RepRap: Blog

Need I say more?

Well, yes. The pads definitely stopped the corners curling. One pad didn't print (dodgy patch on baseboard most likely) and that corner started lifting. Not having superglue to hand after Oz, I put a dab of hot-melt glue on that corner to anchor it down, and that stopped the curl nicely.

The mounting slots for the smaller motors are a little short, but I've fixed the STL file and uploaded it. I'll just hold this one on place with some cunning wire-bending.

Next, the carriage.

Vik :v)

Labels: bracket, motor, reprap

OK, here's the tidied up version. I had to ream out the vertical holes by hand, the horizontal holes were fine and just needed de-stringing. I have seen how threads of molten plastic climb up the curved surface of an acorn nut nozzle and I'm modifying one to see if I can reduce the stringing. The holes in general were smeared somewhat, mostly due to a soon-to-be-fixed software bug which resulted in the extruder not being turned off at appropriate moments.

In the previous post, you can see the part starting to curl like a king-size mattress being stuffed into a queen-size fitted sheet. The curl is not very pronounced, but did distort the 8mm holes making the insertion of an 8mm rod very tight indeed - you can see shavings on the end closest to the camera. The nuts fitted into the rectangular slots at the top without a problem. The other holes were a little tight and required gentle persuasion to drive the nuts home - a bolt and very large washer was used to winch them in.

What didn't fit was the nut down the channel in the 8mm hole. My reaming didn't clean that out enough and I had to resort to a dremmel tool.

It near enough works and I'll be building it into a Reprap as soon as I can.

I'm extruding in 0.55mm layers, 1.62mm outline size and 0.73mm infill size from a 0.86mm nozzle. Max x-y movement speed is set to 238. This gives fat outlines, but because of the jerky movement between points by the head, curved lines are fatter than straight lines and the slow speed minimises the difference in width.

A very respectable 0.5mm width wall was printed by mistake during a buggy phase of this printout when the nozzle moved without being turned off, but this is good as it shows what the hardware is actually capable of - even with a 0.86mm nozzle.

Vik :v)

Labels: bracket, idler, pla, x-axis

Here's the pretty side of 11 1/2 hours of Reprapping. You can see that the PLA started to curl - I'm not cooling layers here so I might have to get that working again.

The paper tube is because I realised half way through that the hole for the axle was not Reprap-friendly as it was not pointed. So I quickly rolled up a bit of the nearest thing to hand (a Catalyst compliments slip as it happens) and poked it in the 3/4 complete hole. I had to roll it around a bit of 6mm rod as a guide to slip it in.

The Reprap-friendly hole shape is quite clear in the top right corner. The loops on the left edge are caused by the nozzle erroneously seeking warmth in its corner due to temperature reading bugs.

Anyway, I'll tidy it up and take some pretty photos tomorrow. Kinda tired right now.

Vik :v)

Labels: bracket, idler, x-axis

I've had a go at printing one of Ed's Darwin corner brackets. On about the 5th layer, the output detached itself from the stage and got pushed around a bit. While this wasn't exactly a huge success, it does look very much like we're on the right track so I've been persuaded to post the video. As per the last one, there are approximately 2.5 seconds between each frame.



Right at the end you can see the deposited part start to detach and go springy before it gets pushed around. You can also see the second head appearing in the right of the frame in the latter half of the movie. The camera moves around a little as the USB lead was dragging on things, but I fixed that with some tape about half way through; not a problem as it actually gave a better camera angle!

Adhesion to the stage (or lack thereof) is my big bugbear, and I'm going to try a light coat of varnish as previous tests have shown molten CAPA sticks to it like glue. If that doesn't work, I'm onto foam bases like the rest of 'em.

Vik :v)

Labels: bracket, capa, darwin, detached, fails, reprap, stage, zaphod