Messages

591

General Mach Discussion / Re: GRex Spindle Step/Dir setup

« on: May 15, 2008, 03:05:15 AM »

Brett - I will leave this one to you, having just browsed through the G100 set up notes. That's the trouble with hard wiring !!!

592

General Mach Discussion / Re: saving work offsets

« on: May 15, 2008, 02:10:19 AM »

Have a look at Config/General Config - botton left hand corner -

Is persistant offsets ticked - if not, tick the box and try again.

593

General Mach Discussion / Re: Tool Offset

« on: May 14, 2008, 05:48:03 AM »

Unfortunately Mach 3 is far more complex than being able to knock a few things together over the weekend, and be ready by Monday.

There are many things to learn, and before designing your own screens, then learning the workings of the ones on offer must come first.

I assume you have set up your system, from what you say, and you have the axis working. I can only suggest that you use the standard 1024 screen(s) set to start with. I, personally, would not even try to write a full screen (s), even though I know my way round the system fairly well. The 1024 set has been designed by the man who designed Mach 3 and must, by definition, be a good start.
It seems to provide all that is required to do some useful work. It has a choice of screen (not for everyday use) to set up the machine, to do diagnostics, to set up offsets - as well as the three main screens.
Screen 1 is the general "maid of all work" and you can control the entire machine from this. If you are doing a small job, and typing in instructions on the MDI line, then you use page 2. This also contains enough information to know what the machine is doing. Page 3 supplies a much simpler screen set with a large tool display. You can still control the machine from here, but it intended for you to switch to this screen for the tool display, and switch back.

You can switch between screens whilst the machine is working. You can make minor alterations to the screens quite easily, which is the best way to start - if you need to alter things. For example, jogging is not available on all screens - you could soon add it.

Most DRO's can be altered. There are some that read information from Mach3 only, but the positional DRO's, the Tool DRO, the Speed DRO can all be written to. Click on the DRO (it will light up) - type in the new information - PRESS RETURN. If you do not press return, the display will revert to the previous information.

The axis positional DRO's display 2 positions - one is the machine co-ordinates, the other work co-ordinates. Machine co-ordinates relate to the homing switches fitted (or not) on your machine. Professional machines have homing switches fitted, and the first job of the day is to home the machine. This puts the table (or cutter) at a position the machine knows, and resets the DRO's to zero. Mach 3 has the equivelant switch "Ref All Home". If you have home switches fitted, then the machine will home. If you do not have home switches set up in your Ports and Pins table, then the DRO's will merely zero without the table moving. You cannot change the machine co-ordinates other than by zeroing them using this switch. Once it has homed, the machine now knows where all other "things" are (e.g. automatic tool changer - chuck centres etc). If your homing switches are not operational then all you have done is tell the machine to regard this poisition as it's new home.

When the machine is moved to a position ready for work, the machine DRO's will change until it gets to a point where it is to start running your program. Dependent on how you (or your CAD) have written it, the position at which you start may vary BUT if you now press the Machine Co-ordinates button, the DRO's will now display the work co-ordinates (or program co-ordinates) - THE FIGURES WILL BE THE SAME HOWEVER. We will pretend you have jogged your table(or cutter) to a position that your program knows as 0,0 (usually the bottom left hand corner of the table). You can now ZERO the work co-ordinate dro's either by using the zero buttons, or typing zero in. If you have jogged to another position to start , say 10,15 then you can type that into the DRO's instead.

If you now press the Machine Co-ords button (i.e. the button surround is lit) the display will still show you the original machine co-ordinates. Toggle it again (the surround goes out) the display will show you the program co-ordinates that you have just set.

The program co-ordinates also record changes to the tool offsets (and any other offsets that you use). Tool offsets are entered in the Tool Table - see Config/Tool table. Enter in the information in the table - the name - e.g. 9mm drill and the diameter (which MUST be in the units you set your machine up in - e.g. 9 mm drill - 0.3543 inches diameter. Dont forget to press return and apply. The details will be saved and available next time you use the machine. There is no tool 0, which means that if you use tool zero all its measurements are 0 as far as offsets are concerned. Length and wear are not important (unless you have an automatic tool changer)

The ideal program would be -  set all home - select the machine offset to move to the workpiece - use imperial (or metric) - select the tool(s) in order with diameters and lengths - cut the work - move the cutter out of the way so you can admire the finished product.

It doesn't actually take all that much doing - setting the machine up takes about 5 or 6 GCodes in a program, once you have it all "set up" on the ground.

I suggest you look through the Tutorial videos which cover a lot of the basics. I downlaoded them onto my machine, and I can refer to them when I want to.

If I've covered a lot you already know, I apologise - once I get on my soap box!!

594

General Mach Discussion / Re: Accuracy of DRO's

« on: May 14, 2008, 04:11:32 AM »

Despite running it through Mach 3 on my office computer, running it through Mach3 on my workshop computer, watching it doing a "dry run" first, crossing my fingers etc etc -

I still wait with baited breath to see the first "cut" come out of the machine. If it's alright - well - GGGGRRRREEEEAAAATTTT

595

General Mach Discussion / Re: GRex Spindle Step/Dir setup

« on: May 14, 2008, 03:56:50 AM »

You seem to be saying that you are running your spindle with a stepper motor or similar - requiring step and direction pulses.

