Yes the 4th axis does look a bit thrown together. Also it's just belt driven from a stepper motor with a single reduction, so the available torque and thus holding force will not be much. It would be ok for light work in wood, but would struggle to do anything serious (such as aluminium) due to the lack of stiffness.

The machine frame looks sturdy, however due to those nice covers we can't actually see what type of linear rails are used on X and Z. We can see that Y is 25mm supported rails, which is good. The pdf says the others are 20mm, but are they supported or unsupported? Perhaps ask for a picture without the covers on...what are they hiding?

The gantry has a piece across the bottom to link the two sides which strongly implies there is only one ballscrew on the Y-axis (I'd normally call that X, but they called it Y). This can cause the gantry to deflect when the cutter is towards either end since it is less well supported. The big spacing of the bearings helps, but it's still not as good as it could be.

There is a very large overhang between the tool tip and where the spindle is supported because they have put the rails on the gantry carriage, not on the actual Z-axis. Again this is adding weakness and potential for resonance.

Also they say they used 2510 ballscrews on X and Y. They would get a much higher feed-rate and acceleration with 1610 screws and on this size the critical speed wont be a problem, so it seems a bit of a waste of money to use such large ballscrews. 7-8m/min is good, but notice how they state the resolution is only 0.05mm - perhaps it's geared up a lot to gain speed at the expense of resolution.


Overall it clearly depends what you want to do with the machine. If cutting a lot of aluminium I certainly wouldn't recommend it. Anything else, well it's less clear cut but still not a good machine in my opinion. The problem is you'll struggle to find much better than that without either spending a significant amount more, or making it yourself.