Saturday, October 25, 2014

Solder Spool Holder

I got annoyed with my thin solders not coming nicely off the spool (the solder was fine enough that it would often go under the spool, kink and otherwise just be a pain.

Here is my solder spool holder 3D printed on my Bukito. I used some skateboard bearings (608 - 22mm OD, 8mm ID, 7mm thickness).

8mm = 0.315" and 5/16" = 0.313 so I used a piece of 5/16" wooden dowel
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And here it is with the solder roll:

Now the solder comes off nice and easy.

I used #4-40 x 3/8" flat head screws to hold it together,  but I imagine that M2.5 should work as well.

I uploaded the FreeCAD source files, and .stl files to: http://www.thingiverse.com/thing:515131

Sunday, October 19, 2014

Marvin

I've been following Nick Lievendag's blog and saw him using Marvin as a quality indicator. Marvin is fairly small - about 25mm tall, so I decided to do a series of prints using Marvin.

Here's Marvin, printed in white PLA using my Bukito:
From left to right: 0.2mm, 0.1mm, and 0.06mm layer heights. The one on the left got chopped because the Windows 7 laptop I was using decided to reboot to apply an update. I'm in the process of replacing it with a Raspberry Pi running OctoPrint, but that's another blog post.

There is also a slightly blue tinge to the feet of the Marvin on the left, which is because I had blue filament loaded for a previous print.

I used the Cura slicer, and the settings were all default (from here). I chose the 0.2, 0.1, and 0.06mm layers just because that's what Cura suggested for low, normal, and high quality.

I then repeated the 3 prints, but with a 20mm diameter, 25mm high cylinder behind Marvin.

Here are the Marvins, front, back and side views, followed by the cylinders. Some of the Marvin's still have the build support between the legs.
So now to figure out why the stringing increases as the layer height goes down.

Incidentally, Cura has a minimum time for each layer, but as far as I can tell, it doesn't actually work completely properly. I'm pretty sure that the print speed slows down, but I noticed when printing the loop at the top of Marvin's head, that it was only taking a few seconds per layer, and not the 20 I had set.

For robot parts, I think that the 0.2mm setting is more than adequate.


Wednesday, October 15, 2014

OpenMVCam

I signed up to get one of the early OpenMVCam boards, and mine arrived yesterday.

One really cool thing is that it uses MicroPython to control it. Here's a photo of the OpenMVCam board beside a MicroPython board (OpenMVCam on the left), along with a photo of the back of the OpenMVCam board on the right. The MicroPython board uses the 64-pin STM32F405, where the OpenMVCam board uses the 100 pin STM32F407.



I decided to use the OpenMVCam to take a "selfie":


This was taken in a mirror using the write-jpeg.py python script, running on the openmv board to snap a photo. I need to figure out how to focus the camera.

Thursday, October 9, 2014

Bukito PLA cooling fan duct

Deezmaker just came out with a PLA cooling fan duct for the Bukito.

It looked cool, so I figured I'd give it a try.
I ran it through Cura with 0.1mm layer thickness and it came out looking pretty nice.

I just received a roll of Silver filament that I ordered from seacans.com. Seacans is located in Langley, BC, so I was able to order it Tuesday, and it arrived on Thursday, and they have flat rate shipping too! I wound up ordering 6 spools of filament, and it was only $9.99 shipping.

Here's another view:

After mounting the duct and fan, I noticed that the bottom of the duct would collide with the 3 mounting screws which hold the bed on. So I used a 1/4" spade drill to countersink the holes for each screw.


 This shows the before and after


 And here you can see that the distance between the bottom of the duct and the surface is less than the thickness of the screw head from the previous picture.


And here's the duct and fan mounted on my Bukito. You can also see the straight lines which originate from near the corner of the bed. This is where the head rests while the extruder is heating up, and the duct would have gone right over the screw head:
I used #4-40 x 5/8" screws to mount the fan, since I didn't have any M2.5mm screws. I also tapped the PLA using a #4-40 tap.