Wow, two pages since my last visit. I better check if my alerts are going into spam!
My apologies, questions going out to me, and me asleep at the wheel.
Here's an attempt to address questions to me in one response:
Yes, the "tractor tread" continuous belt is offered on ServoBelt, for cases where the debris or contamination is so bad that we must mount the static belt on the bottom or side of the chassis. Otherwise the dynamic belt drapes. All the idlers and tensioning idler on Fernando's sketch are not strictly necessary. You'd use some idlers if you wanted to control the loop enough to fit covers over it all. The main downside of this is reduced life, though less expensive to change out the belt.
We recently concluded a life test of the BrecoFlex belting, and the standard grade did approximately 18 million starts and stops (approx 60 lb accel/decel forces). We are now embarking on life test with a higher flex version of the same belting, that has the same ultimate tensile strength. We will have two going, one with low payload and high speed, one with 200 lb accel/decel forces (which is the upper limit we impose on T5x35 wide).
As to backlash in the motor pinion, the "zero clearance" version from Breco-Flex is um, not. There was no difference between it and a carefully prepared and plated standard profile. For the most demanding positioning, we pay special attention to this, and it is our "special sauce". On our rotary stages, we have the pinion and bull-pulley custom hobbed.
Back bend diameter on the inner idlers is per Breco-Flex recommendation.
There's some new propaganda on our site, the pdf of the tech-sheet on the servobelt page is the final print version.
We are currently building 90' and 22' long ServoBelts with dual carriages. I'll post some pics soon.
Mark, looks like you're doing a nice build. I look forward to pics! We too are doing a belt pre-pass to get 3-4:1, mainly for inertia matching. We're also doing a T10. You should be OK with the GT2-8.
Here's some common configurations.
Mike Visit my projects blog at: http://mikeeverman.com/
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