Hello!
I am looking to order a new 3 Axis CNC from China. I have some experience operating and assembling 3 Axis machines, although this is the first machine I buy for myself.
The idea is to get an entry level machine with a working area of around 300 x 300 x 100 mm and 0,01-0,02 mm precision for cutting prototyping foams, wood, plastics and, very occasionally, some aluminum - just for fun. Main objective is producing silicone molds for polyurethane resin casting of plastic prototypes, so I need fine surface detail(smooth).

Anyway, looking around I found this machine called HY 6040/3040, apparently made by RioRand(although I can't tell for sure). Seems like it would cover my needs(and budget) But I wanted to know if someone here had experience using this machine before buying. I know I can't expect it to work right out of the box and will probably need tightening and some extra work before I can get it to produce anything acceptable. There seem to be plenty of these machines out in the wild, however I can't find many opinions/reviews on it. Here is what I have found so far:

- This video where it mills some plastic in 5 axis mode. User Kustom 20 seems to have had an OK experience with it, but not much to say in the way of precision, which is my main concern.
- This shaky and very worrying video where they try to mill aluminum in a ridiculous way. Full of nasty comments.
- This aluminum engraving demo video where the surface quality of the finished piece seems OK.
- They sell one on amazon. The "Customer questions & answers" part has some good opinions of it.

My plan is to get the 3 Axis, steppers-only version and strap a TinyG controller and custom electronics/spindle to it.
What do you guys think? Can I expect proper surface finish and dimensional accuracy when milling, say, RenShape460 or similar materials? Provided the right tools, toolpath planning is used of course
How about its rigidity? The builds I have found so far seem not so top notch. Here are the most detailed images I have been able to find so far.

Thanks! and congrats on this awesome forum