and GPIOs. One novel change is the use of a multi-colored background LCD screen. The idea is that the 'white' background would turn red when an alarm is triggered making it easy to see the error from across the room. The problem: the LCD has no bezel. No way to mount it. Enter 3D Printing 🙂

It started with the idea of gluing the lcds in place, that lead me to design a jig that would hold the LCD screen in position…It failed. Glue was not enough.

We kept with the idea of glue though, trying different brands and polymers but it was known that some-sort of brace was going to be needed. Since I was redesigning the PCB anyway, why not add a mounting/alignment point on the board? This took the form of two holes in the center of the front of the board. Now I could design a brace. The idea was to make a simple brace that pressed the LCD into the front of the chassis to help the glue.

I was sending away for the brace designs to be 3D printed, but after two iterations, I convinced my boss it was worth buying a machine. We got a PRUSA MK3S (well technically it was a MK3 but I upgraded it when the 'S' variation came out).

With a printer in house, the iterations of design were fast and many. I tried brackets with hooks, press-fit, curved back, inverted backs, long flat surfaces, minimal surfaces…none of which worked great. Finally I 'bit the bullet' and designed an entire wrapper for the LCD. Enter the red Bracket, a bracket that, with hot-glue, held the LCD in place properly. Well that was until we took the prototypes to the Las Vegas NAB convention and the warm weather and constant running of the radios showed the glue failing. The LCDs were becoming misaligned. The corner kept rising. Hot Glue just isn't going to work but what do we do?

Then I saw it, a true mounting point that's always been there. Not just an alignment hole, it's one of the four PCB mounting screws. With a taller screw and a little help from the lid, I was able to take glue out of the equation and use physical mounting hardware instead. This design actually holds up. There is a little too much support material for my liking but I think the design is decent.

All in all, I think I wen't past 70 design iterations to get to this point. The fun isn't done though. The leading edge of the PCB is a little thick and that makes it harder for manufacturing to install the brackets quickly. Now that we have a winning design, the next iteration will be a PCB change with the alignment holes and leading edge pushed back.

Here's a few containers I've designed. You can find many of my designs hosted at:

myMiniFactory.com: https://www.myminifactory.com/users/actual_size

pinshape.com: https://pinshape.com/users/208241-actualsize#designs-tab-open

A small plastic tie-off mount is used with a zip-tie to keep the power cable from being accidentally pulled out. The plastic fins of the cable tie-off need a little reinforcement to prevent slippage. Hot-glue has been used until now. I designed a little clip that fits snugly on the back-side of the chassis and tie-off. The clip allows the tie-off mount to spin but not be pulled out. Neat. Once I had the design dialed in, I made enough to share.

This is a 'vane' style air pump/vacuum. The internal core spins inside an offset chamber. The core acts like a centrifuge and tosses its vanes outward. The vanes hit the wall of the chamber, trapping air that flowed in from the intake hole. As the core rotates, the offset of the chamber pushes the vanes back inwards, forcing the air out the escape hole.  This type of pump must be printed in a high-temperature material such as nylon or carbon-fiber otherwise the generated heat will fuse the vanes to the inside walls.  I found this out the hard way.

A hobby motor is meant to attach to the base of the pump by means of a couple M3 machine screws.  The core is friction fit onto the motor shaft. The vanes float freely and the whole system is closed by sandwiching the lid and base together via nuts and some M4 machine screws. I also added some 1/8"NPT Push-Fit hose connectors to the input-output ports.   

Boss asked if I could come up with a 3D printed solution to level the line of storage racks he was installing. We held them up [level] and measured the gap. Using an existing foot for measurements, I designed a set of five risers. Each of varying heights to compensate for the sloping floor.

Here is my design of small printable clips/charms that go on your monies (or anything else) and are meant to help you quickly differ bill denominations within a wallet. These little clips all slide on and off paper money smoothly but have unique textures and contours to allow for easy sight-free organization. The clips are thin enough that multiple devices can be used at once. I find that these clips are also generally useful beyond the wallet. These aides can help keep important papers organized and utilizing different colors only improves usability. It’s taken a few iterations, but I'm very happy with the current results.


For the sake of sharing, I'm including an attempt at a design log. Enjoy...

---Day 1---

Idea: Small clips or charms for paper and card money that allow someone with impaired vision to easily feel the difference between marked items. Function: an alternative to bill folding and other ways of determining multiple bill denomination relative to each other.

