CNC Router - concept to allow a huge

Hi all,

I´m planning to develope and make a cnc router and I have questions to some design topics.

The concept I have has quit a big Z travel (>500mm) what makes it hard to get the mashine stiff enough on a conventional router design (X+Y and torsional for the Z axis). The space for the mashine is limited (router shall be used as a table if not in use and also storage room under the table is required). Router shall mainly be used for alu, wood and foam but I sure want to get it as rigid and accurate as possible. Working area as big as possible and in Z min 500mm.

So I´m trying to solve this issue with a different Z travel concept. The Z travel is moved away from the gantry beam so that I can control the forces better. To reduce the issue with the additional weight the plan is to use pneumatic cylinders to compensate the weight in Z and strong enough AC servos to handle the aditional forces in X.

There are also 4 linear rails for the X and Z axis and 2 rails for the Y axis. This will make the alignment of the axis quit tricky and hard work... but I am hoping solve that issue and so get the forces better under control(more connection points and distances between them to reduce the forces).

The plan is to use filled (damping) steel tubes, WIG/TIG to weld them together and the Alu will all be made out of a huge 50mm thick Alu sheet (I have it so I try to integrate it into my concept to save some costs). To get some more stability and weight onto the table I planned to make a UHPC bed (only the alu working plate will be fixed to it).
Alot of blabla so I made a quick and dirty concept of what I´m thinking about: see the attached screens (it´s really a rough first sketch!).

Questions:
1. Does the concept with the Z travel and pneumatic cylinder make sense?
2. Is the aproach of reducing forces with the con of having to align more rails worth a try?
3. The weight and forces on the X axis are high in motion. Do you think I can handle that from a mechanical
standpoint (make table/bed heavier)?

Please throw your darts and thought´s to this concept, it´s my first mashine and I appreciate (and need) input.


Thanks!
Sebastian


This is a companion discussion topic for the original entry at https://www.cnczone.com/forums/mechanical-calculations-engineering-design/467543-cnc-router-concept-allow-huge-new-post.html