[xxtoni]

Hello everyone,

I finally decided to take the plunge after a lot of reading into building a CNC router.

I currently have a 3x2m router which we bought a few years ago and I am reasonably happy with it there is only one caveat, it is extremely slow.

Despite having very powerful Schneider Electric servos (off the top of my head the X axis has a 1.1kw motor) the machine just can't run very fast with good accuracy. As long as you stay in the 2-3m range the machine is reasonably accurate but when you increase the speed it starts getting all over the place, for example corners will exhibit huge rounding all of a sudden being the major symptom. I tried increasing the acceleration curve and the motors have no problem keeping up but when the router changes direction you can hear and feel the impact that the direction change makes and I'm sure that isn't healthy at all and even with the increased acceleration curve the accuracy and rounding still aren't completely fixed. I am guessing that the reason for this is the weight of the gantry since it's made out of steel but not completely sure about that either.


BUT the machine is accurate enough and most importantly reliable and since routing is just one part of the process in the work we do it can keep up speed wise and it's reliable.

I am however looking to build a second router with better speed and accuracy.

What I'd like to do is actually build a sort of flatbed cutter with tangential and ultrasonic cutting and scoring capabilities and add a spindle along with those to increase the capabilities.

I originally planned on doing a machine based on aluminium extrusions but I found that I can't get them locally so that one falls in the water.

What I do have (in stock actually) in huge abundance is steel tubing, 40x40, 60x60, 100x100 and actually getting any size steel and aluminium tubing isn't really an issue at all. I also have 2 certified welders in my crew so going with the steel and aluminium tubing route seems most likely.

I am currently looking at builds other people are doing to start working on my own design and I'm hoping that some of you guys will be able to point me in the right direction so I can get started.

In a ideal case I'd like to build something like this:



The machine in the video even has the speed I desire, 30m/min, so that's pretty much exactly what I'm looking for.



- How should I "move" this thing ?

I'm not sure what would be the proper way of transferring the motion from the motors onto the gantry for a machine this fast. Are ballscrews the way to go or belts or something else entirely ?

Also what's the best place to get the rails and such, suggestions ?

Steppers or Servos

I am thinking servos because of the speed and acceleration requirements but still not sure to be honest.

Drivers, Boards, Motion Control Boards and Co

The guy in the video I posted above mentions that he uses the following control board with Mach3

CNCdrive - motion controls



So yea, I'm very much a babe in the woods here and my goal is pretty high up there but I just need some guidance on getting started so I don't make huge and fundamental mistakes there, I'm sure I'll find my way along the path.

I have no particular time frame in which I want this build, when it's done it's done and to be honest no budget either to be honest, obviously I want to spend as little as possible but I don't want to build something that will catch fire and collapse under itself in a few weeks.


I'm really looking forward to your replies.

[CaptainVee]

It seems to me the machine makes the rounded corners because of gcode, combined with available acceleration.

I'd say, experiment with that before starting a new build.

[xxtoni]

Hi,

I'll certainly take a look tonight and experiment a bit with that as well but it's not just that.

This machine I want to build is very much a different beast and a different applications. Whereas the machine we have is a traditional router with a spindle this machine is meant to be more of a flatbed cutter where a spindle would be a nice addition.

[pippin88]

The rounding of corners is likely due to constant velocity / tolerance settings. You can set these both in gcode and the controller (depending).