Re: [CAD_CAM_EDM_DRO] Bridgeport MDI update

machines@... wrote:

> I went ahead and bought this machine from the college, plus a load
> more stuff I probably shouldn't have bought as well. Anybody want to
> buy a Murex 330Amp welder ?? <g>
> Got to play with the MDI under power and I must admit it's a queer
> beast.
> The machine is basically a Series 1 with variable speed and a fixed
> head. Power to the axis are by SEM servo's with encoders. Controller
> is an Heidenhain T131. What is queer about it is that it only has one
> drive card and it swaps this between axis as required.

OH NO! That is a mess! These are called 1D or 1.5D machines. I think
you'll find this a very poor substitute for real 3 Axis CNC.

> This means it
> can do canned cycles like drilling, pockets, slotting, bolt circles
> etc and linear moves but it can't circular interpolate.

It can't linear interpolate, either (unless it is parallel to an axis).

> When I found
> this out before I bought it, It put me off but after realising that
> 90 % of my CNC work is only done in one axis at a time I went ahead
> and bought it. Plus point is that if you push in the knobs at the
> side of the handles it turns into a full manual with the controller
> working as a DRO. It also has a limited teach mode on it as well This
> looks like an early version of the EZ Trac but lacking some features.
> As far as I can tell this is a UK only machine and they were not
> fitted with this controller in the US.
> Looks a very easy machine to convert if nessesary but as it's all up
> and running I'll keep it like this until I have problems. I think the
> limited working area of 18" x 12" will be more of a problem than the
> linear axis moves.

HAW! You think YOU'VE got problems. I'D DIE (well, almost) for 12 x 18"!
I have expanded the X travel to about 28", but I can only get about
6.9" in Y right now. I need to hack off some interfering bits of material
in my CNC conversion to regain the full travel of the machine, then
I'll have 9" of Y. This is on the old, round-ram Bridgeport, which
had a smaller knee.

Jon