New Machine Build- aluminium router/miller design

[achiestdragon]

ok got need for a machine to mainly be used to machine aluminium front panels

the main issue is although the machine does not need to be able to do a 20mm dia 10 mm deep cut in solid granite for example more like about 1 to 2mm square aria cut in aluminum at most , maybe copper also it seems that a mini mill would be out of the question as the working travel is just way too small for the task

it would need to be able to take a 800mm by 400mm 10mm thick aluminium plate
but don't see the need to have 3 or 4 tons of machine trying not to crush the desk it would need to sit on just to get the bed travel needed

so looking at a design loosly based on the more conventional wood routers but up rated so that it would take the loads needed for doing aluminium effectively

attached is a pic of the design i am thinking about at the moment

seems the main issue with the wood router designs is in the z axis the travel usualy means the lowest z position has the worst flex and stress on that

so opted to make the whole x axis gantry move up and down the z axis
the weight of the gantry could then be a problem but using counterbalance weights like on an elevator (lift) would balance that out removing the strain from the z stepper
and also using 2 lead screws channel coupled on the z one at each side to keep it equal to each side
(weights and z lead screws not drawn on diagram yet and bed assembly not drawn up fully yet )

the bed moves on the y axis ,, its drawn using skate bearings to run on they have a 700kg load and it seems reasnable that they should take the load my current machine using the same bearings dose not seem to have a problem with that

the machine is to be made mainly from 2" by 3" 1/4" thick aluminium channel section mainly with 20mm thick of aluminium plate used for other parts and 20mm dia stainles steel bar for the bearing rails

the cutter is intended to be a bosch pof-500-a 500w 27000rpm router that has a 6mm or 1/4" tool capacity so the loading should not be as high as most of the bigger mills

planning on making the lead screws from 20mm dia stainless steel with a 4mm per turn thread to give 50 steps per mm (excluding microstepping although it will do that)
and using 220Nm stepper motors

mainly at this point would like some feedback about problems that may need to be addressed using this design for such a task

and before anyone points it out , yes not drawn as yet eather but there will be a coolant system on the machine also

any comments ?