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3D Printer - part 2

Progress on my 3D printer continues.

I chopped out all the MDF pieces in about an hour — it helps having a complete set of plans and dimensions, and a good drop saw! I printed out some NEMA 17 stepper motor drilling templates and taped them to the wood. It's then a quick punch-drill operation and I have all the holes in the right place to mount a stepper motor.

I soon had a good pile of bits, ready to start assembly. I started with the base by gluing on the foot/stabilisers.

The X axis motor bracket and supports followed soon after. At the end of the day I was left with this collection of components and assemblies:

This weekend I tacked the printer bed. I recut the printer bed to give me a slightly larger working area and cut the linear rails to length. Working on a sheet of ex-scanner glass,  I mixed up some 5 minute epoxy and glued the first end into position.

A 3D printer - part 1

Now that one machine is working well, it's time to make another. While idly browsing the wide wide world of web recently, I came across the Printrbot Simple, which is a remarkably simple and compact 3D printer. Now I've wanted a 3d printer for some time, however they have always required a lot of components, many of them specialised and difficult to get a hold of.

The Printrbot Simple however uses laser cut wood for the bulk of it, and nothing too complex for the rest.

So after studying it for a while, I set about making one.

A 3d printer is a printer that extrudes melted plastic to build up solid objects, layer by layer. The quality is acceptable, although not nearly good enough for model making. However a 3d printer really shines through for fabricating components for other machines: brackets, mounts, supports, etc. Items that would require lots of tedious measuring, cutting, drilling, milling, sawing, glueing, and so forth can instead be quickly designed on the ...

MrCNC - part 4

Continued from part three...

At the end of the previous update I was busy waiting for a 5-8mm shaft coupling to arrive. However I realised that with a big of creativity, I could always steal one from elsewhere on the machine.

Using some heatshrink tubing, cable ties, superglue, and flexible tubing from an old inkjet printer, I bodged together this flexible coupling:

That left me with a spare aluminum shaft coupling, just what I needed to finish my new spindle.

The spindle I made out of MDF and consists of:

ER11 collet nut2 608zz ball bearings2 more 608zz ball bearingsA 8mm to 5mm shaft couplingA big DC motor with 5mm shaft, from an old cordless drill

It went together reasonably easily with a good helping of 5 minute epoxy glue.

The hardest bit was aligning the motor and the shaft. If it's not perfect, it rubs and the power transfer suffers.

Meanwhile, a pair of 2 flute, 4mm HSS end mills had arrived i...

MrCNC - part 3

Continued from part two ...

Now that the machine works, it is time to do something with it! My first carving was the LinuxCNC text which took a few attempts to get right, but once working seemed good. Second cut was something called "chips", which it turns out is a lovely wee penguin:

Detail is a bit rough around his foot, and the other flipper snapped off, however for a first go I was pretty impressed. The foam isn't amazing to machine, the beads tend to remain, but it's about all my machine can manage at the moment with it's poor-man's-spindle.

I spent quite a bit of time getting the homing configurations correct, as there are many different variables and they don't all make a whole lot of sense. When I finally got my head around HOME, HOME_OFFSET, MIN, MAX, etc it started making sense and I was able to get the results I was after.

For my second piece, Rachel had said "I...

MrCNC - part 2

Continued from part one...

With the Z axis mostly done, it was time to turn my attention to the Y axis. The Y axis moves across the work, and supports the Z axis.

I started by cutting the two end pieces out and match-drilling them. I now had a problem though; my linear rails were each 1m long, and not especially cheap, so in order to gain some vertical work-height, I had reduced the Y length and now had a gap to span between the outside faces of the machine and the ends of the Y axis rails. In other words, I had to make some spacers. I made these out of 18mm MDF which gave me some extra space for the shaft coupler and 8mm ball bearing at the other end.

As per the Z axis I added the linear bearings with my patent-pending mounting blocks, and another cast "bolt". Some careful measurements and adjustments with my square ensured that both sides of the Y axis were true and then it was ...

