Vertical load 5kg build help

Sorry, but there's no way that the stepper motors you are using will achieve what you are trying to do. Have a read of this post (Vertical linear actuator - help) and you will realise that it is ambitious even with heavier duty components and stepper motors.

Alex.

 

I would like to add to what Alex correctly said that the whole thing is kind of flimsy. I have no idea what you are going to do with this machine but I'm sure it will not be precision work. If you hold one top corner steady with one hand and with the other hand you'll move the other corner back and force I'm sure it will move quite a bit and that's not good for precision. Going the C-beam route will not make much of a difference, in this case.

 

Focus on the structure, not the motion components. Structure is much cheaper. And look into Y-axis racking prevention (this is Z, but same principles apply).

 

Well, I said that it's *doable* in 3-4 months, though for me it was more around a year or so (and of course, continuously, ongoing, since we learn every day!). Though I tend to go after more ambitious goals, so I think basic hobby-grade machine understanding is totally doable in just a few months.

There is definitely some maths you'll have to become somewhat comfortable with- CNC is entirely math, ultimately, and those who try to avoid it tend to do worse vs their potential. You have to understand the basic maths of stepper motor revolutions, belt and screw multipliers, etc, as well as some slightly more complex ideas like screw efficiency (think: coefficient of friction), beam calculations for deflection of supported and partially-supported beams, torque and force, etc. You don't have to necessarily follow along with the large equations to calculate exact numbers in certain geometries or materials, but you have to understand that, for example, a force pushing on your spindle is going to twist your gantry beam, and have an idea of about how much. If you have tool deflection and you don't understand why your circle cut-outs are actually conical, this topic is the problem. For this kind of thing, a basic start would be googling something like "CNC machine frame design" and see where that takes you. Maybe "beam deflection", and see if anything pops- there are several topics that should come out of that. When you find interesting or confusing terminology, you put that into the next search terms.

Aside from that, understanding the electronics- controls, stepper drivers, stepper motors, limit switches, all of that stuff and how it goes together and why is critical. What talks to each other, how does it do so, what kind of signals are we expecting, etc. One way or the other, you'll also learn about grounding and EMI, so to make it easier on yourself, learn about ground loops, capacitor filtration, etc. as well.

Then you have to figure out how they go together- motors have torque curves, which means for a given speed they output a certain torque, which will get converted by your drive system into a force. F = ma, so that force determines what mass you can have and how fast you can accelerate it! Steppers also have inherent limitations on acceleration though, both electromagnetic- how fast it can commutate without losing position and physical- how much inertia the rotor has.

You can go down this rabbit hole for a very long time, just chasing the next search term as you hop from topic to topic. I spent many, many hours just reading along with CNCZone threads- people on forums explaining their thinking or arguing over a particular design idea goes a very long way! At a point where you think you might have a workable design and can speak to the decisions going into it, you can post the build here and we can follow along the process and offer advice, which is also part of the learning process. For example, here's my current in-progress build (which has been slow-going due to other projects and occasionally having to stop and fight the mill): M4: 1510SS Heavy Mk.I - lots of discussion and thinking out loud there.