Messages

121

General Mach Discussion / Re: M5 question

« on: March 02, 2009, 04:52:51 AM »

I think we would need to ask the programmers what the "trip" is for turning off the clock.I would have thought it would have been an M30 command - but it isn't, because when running programs with several "parts", seperated by M1 holds, the clock seems to time each section seperately.

If you are saying it is the M5 command, that would be it, becasue I have that before each "stop" to change tools etc.

122

General Mach Discussion / Re: PWM on spindle

« on: March 02, 2009, 03:33:53 AM »

You are running a little bit ahead of me here. Lets take it a step at a time.

You first must have a detector on the spindle to read the speed of the spindle back to Mach 3. This detector is only required to detect once per revolution. This input goes to the "index" pin - see Config/Port and Pins/Input Pins. The resulting readout on Mach 3 is very accurate (usually within 1 or 2 RPM. (This is not absolutly necessary, but gives moroe accurate control)

I have looked at the picture of the motor spindle/VFD unit and it certainly looks the part. What we need, however is a wiring diagram for it. In other words, what signals does the VFD require from the computer to make it work. My VFD is an Omron. The M3(CW) and M4(CCW) inputs require two pairs of wires to be connected (either pair, but not both) to give forward and reverse. This is completely seperate from the speed control. My speed control requires a voltage (0 - 10 volts) on an input wire to the VFD, This is derived from the PWM output from Mach 3, combined with a Digispeed - which converts the PWM signal to a voltage (and keeps both parts electrically seperate)

Whilst I understand what you are wanting, my sustem would not do that since my VFD must either be controlled manuall, or by the computer, the functions being switched on the front panel.

If you can supply a diagram, or the instructions for the spindle/VFD we can sort it out very quickly.

123

General Mach Discussion / Re: Anybody else having trouble with the editing on the Forum

« on: March 01, 2009, 04:39:56 AM »

Hood - I bow to your knowledge, just downloaded Opera - and everything seems OK now - it certainly seems fast.

124

General Mach Discussion / Re: Turn tool table

« on: March 01, 2009, 04:38:13 AM »

Vince - Just a thought - how do you select the tool in the toot turret. The standard lathe command is T0101, the first two figures being the tool number and the second two being the offset. They are both treated seperately.

You can, in theory, use, for example T0301, i.e. tool 3 with offset 1.

The offsets need to be entered in the tool tanle, as you have done, but the full four figures must be given in the command.

125

General Mach Discussion / Re: Turn tool table

« on: February 28, 2009, 06:22:50 AM »

Vince, I have read, and re-read your post. I think this is what you are saying - Your tools are all set up in a turret, and all referenced to a particular tool, if you change the reference  for that tool, the references for the others do not change.

Your surmise is incorrect ( I think). The tools in your holder are all referenced to a particular distance above the workpiece. The fact that you used one of the other tools to do it is irrelevant. They all have individual references.

The thing that is changing is the height of the workpiece.

The only way to do it, as far as I can see, is introduce an offset - G55 to 59 etc for your different programs.
Your are clearly a long way along the road, I assume that you have home switches, if you have a tool turret etc.
Your tool height, as set, is your "home" for your Z axis in Machine Co-ordinates. When you put in an offset for the X and Y axis, you must also include one on the Z axis to bring the tools down (or up) to the correct height.

126

General Mach Discussion / Re: table coordinates wrong

« on: February 28, 2009, 05:59:31 AM »

Machine Co-ordinates are used by the machine to keep track or where it is. They are of little vlaue to we mere mortals, becasue they are just numbers. As the machine moves, it adds to these co-ordinates, offsets, tool lengths etc etc. It seems to know what it is doing - but not I.

If you say that you do not have homing switches, but you want to home, then, you have in fact home swithces. It is just that yours are manual, not automatic. I assume you must have some stop block or similar that you run up to, so that you know your position is correct. It you then "Ref All Home" because your switches are deactivated, the machine code readings will go to 0,0,0. This is "home"

Press the Machine Co-ords button, so the led goes out, and zero the axis. You are now zeroing the "Program Co-ordinates" This is the one by which we keep track of the program as it moves through.

I do not understand what you mean when you say that you have tied the machine coordinates to the Program Co-ordinates. They will not tie.You can, as just described, have them co-incidental, i.e. there is no offset between them, but they are not tied.

If you now jog your machine to the start position of your program, and type in the MDI line G54, and then zero your Program Co-ordinates display, then if you check the Machine Co-ordinates, this has not changed. If you check the fixtures list, you will find that G54 has changed to relect the new offset between the two sets of DRO's.

As far as I know, the tool display shows your program in  Program Co-ordinates, and if you are starting at 0,0,0 then the display will have the toolpath outlined round it.

The process of  writing a program is  such that you write the program from a 0.0.0 position convenient to the program, not the machine. If you write the program and run it into Mach 3, it will give you the maximum and minimum values of each axis, so you can check if it is too large for the table. If, for example, you then cut a square of paper to those maximum and minimum values , and lay it on your table in the most convenient position, with the 0.0.0 psoition clearly marked, all you have to do is home your machine (by whatever means), jog the machine to the 0.0.0 point of your program, and set an offset,

To do this , you simply type in the offset number you wish to use,e.g. G56 then zero the Program Co-ordinates DRO. If you check G56 fixture you will find it reflects the offset from your Machine 0.0.0 position.

If you add  G56 , followed by G0 X0 Y0 to the beginning of your program then :-

If you "home your machine" and run the program, the first thing it will do is move to the 0.0.0 position of the program.
Obviously, if you fit in a block or something to poisition your workpiece to, then, the program is repeatable and accurate.

