Sunday, 30 November 2014

Mounting motors

Got a bit of time in today to mount some motors. I loosely mounted the Y axis motors, but without hot bed and belts I cannot finish them. I mounted the Z axis motors and rod holders, but found that the regular holes were too high for the motors, since I have shorter motors. They would be hanging in mid-air, held up only by two screw on the wall. Not good for something load bearing.

My first fix was to drill the holes further down, so the motors could rest on the base as they should, but then the rods were cut too short - and other things might be off as well.

Instead, I made use of being in FabLab, where there's an industrial laser cutter free to use. I cut a plate of 5mm MDF and 2 of 3mm, one with a cut-out for the motors, and all with screw holes, then I had handy little platforms for the motors to sit on. 15 minutes of work, tops.

The screws for the Y motor didn't fasten properly, but started spinning instead. The first ones didn't, but then they didn't have star washers. Maybe that puts them over the edge, and it's time to switch to 4x20mm screws instead of 3.5x15.

I found my spare fans at home, but they're all too big, so another fan goes on the shopping list.

No picture today since my laptop was out of power and my phone is totally dead.

Friday, 28 November 2014

Motor assemblies (mostly) built

Y Motor Assembly

The stepper motors do not have a flat part on their axes. I might want to come back and Dremel one. Also, the axes are a little short, the manual suggests 3mm axis should stick out from the pully, but even all the way in only 2.1mm is sticking out.

Ha! Guess what I forgot when bringing both parts and frame over to FabLab? The woods screws to mount the parts onto the frame:)

Y motor assembly is done except for mounting on the frame.

Z Motor Assemblies

Calls for 2 pieces of rubber tubing. I believe they came with the print, but I don't see them now. Ha - they were where I'd forgotten them last time.

The wires are supposed to be "towards the back". It's not clear what that means, but from where it'll be mounted and various images, I guess it means towards the mount, like this:

I'll get back to which hole is the "mouse hole" once I can mount them. Right now, they are done but for mounting.

X Motor Assembly

There's a much larger gap between the motor and the bracket than the +/- 1 mm tolerance indicates. Did I do something wrong? Or just get the wrong motors? They seem shorter. I will add some nuts.

The screw is thus also way too short if it doesn't let the head through the bracket hole, and none of my screws go through that easily.
Can't do more on this until I get the bits of electronics and a longer screw.

That's all I can do for tonight due to lack of little bits of electronics, print beds, rods, and polypropylene strips. I wonder where those are normally used, so I can find them?

Wednesday, 26 November 2014

Got my bearings wrong

Picked up two packages today, one of 5 stepper motors (those have gotten cheap!), and one of linear bearings. Alas, I had forgotten to double-check with the sturdy bom, and got LM8UU rather than LM10UU. No wonder they seemed small.

I should also keep in mind that two kinds of ball bearings are used, 7 608's (8mm x 22mm x 7mm) and 4 624's (4mm x 13mm x 5mm). I think the 608's are the kind I already have a small mountain of.

I'm getting the hotbed pieces from nophead after all, getting the necessary pieces from elsewhere would be more expensive and more work after all. I'm impressed with the price nophead has managed to get the kit down to. And they are being very helpful, so I'm happy to throw more business their way.

If you're thinking of making a Mendel90, and customizing it is not what you're aiming for, get the kit. It'll save you time, headaches, and possibly even money.

Sunday, 23 November 2014

Putting bits and pieces together

At FabLab with plenty of time and space. Let's see what I can throw together.

X Idler Assembly:

Requires 2x624 ball bearings, which are 13x5x4mm. My own are much bigger, FabLab has some that are 13x6x5. Also need two linear bearings LM8UU - they should be 15mm wide and 24mm long, but the chamber for them measures 26x19mm, not exactly a snug fit.
The normal place for bolts and nuts didn't have the M3 20mm I need a lot of, but I got help to find the secret stash. Now I have plenty.

X Motor Assembly

Missing polypropylene strips, will leave the clamps open for now.

I realize now my motors aren't NEMA17, but some odd ducks recycled from elsewhere, maybe NEMA23-ish. Add to shopping list.

Don't have the 15 pin IDC either, nor 1.2m ribbon cable. Can't get very far on this right now.

Y Idler Assembly

Also missing the right ball bearings for this. Attaching screws.