MrCNC - part 1

Today I present the latest project to come out of my workshop: a CNC machine! CNC stands for Computer Numeric Control, which is a fancy way of saying computer-controlled. A CNC machine has a rotating spindle that is movable in 3 dimensions and is able to carve, cut, and machine objects according to the input file on the computer.

Building it has taken most of the past month. An initial plan was roughed out on the computer and I started ordering bits online.

The first bit to be built was the bed of the machine. I made this out of Open Beam, which is aluminium extrusion, 15x15mm with built in slots to accept M3 nuts. This makes it easy to bolt the bits together, like some kind of giant Meccano set. The corners are chopped up T connectors and help square things up.

Ends for the bed were made out of 6mm MDF, which is g...

A vertical drill press

If there is one thing every engineer needs, it's a drill press. And I may be an engineer, but I did not have one. So I decided to make one. The thought pattern went something like this:

I have a pile of fairly crude model railway carriages that aren't being used. I should reuse their components and make my own carriages. I could cast the bodies. I need to make a master for the casting. I could design it on the computer and get it laser cut? No, that would take too long (1 month waiting period on laser cutting!) I could cut them out by hand? Mmmm I could, but it would be hard to get them perfect . If I had my own laser cutter I could cut them myself. Hmm… no, laser cutters are too expensive, and too dangerous. What if I had a machine that could cut them, but not using a laser? Michael does some googling … hmm, that machine would be called a CNC router. Does some more googling… and they can be very accurate and cut almost as ...

Introducing Utrainia

I haven't written in my blog for quite some time, but that doesn't mean I haven't been active. Moving to Masterton meant I had to leave my model railway behind, no small sacrifice! However I've been busy modelling while up here, just on a smaller scale.

In my 6 months up here I've built 3 small N scale modules. Each one is a small self-contained scene, 750mm long by 300 to 400mm wide. So far I have a coastal scene based on the Kaikoura Coast, a blizzard scene based on Marias Pass, and a prairie scene based on a lonely grain elevator near Lind, Washington.

Each module connects together to form a larger railway. They're all small and lightweight, and easily portable, so next time I move they can come with me.

I've been haphazardly sharing my progress here and there, but never on my blog. One day while pondering over dinner what to call my railway I had a brainwave: Utrainia . Utrainia is a portma...

DIY earrings

Recently it was my six month anniversary with Rachel. She'd been dropping many "subtle" hints about all the things I should buy her to celebrate, but why buy when you can make?? So since jewellery featured so prominently in her wishlists I decided I'd make her some earrings. After tossing around a few ideas I happened across my old metal casting gear and half a white metal ingot, which gave me the idea of casting some earrings. And so with much vigor I launched into my next project.

Step one was to make a postitive to cast from. I dug out my trusty supply of blue plasticine and set to work. Working with a scalpel on an old mirror I made up positive and a box to hold the plaster.

Step two was to make the negative. I poured some plaster into the mold and then put it on a vibrating table to vibrate out any air bubbles. The plastic tray is to catch any spills.

A few hours later it ha...

Mr Blimp

We have a lot of helium here at the flat, a lot! As in two canisters worth. But anyway, I started my weekend by cleaning the garage and doing the washing, but by Saturday afternoon I was all done and had nothing to do. The thought of wasting an entire weekend without making something sent shivers through me, so for whatever reason I decided that I would make a cellphone controlled blimp. I suspect that decision probably had something to do with the package I'd just received from China, that contained a $6 bluetooth serial interface board. I was itching to use it!

A quick rummage around later and I found some spare LB1973M ICs, perfect for driving two small DC motors. Also in my DealExtreme package were a couple of mini solar toys which had some very small motors and gears, ideal for powering this thing.

A few hours later and I'd designed my circuit:

Based around an Arduino, i.e. an ATMega168. The power comes from a sma...