RepRap: Blog

Having drilled my left thumb and nail for M3, I'm now back in the workshop once again and working on Wedgewood. I promised the guys in the #reprap chartoom on IRC (Chatzilla or similar needed) that I'd give a quick update. As you can see from the photo my good camera is broken too, other than that there is a railcar-like X carriage and on the right a contrivance to dangle it all from the Z axis.

The wheels are made from two skate bearings with a washer between that is thinner than the rail. This causes the bevelled edge of each of the bearings to run on the corner of the top of the rail and self-centre. Runs nice and smoothly, should also be robust enough to dampen oscillations of the drive rod. Yes, that is a Ponoko lasercut extruder (from an old extruder kit) plugged into the X Carriage - both the MDF carriage and lasercut extruder are compatible with the Darwin exchangable head holder. I love standards :)

The stepper will be screwed to the block on the far right and coupled to the horizontal threaded rod. Probably put a bearing in there to reduce play too as I'm using cheap stepper motors.

Oh, I can also report that brazing thermocouple wire doesn't work - it melts way before the brass. I'll have to locate some silver or 95/5 solder. Flash-welding the stuff is looking more convenient by the day.

Vik :v)

Labels: wedgewood, x carriage

Here's Wedgewood with the Z axis components (minus the actual coupling for the X axis) in place and supporting the aluminium T-section that will serve as the X axis slide. Tests conducted by twiddling the vertical shafts by hand suggest that there is no need for guide rails on the Z axis, so that simplifies construction a bit.

Also, note that I've trapped the nuts for the Z axis between slabs of MDF. Another quick construction technique.

So far, all of the bits can either be reprapped or made from MDF and epoxy or CAPA.

Vik :v)

Labels: wedgewood, x axis

I've been away for much of the weekend, and crook yesterday so I've not had much time to work on RepRap. Next weekend is a 2 day chainsaw course, so I'm working on Wedgewood whenever I can. Here you can see the beginnings of the Z axis mounting scheme, using the PLA bearing holders I printed earlier to anchor the Z axis studding (one on the top that's hidden from view, and one on the bottom). I've removed the deposition bed so you can see the bearing holder.

The two nuts in the middle of the studding will be held captive by the X axis mountings. Given the weight of the head and X axis, it is unlikely that I'll need any anti-backlashing but it can be done if need be.

For the moment I'll use 2 tin can stepper motors to drive the Z axis, which neatly eliminates the need for a chain or driveshaft to link the two halves and gives me more torque where it is needed most. I've only got 2 of the Jaycar YM2751 steppers as the depot ran out of stock, so we'll see if they get stock before I can finish the Z axis.

The object of the exercise? To see if the Z axis on a Wedge design is going to need guide rails or not.

Vik :v)

Labels: wedgewood, z axis