Morgan frame – December 2012
Morgan year end
Due to the holidays, development on the Morgan frame has been halted for 2012.
Progress so far…
1. Working electronics
2. Functional SCARA arm frame
3. Experimental Z axis
The z axis is a bit of a problem at the moment. Wobble in the threaded rod-motor combination cause the build plate to wobble sideways. I now understand why low cost system opt for a second z motor to stabilise the z-axis.
Thanks for your interest. Work on Morgan will continue in 2013.
Cheers,
Quentin
Frame taking shape
The frame is finally starting to take shape. The interesting thing is, that even after all the planning that went into the build, it is still changing subtly as I go along.
In the picture you can see the double arm SCARA, the belt pulleys and the sliders for the z-axis. Still to come:
The build plate, top mounted z-drive, the motor mountings for the two arm motors, and the Bowden extruder.
The movement is smooth, and it looks very promising indeed!
Cheers,
Quentin
More Morgan
The building of Morgan is continuing, and progress, while slow is steady. December will so far still be the month of completion of the first Morgan prototype…
Some pieces awaiting assembly…
Cheers,
Quentin
Printing progress
While furiously printing parts for the upcoming Ecksbot build at the house4hack course, using the Ecksbot borrowed from Peter, I am printing a few pieces for the assembly off the first Morgan prototype. Watch this space.
Z-axis
The bearings are only coming at the end of the week… but I got some second hand ones to play with at least. A good thing as well since there are still a few issues to work through.
I’d like to have a working framework by the end of the week, and then it is picture time!
Build progress
It is now becoming unbearable… My whole study is filling up with bits and pieces that I built / collected / hacked out of old stuff / bought etc. Morgan is in its last trimester!
Tomorrow night I will (hopefully) get my LM8UU bearings and two 50cm smooth rods for the Z-axis.
In the mean time, I’m hacking my pololu drivers: the micro stepping mode is not enabled, and to get that working I need to replace the ROSC resistor with a short to ground. The little 0604 links are 7c each… won’t break the bank. If I did not make the step-sticks yet I might have added a solder-bridge on the step-stick in order to program it with a soldering iron in stead of messing about with little specks of 0 ohm resistors.
Exiting times…
Faultfinding, and success
After failing to make the motor run properly, after trying quite a few different firmwares, I came across a testing firmware for RAMPS, that will wiggle all the motors, pulse all the heater outputs, and read the thermistor inputs continually.
http://reprap.org/wiki/File:RAMPS14_test.zip
After fixing the weak connection on the motor connector (usual suspect) I found that all the drivers worked fine, except the X. All were tested using the same Pololu, so the actual driver can be excused.
This set me on a path that almost cost me the new board… The 10k and 100k resistors were reversed, and in swapping them I unfortunately lifted one of the pads. I had to solder a 10k Resistor on solder-side to fix it up again. This did not solve the problem though.
With the program running, I measured the frequency of pulses going to each of the pins. It turns out that all the inputs were fine, except the STEP line. Well, no STEP, no step. Makes sense. I found a dry joint in the header going towards the Arduino, and realized that it was where I tacked the header on to straighten it before soldering. After a quick re-flow RAMPS is wiggleling on all its axis!
Now I have no excuse but to start assembling the mechanics of the bot.
My RAMPS is dead, Long live RAMPS
Yes, even though I tried, my first RAMPS did not survive the fall. Pads ripped out – Hard to fix on the stepper headers.
Anyhoo, borrowed an hot air solder station from Guy at House 4 Hack Tuesday night and built my next ramps. It is such a pleasure to work when you have the right tools. This weekend I will wire it up just to see some steppers turning, to motivate me to continue.
It is so nice to have found some fellow hackers. Finally people not glazing over when you start to talk about electronics, programming, robotics etc.
Arduino Madness!
Communica finally did something right, and Boy, did they deliver!
Arduino arrived at Communica, with the bottom dropped out on the pricing! I just got myself two more Arduino Mega’s – for around the price I paid for the first.
Go check it out, while stocks last… 😉
