another mini vmc project

[guido]

I am planning to design an mini VMC. Something similar to the Haas office mill but probably a table top version.
The aim is to design an accurate machine to machine aluminium at acceptable speeds. I will be going more for accuracy then speed.

Cost is also a big concern. Would like this machine to be affordable for a hobbyist.

Travel around 200mm for xyz. But willing to go smaller if cost or overall size become a problem.

Probably will be making the frame parts of welded steel and let them be milled and grinded bij some company. Or at the company I work.

The machine will be enclosed because of the use of coolant.
Ballscrews and linear guides will be protected.

Probably will try to keep it modular in the sense that it should be possible to use other linear guides and ballscrews. Depending on budged and desired accuracy.

Most likely will go for servo drive.

However I'm not a CNC expert. Would like to get some tips on toolholders and good sources for linear guides/ ballscrews/servos etc.

[JFettig]

Ebay is likely the best place to get your linear slides, maybe ballscrews if you choose to go with precision ground. I plan on going with preceision rolled screws for my machine becuase of the high price tag of ground screws.

Are you going with a gantry type machine like what stevie is making or a traditional machine similar to mine?
Theres another way I would think about doing mine if I had longer rails which is exactly like a haas where the table moves over rails rather than how I am doing mine and typical machines are done.

I have not decided on what to do about tool holders for mine, I have a custom rig I designed that I might use if I dont get a common tapered spindle which will be hard to find.

Jon

[guido]

Found an interesting supplier of linear slides. www.abbatech.com.tw
Got info that they are relatively cheap.

Most likely not going for gantry style machine but a more traditional machining center setup. Ganty style is usefull for bigger machines but not for the size i'm aiming for.

Rolled ballscrews are cheaper but accuracy not super. C10 grade rolled screws have +/- 200 um deviation for every 300mm of travel.

Guido

[jarr88]

would a person just be able to use 1/2 standard treaded rod witha delrin nut and still retain accuracy for a drill press mill router

[Stevie]

Originally Posted by guido Most likely not going for gantry style machine but a more traditional machining center setup. Ganty style is usefull for bigger machines but not for the size i'm aiming for. Guido

Yes mine is 830mm x 375mm x 305mm travels (max) quite big

[jarr88]

thanks for replying