Lunchtime day dreaming; thought of an idea for Money charm/marking device.

Got home from work, so now it's time to work:

My initial model idea looks nothing like what I later end up with. Its bulky and more suited for clipping onto a credit card. The idea was there but not the form. I just kinda thought of the idea and went with it. After that I tried to think up some design goals to meet:

Design Goals for Bill Charm - clips to help know what's in your pocket:

light weight - anything extra going in your pocket or wallet kinda sucks. try to make it less sucky. Should be light enough that a few can be in a wallet at a time.

thin but durable - too thin and it wont last and lose its spring. too thick and it will get in the way. Probably shoot for credit card thickness. Header can be a little thicker maybe.

easy to use - should clip on and off the bill easily/smoothly. Sharp edges aren't needed here. also, its not meant to keep the money together per say, the main goal is to mark something without falling off. if it helps group things, great

easy to understand - the identifying marks should be intuitive and understood by both people of all vision levels. I'll have to think on this one a bit.

easy and fast to print - no supports. shouldn't have to lose a finger to pry it off either. uniform theme - make the design consistent for all markers. Use different colors if possible, no reason to assume total vision impairment.

New design and first print came out surprising well. The head is too thick and the corners need to be mitered. I thought the clip portion was going to be too thick, but it's not bad. The idea to have the rounded outer frame and nubby center seems to be a winner already. The reliefs and curves are just instinct. I think having the center have the dip makes the clip work better, but I wouldn't actually know because I put it in before trying it without it. Because the center sticks to the print bed while the outer rim barely makes contact, the process of removing the print gives it the offset and springiness needed to let a bill slide in and out on its own. It helps that I know the design; but the different textures make it easy for operation with my eyes closed. I'm pretty happy with my first attempt. I still don't know what to do about the actual identification markings. Right now I'll stick to a simple Braille character of '1'.

Just started the second print and was able to step away a bit. Per usual, the self doubt has set in. I hope I'm not just making a bookmark or a semi-fancy paperclip 🙁 It slips on easily enough to be used as either, but I swear I didn't think about that until now.

Second print came out nice also. The rounded corners help the header easier to glider over. The thinner header is maybe too thin. Or maybe not. Not sure. I find myself using the Braille character as the means of first contact because its thicker than the rest. That could be good, the fact that the identifier is being used to identify itself. I'll call it a night and mull it over in traffic tomorrow.

---Day 2---

Hmmmmm...tried the device in my wallet. sticks out a bit much. It does remind me of a folders divider tabs, which is something I was going for. Kinda nice to grab the tab and out come the bills, loosen the grip and the clip comes off. I should go to sleep.


Home from work, time for a print 🙂 Darn. My printer started to not work as I started another print. I'm still pretty new to the machine and printing, so I'm not totally sure what's wrong. The hotend to bowden tube connection seems to be jamming, though nothing obstructing. I haven't clean-cleaned the nozzle yet, maybe that's the issue. I bought this printer as a kit from China and am just kinda glad it worked. I'm going to have to give it all a tune up and hope I can get another print, otherwise the last version will have to suffice. If I didn't want to make a couple prints right now, I'd be happy to spend the time tinkering with my toy, but right now it just feels inconvenient. Oh well.

...I think the lining tube inside the hotend got funky.

(replaced hot tube with spare)

...soooo, that lining was important. my spare hotend tube looked like it would work. Now I have filament stuck in between the top of the heatsink. All coiled up, almost as if there was too much room in the little chamber. If only a lining could be placed inside to prevent such an issue...live an learn I guess. Use the right parts. I was able to get it out with a heat gun and tweezers but this is a little discouraging. I have an older hotend setup from when I first 'tried' to make a delta type printer. I'm just not sure the total length is there to clear the mounted fan. I should step away before I make a worse mistake or get hurt. Back to SketchUp for the design; I'm sure I'll get the printer up and printing again soon enough...

--- Day ???---

Well I ended up moving and my junky printers have been put in storage to be fixed another day.

--- About a year ago ---

I bought a PRUSA MK3S and have been very happy with its quality results. No new improvements to the clips. I kinda forgot about them and have been designing other things to print. Oh well.

One reason I picked up 3D printing as a hobby was because I wanted to make moving pieces of art. Being able to print nearly any shape I can draft really lets my imagination take flight. Here are some automata designs I've completed.