The spindle does not share a channel - it has it's own output, which can be configured just like an axis.

If you look under Config/Ports and Pins/Motor Outputs, the bottom line is for the Spindle, which you can configure to the pins/output port etc you are using.

As you say, you can then set Step/Dir option in the Spindle Setup page.

596

General Mach Discussion / Re: Few questions about configuring Mach 3, Pointing device Problem

« on: May 14, 2008, 03:48:40 AM »

I am a little at a loss here - do you mean the laptop pad and buttons in place of the mouse?

I am using a Toshiba laptop for mine and I don't use the touch pad.  I use a USB mouse and have had no problems at all especially one of the optical variety. I find a mouse much easier than a touch pad (and much quicker).

When I first started, someone said they were suprised being able to run Mach3 on a laptop. Apparently the cheaper ones "share" memory and other features, especially with graphics.

To be fair, it was my daughters computer. I formatted the hard drive, which wiped all the **** she had downloaded, and ran Windows in again from her recovery disc, which left me with a blank computer. I plugged it in and it has worked perfectly. I only have Mach 3 in it. I have a wireless dongle that I can plug in to connect to my home system to pass programs to and from, but I remove that when not needed. This will stop any virus from getting at it (I hope)

597

General Mach Discussion / Re: limit switch response

« on: May 13, 2008, 04:03:46 AM »

I must agree with Hood

Although you don't think you are homing, you must by definition, tell the machine where it is in relation to the workpiece before you start machining. That is homing in the same way as running to the end of the limits and touching a switch.

Because Mach can use limit switches as homing switches, there seems to be a misconception that home switches MUST be in some inconvenient place. Depending on the type of switch, you can have the homing swtich right in the middle of the machine.

As I said above, I use a laser shining on a detector, it is accurate to 2/10 of a thou. I have several detectors on a bar, and can line up to which one I wish, depending on the job in hand.

Even without homing switches, you can set your soft limits up inboard of your physical limit switches. Soft limits run in Machine Co-ordinates, not program co-ordinates, so therefore once set should guard the ends of your machine. Provided you do not then mess about with your machine co-ordinates you should be alright.

598

General Mach Discussion / Re: Accuracy of DRO's

« on: May 13, 2008, 03:22:02 AM »

Whilst I cannot see why you say your steps per inch are give and take 100 (it should be an exact figure all the time - unless some allowance is made for backlash) - well the answer is - stepper motor manufacturers will guarantee positional accuracy of their motors to within + or - whatever of each step. The step is correct, but the motor might stop a little to the right or left of a central position. The beauty about this, however is that in-accuracy does not accrue, since movement to the next position - whether one step or 10,000 - the final resting place will still be within + or - of the central position of that particular step. Steps are normally now 1.8 degrees so the error is very small.

My steps per inch ar 60,000. It follows then that there are 60 pulses per 1 thou of movement. In theory therefore I should be accurate to 1/2 of 1/10 of a thou. Unfortunately my Gecko drives deal in 10 micro steps. These are not full steps of the motors and, therefore their position cannot be accurately guaranteed like a full step - although one must say that if there are 10 of them, they must be more accurate than one full step. I can therefore certainly guarantee 6 steps per thou which gives me 1/2 a thou accuracy and if Gecko can add the other 1/10 then so be it.

At 253,360 then you have 253 (or 254) per thou, and even allowing for micro steps you (as you say) should easily split the thou into 25 - not 20. The distance you travel does not matter (providied your pulses per inch are correct).

To me it is the repeatability that is the amazing thing about CNC. I don't mind turning one bit by hand, but if I have another 19 to do - over to the machine - and they all come out the same (hopefully)
 

599

General Mach Discussion / Re: indexing

« on: May 13, 2008, 02:52:12 AM »

I don't know what type of indexer you have - mine is an optical refector - but whatever it is, the information is available on the diagnostics page.

If you turn the spindle, you should see the indexer "led" flash. I must assume , from what you say, that you are satisfied that this is working.

1. Check, if you can, that your indexer is "working" at the spindle, then at you BOB.
2. Check your have the indexer properly configured on the Config/Ports and Pins/Input signals/INDEX (not timing) pin. If you are getting an incorrect reading - i.e. off when on, etc - click "active low" - check it is enabled with the correct port and pin number.
3. If you are getting the indexer showing on the diagnostics page, you might check the debounce settings on the General Config page and adjust it to get the best result.

600

General Mach Discussion / Re: Tool Offset

« on: May 13, 2008, 02:37:57 AM »

If you have tool changes on your program, then Mach can do several things with them.

1. Mach will ignore the tool change completely.
2. Mach will stop, turn off the spindle and wait for you to do what it is you want.  (You can manually change the tool, set it to the correct height, depth etc., and change the Tool number.  On one of my programs, I had to move the workpiece, jogg the tool to a new position etc.) When you are ready to continue, press "cycle start".
3. Auto Tool Change - Here Mach uses the M6 macro and executes a Visual Basic program. This can be anything, since most tool change system differ. You can have the spindle stop, the tool move to a safe position for you to change, or you can use an automatic tool changer and let the machine do it for you - but you have to write your own program (although there are some about in this forum that you can use).

See Config/General Config/Top left hand corner of the page to select what you want.