Wednesday, July 27, 2011

X & Y Axes operational from the controller



I was finally able to get time to integrate the full anti-bounce board with the x and y axis limit switches.










The two axes are playing ping pong and running at a speed of 65 mm/sec with no slippage and no heating of either the steppers or the driver chips. I've run them all morning with no mishaps.


Now I am going to have to see to writing a gcode interpreter and taking a shot at the TFT 320x240 graphics touch screen for system control.

5 comments:

Bogdan Kecman said...

Have you tried pushing the driver+motor+firmware combo to check what max speed you can achieve without slippage?

Are you counting steps between button presses? Would be cool to count steps between them and calculate deviation after few hours running. Even without slippage there is a significant chance of non equal number of steps per iteration because of imperfect switches.

arhi

Forrest Higgs said...

"Have you tried pushing the driver+motor+firmware combo to check what max speed you can achieve without slippage?"

Yup! 65 mm/sec is about the top. :-)

"Are you counting steps between button presses? Would be cool to count steps between them and calculate deviation after few hours running."

Done that. Wrote a file on the SD card with the data.

"Even without slippage there is a significant chance of non equal number of steps per iteration because of imperfect switches."

There definitely is.

As with Rapman, however, I only expect to reset to minimum limts switches once during a print, so that isn't really an issue. The reason I am using double limits switches is to have a positive signal to stop the steppers from trying to push the printer carriage off the ends of the x or y axes. Rapman has a problem with that from time to time.

As well, with minimum and maximum limits switches I can define a specific zone on the print table for a print.

Bogdan Kecman said...

I understood why you put switches on both sides (I did too :D on the testbot), as it will help a lot with "everything". Primary reason I'm using both side switches is that I want to have firmware that does not need to know the print area + I want to have firmware that is able to do relative movements too so home does not need to be "known physical location"

Forrest Higgs said...

Absolutely! :-D

powtac said...

We started to build a 3D printer as well and we had similar problems: http://6brueder.wordpress.com/2011/12/27/x-schiene-extruder-und-heizbett/