Messages

821

General Mach Discussion / Re: Griffin powermate doesn´t work. Need help...

« on: March 12, 2008, 10:57:33 AM »

If you look under Config/System Hotkeys you will see the box for setting the keys to jog the axis.

You can set whatever keys you like to jog the axis.

I assume the Griffin puts the equivelant of keyboard strokes into the computer, so select which jog you want to configure, e.g. X++ and then press a key, or do what you want to do with the Griffin and see if it registers.

If the Griffin is a rotary switch - i.e. you turn it, I cannot see how you can replace a keystroke with it. In Mach3, if you press a "jog" key, the jogg continues until you release it. It is not a mouse like function with continuous movement.

822

General Mach Discussion / Re: Help... Can't get motors moving

« on: March 12, 2008, 05:34:03 AM »

Wolf -

I cannot understand your settings - particularly steps per unit.

This is the number of pulses the computer has to give out for one unit of movement.
Normal motors take 200 per rev. The driver board may be putting out 1/8 steps - so that is 1,600. I don't know what your connection to the leadscrew is but mine is a 3:1 reduction - so that is 4,800 and lastly my leadscrew has to turn 10 times to move the carriage 1 inch. - i.e. the computer has to give out 48,000 pulses per inch of movement - not 200 or even 500.

Even thogh you are messing about on the workbench, set the motor up as though it was in the machine. The reason I would think, that your motors are not turning is they are going that slow you can't see them.

Your maximum speed on motor tuning is the number of units per minute the motor will move the carriage - I don't know what you have in mind - but try 10 inches per minute, acceleration is not particularly important - set it at 1.

When you are jogging, there are settings for the jogging speed in relation to full speed - set this at 100% - i.e. full speed when jogging.

Easy CNC etc are standard fare for Mach3 and you should not have any troubles - they are literally plug and play. Don't start swapping and changing configurations unless you know what they are.

The only other thing to check is  - does your board have an "enable axis" pin - if so make sure this is grounded of whatever to make the axis work. Do not, at this stage, try and connect it to the computer - just ground it with a bit of wire or something.

823

General Mach Discussion / Re: Griffin powermate doesn´t work. Need help...

« on: March 12, 2008, 05:09:54 AM »

The Griffin site doesn't give any clue.

What are you trying to do with it.

824

General Mach Discussion / Re: z gauge block not offsetting??

« on: March 11, 2008, 05:00:00 AM »

I think if you look at the offset page on Mill - I take it that is what you are using - then (although I haven't used it myself) it seems that the settings you put in on this page are transferred to the active work offset - G54 to G59.

Do you then need to select this work offset to bring these into play .

Try (on the offsets page) selecting say G57, setting your offsets, then before you press cycle start, type in manually " G57 ". I would think it is set up this way so that you can put in several offsets for a program all at once, and select them as you need them.

If you try setting up some offsets on this page, then check with the fixtures table under "Config" you will see they are transferred.

825

General Mach Discussion / Re: pulse? or step and direction control for spindle speed?

« on: March 11, 2008, 04:41:52 AM »

Get a digispeed (Australian) - look it up on the web - very good service by post - worked first time - you only need the cheaper one - the DC01.

This connects to the PWM output of the computer - and converts the signal directly to a voltage. The voltage depends on what voltage you want - so if you put 10 volts in, the output will be between 0 and 10 volts - depending on the pwm.

The two parts of the board are electrically isolated, so there is no danger of anything going wrong.
Only uses one output pin.

826

General Mach Discussion / Re: Any one know how to build a cheap linear encoder?

« on: March 11, 2008, 04:11:34 AM »

I think that would do the trick - a couple of pulleys one at either end, with a belt. Fix your "mouse counter" to one of the pulleys.
If you could somehow "spring" the mouse counter so that was actually turned by friction off the belt, you would get very good resolution.

My first thought was to just attach the mouse wheel to the spindle of one of the pulleys, but you woud then need small pulleys to get anything like the resolution you are looking for.

Carrying one from that - why do we need the pulleys - mount the "mouse" on the table and have it sprung onto a small track on the frame of the lathe/mill - either use a friction contact, or a length of fine toothed rack material which is available at most engineering outlets. In my catalogue this goes down to 1mm teeth spacing, I dont know how many slots in a mouse wheel, but that should give you the resolution you are looking for.

827

General Mach Discussion / Re: upgrade problems

« on: March 10, 2008, 04:43:33 PM »

Mark - Just a quick look at your config screen, the axis want to be unticked for linear work - you are showing them ticked which is angular. That, in itself, should not make any difference, because I understand the only thing it alters is changing from inches to mms (angular doesn't change)

I cannot speak for Mach 2, I never ran it.

I am at a bit of a loss at your system. The way I mill is my X0 Y0 are at the bottom left hand corner of the table. My Z0 is with the tool tip touching the top of the work. I set all to zero and away I go.

If you are manually changing the tool, then I would ignore M6 and halt the program with command M1. Mach 3 will then allow you to jog from where ever you are to where ever you want to change the tool - and the DRO's will keep track of the movement

If you then change the tool, and touch the new tool onto the top of the work - set the Z axis to 0 again. Then lift it and move it to where ever you want to carry on, which can be where you left off, or somewhere completely new. You can either jog to a new position, or enter codes manually. Press cycle start and the program will continue.

The one thing you have to do is put in the M1 commands, otherwise Mach3 does not always start from where you think it will. Apparently - and I have no rule of logic for this, it sometimes steps back to find a place to start from - I don't know why.

Hope this helps.

828

General Mach Discussion / Re: z gauge block not offsetting??

« on: March 10, 2008, 04:15:37 PM »

I think you will be running the mill in Machine Co-ordinates - which does not take into account your offset of 2 ins.

I have just tried setting the Z offset on the offsets page - it does this correctly. If you then go back to the Midi Alt 2 Page, make sure that Machine Co-ords is not flashing. You must run the program with offsets activated.

829

General Mach Discussion / Re: Any one know how to build a cheap linear encoder?

« on: March 10, 2008, 03:59:36 PM »

There are many ways to build a linear encoder - but if you are talking, as I am sure you are, of something that can measure movement to, say, half a thousanth of an inch, I would have thought it in the realms of "too hard" for the average person. I don't know how the ones I have seen even work, but I would imagine some sort of wire matrix laid along the measuring distance. The machinery to lay down such a thing to that accuracy must be specialised.

A simple way, (without me thinking too much) would be to have a "stepper" motor connected to the moving part, so that it rotates, and some sort of "computer" counting the pulses it gives out. If it were free running, as on some of these sepcialist "fifth wheel" measuring devices it would be accurate.

Another way would be a disc which spins as the part moves - with a number of slots in it - and , of course, some form, probably an optical, counter.

The best linear encoders I ever saw were on the coal mine winding gear at the local pit. This was a worm drive on the winding engine moving a marker. When this lined up with a chalk mark on the wall the "driver" knew the cage was accurately aligned. (There were two marks - one to wind with men in, and one to wind with coal tubs in - the latter stretched the cable further). The distance involved was between 200 and 500 meters. Most miners would only "travel" with a driver they knew.

830

General Mach Discussion / Re: Backlash compensation for a rotary axis ?

« on: March 10, 2008, 03:41:26 PM »

Greg -

In that case, get the thing built, with as little backlash in it as you can - but then, I think, you will have to use mach3 backlash compensation. It should be OK because the holding force will always be in the direction of the cut.