Saturday, 17 January 2015

Wire *all* the things!

Wiring is go. I have checked and double-checked the resistances, and the look fine. I'm concerned about the big black (12 PSU wires together) and whether it's really properly connected and going to stay there. Otherwise, looks good.

More problematic is the extruder hotend. As I mentioned earlier, bits broke off when I was fiddling with it. Having stiff wires coming out horizontally is not really the smartest design. As the photo below shows, some crucial wiring is missing. The wires on the left (which are kind of loose) measure 10 Ohm across them, so that must be the heating element - the thermistor should be about 100 kOhm. I'm slightly surprised to see no hole in the screw inside the right-hand hole. I'll have to try to unscrew it and see what comes loose:)

The X belt on the right also looks... different. Is it really supposed to slant like this:

Monday, 12 January 2015

Power up!

PSU Assembly

Time to add the power supply, now that all the wires are hanging prettily out the sides. It's slightly tricky to get it in with the thick bunch of wires coming out the back side. First the washers in the right-hand bracket were in the way, so I had to use smaller ones. The wiggling in and out while figuring that out was enough to break the top notch, so now it'll get fastened with one screw only. By bending a piece at the back and putting the PSU in from the top, I was able to get it in both brackets, but it wasn't happy with going all the way in on the right bracket due to the screws on the fan guard.F Finally squeezed it in with a clamp. Alas, the screws for the PSU mount are neither M3 nor M4, but 6-32 (whatever that means). I just plopped in an M3x20, which should hold up by tension alone.

Don't have appropriate wood screws for the resistors either, so I drilled M3 holes for bolts instead. I hope I didn't get too much MDF dust into the PSU this way. Also, it turns out these resistors are slightly bigger than the ones the holes were placed for (see picture below). The M3x20 screws were almost but not quite long enough for this. Instead, I found some M3x30, but with 3mm hex head, which we don't have a bit for. So screwing in by hand with an overly long L hex. Bother.

The wires on the inside are rather squished. If I were to make another of these, I would make the Y axis a bit longer, so there was room enough for the wires to breathe.

Had to extend some of the wires a bit. Got the big honking power wires set up, and the Melzi mounted. Next time, wires!

Also notice in the FabLab room:

Tuesday, 6 January 2015

The Strange Case of the Broken Hotend

X Axis Assembly

My fears were grounded - the wires to the hotend fell off. Need to get a new one, I guess. On the left side (taken from below), the thermistor wires are top-right and bottom-right, and the hole for the hotend itself is on the bottom-left. On the right picture, a lost hotend connector.

Fastened the extruder on the carriage. For lack of wing nuts, I used normal nylocs and a long pair of pliers:

The sideways mounting of the connector on the X motor got in the way. When I tried to move it to live on the top, it turned out FabLab has no PZ1 screwdriver or bit that isn't horribly stripped. So for now the connector still lives on the side, but I need to remove it if I am to remove the extruder:

Adding the fan was a bit fiddly at first, then suddenly easy. Probably by way of bending the thermistor cables.

I lasercut a little piece of wood to trigger the X microswitch before crashing the wing nuts of the extruder into the X axis bearings. My machine now has duct tape on it, as is proper:

The fan connectors from my extruder are wrong, they have red and black on the outer sides of the plug, not lining up with the markings on the X motor connector.

PSU Assembly

The PSU wires are a bit shorter than required, some from previous cuttage, some just from the way they were. A lot of the wires are really thick, I may have trouble getting them into the Melzi (PZ2 bit for scale):

Also, there were fewer wires than expected, but a bonus white one that I have no idea what's for. The yellow wire has a lot of heatshrink on it because I had the piece too close when soldering the tip and it shrank right there. BTW: German for heatshrink is "Schrumpfschlauch" (I kid thee not), but I like to call it "Schlumpfschlauch".

I misread the instructions for the 4R7 and put green on one end and black on the other at first. This gave me the opportunity to try out the solder removal tool that's the right-hand part of the solder box. Worked incredibly well. If I am ever going to salvage stuff again, or just want better soldering irons at home, I want this.

All in all, good progress (except, of course, the hotend). I really hope it's easily replaceable.

Saturday, 3 January 2015

New year, new rods, new problems

Actually, same quality rods, just smoothed out with a metal sponge. I might need to go back to the other rods and do the same.

Y Axis Assembly

Fastening the final nut for the right-hand bearing is quite tricky, since there's limited space, not even enough for a hex wrench. But I got it fastened. It doesn't move very smoothly, but reasonably so.

The hole for the Y idler was too far back - I must have cut the belt too short. Drilled a hole further in and fastened with a 4x20 wood screw. I'm a bit concerned about the idler slipping over time, though, and also that the belt is somewhat far out on the motor pulley.

The ribbon cable for some reason is way too long. I must have cut it wrong - looking at this example, there shouldn't be any spare length at all. But that's not critical, merely messy, so I'll leave it like that for now.

X Axis Assembly

Using a good metal saw is really a lot faster, easier, and more accurate than a Dremel. And doesn't eat the disks, either. And hammering the ends a bit make them nice and rounded for going into the linear bearings.

Re-did the Z axis smooth rods to be smoother. So nice and shiny now!

Tightening the X axis clamps, I hope they're meant to bend a little. Only enough to be visible when seeing a reflection on them. This is the first time I've had a reason to use three hex bit extenders in series:)

Again, the belt is too short. This time, the only solution is to have fewer teeth showing at the ends.

Turns out the adapter holder on the extruder motor was on the wrong side, so had to flip that. At least that allowed me to add a washer I'd forgotten.

Why am I surprised anymore that FabLab doesn't have any M4 wing nuts? Anyway, something is odd: There is a nut trap on the underside of the X carriage, yet the other side gets wing nuts. I guess I have to run a bolt through from the nut trap side. Weird, and not clear from the manual.

I hope I haven't damaged the wires from the hot end by all the manipulation and schlepping around.

My extruder is a slight variation in design from the one the manual expects. I'm going to have a bit of overhang of wing nuts over the edge of the carriage, about 2cm. I should add a bit to make the microswitch trigger earlier.

Current state: