Sitola/Baumer CNC Foam Cutters

Hi,

I work with Sitola and Baumer CNC foam cutters. I'm trained in CNC mills and lathes, but I've never seen anything like them before in my life and I'm not finding much online to help. Three axis, I guess - X horizontal, Y vertical, Z is the blade angle.

Specifically, I would like to know how to cut down on blade deflection. We cut 2D shapes into large blocks of foam with blades that are 1/8" wide and approximately 83" long. As you can imagine, the blade deflects during cutting and my parts come out awkwardly shaped (for example, some of our round pieces come out oval-shaped and larger than drawn). Some of our machines have center supports/blade guides which helps, but I'm having issues with the one that we can't put a blade guide on due to how big our foam blocks are.

The only way I can figure is to run the machine slower, that helps with the ellipticity, but I can't figure out why they're coming out too big. It's not always a big deal, granted (our tolerances are ridiculously big) but problems compound sometimes and we have to scrap the whole block/rail/what have you.

Also, if anyone has any ideas on what feed rates to use for different density/hardness foam, I am out of ideas for where to look.