Y Motor Assembly

Obviously don't have the motor. Got the M3x8mm screws

Y Carriage Assembly

No Dibond nor linear bearings yet. The bearing holders don't have nut traps in sturdy, I guess they take regular nuts with washers galore. Surprisingly not star washers. I added the bolts that I could, using 20mm in the anchors since I don't have 16mm at hand.

X Carriage Fan Assembly

Don't have a fan here. I might have one at home?

X Carriage Assembly

More missing linear bearings. Odd, there are M4 nut traps but no M4 nuts or bolts specified in either the BOM or the manual. Ah, those come later. Attached the pieces loosely for now.

PSU Assembly

Want to print this part of the manual in color to be sure I get the wires right. Plus, I'm missing the resistors.

Can't do the assembly of subassemblies meaningfully. All that's left to do today is the extruder connection PCB - yay soldering!

Things I may need to pay FabLab for

1662mm of 34 way ribbon cable.

Shopping list

4x624 bearings
15 way D IDC socket
M3 star washers
Polypropylene strip 501 x 25 x 0.5mm and 410 x 18 x 0.5mm
1 Dibond sheet 216x216x3mm
M3x16mm bolts
Fan 60mmx15mm (I think I have one at home)
THS15 Alu clad 10R
THS15 Alu clad 4R7
2 smooth rods 10mmx403mm
PCB bed 214x214mm
Glass sheet 214x202x2mm
4 hex male/female pillar M3x20mm
Polypropylene strip 278x33x0.5mm
Belt T5 6mmx680mm
Belt T5 6mmx905mm
Smooth rod 10x290mm
Smooth rod 10x432mm
2 brass nuts M8
2 smooth rods 10x336mm
2 threaded rod 8x296mm
1 micro SD card (no, I don't have any randomly lying around!)
MicroSD to USB adapter

Saturday, 22 November 2014

Drilling and framing

Drilled all the holes in the MDF this afternoon. However, due to missing strange sizes of drill bits and plain oops, I drilled the following differently:

The 1.7 mm and 2.5 mm holes were drilled with 2mm
The 4 mm holes were drilled with 5mm by accident - I don't actually have a 3 mm wood drill, so the second drill bit is 5mm, not 4.
The 4.4 mm holes on frame_left are drilled with 5mm. I will need to use washers.

Also a piece of wood under the boards would probably have prevented a lot of flaking off. Especially the larger holes look pretty bad. Dammit.

Ah, fuckit. This will be the first, straight-forward, ugly version. I can do a fancy painted one later.

Drilled the last few holes with a correct underlay, and they were perfect.

The left and right stays are a little off vertically. I hope that doesn't warp anything.

Adding the ribbon clamp and cable holders required opening the model in OpenSCAD to see where what goes.

Skipping the bed fan assembly for now, since it's optional.

Can't do the X idler yet since I don't have linear bearings here. There were some at FabLab, so I'll take the bits there at next opportunity. Same for the X motor assembly and thus the Z axis.

Oh. All my small bolts and stuff is actually out at FabLab, too. I guess I'll just print the install instructions, sort out the printed parts, and bring them out next time I go there.

Skipping the heat shield since I'm starting out with PLA.

Skipping hot end and extruder motor since I have a Wade's extruder already assembled.

Holding off on the spool holder for now, can add it when I'm actually printing.

I will need to check carefully for any differences in electronics setup between dibond and sturdy rather than just expect the manual to apply directly. Don't want to try my Melzi electronics by mistake - that should only be done on purpose:)

Here's the frame, at least, front and back. You can see a few of the drill flakes on the back.

Friday, 21 November 2014

Starting on Mendel90

Work has started on my Mendel 90. I have the printed parts and the sheets, plus whatever I can scrounge up of screws, electronics and bits and pieces.

I've decided to make it not just functional but also pretty, so I'm painting the printed pieces bronze and the sheets copper. I would get copper rods instead of iron, except that I don't know if there is a difference in materials quality.

There are a few differences in overall build between the "sturdy" version that I'm building and the "dibond" version that's described in the manual. First difference I notice is that the square tubes under the base are not present in "sturdy", presumably because it's sturdy enough as it is.

Here are all the pieces I got from nophead, the first few already bronzed: