Opinions on this router design

[NB70]

What do you think of this design for a router? It is based on the other build threads here - it would be used for hobby wood working, occasional plastics and it would be useful to have it make replacement aluminium parts for itself. The range of motion is 1160 X 600 X 160mm - I'm aiming for around a quarter size sheet of plywood cutting area. I'm planning on using 1610 ballscrews on the X and Y, with a 1605 on the Z.

The base is 50 X 50 X 3mm welded steel box section. Plates with bearings or rails will be 20mm ecocast aluminium. The gantry is two pieces of 90X45 aluminium profile in an L-shape - from one of JazzCNC's original designs. The rails and bearings are the Hiwin type 15mm guideways - I will mount them on epoxy for the X-axis and directly to the aluminium profile for the Y (if this is possible?).

To keep the initial costs low I will start by using some components I already have with the plan to upgrade later. I will use the stepper motors, power supplies and drives (M542s) from my existing machine - an MDF router. Also I will design the frame for an 80mm 2.2Kw spindle but initially I will be using the Kress routers I already have.

What do you think?
Nathan