After a couple of false starts I have finally settled on a design I am happy with, I was going to build a 4 metre long table but unfortunately the boat has to live in the shed as well so the router has to be somewhat smaller. Last time I started from the bottom up but this time I am starting from the top down, so here is what I have come up with for the Z axis, aluminium box is 75mm by 6 that I got a friend to mill out a slot and drill some holes.
The ballscrew just fits inside which is a bonus, it just needs a small plate underneath to give clearance over the corner radius of the box section. The slot is for the ballnut to attach to the spindle plate, I have the linear rail blocks made that the plate will attach to, you can see them in the photo's, I just have to cut out the plate, it will probably be cut from 100mm flat bar, and bolt to the bearing blocks I have made.
The plan is to do exactly the same for the Y axis and similiar with the X, for the X it will have the ballscrew on one side, kinda like those cantilevered designs, I have a friend that has done similiar with a bigger machine and it works fine so I am going with that idea.
I have a few ideas to try with this machine, PCB milling is high on the list and I am designing a 4 spindle attachment to put on, it is easier than a toolchanger and hopefully will work out, I am going to try it out.
For the standard spindle I am going to use a three phase spindle and VFD - funds allowing.
I have my own servo drive design based on the Elm Chan high power design that I am going to test out on this machine as the new firmware that has been done on the drive hasn't been trialled on a ballscrew machine as far as I know, if it works then I am going to post board layout's and parts lists for those that want a cheap intro into servo's.
Phase two for the drives is to bypass the step/dir side of the input and control the PWM scheme directly from EMC, taking encoders to the controller. The advantage of going DIY on the electronics is that I can build in some connectors that will allow me to just plug and play while I am changing the control of the servo drives.
Any hoo, enough of my rant, here are some photo's
Cheers.
Russell.