Titan tension adjust

I'm looking for guidelines on how to set the tension adjust on an E3D Titan. Right now I have it at the least tension (thumbscrew fully clockwise), and I've left it there as I have no understanding of how I should set it or what the consequences of changing the tension would be. I switched to the Titan a week ago, and have mostly had good prints, but on one object (http://www.thingiverse.com/thing:13910), the print has failed twice with not enough filament getting through the extruder and some signs of grinding in the form of debris on the extruder gear. It may be due to other things, as I'm trying out some PLA that I have not used before, and it's a print with an unusually large amount of retraction. I'm not suggesting the problems are necessarily related to the tension, it just got me thinking about it.

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See my blog at [moosteria.blogspot.com].

The extruder should never, ever grind a divot into the filament. The motor should start slipping before that occurs. If it's grinding filament, the tension is not set high enough. Tension should be set so that that it almost crushes the filament. That will ensure that the drive gear teeth are biting deeply enough that grinding cannot happen.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Thanks for the comment. I'll try cranking the tension up a bit. It seemed counterintuitive to me (more tension = pushing it harder against the gear, hence more grinding), but I know intuition is not always a good guide. In this particular case, it seems like raising the temperature solved the problem, as I did a successful print in the time between sending the message and seeing your reply. (It's Makerbot PLA, which seems to need higher temperatures than other PLAs).

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See my blog at [moosteria.blogspot.com].

With PLA, I've had pretty good luck with the Titan setting the hex screw in line with the middle bar. If you look at the clear side of the Titan, there are 5 bars and behind the bar you can see the hex nut. For Ninjaflex, I had some issues getting it set just right, but with PLA I've not had any issues with grinding or printing with the hex nut behind the middle bar. I still have to give Nylon and Wood Filament a try with it.