MakerBot Industries

Many of us print without difficulties with the OEM filament delivery design on the MK6. It works here in PA.

I have been using my TOM standard MK6 (with the stepper rather than the previous DC motor) for months now without any problems. I was a bit afraid to over tighten it when I just started and quickly realized that it was a lot sturdier than I expected.

I have only used MBI's ABS filament so far and the tensioner has been performing perfectly. Unless you are pushing (and expanding) the limits of your TOM like some of the more advanced users are doing (Jetguy is one that is at the "bleeding" edge and very active in this forum) my guess is that you would be OK with the standard tensioner.

One quick test of the extruder head that I did is that you should be able to extrude by pushing the filament down with your hand when the nozzle is at 220C. You can also see the force it requires to move the molten ABS through the nozzle (in my case it is a 0.5mm one).

Even I use the box stock Mk6 tensioner without any ratchets or other attachments. It's hard to beat for speedy change of filament which I do more often than most.

That's not to say I never had a failure, but 99.999% of the time it was my mistake which happens a couple of different ways.

1. If I use a filament that I had previously extruded with and not cut off the end, may be fatter (larger diameter, from the heat and pressure) thus the starting tension changes when I get to the smaller part. Human error-but also the nature of a fixed setscrew VS a spring tensioner (this is where a Wade's has the advantage).

2. Simply forgot to crank down the screw—duh-extreme operator error.

3. Maybe I didn't tighten it down enough and then a 8+hour print with tons of reversals loosened the screw.

Simple prevention methods—before EVERY print, tighten the screw. Always cut a fresh end on filament when inserting. And, even check the screw after the first few minutes of extrusion.

The standard tensioner pushes a static piece of plastic onto the filament. So on one side there is the extruder motor + gear trying to push the filament down and on the other side there is the tensioner pushing hard trying to stop the filament from moving at all.
Sure you can drive your car with the parking brake partly on but you are wasting energy, wearing out the break and if you go faster you're also overheating the brake.
The Wade style tensioner (all variations) use a ball bearing to apply pressure on the filament while not acting like a brake.
So the standard tensioner does work, just like driving with the parking brake partly on does work, but that doesn't make it a good idea/design.
The one thing I have seen reported is that reversal might cause the tensioner to loosen up, meaning that it needs to be retightened more often than other tensioner designs. But that may have been incidental reports and not the norm.