Print your own workshop tools

One of the reasons I never have any money is my good mate Mat, who has the natural ability to sniff out anything cool in the world of technology, make it do stuff it was never intended to do and convince you that your life isn’t complete until you own one too.

I can safely say the boy has outdone himself this time by getting one of these!

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Yep a Makerbot clone, CTC 3D Printer costing an eyebrow raising £280 from eBay! That’s not much more than a decent quality normal printer I hear you say. Exactly!

I’ve been interested in these things since they first appeared and dismissed them as a complete waste of time unless you were an art student or involved in design/graphics/manufacturing. Not any more! Admittedly you’re buying at the cheap end of the market here but the CTC printers are all open source with a huge community and following out there providing designs to print along with hacks, mods and updates.

In short, all you do is load the design you want to print onto an SD card and plug it into the printer or hook a PC to it to upload the slice files, which contain the data the printer needs. Press print and off you go.

If you’re like this guy (please watch this because the guy is very talented and I wish I had that kind of artistic ability) you can design everything yourself using free software or you can hit the repository of all things printable at Thingiverse, pick what you want or feel you now need just because you can print it and off you go.

We’ll get the the how it does it in a moment, but back to the title of this instalment.

Ever since I’ve been playing with electronics and bits I’ve always wanted a more professional and posturally pleasing way of holding circuit boards that I’m working on, rather than being hunched over them like Quasimodo, firing bits and pieces off all over the floor as I try to solder them.

I wouldn’t mind a Panavise, but they’re stupid money for what you actually get and you have to buy all sorts of add-ons to make it workable to all situations that may arise.

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Equally, I was considering one of these, but again at £70 is a lot of dosh for not a lot.

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My solution so far has been this –

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Don’t laugh, costing a grand total of nothing and made from some off cuts of wood laying around the garage it’s done me all right so far. It has it’s limitations in that the wood sticks when you try to release it’s arboreal grip on your PCB and you have to use masking tape to hold stuff in place as you wrestle to invert the board to solder, but it works.

So when Mat said “so what do you want to make?” the reply was “how about one of these?”

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Thingiverse has the project files there all ready to go, so on a freezing cold weekend why sit in a subzero garage trying to assemble another Chinese QRP transceiver, when you can sit indoors watching a cool toy print you something useful?

If you envisage high quality plastic akin to injection moulded products printed in the blink of an eye, forget it.

This is a slow process and is very much a hands on affair with a sprinkling of trial and error thrown in for good measure.

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The printer slowly builds your wanted item in layers (or slices) with an outer shell of a defined thickness containing a honeycomb cellular structure out of, in this case PLA which is fed in filament form into the print head which is at 200+ C , where it melts and is extruded out onto a heated glass platen. The number of shell layers and the size of the honeycomb interior can be varied and will influence the mechanical strength of the finished article. The more dense you make it, the longer it takes to print.

I think Mat was very much up for the challenge as all his playing so far was printing upgrades and mods for his printer (print your own printer – very chicken and egg!), light sabres and copy of Deckard’s LAPD 2019 Blaster from Blade Runner.

Here’s the CTC putting the final shell layers on one of the frame pieces of the PCB holder

https://www.dropbox.com/s/qo1vsiuju97mth2/20160214_003916.mp4?dl=0

So after almost 12 hours we were rewarded with a pile of component pieces

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If you notice, some of the parts aren’t very smooth. This is down to the need to apply a layer of adhesive (Purple coloured Pritt stick, nothing fancy) to the glass platen prior to printing to give the extruded plastic something to hold onto otherwise it just smears and runs around uncontrolled. Where we tried to print several of the smaller pieces in one run to save time we obviously just missed applying the glue layer in some places. Nothing lost as this is all about function, not form.

A quick trip to Screwfix and B&Q secured the necessary metalwork to assemble the holder.

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And there we go! Not bad for a first attempt. There were a few minor snaggings worth mentioning. The design encompasses captured nuts on the black PCB holder/jaws. Unfortunately when pushing the M4 sized nuts into the printed hexagonal shaped holes the pieces split because they were just a little too small for the job. Added to that the plastic construction is laminar and any force driven between those layers causes it to fracture.

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The top item is the broken part and you can clearly see the thin outer shell containing the large honeycomb internal structure. After a bit of thinking we decided to double the shell layer thickness and decrease the honeycomb size by 50% and try again. The bottom part is a print we abandoned a few minutes in due to a rethink, which gives a good visual as to how 3D printing works. You can print with 100% density i.e. solid BUT it’s still a laminar construction not a single solid piece. That said the final jaws we printed are as solid as you like and do the job nicely. A gentle application of a craft knife blade shaved off sufficient plastic to allow the M4 nut to sit snugly in its allocated hollow.

Total project cost £12-62. Exactly! Plus this was so much more rewarding than just buying something. The bonus of all this is, when I put my soldering iron through it or knock it off the bench or it breaks, press PRINT and your spare part is there ready for you in the time it takes to make and drink a couple of cups of tea.

Here’s the best bit. If you don’t want to spend out on a printer of your own or need a single item printed in a special medium (you can print all sorts of resins and plastics) there’s a community network called 3D Hubs which is tied in with Thingiverse. Here, commercial and private owners offer the use of their printers to print whatever you want. Yes it costs you, but you’ve got access to all sorts of grades of printers depending on what you want to make. I was pleased to see that I’ve got 4-5 local 3D Hub members very close by, if you live in London you’re tripping over them at every street corner!

 

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