More Bumblebee stuff

At dinner tonight I got to thinking about the best way to power the Raspberry Pi and it came to me.  A very simple, effective, and inexpensive solution.

Instead of using a 7805 regulator I am using a BEC that normally I use in my RC airplanes.  The one I have right now is rated at 5 amps at either 5 or 6v.  Sure enough when I wired it up to the Pi everything started up just fine and I'm running some test prints just to be sure, but I think it's going to work out great.

It even has a low voltage alert in case for any reason it stops getting the clean 5v, and it has filtering and smooth regulated power for the Pi.  Best part is they only cost about $6 and install in a flash.

So all I have left is to cleanly mount it and the wiring, then make a board for the lights and add switches to them both so I can turn the lights off and on, and install my emergency stop switch that will kill all power to the motors and the Rambo board in case of a  mechanical issue.

Bumblebee II is running again

I finally got both my printers running again, the Hippie was pretty easy, it just needed a new hotend as the thermistor on the current one (which is over a year old) broke.

The Bumblebee II I was switching back to the E3D V6 hotend, and I was finally able to get it to print reliably and consistently.  I think the whole issue was related to my extruder, up until a few months ago I had been using a Maker Gear geared extruder and it had tons of torque so adjusting it wasn't that critical.  I switched to a Bulldog XL after the planetary gear was worn out in the Maker Gear extruder, and I had been struggling with getting consistent prints.  Half way through the print the filament would stop feeding, or it would strip it out.  I did some experiments with temperature and filament tension on the Bulldog and finally got the right settings.  I have to run the E3D a little hotter probably because of the active cooling, but the prints have been coming out great finally.

I started working on the onboard power system for the lighting and the Raspberry Pi and the lighting sections are working fine, but the Pi doesn't seem to be working correctly.  I need to pull out a monitor and keyboard and test it tonight, I'm not sure if it's not delivering enough current, but I also ordered 1.5a 7812 and 7805 chips from Mouser just so they won't run as hot.

Printing on Etched Glass part 2

I really wanted to be able to print without any slurry whatsoever, so I went back and did some more testing tonight.

First I tried running the bed colder, and that seemed to make things worse.  I went back to my normal bed temp and tried to run the nozzle slightly cooler, and that had a little bit of improvement.  I was still having trouble with the first layer peeling up, so I dropped the speed way down to 10mm/s and that worked beautifully.  So my next test I heated the bed higher and low and behold I got a nice print of my standard test print a RoundTuit.

I've been experimenting a little with the nozzle height, and basically you just need your nozzle adjusted correctly, and it seems to print well.  I've gone back up to my normal nozzle temperature of 220, and I'm printing with a bed temp of 140 right now.

Time to do some other prints and see how those do, if they work well then I need to etch my borosilicate glass and install my new bed and I should be all set!!!

Experiments in RepRap

Finally got some free time to do some experimenting with the RepRap again, well I chose to do some experimenting. I've actually got quite a bit I should be doing :)

The first was switching the Bumblebee II over to the new 512mb Raspberry Pi that I got today.  Shut down the old one, moved the SD card over and plugged everything in to the new one and it was up and running.  The memory does make it a bit snappier, but more important I can load almost all the gcode files into pronterface without an issue.  It's still just a bit much for the full MendelMax part plates, but I have those on an SD card anyway so it's not really a problem.  I'm still waiting for the new WiFi dongle to come.

The next thing to experiment with was kind of driven out of necessity.  The window tint once again started to come off the bed, and I decided to go ahead and try the glass plates that I etched at TechShop in Raleigh.  I had about 4 different patterns to experiment with.

I tried the plain checker one first.   It seemed to do well except on the parts where the glass was still smooth.  After several layers that part of the print started to peel up.  So I ended up stopping the print on that one (and yes, I'm using RoundTuit's as my test prints)

Next I decided to skip the other patterns that had smooth glass in them and go to the 100% etched piece.  While it did much better it still had some trouble starting a thread of plastic, it ended up pulling it up off the glass as it moved away from the start point.  So I ended up applying an extremely thin coat of slurry and that seemed to do the trick.  Nice matte finish on the bottom, no warping, and it came off the bed very easily.  A nice side effect is that the rest of the slurry left was easy to scrape off with a razor blade.

So for me right now the 100% etched piece with light slurry is a huge improvement over the window tint I've been using.  No worries about having to replace the tint when it get's damaged or starts to break apart, and it seems to work great with no warping.

I'll probably buy another month at TechShop and etch the borosilicate piece I have for both the Bumblebee II and the Hippie printers.  I also have a few other things I want to cut before I have my laser cutter up and running (I've started ordering the last pieces I need)

More on the Raspberry Pi and the Mendelmax

Well I've been printing using the standard (well slightly modified) pronterface on my raspberry pi straight to my mendelmax. I have not been able to get the wifi working, but I do have a shared drive that I can access with my Mac Pro. So my tool chain is to download the stl, slice it then save it directly to my raspberry pi. I then use vnc to run pronterface and load the file and start/monitor the print.

The one big issue I've run into is the memory on the Pi. I still have the 256mb version and it will do fine for probably 75% of the things I've printed. But on complex objects, most notably the x carriage for a mendelmax, it runs out of ram and shuts down pronterface. I can still print from the sd card, but a newer version of the Pi with the 512mb will be ordered shortly :)

Other than that the latest distro is much faster, I'm seeing much better performance when I vnc in, and I can actually move windows around and use it while on a 4g connection.

I'll probably be ordering my new pi this week, and then anxiously awaiting its arrival :). The current one will probably be going into my CJ as the main controller for all the devices I want to add in it.