I recently purchased a small CNC router, fully intending to heavily modify it and turn it into a more respectable machine. This machine started out life as a Vevor 3018, the previous owner had upgraded it to a 4030 and upgraded the spindle to the high speed spindle motor. As built, these machines are real lightweights, the frame is made of 2020 and 2040 aluminum extrusions. But, Awesome CNC Freak has shown that with some TLC these little guys can be used to do useful work. He's machined a lot of the parts for his DIY 5 axis CNC using his modified 3018.
These are some of the cons that I see and what I plan to do about them:
1) It's a lightweight, it has no mass to it, and no base. I plan on adding a substantial base to this little guy. The first plant I worked in made laminated plastic sheets, I saw them make sheets anywhere from about 20 thou, up to 11 inches thick. In the years that I worked there, I accumulated several of their rejects. I'm going to use a 400mm x 600mm part of one of those 30mm thick sheets to make the base that every thing else will be bolted to. That 400 x 600 x 30 mm piece weighs over 20 pounds, and I can bolt that to the bench if needed.
2) They only used 10mm guide rails, those things will flex like crazy. I'm going to up-size the 10mm unsupported rails, to 12mm fully supported rails. Just going from 10mm to 12mm rails would be an improvement in rigidity, but using the fully supported rails should make that an orders of magnitude improvement. The X axis rails will be bolted to the base, further increasing their rigidity. The new 12mm Y axis rails will also be fully supported, and bolted to new 2040 extrusions - instead of being just a 10mm rail hanging in space. I also plan on bolting those new 2040 extrusions together, which should also help to stiffen up the gantry. If I have to, I can use this guy to mill out new gantry side-plates out of some more of that 30mm stock.
3) The Vevor control board leaves much to be desired, it's being replaced with an ESP32 control board with MUCH better stepper drivers.
4) They used about the cheapest, lowest torque Nema 17 steppers possible. There's no ID on them at all, but they're about the right size to be the 40-ish oz.in version. I already have MKS42 closed loop stepper controllers for these guys, If I need to upsize the steppers, I can go to 84 oz.in or 92 oz.in steppers in Nema 17, and still drive them with the MKS42's.
5) The stock Z axis just plain sucks, it's made out of injection molded plastic and it's only got 40mm of travel. It also has 10mm rails, but they're a LOT shorter that the X or Y axis rails so that alone makes them much stiffer. I can 3D print a temporary replacement that will give me more travel while working on a permanent solution.
6) The spindle, where to start, it's a GS-775M , 20K rpm, 75W motor. But at least it's got an ER-11 collet adapter on it. I can't complain too much I guess, my Unimat's motor is 100W, my Sherline's is about 125W, and my first CNC - back in the late 90's - had a whopping 60W spindle motor. Awesome CNC Freak used a 200W motor with a speed reducer in his 3018, might do something like that. And then there's always that 1KW water cooled spindle and VFD that's been sitting in a box waiting for me to finish its' project.
7) This thing is drip-fed g-code through a G-code sender, I've got a used Tiny PC coming that will do just that. I've accumulated a DDCS stand alone controller and stepper drives over the years, which are also a possibility.
This and my other unfinished projects will keep me busy over the winter.
Don
