The 3D printing of prototyping jigs - Embedded.com

The 3D printing of prototyping jigs

I feel like an old fool (but where are we going to find one at this time of the day?). Do you recall a few years ago when I built a simple Geiger counter. When I first turned it on… nothing happened. One problem was that I had no way of telling if the thing simply didn’t work, or if it was working just fine and dandy but there was no radiation around to trigger it.

Eventually, my chum David Ashton said “Send it over to me in Australia and I'll take a look at it” (he probably added “mate” on the end). So I trundled down to the post office and bid my Geiger counter a fond farewell, then I returned to my office to discover a package containing radioactive marbles (see I have radioactive balls!).

Thus, I'd gone from having a Geiger counter (but no radioactive source) in the morning, to having a radioactive source (but no Geiger counter) in the afternoon. I tell you, I couldn’t make this stuff up if I tried.

The reason I mention this here is that something similar just happened. It's like déjà vu all over again. (Did somebody just say that?) A while back I purchased a cheap-and-cheerful 3D printer. The first problem was that (unlike the Makerarm multi-function robotic arm) my printer wasn't self-aligning, which ended up causing loads of hassles. The second problem was that — after creating and printing a simple test piece — I couldn’t actually think of anything I desperately wanted to print. Sometime later, a visiting friend mentioned that he wanted to get into 3D printing, so rather than have my unit sitting in the corner of my office gathering dust, I gave it to my friend.

And then the wheel span — things changed when I was visiting the UK last week and I met up with my chum Steve Manley. Based on this meeting, I went from having a 3D printer (but nothing to print) to having things I want to print (but no 3D printer). I'm too young for all of this excitement. Stop the world, I want to get off!

Before we go further, let's remind ourselves that Steve used to be an aircraft fitter and he is amazingly talented when it comes to creating jigs for use with his construction projects (see Creating an 8x8x8 3D LED Cube: It's All About the Jigs).

Steve's original 8x8x8 cube was based on regular tri-colored LEDs, which had to be time-sliced (multiplexed) in order to control them, thereby reducing their brightness. Since that time, we've both been experimenting with WS2812-based components (see Using WS2812-based NeoPixels in embedded systems). These little beauties have four pins (5V, 0V, Data-In, and Data-Out) and can be daisy-chained together such that you can control hundreds of the little rascals with a single pin from your microcontroller. In addition to red, green, and blue LEDs, each device also boasts a controller containing three 8-bit PWMs (pulse-width modulators) — one for each LED.

Recently, Steve decided to construct a 12x12x12 cube using WS2812s in 8mm LED packages. I can only imagine how amazing this is going to look. I can’t wait to see it. In fact, Steve has already constructed a 4x4x4 version as a prototype. As you can see in this video, before anyone could stop him, Steve had whipped his little beauty out in the middle of my brother's front room (I mean his cube, of course; stop sniggering for goodness' sake).

I'm sorry to say that the video really doesn't do this justice, but — for some reason — the following still image gives a much better impression.


(Source: Steve Manley)

The thing is that Steve recently purchased a 3D printer. He taught himself to use the free version of SketchUp, and he's been 3D printing furiously ever since. He started by creating the most amazing base-plate and face-plate for use in his clock (see Upping the stakes in the Cunning Chronograph Competition). Now he's 3D printing stuff all over the place. Take a look at the following photo, for example:


(Source: Steve Manley)

This shows the back of Steve's Cunning Chronograph mounted in the wooden case he turned on his lathe. The big white disk in the middle is the back of his 3D-printed base-plate, but the items we want to focus on here are the 3D-printed brackets he's created to hold his circuit boards, which can quickly and easily be snapped in or out. (Also observe the incredibly neat wiring harness — I strive to meet this level of sophistication.)

Now consider the following close-ups of the 4x4x4 cube. First we see the front view. Observe that Steve has arranged things such that the diode packages are pointing forwards. This is the first time I've seen things done this way and it dramatically simplifies the task of connecting everything together.


(Source: Steve Manley. Click here to see a larger image.)

The packages are usually arranged pointing upwards, which complicates the wiring. I'm assuming people do it that way on the basis that the end result will look much the same if you were to take a 360° walk around the cube. This may or may not be true, but Steve makes the very good point that these cubes typically end up sat in the corner of the room, in which case having the packages pointing out into the center of the room makes a lot more sense.


(Source: Steve Manley. Click here to see a larger image.)

