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

The Lathe still works

So I have finally got everything in place to use my CNC Lathe. To test it I ran it in manual mode. I stuck with the default settings of 80 mm/min, 0.25mm X incremental feed & 0.1mm Z incremental feed. I had a play with the spindle speed just to see what would give the best finish. There didn't seem to be much difference but I was just using a pretty soft piece of some kind of plastic.

This was all I did, the spindle is quite loud so I didn't want to be running this too late. I'm not quite sure what kind of plastic this was but I did get a fair few pieces of what seems to be Delrin that I will be experimenting with once I work out how to hold them as the chuck doesn't open far enough to hold them.

This machine is fairly old and is controlled from a 486 running windows 95. Not the world's oldest machine. But fairly old. The interface is all DOS based so to improve startup time I have disabled the windows GUI entirely and just boot into DOS. The interface, while definitely classic it isn't too hard to use or hard on the eyes, which can be a problem with some of these older user interfaces.

I shot a video of me machining this piece with my phone sitting on top of the safety shield. During the video you can hear the different pitches as I adjust the speed of the motor to see if that would change the finish. Watching the video and also while using the machine there is a lot of backlash evident in the Z axis so I will try to work out what is causing that and hopefully remedy it.

With this now working I should be able to power the spindle for the mill from the accessory port on the control box for the lathe. This will give me a chance to fully test and even start using it to make parts.

I have the manuals for this lathe so I will probably put together a program that will allow me to turn down the Delrin blanks so I can mount the securely in the better chuck. But we'll see about that.

Cheers,
Rex

Oil Burner Atomiser

Due to some offcuts of 12mm square bar from the frames of our Heisler loco becoming avaliable I'm going to make some small test runs of making some atomizers for it.

I can't find any open source CAM software for outputting to a lathe so I'm going to be writing the G-Code by hand in gedit. I'm getting the design from here which I've found to be a very good resource for info in the shay and heisler locomotives. I am making some changes to simplify construction with the avaliable tools (rounding to the nearest metric drill size).

I can post up some CAD files of the proposed design and the G-Code if anyone is interested.

Cheers,
Rex