Messages

1811

Mach4 General Discussion / Re: Zeroing and extents

« on: January 06, 2020, 12:51:39 AM »

Hi,
the <Display Work Envelope> displays the machine boundaries as defined by the soft limits.

There is no feature or function, to my knowledge, that displays the rectangle containing the current Gcode job.
The Gcode toolpath will be displayed within the machine boundaries.

I daresay that it would be possible to have the work extents (distinct from machine extents) displayed.
The method I would adopt is to read the work extent DROs. The DRO's are the registers:
core/inst/PathXmax,
core/inst/PathXmin,
core/inst/PathYmax,  etc

I am unfamiliar with how the tooplath is drawn, other than it is an OpenGL window. What I would do, or at least try, is write a macro
that made some fictitious G0 moves which would be prepended to your Gcode job.

Lets say for example your Gcode job has work extents (in machine coordinates units) of
X: 10-120
Y: 12.5-45
then your macro would generate these lines:
g53 g0x10y12.5 --rapid to the lower extent of each axis
g53 g0 x120 ----rapid along the lower X axis extent
g53 g0 y45----rapid along the right hand most Y axis extent
g53 g0 x10-----rapid along the max Y axis extent to X min extent
g53 g0 x10 y12.5-----complete the rectangle

We only wish the last four lines to be visible thus we would use the API:

Code: [Select]

rc = mc.mcToolPathSetAxisColor(
number mInst,
number axiscolor,
number limitcolor)
What I would do is 'obscure' initial rapid by setting the axis color the same as the back color.
Then set the color for the next four lines as green/black/blue as you desire. The set the axis color back to whatever
it was prior to this sequence so the normal machine extents etc display normally.

I have not tried this so I have absolutely no idea if it would work.

There are a number of issues or questions that have to be addressed.

Given that the macro contains API calls it MUST be contained within a macro as the Gcode interpreter would baulk
if it encountered an API call in a Gcode file.
Second issue is: 'will the tooplath of a macro be displayed along with the Gcode toolpath OR is the macro ignored while
loading and drawing'....some experimentation is in order.
Third issue: 'if, as I have proposed the toolpath be the combined view of the Gcode job AND the extents macro how would
the display work if it were subject to user rotation or zoom?
Fourth issue: 'can we write a macro that includes g0 rapids and thus be displayed in the tooplath but WHEN the Gcode
runs actually skip over them? We don't want the machine to actually move at rapid speeds around the work extents,
it would almost certainly collide with the vice. So what we want is for the machine to display a path that will never actually
be executed. I have no idea whether that is possible.

Just thinking about it is giving me a headache!

Craig

1812

Mach4 Plugins / Re: Galil plugin compatibility

« on: January 05, 2020, 09:39:12 PM »

Hi,

Ask Renishaw for a demo of their Ball Bar system and you'll see the gulf between what you think you have and what you actually have. It will show you out of squareness as well as an absolute dimensional circular plot in both directions. Run that a few times at different speeds and then you will really know what you have.

I would dearly love to do just exactly that but Renishaw measuring equipment is beyond my means. Of all the inaccuracies that I know of and probably those that I don't
know of out-of-square is one of the more difficult for me to measure. I have an AA granite square (only 150mm x 150mm x100mm) and using that I have identified
an out-of-square between X and Y of 8um per 100mm, between Y and Z of 6um and between X and Z of 11um per 100mm. Measuring such small quantities is a challenge,
they could easily be double my measurement but could be less too. All I can really say is that these are my best measurements but my 'confidence interval' is wider
than the absolute measurement.

A ball-bar measurement would probably be more conclusive and informative. To this end I have made an LDVT with a resolution of 10um, and with successive deign and
build revisions I hope to get to 2um. Amongst the things that I wanted to do with it was a ball-bar device.