Above we see back of the cube, which gives us a good view of the wiring. Do you see how accurate and precise this all is? How on earth can Steve make it look this good? The answer is that he's 3D-printed a suite of jigs, such as the little beauty shown below:


(Source: Steve Manley. Click here to see a larger image.)

Now, the above jig is used to connect 16-LEDs together to form one 4×4 panel (following this proof-of-concept, Steve is now working on creating a jig for a 12×12 panel), but there's work to be done before we reach this stage — the four leads coming out of each LED have to be bent and have loops formed in a very precise way. Thus, Steve also created the two jigs shown below:


(Source: Steve Manley. Click here to see a larger image.)

The jig on the left (with the covers on) will accommodate a 5mm diameter LED package, while the jig to the right (with the covers off and a LED inserted) is designed to hold an 8mm package. Although it's difficult to see, the hole in the center has a flat edge on one side, thereby guiding the LED into the correct orientation.

Once the covers are attached, you simply use a set of needle-nosed pliers to bend the leads, loop them around the vertical pegs (which are formed from hardened steel drill bits), and snip off any unwanted excess. You have to see Steve doing this live — he provided us with a demonstration — he manipulates his pliers like a surgeon handles a scalpel.

Steve actually presented me with the above jigs as a gift. He also presented me with the jig shown below. Can you guess what this jig is for? I'll give you a day or so to offer your suggestions in the comments below, and then I'll reveal all.


(Source: Steve Manley. Click here to see a larger image.)

So, there we have it. Seeing what Steve is doing has reawakened my interest in 3D printing. Quite apart from the jigs, I keep on thinking how neat and tidy the inside of his Cunning Chronograph looks — and how quickly and easily he could snap the circuit boards in and out of their corresponding brackets. So, do I start looking for a new 3D Printer, or do I wait for the Makerarm multi-function robotic arm to become available? Decisions… decisions…

18 thoughts on “The 3D printing of prototyping jigs

  1. “Curious…nI designed and printed a number of 'jigs' and some 'moulds'… I never thought it was anything ground breaking – just an obvious solution.nThe only one that I thought was mildly unique was to make the FFF/slicing settings on a 'break-away'

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  2. “OOPS – I guess I have to qualify this by saying I was raised by a family of metal fabricators who used huge subtractive manufacturing machines and made moulds. So, I already had done the same using those tools before I was 8 y/o…”

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  3. “I did woodwork and metalwork at high school — then a 6-month apprenticeship at Rolls Royce as part of my university degree (mills, drills, grinders, lathes, welding, etc.)nnBut I know a lot of folks who never did any of this sort of thing — so to them

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  4. “### “So, I already had done the same using those tools before I was 8 y/o…”nnSo now we all know who to come to if we need help with anything LOL”

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  5. “Yep. Well, after many years of doing embedded systems as work and hobby I decided I'd go back to my 'roots' and build a reprap-like printer at home (this was about 6ish years ago). Since then I have built several more for myself and friends and have a f

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  6. “Oh, as a 'plug' for my preferred tool… I am not a menu monkey (swinging from the menu looking for the right item in a menu tree to get the results). I prefer being productive with each button press. So I use OpenSCAD and code my designs so I need not

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  7. “About a year ago I needed to have a 'heat director' to attach a heat gun to an anemometer/temp gauge for testing an SoC at temps… I wrote about 12 lines of OpenSCAD code and then printed it…”

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  8. “About 3 years ago we needed a 3D 'replacement' of a PCIe board for testing air flow testing purposes. I took the dimensions from the drawing and designed/printed a board (adding places for thermocouples)…”

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  9. “http://www.turbosquid.com/3d-models/max-time-machine-1960/729444 – grab the model and 'subclass' the bits that you want then add your changes… I don't see another model in my really quick search.”

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  10. “Max… Thingiverse.com is my first place to find models (as well as pushing a number of them there when I can – and remember). So, maybe you can have a look there for a lot of usable designs and/or design ideas.”

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  11. “It looks like a fantastic site — two things that would make it more useful would be:nna) If I had a 3D printernnb) If I knew how to use a 3D modelling applicationnnLOL”

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  12. “3D printers are getting a lot cheaper.nOther than using CADAM in the mid '80s I had no modeling experience. So, I learned – well, that and my choice to code my designs rather than using the menus and mouse. I tried at least 15 CAD apps and learned that

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