Build Log: 3-4 Axis Mill/Router

[IanS1]

I've finally managed to get some time to make progress on my mill design so your thoughts/critique would be much appreciated please folks.

As I want to machine Ally and other sheet steels I've taken JAZZ' advice onboard and decided on a fixed gantry / moving table design. The overall length is 1500mm ish, overall width is 1200mm ish and the Z axis has 220mm movement. This should give me approx 750 x 750mm cutting area.

The 220mm Z axis movement is required for machining/drilling 200mm wide Ally plates stood on end. Most of the time I will be cutting Ally plates which will be no thicker than 10mm which gives me the dilemna of a huge Z axis movement or some sort of adjustable bed/table.

I have thought about having a fixed bed with some sort of stackable table which will allow for less Z Axis travel but this obviously opens up potential problems with stability of table because of the distance from the rails/bearings to the cutting surface.

How difficult would it be to implement an adjustable bed/table? Any thoughts on the stackable table?

The gantry ends are currently drawn with the intention of looking into getting them cast, could be way to expensive though. They're approx 450mm width x 400mm height and 80mm thick. If the cast turns out to be to expensive they'll be machined out of 40mm thick Ally and sandwiched together.

The gantry ends can also have some triangular supports added to the outsides for even more stability if needed. I also have a 20mm thick plate across the back joining both gantry ends and hopefully adding even more strength/stability if needed. Would bolting the gantry ends all the way through the 80 x 40 x 5 frame with QTY 8 x 16mm bolts per side be sufficient?

The gantry crossbars are drawn at 80 x 80 x 1100mm and braced from the back with a 25mm thick plate.I'm still not sure if this will be strong enough, any thoughts?

The Z Axis/Spindle support plate is drawn at 600 x 240 x 30mm thick. Will this be thick enough? Any thoughts about the actual spindle? Is the 2.2kw chinese spindle any good for cutting Ally or will I need something better?

The plate thickness around the gantry carriage is 30mm front, 20mm rear and 40mm top and bottom for the bearing plates. The motor mount/support plates at the top of the carriage are 25mm thick.

The frame is made up mostly of 80 x 40 x 5 box section accept for the four corner posts which are drawn at 80 x 80 x 5mm with 10mm thick base plates which will have an adjustable foot attached to each corner. I want to try and keep the front of the frame open to allow for easier loading of Ally plates.

The table still needs some work doing, perhaps a 40 x 40 box section frame underneath to give it some support. The table plate is 900 wide x 750 length x 30mm thick. Would that need extra support underneath?

Still loads to do but I'm hoping the basics for a strong machine are there.