Sunday, June 26, 2011

First usable part, and more improvements

Today I tried to print the modular spool hub again- this time with the heated bed.

I first changed some Skeinforge settings based on what I learned yesterday - mainly turning on comb, and increasing my perimeter flow rate over operating flowrate to 1.15 from 1.10. I noticed a couple of the perimeter layers of my minimug were not quite fully atached, so the perimeter adjustment should theoretically help that. I also upped my width over thickness ratio to 1.5 in both skeinforge and repsnapper to hopefully reduce the printing time.

Speaking of the minimug, it may have been watertight, but it definitely didn't hold alcohol. I'm guessing PLA is fairly hydrophobic. Good thing I decided to use some cheap rum instead of the good stuff. I'm thinking that my printer should be called Kraken in honor of that...

I was running into some issues with the X axis skipping steps on the first couple of tests, so I readjusted the trimpot a few times, and also adjusted the tension in the X belt. It had become a bit loose over time. On to the printing!

Excellent! I didn't have to fiddle with any other settings than the 2 W.O.T settings in Skeinforge and the corresponding values in Repsnapper and it still prints well! The heated bed worked really well to keep the part stuck down. I used a bed temp of 55 C, although since my thermistor is taped directly to the PCB instead of the top of the glass the actual temp was probably a bit lower. A few quick squirts from a can of compressed air cooled the part quickly and allowed it to pop right off the glass. Now back to the drawing board to design up some of the crazy ideas I've been having for new parts.

Edit: changing the repsnapper settings doesn't actually change anything. I'm thinking that by changing my W.O.T. to 1.5 reduced the apparent amount of extra plastic being extruded. I will print up some more test cubes later this week to see what else needs to be adjusted...

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