Filament Calibration

[DGBK]

So, I recently re-calibrated my printer, and I had to change the arm lengths to get use of the whole bed. I used an online calculator to calibrate it, and I was unable to get below 0.09 mm standard deviation prior to changing the arm length. This is why I'm hesitant to change the length back.

I haven't measured yet, but I believe this will slightly decreases the size of the parts. It got me thinking...

If my parts are printing smaller than I expect, does that mean my extruder is pushing too much filament for the distance the hot end is moving? I'm currently printing a calibration tower, and I noticed that the stringing that I fixed prior to calibration is back. This makes me think the back pressure has increased due to the smaller print size.

I don't want to change the arm length due to the reasons discussed above. Would it make sense to adjust my extruder's steps per mm by the percentage difference in the x/y directions?

Thanks

[Xenocrates]

I would think modifying your flow rate is better (though they probably do the same thing) because it's easier to revert to one than to recalibrate your extruder. I would also modify your scale factor as soon as you measure it in order to still produce accurate parts

[Polygonhell]

I don't want to change the arm length due to the reasons discussed above. Would it make sense to adjust my extruder's steps per mm by the percentage difference in the x/y directions?

Thanks

When you change the arm length, you affect only the X/Y scaling, it also adds some doming (like delta radius), but it's by comparison a minimal effect. If you increase steps to compensate then you change scaling in X/Y and Z, so now your Z scale will be incorrect. How much did you change the arm length by?
You might want to start by printing a say a 100mm square to see how much your X/Y is off by.
SeeMe uses cast arms I'd be surprised if they varied by more than a few 10ths of a mm.
You might be better off finding a different calculator that gets you close to being able to use the entire bed without having to change your X/Y Scaling.

[Jimustanguitar]

Adjust your XY scaling to correct for the root cause. Don't patch a spare, if you know what I mean.

[DGBK]

Thanks for the replies.

I'm using 300 mm carbon fiber arms from TrickLaser with the new SeeMeCNC trucks. The results so far have been much smoother than my original stock setup.

I'll try to recalibrate with properly scaled arms. I did a 20mm x 20mm cube, and it came out to be 19.6 x 19.6 mm. Using a post by MHackney, it appears this means I need to correct my arms in the other direction (from 304.1 to 298.02). I'll do that and see how close to a full bed calibration I can achieve.