Friday, 26 February 2016

Old dog, new tricks....

It has long been a theory of mine that the older you get, the harder it is to learn new things.
I still consider that to be true, which is why I'm always amazed when I accomplish something I've never done before.
I first did machining (milling and turning) back in the training centre at Marshall Aerospace in 1987/88, then didn't touch a lathe or milling machine until I started at Cambridge University's Department of Engineering in January 1996.
Since then, regular use has made me reasonably proficient with both machines, but soley manually controlled machines - not CNC (computer numeric controlled).
When (thanks to a half-million pound grant) we were recently able to treat ourselves to a new milling machine to replace the aged mill we'd had since the dark ages - a fantastically versatile machine but sadly worn beyond  limits - we ended up with a brand new XYZ SMX3000 mill which is a modern CNC machine that frankly scared the shit out of me.
I quickly got used to using it in manual mode, but the whole concept of CNC programming remained a mystery to me.

However, things move on and there comes a time when you realise you need to grasp new things before you get left behind for good. With the help of a colleague I'd had a fiddle around with the programming software and got to the point where I at least had a vague idea of what was going on.
Then yesterday came a point where I needed this facility to modify a component and the guys who were experienced with CNC were all tied up with other jobs. Down to me then. Oh well, here goes nothing.
Talk about throwing yourself in at the deep end. It wouldn't be so daunting to have a simple thing to machine for your first attempt at CNC, but the component I needed to modify was a supersonic wind tunnel liner that had already been machined at a considerable cost in materials and man hours, and here was my big opportunity to fuck it up.
Theoretically all I needed to do was a three step programme that would enable me to mount a window and its retaining flange into the liner so we can mount a GoPro camera into the liner enabling us to view flow visualisation inside the tunnel during a run, and potentially to use a laser sheet to illuminate particles in the flow for analysis.

After spending significant time getting the workpiece set up so that the surface error was within a thousandth of an inch, setting up the cutter and programming the CNC controller, I got my CNC-familiar colleague to double-check my programme.
With my heart in my mouth I started the process.


OK, so in the scheme of things this is small potatoes, but once the milling was done and I'd fitted the other components I'd already made, I did feel like I'd achieved something quite big for me.
For someone who has clung on desperately to the old-school manual methods for so long, assuming there would always be someone else to deal with the complicated CNC stuff, it was immensely satisfying and has kindled a wee bit of excitement at the prospect of having another go.

Not all new things have filled me with this sort of dread though. 3d printing has been something I've taken to like a duck to water. About the same time as we got the new mill, we also purchased a Stratasys Objet 24 printer which cost about twenty grand and has proved to be an expensive to run and hugely temperamental pain in the arse. But when it's behaving itself, it's a fantastic piece of kit which has enabled us to manufacture parts that would be difficult or even impossible to make with conventional techniques. Thanks to a course that taught the basics of SolidWorks, I'm now able to design a part on the computer and create it on the printer, and given that almost everything we make is a unique prototype and definitely not available off the shelf, this capability has made things significantly more interesting.
Obviously the old saying 'All work and no play makes Jack a dull boy' is as true here as anywhere else. In the same way as the nozzles in an inkjet printer get gummed up if it's not used for an extended period, the Objet 24 needs regular use to keep it running smoothly, so if there's no legitimate use on the horizon, it's open season on 'private' jobs.
The latest of these has been my 'Multipass' as seen in the brilliant movie 'The Fifth Element'.
Sometimes you just have to get your geek on.