127

General Mach Discussion / Re: Homing and limits don't work right

« on: February 28, 2009, 05:00:30 AM »

While Hood looks at you XML file, try a bit of trouble shooting.

Go to Config/Ports and Pins/Inputs and disable all the switches. Try then activating the limits one at once and test them all, either by running you table against them, or by manual activation and check that they all work correctly, by looking on the diagnostics page, and watching for the appropriate signal.

If all you limit switches are fine,  make sure these a de-activated and then activate a "home" switch. Now test this by manuall switching it, and make sure it is recognised in the diagnostics page - if it is, fine, if it isn't, your config might be wrong (active low/high) , Once it is working correctly, set it up for auto zero, then run your "RefAllHome". The axis that are deactivated should just go to zero, the one you are testing should move, hit the switch, and as you know, back off.

If this works correctly, then switch on the same limit switch, so both functions are now active, and see if it works correctly now. You may find that it still fires up the "estop". This is because the switches you are using have electical "bounce". All switches have, some more than others. Go into Config/General Config, top right hand corner, and add some "de-bounce". Start with, say, 200, and try that. If this cures the problem, work down from the 200 figure until the problem re-appears, then move up again until is goes away.

This shold cure the problem.

Repeat for the other axis.

128

General Mach Discussion / Anybody else having trouble with the editing on the Forum

« on: February 28, 2009, 04:36:59 AM »

The layout of the "reply" page now has a line down the centre with the  "up/dpwn" arrows on it. The icons above the reply area do not always display properly. The reply page keeps timing me out (although my replies are often long winded).

The text in the box keeps jumping up and down.

If fact, all in all it's getting a bit of a ****.

Anybody else having problems. The ony thing I can think of that I have changed recently is to download Internet Explorer 8. Is this full of bugs, or just not compatible with the Forum

129

General Mach Discussion / Re: how to set up auto tool zero fot (X,Y,AND Z)

« on: February 28, 2009, 04:30:32 AM »

I'll start you off with the few of the basics, so you undertsand where you are coming from. No doubt a few others have ready made programs for this. I don't.

The input into Mach 3 that you use is the "probe". See Ports and Pins/Inputs. A signal on this pin (whichever you allocate) will stop the axis moving. To do this you need a lead from pin, and a +5 or 0v lead to your detector.

The way I use mine is as follows - bear in mind that the inputs to my computer are direct to LPT1. This means that a 0v signal on the pin will activate it. I have a small jack plug which I can plug into my control box. Out of this plug comes a two core lead. One core is to 0v. The other core is to the pin. In practice the 0v lead is not required becasue the mill/lathe is earthed anyway. The wire going to the pin is soldered to a square of copper clad, nicely polished (thickness 1.55mm).

In practise if I need to set a drill height, I plug in the lead, lay the copper clad beneath the drill, and jog the drill down to it, leaving it a little short. If you then type, on the MDI line " G31 Z (and a minus number slighly below your copper clad height) the drill will move down, and the stop as soon as it touches the copper clad. You can then set the height of the drill (remembering the 1.55mm thichness of the copper clad), so I set my Z axis at 1.55, which is the equivelant of 0 if the tool had been touching the workpiece. (the 0v lead has a clip on it, so if I am unsure the drill is properly earthed, I can clip the earth lead on)

The other axis  work on the same principle

The problem is I do not know how your particular set up is wired, what BOB.s you have etc , so you will have to experinment a little to get the leads right. There should be some documentation with the BOB. Once you have that figured out you are ready to move on to some of the full automatic systems that others have devised.

130

General Mach Discussion / Re: Where to input value to let X-Y table move certain distance directly?

« on: February 27, 2009, 03:50:59 AM »

I don't understand why you don't want to write G Code for "this simple job"

You are going to have to write G Code whether you like it or not, becasue the machine only undertsands G Code.

Whether you write one line at once (on the MDI input - which takes one line instructions at a time)  or you write a small program to do all the lot at once makes no difference.

For your job, there are two commands - G0 and G1 - G0 moves the table at it fastest speed as set on your motor tuning: G1 moves at a cutting speed set by F command (feed)

So your code will be

(start at 0,0)

G0 X0 Y0 (included for completeness - the table will not move)
G1 F** Z**    (the stars after F determine the depth per minute at which the drill will drill, after Z they determine depth  - this should be a minus figure)
G0 Z**  (the stars after Z determine the height which the drill lifts to clear the job)

If you have set up your job correctly, (at X0 Y0 and with the drill touching the work - Z0) then a safe height is 5 (mm) (0.25 inches).

If you repeat this code three times, putting in the three other locations (instead of the original X0 Y0) then you have a 12 line program that will run off your job.

You should finish (although not compulsory) by lifting Z well above the job, and moving the table out of the way so you can get your work out.

e.g G0 X -25 Y -25 Z 25 (assuming metric set up - use 1 instead if in inches)

M30


Use the M30 (end of program) and also type <enter> a couple of times afterwards.

Using cut and paste, such a program can be written in a couple of minutes - less than it has taken me, and the satisfaction it gives you watching the machine is enormous.

Try running you program first without the drill, or better still run it on Mach 3 without your machine connected. The toolpath will show you the different steps and hignlight each one as it does it. You can be fairly certain that if it runs "dry", when you put in your tool it will do the job.

The temptation always is to just get on and "do" using a combination of CNC and manuall commands. Believe you me, the satisfaction comes from the CNC, there is no simple job.
Yes - you must sit down with a pencil and paper and draw out what you want to do, then write down your code, and then type it in. The beauty about it is that you can save the program under GCode and then use it again (and again etc) either a a program, part of a program, or the basis of some larger program.

If you already write programs, then I sincerly apologise, I'm on a high this morning.