Drawing with Fusion 360

So I've been having a quick look at Fusion 360 from Autodesk as a program for generating the G-Code for running the CNC Mill. It is possible to write the code by hand, and I have done a little of that for the lathe, and probably will continue to do that for the lathe. However the mill can produce more complex shapes and it will be easy to pass large, complex programs onto it for machining.

Probably most important however is that I can run previews of the toolpaths and the software can calculate the best path using various optimizations or change a tool quickly then re-calculate.

Before I can generate G-Code out of Fusion, I need to be able to draw in it. I am starting by drawing the stock I'm using to make the part out of.

This is a piece of some kind of machineable wax that came with the Mill when it was given to me. It already had the slot in it which I am planning on using to hold down this with. It should be pretty easy on the tools which is good because some of them are pretty blunt.

Here goes. I've had no training on Fusion 360, only other CAD software so I am working mostly from guesswork here. But I did manage to make this part.

I am liking some aspects of this software. It has a number of elements similar to Pro/Desktop which is was I first learnt. Everything can be drawn from constrained sketches which are then transformed. This means that if you've made a mistake in a sketch you can go back to it, fix the mistake and re-calculate all of the parts that are dependent on the sketch. Also being constrained you can make parts that will scale with only one change in dimension.

Keep an eye out for some chips coming soon.

Cheers,
Rex

Something a little different

So I dont like doing things the normal way. Here is more evidence.

This is an iMac G3 and I am planning on setting it up to control the CNC mill and hopefully I can find a way to use it to drive the lathe as well.

CNC Mill Moves, With evidence

The mill is running again, in it's new spot inside the house so I should be able to get to work on it a bit more often. This is where it is now, on the new desk with my laptop beside it running the controls

I had the lab power supply out to see if I could run the spindle off it. However even with the knob for current all the way up it was still getting limited so I think that's going to be a no-go. The good news is that I can still run it from the accessories port on the Lathe control box because I haven't gutted it yet.

It's a little bit dirty but not too bad and with the shield shut then there shouldn't be any issues with bits getting into the rest of the room which is good considering this is above my servers.

Here's the interface I am using for now. I'm hoping to get Machineface/Cetus/mkwrapper working so I can use any computer to control this, but for now I'm connecting with a VNC connection because mkwrapper doesn't seem to like being run in such a way as it can be accessed from outside that computer.

Finally, here is a short video I took while I was making sure everything still worked. I still need to set the maximum speed and tune the acceleration for each of the axies but I will get to that eventually. You can hear that when it's set right it's nice and smooth. But otherwise it sounds like somethings grinding.



Cheers,
Rex

The Mill moves again

On the weekend I had the opportunity to play with the CNC mill again.

We last left it running, with the power supply integrated into the case. The old computer power supply had enough juice to run the beaglebone, but unfortunately not enough grunt to energize the stepper motors. As soon as I tried to power them up some kind of overload protection would shut the whole thing down.

To help pinpoint the exact problem here I connected my benchtop powersupply in parallel with the computer supply over the stepper driver input. This worked and I could switch machine power on and off without issue. To see if the problem was just an initial surge overloading the PSU I unplugged the benchtop supply to see if everything would still run. It did; but the PSU started to make a funny sound and I'm sure I could smell something wrong. I plugged the benchtop supply back in and the noise went away immediately, with the smell disappearing shortly after.

So it looks like I don't have a big enough power supply. The solution? I've ordered a 240V to 12V 20A swichmode supply from eBay. At the price I decided to get the 20A model as it might be a little marginal at the rated power. By getting well over I should have plenty in reserve, particularly if I want to run the spindle off it as well.

Hopefully this will arrive by the end of the week and I'll be able to install it either next weekend, or the weekend after.

Busy times at the moment, I've got something else on order from eBay that should arrive early this week. That will be an interesting little project. And I picked up something interesting from the market today which I'll do a little post on as well. So keep an eye out for those coming up.

Cheers,

Rex

Mill Woes

Just a quick update on how the mill is going as that's the only thing that's actually had anything done on it recently. I finally got the software issues sorted and worked out a display, then when I pressed the go button to power on the motors they hissed like they should for a fraction of a second. Then.. all of the power died to the board.

A second test confirmed that this is consistent behavior unfortunately. I think what is happening is that the turn on current draw of the steppers is too high for the computer PSU and it trips the overload protection. To test this what I'm going to do is connect my bench power supply in parallel with the computer supply and then after starting the motors wind down the current. That should tell me if the computer PSU will handle the base load current.

If it will then I will probably put some kind of large capacitor across the 12V rail and GND to help minimize the surge. I may do a quick writeup on the display arrangement I finally got working, particularly if there is some interest there.

I'll report back how I go with this.

Cheers,
Rex

Nearly time to start Milling

So one of the other projects I did some work on over the weekend was the Mill. I now can move all 3 axes and using the mkwrapper tool I can control it from my tablet, laptop or phone without having to put a screen onto the Beaglebone that is running the mill. Something I think I will have to add though is a button as part of the GUI that allows the Beaglebone to shut down cleanly without having to ssh into it. That shouldn't be too hard and will probably be one of the things I will work on along with the rest of the GUI now that it will move.

Below are some pictures of what I did. Not very exciting though mostly just soldering and tracing wires. I even managed to get 2 out of 3 motors spinning in the right direction.

 This is with the Z Axis and the X Axis wired up, Z on the right, X on the Left.

Now all 3 have been done. The 3 unconnected wires will be used for e-stop and some limit switches
I think, possibly for spindle speed manual override. I have another Cable that I will use for the other needed signals.

In the back right you can see the connections I have made so far. I will put a proper enclosure
over the connection before I call this project finished.

This is a closeup of the final connection. The knot is for strain relief in the main cable.

 Thinking back now even before I have finished there are some things I would do differently. If I were to start again I would probably not cheap out and use more plugs, one between each motor and an enclosure proably on the back wall, then the big grey cable would have a plug on both ends rather than being soldered to the mill at one end.

Anyway, full speed ahead and onward ho. If I get to the end and decide it isn't working then I'll change it.

I have another 1 or 2 projects that I got up to over the weekend coming up so keep a wearther eye out.

Cheers,
Rex