A 1 third perfect print...then.....

I am so close to making "Woody" work it's not funny.

Here are some pics of the herringbone gear I printed this morning.

The print went perfectly until the direction changes at halfway up the gear and the top round part.

This has be baffled. How can the calibration be out when the bottom third is perfect including the center hole at 4.67mm and then the printer skips 5mm exactly to the right at the file part where the teeth change direction and again when it gets to the top round part.

The calibration must be right for the bottom third to be lined up perfectly, right?

Edited 1 time(s). Last edit at 05/08/2012 01:01AM by gregted.

Your skipping steps, my first guess assuming it's nt mechanical is that the stepper driver is overheating as the print progresses.
Turn the pot anti clockwise just a small fraction and see if that helps.

Thanks Polyhonhell,

I turned the pot down and the next print went better.

Now I just have to stop the small gear on my extruder from breaking out the grub screws that hold it on the shaft causing the extruder to not extrude on a perfect print.

Have filled the base of the small gear with epoxy and I will re drill the holes for the grub screws when it sets and I hope this makes it stronger.

It's a good thing I like to tinker or woody would be firewood by now.

You can also cool the drivers with a fan. There's sort of an art to this process, since if you turn the drivers down too much, the motors won't have the torque they need to go at high speed and you'll need to slow down to prevent skipped steps. But if they're up too high without active cooling, they'll periodically shut down to prevent themselves from melting, thus causing skipped steps!

Thanks Pointedstick,

I have fitted a small heatsink and fan to my extruder motor and this has helped. The type of fan is off an old cpu and the holes match my steppers nearly exactly so with a small flogging out of one hole, I could reuse the original holes through my steppers to mount the fan and heatsink.