I figured I'd start a new thread so I wouldn't have to hijack anyone else's threads with my questions. Also, if I ask all of my questions in one place, anyone who has the same questions/issues as I do can find them in one place.:)

Ok. So it seems like I have all my axis moving the distance I tell them to just jogging at a very low feedrate in pronterface. The x and y lock and hum at anything above 180 but the z is alright. The difference between the three is the z is direct driven and the x and y are geared down with pulleys. I had to set the steps per unit for the x and y to 4133 and the z at 1312 in the firmware (marlin).
Any ideas?

I think I had a similar problem on my first ever test run.  My current potentiometers were turned up too high on the pololu driver boards.  Try turning them down and ramping them up to the point where the motors don't skip steps.

Nate

Quote from firepinto on February 23rd, 2013, 01:26 PM

I think I had a similar problem on my first ever test run.  My current potentiometers were turned up too high on the pololu driver boards.  Try turning them down and ramping them up to the point where the motors don't skip steps.

Nate

Oh, is THAT what that is Nate? Thanks! I'll try it now.Well, changing the pot on the driver at least got it to go up to 210 mm/min. Seems like up too high and it gets really rattley/grumbly, too low and its a more quiet hum but still too high of a feedrate from pronterface makes it so it won't move at all. I'm messing a little bit with the firmware and the best results I've gotten from changes was changing the default xy jerk settings from 20. to .5

Code: [Select]

// default settings

#define DEFAULT_AXIS_STEPS_PER_UNIT   {4133.3438,4133.3438,1312.3359,760}  // default steps per unit for ultimaker
#define DEFAULT_MAX_FEEDRATE          {189, 189, 5, 45}    // was 500,500,5,45 (mm/sec)    
#define DEFAULT_MAX_ACCELERATION      {189,189,100,10000}    // was 9000,9000 2-21-2013joe X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

#define DEFAULT_ACCELERATION          1500   // was 3000 2-21-2013joe X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION  1500   // was 3000 X, Y, Z and E max acceleration in mm/s^2 for r retracts

//
#define DEFAULT_XYJERK                0.5   // (mm/sec)
#define DEFAULT_ZJERK                 0.4     // (mm/sec)
#define DEFAULT_EJERK                 5.0    // (mm/sec)


I think I'm going to try using 24 volts for the power supply. I read on the reprap wiki that if the D1 1N4004 diode is installed on the RAMPS board, you shouldn't use more than 12V (17V actually per Arduino) because that diode powers the Mega when it's not connected via USB. My board has the diode installed so I'm takin' it out and powering the Mega with a wall wart. The thing is though that I can't move the machine with the LCD control at all with the USB plugged or unplugged.

I was also toying with the idea of using a 3mm multi start lead screw nut pressed into a gear, driven by a worm gear to feed the filament into the extruder. Can't find any so I might have a lathe guy make one for me. I did some mill work for him so he won't mind.
[attachment=3437]

Well, I cut out the 1n4004 diode (D1) and wired up the 24V power supply; retuned the drivers and got it going. The max feedrate went from 290mm/min. at 12V to 875mm/min. at 24V. My hot end didn't seem to like the voltage increase though. It started smoking so I quickly shut it down. I think I should have left the 11A rail at 12V and only put the 24V on the 5A rail. Not sure about this though. It's a G3D hot end and I haven't looked up it's max voltage. I wonder if I can use that PID thingy in Marlin for this. I've got a 36V supply on order but I need to replace the 25V max G3D drivers that came with my ramps board with some 45V max Pololu drivers I got. I read that they have a slightly different pinout so I'm guessing I need to study that and figure out if I need to change the pin allocations in the firmware or? I'm sure I can use the machine as it is right now but it just hasn't met my greatest expectations yet. That and I don't know how to set the feed rate lower in skeinforge, kisslicer, or slicer yet. I've got a lot to learn. At least it's fun!

I've never used a knurl before. Guess it's not so bad. I only wish I had a 1/8" instead of the .150" I used. Getting closer! Thanks for all your help guys!