Topics

1

Mach SDK plugin questions and answers. / input/output and pulse analysis probe.

« on: August 12, 2008, 06:09:43 AM »

Hello all.
With the help of Mr Leed3 I'm hoping to develop a small DIY type probe that can be connected to a spare input and will enable the user to place the tip of the probe on any other input or output and the PC screen will display if the input is high, low or if there is a pulse train on it (maybe even a graph showing the pulse train so pulse width etc can be viewed). First off, in practice how fast can data be read from the parallel port (I know this is dependent on machine spec but on average)? Is there already a plug-in or mod that does this? I suppose the last question is would anyone else find this a handy addition? I like to measure things when setting up or looking for faults and thus this is why I thought of it but maybe it's only me  . All comments will be appreciated.

2

Show"N"Tell ( Your Machines) / Warco VMc /Chester 626 knee mill CNC conversion

« on: July 13, 2008, 12:19:42 AM »

http://www.chesteruk.net/store/626_turret_mill.htm Sorry I'm not sure how to post the picture yet.

I'm hoping to CNC this mill and have already started to get a few bits and pieces together which is probably the wrong way to go about it as I won’t profess to know much about the whole conversion business.

Parts list so far is:-
CNC4PC  Bi directional buffered break out boards X 2
CNC4PC  Charge pump board
Motion control products (MCP)  MSD542 micro stepping driver X 3
MCP  34 frame (86BYG450B-011) steppers 3 Nm X  2 for X and Y Axis
MCP  23 frame (FL57STH)  Stepper motor  X 1 for Z axis
Power supply supplied by MCP for the above steppers and drivers.

I started building the box of bits as I had in mind to build a Router but when this Mill came up as a damaged unit in an auction I couldn’t resist and thus my project has now changed with the idea that once I get a CNC’d Miller it will make it a lot easier to make the router table.  In the same auction I also got a Chester Craftsman lathe which I may CNC later depending on my success with the mill.
That’s as far as I’ve got.

What I need to do now is:-

1, Build a base with casters on to actually get the lathe and miller in to my work shop    as I can’t lift the things once inside.

2, Ask some learned fellows a few questions to get me started.

One problem I’ve got is I can’t get Mach 3 to run on my Vista machine ( the driver test fails) but I’ll go through all the set up install steps again as I’ve probably missed something (I’ve installed the memory override dll)

With reference to number two above:-
What sort of drive ratio should I have on the X and Y axis ? I was thinking of using the steppers in 400 pulse per rev mode and each rev (using the standard ACME screws) gives me 3 mm travel.
As the longitudinal travel is 365 mm and I guess it would be nice to be able to travel this distance in high speed non cutting mode (Jog mode ?) in about 30 seconds this would mean 120 ish revs per traverse and 48 K pulses or 1.6 Khz (please tell me If I’m talking utter rubbish here) . If my calcs are anywhere near correct then I could afford to have a 10:1 reduction ratio on the stepper as it should be about to run at 16 Khz no problem (shouldn’t it ?).  Cross travel is half the distance but the same gearing would be ok. The thing that worries me is looking at some pics I’ve found on the net, some folks seem to have coupled the steppers direct or at least through a 1:1 ration pulley system. Surely this would give you an unusable traverse max speed and need you to get bigger motors….hmmmmm…
Last question. I’ve seen a Mill doing thread cutting under control of Mach 3 on you tube and it looks very impressive but how does the Z axis the cutter and the rotating work piece stay in sync ?? I can see how the Cutter and Z axis does but the spindle is free to rotate, Isn’t it ?
Anyway thanks in anticipation for any help or suggestions anyone has.