Foundation about building a five axis cnc machine ?

[tgt1997123]

Hi everyone,

I'm currently in university majoring Mechanical Engineering and i want to build a pocket NC ( 5-axis CNC milling ) but I'm now not knowing where to start. Therefore I would like to ask about some books/websites or any sources to learn about this topic.

[orangezero]

A good start would be looking through the pocketnc tutorials and other info they've provided. Then consider what you want it to cut. Foam and plastic cutting would be much easier to do successfully than aluminum, for example.

The difficult part with electronics is actually getting a 5 axis cnc board that works for all five axis. I think I read in a googlegroup somewhere about all the magic the software people had to do to get the hardware working correctly for the pocketnc. They've since changed hardware as it worked but was difficult. You could go cheaper with some 3d printer boards that use various forms of g-code implimentation grbl, smoothieboard (v2 sometime soon), tinyg (or tinyg2 soonish?), machinekit, beaglebone boards (Cramps, beboper++, etc). They all seem to promise better support for 5 axis in the future, but when looking at specifics often the various hardware boards with five slots is really only 4 axis as it simply duplicates the Y axis, or perhaps the fifth is for an extruder and software won't recognize a rotary axis at all. Grbl requires a special build, which complicates things. I'm not sure I've seen a 5 axis smoothie machine, but it looks like the firmware allows it. But even if the hardware allows it, the software they use may not.

Personally, I'm leaning towards a linuxcnc software machine, using autodesk fusion 360 (really, the only thing making 5 axis possible in the last few years, can't stress this enough if you want to stay inexpensive!!!!). Before fusion360, I'm not sure any hobby people seriously considered 5axis unless they liked to program their own software or had $$$$$. Linuxcnc seems to allow for 4th and 5th axis without too much trouble. Its been around for years and has a huge community forum. Mach3 is another option but costs more, also very popular.

There is also the difference between true 5 axis and 3+2 axis. It is my understanding that linuxcnc/fusion360 allow true 5 axis (meaning, I believe, that all axis can be moving at once). I currently have a gecko g540 which is a 4 axis hardware solution and generally well respected, but adding a 5th axis is probably beyond my understanding.

I should have started here, best to start with a three axis and learn from there. 5 axis should be challenging for sure. If you want to save a lot of money, buy hardware that allows you to add more stepper motor drivers to make a 4th or 5th axis now and then you can just add more parts later. I would suggest a board that allows you to remove the stepper drivers from sockets if/when you fry one. If you have them soldered on, losing one axis means you need an entirely new board.

Perhaps the cheapest would be five TB6600 drivers hooked up to a cheap breakout board, but I'm not sure how decent those TB6600 are anymore.

Hope this helps some. CNCzone has such a wide variety of expectations that someone will laugh at all of this I'm sure. I'm not looking, and I'm sure you aren't, to produce a machine which replaces a $200,000 commercial product.

Is perhaps the cheapest example I've seen if you just want to learn how to make a machine.

This parts seems crazy cheap, decent backlash, and a 30:1 ratio. If you need motors anyway, I'm just not sure two of these for $200 wouldn't be an amazing start to a build for very little money. There are other videos online, but I haven't seen it in too many builds.

I'd be wary of some of the 4th and 5th axis chinese made router tables. I've seen some youtube videos that have huge amounts of play and I can't imagine it working. Some even seem to have a 1:1 motor to table turn, which just can't be very good either.

5 axis is something I abandoned four or so years ago. It may be workable now. Been doing too much reading the last week or so. Best of luck.