Messages

6211

General Mach Discussion / Re: Probe not stopping "Z" axis

« on: October 21, 2017, 06:09:36 PM »

Hi John,
just noticed a typo which could throw you out...

I wrote Z=0.005...it should be Z=-0.005   The negative sign is critical to understand...negative Z below the surface, positive Z above the surface.

Craig

6212

Mach4 General Discussion / Re: Mach4 Spindle At Speed, Spindle Zero Problem

« on: October 21, 2017, 06:00:34 PM »

Hi Hakan,

I was saying this from the beginning and that is the reason why we couldnt use the ISIG_SPINDLE_AT_SPEED and ISIG_SPINDLE_AT_ZERO because they assigned to some function but function is not defined within Mach4 and software does not let user to define that function.

Rubbish! The SIGNAL is defined the ACTION is not. The modern programming paradigm is the an object and its action are separate. You create what ever function
you require to achieve the behaviour you want and then you LINK the OBJECT (input signal ISIG_SPINDLE_AT_SPEED) to your desired ACTION ( your function)
In this case we used a particular API call to make our function (mc.SignalWait()) but unfortunately that particular API has limited input range but otherwise
preforms perfectly. If we chose to use a different way to make our function that didn't use that particular API call the we could have used ISIG_SPINDLE_AT_SPEED
throughout.

Spindle at speed signal is the best and cheapest way to make the machine know that spindle is at commanded speed, most of the VFDs providing this function, if u dont use it u have to buy a spindle which has encoder installed or u have to install a encoder or rpm sensor to the shaft of the spindle, first one is expensive and second one is dangerous so best and industrial way of knowing that the spindle is at commanded speed is using this function and it must be implemented to industrial version.

Certainly using the At Speed or Is Stopped signals provided by VFD is cheap and easy...look you've done it yourself. My VFD and its hardly unique, a Delta, synthesises
and encoder output which can be read by Mach. Its built in...no cost involved. Yes if you require exact and/or physically confirmed rotation then you'll need a tacho
or similar. The At Speed signal cannot determine if the rotor is spinning except indirectly and so would fail a safety test which might be required of a coolant pump
or a lift motor. Such applications require a tacho or indexer, safety requires it and is in effect leaglly mandated by Codes of Practice and various National Standards.

My spindle can use the 'Wait on Spindle to Stabilise' and 'Percentage' functions already in Mach4 for exactly that purpose. You may recall early in the piece I advised you
that you could use either of two methods to achieve what you wanted. You chose to go with the  At Speed/Is Stopped route whereas the other method reqired
you program your VFD to produce a pulse output and have Mach use its inbuilt functions to read and act on it.

Craig

6213

G-Code, CAD, and CAM discussions / Re: Complete newb, need help

« on: October 21, 2017, 05:25:46 PM »

Hi,
couple of observations both F and G1 are modal.

So when you specify the feedrate F as you do on the first line, it will stay like that for all subsequent lines until a new Fnnn word is issued.
Likewise G1 which means 'co-ordinated linear interpolated move at current feedrate' is modal. There is no need to write it on each line. It won't matter
if you do and sometimes may make the code easier to read but it can sometimes clutter things up.

Code: [Select]

m3
g1 x0 y0 f0.5
x15
y0.5
x0
y1
x15
y1.5
x0
y2
x15........
Somewhat tedious to code but as simple as it can be and you'll only have to do it once. There are other alternatives such as using loops but
Gcode doesn't have conditionals and so can't be used as a general purpose programming language. Over the years various cheats and workarounds
have been devised some of them very clever but far from intuitive, why complicate this thing?

Just as a matter of interest what sort of high voltage are you talking about? Some years ago a friend and I were working on an electrostatic precipitator
and I was regularly generating 70kV DC from my own design/build inverter. High voltage sure does teach you some important lessons...fortunately our
experiments were all energy limited so we lived long enuf to learn them!

Craig

6214

General Mach Discussion / Re: Probe not stopping "Z" axis

« on: October 21, 2017, 04:41:13 PM »

Hi John,
no disrespect for the Gcode publication you got but if you wanted to know about the Quran, for instance, would you read it in a popular magazine or would you
get a genuine copy? In like manner Peter Smid's book is the authoritative source.

Craig

6215

General Mach Discussion / Re: Probe not stopping "Z" axis

« on: October 21, 2017, 04:33:16 PM »

Hi John,
I notice you are using a Z drill depth of 0.062 inch, ie 1/16 inch. If you are using 1/16 inch circuit board its not enuf, if you are using 1/32 PCB then
the drill will penetrate which is good. Are you happy that the drill will mark the material underneath?

Next issue is this confusion about the Z axis co-ordinates. It is very common to define the very top of Z axis travel as MACHINE co-ord 0. Your
Z axis can go 2.75 inches lower so your machine co-ord at that point would be -2.75.

When you are machining a PCB you'll be in WORK co-ords. Notice the Gcode you posted shows a Z of 0.1 inch when above the board, but that's higher than
the very top! So the Gcode you have posted is written in work co-ords. It expects the top surface of the board to be Z=0 Then Z=0.1 means a tenth of an inch
above the PCB and Z=0.005 as 5 thou below the surface, probably the cut depth of a router bit if you are mechanically etching the board.

So the procedure is to set the PCB blank in its jig and manually jog the spindle down until the tool just touches the surface of the blank and then hit <Zero Z>.
Now set the code to run, any positive Z means above the board and safe and any negative number means the tool/drill is engaged with the workpiece.

