Messages

2491

General Mach Discussion / Re: VFD recommendation

« on: August 15, 2006, 04:22:00 AM »

Hi Ian,

do you have any part numbers for the unit you are using.

Thanks

Graham.

2492

General Mach Discussion / Re: G54 offsets questions

« on: August 14, 2006, 04:46:15 AM »

Mike,

G54 is also active just the same way as G92.

Graham.

2493

General Mach Discussion / Re: G54 offsets questions

« on: August 13, 2006, 04:48:35 AM »

Hi Mike,

there is nothing wrong with using G92 as a datum point, that is what it is for,  changing to G54 will not improve the accuracy of the homing switches.  The main advantage of using G54-G59 is that you can change from one datum point to another in program.

e.g.

If you have two fixtures on your table you can have one datum at G54 and the second one on datum G55.  The code would be something like this :-

G20 G40 G80 Etc
(STANDARD SETUP LINES)
G54 G00 G90 G43 X0 Y0 Z1. H1 (MOVE TO FIXTURE 1 AND DRILL A HOLE AT X0 Y0)
S1000 M3
Z.1
G01 Z-.25 F2.
G00 Z1.
G55 X0 Y1. Z1. (MOVE TO SECOND FIXTURE AND DRILL A HOLE AT X0 Y1.)
Z.1
G01 Z-.25 F2.
G00 Z1.
M30

To set the fixture datums you go to 'Operator' and 'Fixtures' off the window menu.  You will see listed in the new window a list down the left hand side the top 6 are marked G54 to G59 all you have to do is set your X,Y,Z,A values into the corresponding row.  These values are the same as the known position for your G92

Remove all G92 commands from your code including the X,Y,Z and A and just enter a G54 instead.  This will then tell mach to use the G54 datums stored in the fixture list.

The advantage of this is that if you have more than one program that uses your indexer and the datum point for each program is the same then you don't have to worry about changing the G92's in each program.  They will all use the same G54 setting in the fixture list.

I hope this helps.

Graham.

2494

General Mach Discussion / Re: strange holes

« on: August 11, 2006, 04:06:18 AM »

In the picture on your first post,  are the 'stange holes' where the cutter starts cuttting that section?

2495

General Mach Discussion / Re: strange holes

« on: August 10, 2006, 04:15:44 AM »

Are all the holes at the Z plunge in point of all the different cut sections?

Graham.

2496

G-Code, CAD, and CAM discussions / Re: Drilling in Mach3 and PMPost postprocessor

« on: August 10, 2006, 04:04:21 AM »

What do you class as a helical drill?.

What is the application?.

post a picture or a web link of the tool you are talking about.

Graham.

2497

General Mach Discussion / Re: strange holes

« on: August 09, 2006, 03:19:25 AM »

Looks very odd.

Post the G-code so we can have a look at the z moves.

Graham.

2498

General Mach Discussion / Re: Backlash

« on: August 06, 2006, 04:54:50 PM »

Hi Rusty,

thats a lot of backlash,  Mach3 will compensate for this but you may still have problems.

The main problem is cutter push and pull,  with that amount of lash the cutter can get hold of the work and drag it in to the cutter, scrapping the job and the cutter.

You may be better changing the chain and wheels for tooth belts and pulleys.

Graham.

2499

General Mach Discussion / Re: VFD recommendation

« on: August 06, 2006, 04:46:11 PM »

Hi Chad,

the application is a lathe, After reading up on all this I think I am going to go down the AC route, I have a homann digispeed on the machine now but the setup is not as good as it could be.  This is not the fault of the digispeed, its the crap motor and controller.  Its gutless at low speed so my threads go out of pitch when the motor starts to stall.  Also the thing will only run at about half speed in reverse.

When I use CSS with very light cuts (.025") on a 5" dia steel billet the motor struggles to accelerate.

This could all be down to me expecting too much from a 6" chuck lathe,  I am used to using lathes with 36Kw spindle motors. I don't stall them very often, but it has been known

Graham.

2500

General Mach Discussion / Re: VFD recommendation

« on: August 06, 2006, 06:03:37 AM »

You may be correct, I think they are just listing the two types under one heading, I just clicked the VFD link and thats the page it gave me.

The range is so vast that I don't know what I want or need to give me the best results.

All I want is to drive the unit from mach3 with as little extra gubbins as possible.

The motor I have is 180 VDC, 850 watt, 5000 rpm, 5.2 adc

Any ideas on what I need.

Graham.