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Re: Mike's ORD Bot build

PostPosted: Tue Feb 21, 2012 5:33 pm
by mike
  • Got the X axis set up
  • Added some feet for leveling and to get it off the steppers.
  • Put together the MakerGear plastruder.
  • Mounted the plastruder with a piece of ALU angle extrusion.
I'm not happy with the plastruder mount -- My choice of mounting location has a couple of bolts interfering slightly with the belt drive :evil:
I'm going to move the mount and redo the belt attachment to see if I can clean things up.

Re: Mike's ORDish Bot build

PostPosted: Mon Feb 27, 2012 8:10 pm
by mike
It's printing, or at least extruding plastic in recognizable shapes!

Printed a 10x10x5mm 1/2 cube & tried a 20x20x20mm cube.
There was a glitch that caused a Y axis shift about 4mm into the 20mm cube -- I'm not sure yet if it's hardware, firmware, or Gcode.

Next up -- Install limit switches. Since this requires partial disassembly, I might add some holes for wire management at the same time.

I was about to ask for Z axis limit suggestions, but remembered Ben Jackson's idea to put them at the top: http://www.buildlog.net/forum/viewtopic.php?f=16&t=1035&p=8247#p8241

Is anybody familiar with extruder PID tuning? I'm using Marlin with the Makergear hotend configuration.

Image

Image

Re: Mike's ORDish Bot build

PostPosted: Mon Feb 27, 2012 10:59 pm
by JeremyBP
Is the PID not working well? If you give some more description of the problem, I might be able to figure out some suggestions.
Looks good so far with the prints though. I'm guessing that the Y-axis skipping is either a firmware issue (acceleration/feed too high, probably the former) or a mechanical issue (pulleys slipping or binding).

Re: Mike's ORDish Bot build

PostPosted: Tue Feb 28, 2012 9:47 pm
by mike
I'm having a problem getting to a stable temperature with the M109 GCode.
During the 30 second TEMP_RESIDENCY_TIME after reaching the target temperature, it keeps cycling more than 3 degrees over/under the target, and resetting the timer.

I've set Marlin up in Configuration.h, to use the Makergear hotend value set.
The thermistor supplied with the hotend came with a beta value (4066), but I'm not sure if that needs to be plugged in somewhere.

Any tips would be much appreciated!

Re: Mike's ORDish Bot build

PostPosted: Tue Feb 28, 2012 10:20 pm
by JeremyBP
Try turning up kP a bit and see if that helps. if it gets more unstable, turn it back down and increase kD a tad.

Re: Mike's ORDish Bot build

PostPosted: Sun Mar 04, 2012 6:21 am
by mike
Just a quick note to mention that I was able to fix the glitch causing a Y axis shift by reducing the current on the Pololu stepper drivers.
Curiously, increasing the current made it worse, and reducing the current eliminated the problem.

Re: Mike's ORDish Bot build

PostPosted: Sun Mar 04, 2012 1:57 pm
by jv4779
That sounds like the stepper driver is overheating and doing a thermo shutdown.

Re: Mike's ORDish Bot build

PostPosted: Mon Mar 05, 2012 5:36 am
by mike
Tried printing the squirrel that JeromyBP printed on his ORD Bot (forum post).
I've got some tweaking to do -- the top of the tail & the ears are pretty much a molten blob, but I'm pretty excited about getting it to print at all!
IMG_20120304_175255.jpg

Re: Mike's ORDish Bot build

PostPosted: Mon Mar 05, 2012 7:39 am
by nrp
You need to allow the layers to cool when using PLA, or you'll get drooping and blobbing on quick layers like you're seeing at the top of that print. A fan fixes this. I use a 120mm fan blowing across my print area, but others use 40-60mm fans attached to the X carriage blowing directly on the extruded plastic.

Re: Mike's ORDish Bot build

PostPosted: Mon Mar 05, 2012 2:36 pm
by JeremyBP
Looks awesome especially for a first(?) print!
If you're using slic3r for g-code generation, try setting the minimum time per layer to something between 10 and 16. Also, make sure cooling is enabled.
If you're not using slic3r, you should be. :D