Craig

6216

Mach4 General Discussion / Re: Mach4 Spindle At Speed, Spindle Zero Problem

« on: October 21, 2017, 04:10:51 PM »

Hi Hakan,
I had a reply from Rob at Artsoft about the input signal snafu I blundered into. He confirms that we would require an expansion board to use ISIG_SPINDLE_AT_SPEED.
This poses another question. Certainly we know that ISIG_SPINDLE_AT_SPEED is defined and it works, we can see the LED turn on and off. We wished to
make use of it in our mc.SignalWait() API call but it didn't work there and Rob confirms that some expansion would be required for it to work.

I'm guessing here, but based on a few related observations ALL of Machs input are numbered 1 thru to whatever. Internally Mach has no idea what ISIG_INPUT#17
or ISIG_SPINDLE_AT_SPEED means, it recognises input #17 and input #181. So the labels are defined for our benefit because we don't immediately recognise
input #181 for instance. It would appear however that not all API calls are created equal, in this case mc.SignalWait will accept inputs 1-64 but not higher
but mc.SignalGetHandle() will tolerate an input higher than 64, our #181 being the numeric equivalent to ISIG_SPINDLE_AT_SPEED for example.

What is not clear to me is what sort of 'expansion' is required. Given that input #181 can be read and interpreted by Mach in some instances suggests there
are enuf bits for several hundred inputs so it won't require a hardware expansion. I can only guess that mcSignalWait requires software extension.

Craig

6217

General Mach Discussion / Re: DRO are not to set valeu in it

« on: October 21, 2017, 03:21:08 PM »

Hi,
I've just been trying it out. Writing direct to an axis DRO when the machine is unreferenced does work.

If you write direct to a DRO the machine co-ords cannot change. This is a fundamental fact of CNC, the ONLY way to change machine co-ords
is to physically move the axes by jogging/MDI/Gcode OR referencing. To write to a DRO may cause the current position to be changed to the number
you entered but because the machine didn't move and therefore the machine co-ords didn't change then the work offset must change the exact
but opposite amount that the current position changed.

What's the point? If you want to manipulate the work offsets so the current position is a certain number then change the work offsets directly on the
Offsets page. Until I understood this I have done exactly as you are doing but because it relies on Mach to re-calculate the current work offset, and it
didn't always do so in a predictable manner; I found it more 'honest' just to change the work offset directly.

Craig

6218

Mach4 General Discussion / Re: How to use G28.1 on Mach4?

« on: October 21, 2017, 02:52:57 PM »

Hi zarsss,
what exactly do you want to do?

'Ref All Home' drives each axis in turn until the home switch goes active. Is that what you wish? Or do you just want the axis to drive to machine co-ord
zero for that axis? There is a world of difference between the two. Secondly do you wish the machine co-ords to be set to zero or your nominated offset
when its gets there as would normally occur when referencing an axis?

Mach4s API gives you some very powerful instructions and any and all of the alternatives above can be done no trouble. If you can tell me exactly what you
need maybe I can help you code it.

Craig

6219

Mach4 General Discussion / Re: USB port setting

« on: October 21, 2017, 02:34:52 PM »

Hi Daniel,
I see that Eagle PCB software has changed hands. It was developed by Cadsoft, a German company I believe. For a period of time Cadsoft was owned
by Farnell who own Element14. Element 14 used to sell licences and pretty reasonably, I paid $700 for a single licence for the full blown program. When they
released the newest version (at that time) V7.1 they upped the price to something like $2300 NZD...bastards! Element 14 are still selling perpetual licences
but the prices are pretty steep for the complete program, I did see a Maker edition, cut down to be sure for $230 NZD.

More recently Autodesk have bought the software and have gone to a subscription model. Whether the community of users tolerate that remains to be seen.
I suspect that Eagle will become very much less popular. Autodesk have a policy...'Bend over with trousers down while we extract the money we want'.
Shame...used to be a good program....trust Autodesk to ruin it.

Craig

6220

General Mach Discussion / Re: Probe not stopping "Z" axis

« on: October 21, 2017, 01:56:02 PM »

Hi John,
G82 is a canned drill cycle with dwell.
The P is the dwell time when the drill get to the bottom.
R is the retract height. You are expecting that the drill tip starts out at 0.1 inch, that is above the board, it drill down at 20 in/min until 0.032 inch below the top
of the board, dwell for 1 second and then retract at rapid  rate to Z-0.1 ie 0.1 inch above the board.

All of these values are set when you set-up PCB-Gcode. What thickness is your board?, I would guess it is 32 thou or 0.8mm. Your drill, if everything is perfect,
is going to get to the bottom surface of the board but not penetrate it. Is that what you want? I use 1.5mm PCB and I have the drill go to Z=-1.8mm so
it reliably penetrates the board and I'm quite OK with the drill digging into the spoil board below. Dwell only need be 0.25 sec or so.

The only real error in the code you've posted is that your machine is in XZ plane mode? You want to be in XY plane mode. Try putting a G17 to select XY plane
mode right at the very top of the Gcode job, I'm surprised that its not already active with all the preparatory codes.

If you think that you can do CNC jobs without being able to read and understand basic Gcode... you are wrong. It is a required skill that you be able to understand
little chunks of code like this example and be able to understand what your machine will do when it encounters it. On the Program Run page there are two buttons
to provide concise notes as to the meaning of G and M codes. The CNC bible is:

CNC Programming Handbook by Peter Smid

its a dry read but very good. No doubt there are other texts and probably plenty on the net, find them and
read them, we are not born being able to read Gcode, it something we have to learn. If the value of a hobby is what you have to learn in pursuit of that hobby
the CNC rates very highly...you have to learn untold things to be any good at it.

Craig