How hard is Linuxcnc to learn?

Hi, I want to make a 4 axis CNC Mill with AC servos, Linear Encoders and a Tool Changer. The mechanical aspect of the mill doesn't daunt me but the Electrical/Software does. I think I want to use the Mesa cards as they support the high frequency step rates and Encoder Feedback needed. I'm thinking 6I25 Superport FPGA + 7I85S + 7I75 is this correct / enough for what I want?

I'm new to the forums and I've read through some of the Knowledge Base to try and get a better understanding but I'm a little lost. My trouble is I don't have any hardware to just tinker with and figure things out for myself, the hardware is expensive and I want to be sure I've made the right decisions. Would it be worth while buying some cheap stepper hardware just to wrap my brain around it all?

Cheers,

Fenza

Haha that thing looks strangely brilliant! Maybe a 3D printer would be slightly more useful for me though

I've just checked all the computers I own and unfortunately none of them have a parallel port. What options are there for doing something like a 3D printer on the cheap in Linuxcnc? These stepper drivers are very common in 3D printers ( www.pololu.com/product/2987 ), I'd rather use something like that than a few hundred £££ worth of electronics simply for learning purposes, really all I need is the Mill but a 3D printer would be pretty cool.

Cheers,

Fenza

I'll have a look for a parallel port header though I'm not getting my hopes up, it's a 'Dell'.

Hmmm buying Mesa cards would probably be the best option thinking about it, but if I'm going to be buying the Mesa cards I only want to be buying them once. The issue is I don't really understand which cards will be best for my mill, I can be quite flexible as I was intending to buy a dedicated PC when I've got everything figured out. I'm kind of going round in circles thinking like this, I need to understand how it works and the best way to do that is to simply do it, but I don't want to be stuck with an expensive board or have other issues because I bought the wrong thing.

The Servo drives I will be using are these ( uk.rs-online.com/web/p/servo-drives-controls/7701400/ ) they accept Pulse + Direction signals at 4Mpps and the Linear Encoders are Incremental A±, B±, Z± at 15 or 8.3 MHz. Ideally I want to base all my controller electronics decisions around these two components.

If I have to just take the plunge rather than play around with some cheap 3D printer style project then maybe that's what I need to do, I'm just apprehensive buying stuff I know such little about.

Have you got any recommendations for what Mesa cards would suit me best? I'm also assuming Mesa is the option for my needs by the way. I'm open to other suggestions, even none Linuxcnc if it can compete.

Cheers,

Fenza

Thanks for your continued support Andy it's much appreciated

I haven't bought any motors yet, I was going to buy the matching motor for the drive from RS, here's a link if you feel like checking it out ( uk.rs-online.com/web/p/servo-motors/7701485/ ). They are quite expensive at ~ £2,300 for 3x axis (I'll add the 4th at a later date) but it was the higher performance that attracted me to them. The Servo motors use 20 bit encoders 1,280,000 cpr and the drives have dynamic auto tuning which alters the servo tuning in real time based on the machining conditions, I thought this would be useful for when I have real heavy parts on the table.

I've searched for servos quite a bit and the best alternative that I could find were the DMM Servos ( www.dmm-tech.com/index.html ) they're ~£800 cheaper for a similar system but at a lower performance. If you know of any good sources for servos I'd love to hear them!

I've never seen the General Mechatronics stuff before, they can run on CAN bus and utilise the linear encoder feedback too! Their systems look real neat. I'll do some digging, do you know if they have a good reputation?

I did look into ±10V analogue velocity control but I was under the impression digital commands offer greater performance?

Cheers,

Fenza

I'll check them out!

I've looked at the General Mechatronics and I think the encoder feedback only supports up to 500KHz... So I think Mesa is the way forward for now. I've got some digging to do.

Cheers,

Fenza