MakerBot Industries

I've experienced almost the exact same scenario except I haven't switched back from 3dprinterstuff filament to MBI yet. I will make the switch back as soon (hopefully this weekend) as I receive more filament from MBI. I will let you know what I see.

I've been printing on two different MK7s for several months now. On the first one it was very hard to feed plastic at first, but with effort I was able to do it with all the washers, just by pushing hard; I found that thinning the plastic a little with a sanding block seemed to help. I think it did 'bed in' eventually because it works very consistently now and feeds reliably without needing any pressure. For whatever reason, the second MK7 has worked as it should from day one. Most likely there are small variations in the plunger washer thickness or something like that.

Re the 3Dprinterstuff product, I had similar problems with the reel I bought from them. I think it's not as consistent in size as the MBI product, and I also suspect it is made in a way that makes is slipperier (mineral oil?). After a fair amount of annoyance with it I did eventually get it to work reliably by carefully cleaning the pusher gear and adding a sponge filament cleaner (thing:14196). I suspect that the pusher gear will need a good cleaning every so often, fortunately it's not hard to do because the MK7 is such a simple design.

I ran a 6 hour print today in the new configuration, and it ran great. Minor issues here and there, but overall a success. I just assembled this thing - http://www.thingiverse.com/thing:15289 - and I'm going to do some testing with it. Initial testing tells me I need a stronger spring, but the design seems to have some potential.