Saturday, November 24, 2012

Neat and tidy networking


Though it may not be apparent by looking at the state of my lab and other areas, I do like it when things are organized. A while back we had a satellite installer that needed access to our internet equipment, and I had to show him to the area in a storage room where a huge tangled pile of cables, power strips, wall warts and boxes sat in a jumble.
I resolved to do something about it, and this is the result. A piece of OSB/plywood cut to fit between two floor joists, two pieces of wood alongside with screw eyes in the end which, along with a pair of drywall screws serve as a hinge, and a latch to hold the whole thing up in the ceiling when access is not needed. Everything is either screwed down or zip tied. In the case of items that have those slide-lock screw holes, after being slid into the locked position a drywall screw is driven in next to them to keep them from moving.  All the cables run up and are zip tied through the pivot point so they don’t tangle.
Just recently another installer needed access, and he was very surprised when I flipped the latch and dropped this out of the ceiling. He thought it was pretty darned nice.


Very cool 3d printing resource

Visit http://hobbydev.ru/ and drag in a gcode file to visualize how your printer will run the print. Shows 2D and 3D views and you can drag the sliders to “watch” it lay down the lines and layers.

Friday, November 16, 2012

Eliminating wobble

I’ve been fighting Z axis wobble for several months.  Last week I noticed this post on Thingiverse. All it does is to replace the 5/16″ Z axis drive rods with #10-24 rods.  I recreated the parts in OpenSCAD so that I could make SAE versions and installed it on my printer.
My Z axis wobble is essentially gone now.
I do have other issues – I fried my display panel plugging it back in incorrectly, and since I had to reprogram the firmware and I accidentally lost the previous copy I had to start from scratch on my firmware, but in the end I printed this with basically no wobble:



Thursday, November 1, 2012

Thoughts on nozzle size


My first RepRap was a MakerGear and came with a 0.35mm nozzle.  I’ve been using that as my standard up until recently when I bought a couple of 0.5mm JHeads.
It seems to me that the main difference is how well you can print thin objects. If I have a wall that’s only 2mm thick and I’m laying down 0.75mm wide perimeters, Slic3r may not be able to put any infill inside of it, leading to weak, hollow objects.
EDIT (March 6 2013) - Newer versions of Slic3r have even remedied this problem.  It seems to be able to do reduced extrusion and infill narrow gaps.  So IMO 0.5mm is just fine and tends to clog less.  I think the only remaining downside is that it does dribble a bit.
On the plus side, I can run the layer thickness up to 0.33mm rather than the 0.25 that I usually print at – and I could probably go even higher for some objects, which results in a significant reduction in print times.
One interesting thing that I need to investigate – a few days ago I was printing the aquarium pump bushing shown in a previous post, and I forgot to put Slic3r on the “big nozzle” settings – I sliced the object with the settings for 0.35mm.  It actually printed beautifully.  I guess the volume of printed material is going to be correct regardless.  I haven’t taken the time to think about the actual consequences of using an incorrect nozzle size in the final print.