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3d Printer - part 7

Progress continues on my 3d printer...

Power Supply

Meters for my power supply arrived a few weeks back, but I only just got around to installing them. I had to drill out a 38mm hole for the mechanism to fit inside of, but I only have 45mm+ hole saws and 32mm spade bits, which made things a bit complicated. If only I had a CNC machine, this would be a piece of cake! For some reason that did not occur to me and instead I used a 32mm spade bit followed by a few minutes on the Dremel with a sanding disk. Did the job pretty well, even if it did cover the garage in MDF dust.

A couple of hastily drilled mounting M3 holes and a whole lot of epoxy leaves this:

I wired the voltmeter in parallel, and the ammeter in series with the output. Nice and simple, works a treat. Completed power supply was reassembled and tested on an RCD protected output, just in case. All tests passed and the meters were even wired up correctly.

Printer

Testing showed that t...

3d Printer - part 6

Progress continues slowly on my 3d printer. While waiting for the increasingly erratic Chinese postal system, I set about getting the extruder and hot-end working.

The hot-end is responsible for turning the plastic filament into a model, by melting it and squeezing it out of a tiny hole. The filament looks a bit like white spaghetti, or like the cutting cord used in line-trimmers in the garden.

The extruder grabs the filament and pushes it down a tube to the hot-end. The hot-end has a large block of metal with a heater and temperature sensor built into it; these work in concert to keep the metal block at a constant temperature, about 180°C for melting the PLA plastic that I have.

So I sent about making sure it was all going to work. First test was to ensure that the temperature sensor worked correctly. The hot-end I'd purchased had a thermistor built into it, which is a type of resister that changes its value as its temperature rises and falls. I did some tests ...

3d Printer - part 5

Continued from part 4.

My linear bearings finally arrived, just under a month in transit. I wasted no time at all in putting them to use. First I added some supports to mount them by; these are just my usual 1mm thick sheet of styrene, epoxied to the bearing with a couple of supports on each side.

Y axis limit switches were then added:

And then the Y axis was joined to the Z axis. I used some MDF spaces to ensure the Y axis was level with the rest of the machine and glued the whole lot in place.

I then clamped it with whatever heavy objects I could find. It may be a mess, but it worked!

While that was setting up, I started building the electronics. I used a similar approach to my CNC machine, using female mating sockets and some self adhesive copper strip to form bus bars. The various components then get soldered up into sub-assemblies that plug into the female headers.<...

3D Printer - part 4

Progress continues on my 3d printer. This week I have been continuing to work on the Z axis. With the rails and bearings ready I needed needed to make something to connect the threaded rod to carriage. I decided to use my tried-and-tested method of casting a white-metal block directly around the threaded rod.

To do that, I fixed up my previous mold and found some white metal. I melted it on the stove (thanks for the tip sis!) and poured it into my mold, tapping it a few times to get rid of any bubbles. Then I pushed a block of wood down on the top and waited for it to cool. I destroyed the mold to remove my item, but never mind. I don't anticipate needing to make any more for a while. I gave it a quick clean with a file and used my drill on grunty-mode to remove the threaded rod. I gave it a zap with CRC and drove the rod through a few dozen times to clean out the thread. Here is the finished block:

I threaded it on to the rod and wondered how I was ...

3D Printer - part 3

Just a quick update: my stepper motors have arrived!

Of course now I realise that there was quite a bit I could've done without the stepper motors :)

I've wired up limit switches for both the X and Z axes:

And I've made bearing blocks for the Z axis, seen here with the motor on the wrong side. I have also made up the brackets and support for the Z axis.

A quick test fit of the various bits to see how it all fits together:

Now I need a 5-to-8mm shaft coupling (although as I've learnt I am capable of making them myself) for the Z axis leadscrew, and a 2 sets of linear bearings for Y axis. I ordered the bearings nearly a month ago, but they must be taking the scenic route to get here as they still haven't arrived. In the meantime there is plenty I can do, e.g. wiring the whole thing up.

Still, exciting progress :-)