Bantam - changing to a front ballscrew concept

How's the redesign going, Fatty?

It only took a few hours(!) to create a new assembly with the ballscrew assembly mounted on the front of the machine, close to where the original leadscrew and rack would have driven the saddle. Obvs, I've tried to reuse as many of the original parts as possible - where it makes sense of course.

Here's what I've got, in a sort of "ghost view":

The servo motor bracket and mating encoder bracket are unchanged, as is the travelling ballnut yoke. I had to model the underside of the saddle to enable me to design a suitable mating bracket to engage with the ballnut yoke and connect to the bottom of the saddle. 

There's a new bracket where the original leadscrew / power shaft bracket used to be. That's the main challenge here, work-wise, as it's going to require a fair bit of metal removal. 

Rather than fuck about with poncey 10mm carbide cutters, I'm going to use my 50mm Korloy face mill. It's easy to forget that these are intended for bigger jobs than simply facing off stock. I have a suitable piece of 1.5" x 2.5" loominum (6082?) that will be spot on for the job, so here's the work set up with that stock. 

Same toolpath in simulation:

Bottom line - am I expecting a silly / unrealistic spindle power requirement with these settings? Given that this is expecting to take 18 mins to complete, it doesn't sound completely daft. I've got the best part of 3kW available, so I should be trying to make use of that.

Here's my spreadsheet with the settings I've chosen. For no good reason, I've dialled back from the original 10mm depth of cut (roughing stepdown). And the 0.1mm feed per tooth is at the light end of the typical range (0.1 - 0.5mm), so I'm not exactly pushing things here, even at 2000rpm. 1.3kW estimated power should be well within the machine's capability

OK, so let's prepare some stock and set to.

It was covered in dried coolant and swarf. Amazing what a bit of Swarfega will do!

Square it off to length (229mm)

Nom, nom - let me at it! Nice sharp APGT1604 inserts on Korloy face mill...

That is fairly noisy but nothing alarming. Pretty sure I could at least double the MMR eg by upping the spindle speed or increasing the feed per tooth or both.

That makes some decent looking chips.

This was a 3D Adaptive toolpath with zero "stock to leave". The bottom surface comes out nice and flat due to the wiper feature on the inserts. The sides are non functional and barely visible, so I don't see any justification for any kind of finishing operation, so that will do for this side.

The angled face actually has 1mm stepdowns but from a distance you can barely see the steps anyway.

Now I need to flip it over and machine the other side...