My current mini-mill has a resolution of 1um. Note that does not rely on microstepping either. One full-step of a 5 phase Vexta stepper is 0.72 degrees and through
the low lash (2 arc min) 10:1 planetaries that is 0.072 degrees or 4.32 arc min per fullstep. Given the predicted lash of 2 arc min I thought it fruitless to go for even finer resolution.
In the event the lost motion due to the torsional flex of the couplers dominates the lash. As it transpires on the two occasions that I crashed badly the wee aluminum
coupler sheared off rather than even worse damage, the mechanical force when you crash, even on such a small machine are still in the tens of kN range. The couplers
act a bit like a mechanical 'fuse', and I have retained them because of it. This was not 'by design' but a consequence of buying el-cheapo couplers and funnily enough they
have an advantage I had never considered and will tolerate 3-4um lost motion they cause.

My new build has a 160,000 line encoder so I could have resolution as fine as I like within the signalling capability of the ESS/BoB/servodrive. My intention is however to
retain 1um resolution, if I can contain lost motion, out-of-square, ballscrew inaccuracy, linear rail inaccuracy to better than 5um I would be delighted. Finer resolution
is not required. I am trying to achieve a linear rigidity between the Z axis and the vice of 10um per 1kN. To obtain that sort of rigidity even in a small machine requires
thick sections of cast iron, and getting stuff cast is not a cheap undertaking.

Ballscrew inaccuracy, linear rail inaccuracy and flexure of both is beyond my control, all I can do is buy the best quality I can find, in my budget. The squareness and rigidity
of the beds/frame into which those components are placed are my province however.

Regrettably the gear needed to 'qualify' my machine could be as much as the machine itself. At this stage I have a 36 x 24 B grade granite surface plate, the granite square
I've already mentioned, micron reading Mitutoyo dial and test indicators. A set of matched parallels is still required.Still looking for a good height gauge I can afford.
I can borrow an A grade set of gauge blocks. I'd really like an auto-collimator but even second hand they seem to be in the $2000-$4000 range.

If my machine is inaccurate it will not be for the lack of me trying to achieve it.

Craig

1813

General Mach Discussion / Re: Losing computers

« on: January 05, 2020, 01:39:17 PM »

Hi,
I have a dedicated PC for my Mach4 machine but also I have run it via the ESS with my laptop, so yes it is possible to
run a machine with a laptop which can and does get used for CAD/CAM and general srfing...and writing on forums.

Mach4Hobby allows you up to five licensed PC's for each Mach4Hobby purchase, so you could have different machines
with different PC's no trouble. You can also have multiple profiles, say one for your mill and one for your lathe and just
use the one laptop to run both.

Craig

1814

Mach4 Plugins / Re: Galil plugin compatibility

« on: January 05, 2020, 01:14:11 PM »

Hi,

EVERY system ever created has lost motion, and 18microns is NOT 'no backlash whatsoever'

18 microns is the potential inaccuracy, not backlash. I have the original manufacturers test certificates and all my ballscrews
had less than 12um error in 300mm and less than 0.6umm cyclic. You are right I do have backlash, the planetrary gearboxes
I use on my current mill have 2 arc min lash or 0.7um linear. There is even a larger source of lost motion,
the torsional flex of the coupler. The two combined is 4um. This is my current machines effective
resolution and repeat accuracy. Further this is my measured result over a range of reversals an load conditions.
The faster the reversal and heavier the load the lost motion is up to about 4um, under less challenging conditions its
somewhat less, I struggle to make any sensible measurements of such small amounts.

I do not have ball bar but I cut an interpolated circle in aluminum just before Christmas and could not measure
any out of roundness with a 0.01mm reading 75-100mm micrometer. This is consistent with my assertion of
4um repeat accuracy.

My new build will not have reduction boxes and therefore no backlash and I am thinking of bellows couplers
so it will have GENUINE sub micron backlash/lost motion.

I had an email from the Ebay supplier from whom I bought the Delta servos, and they have been able to secure an even
better deal from Delta. They offered me 750W B2 series (17 bit incremental) for $379USD and 750W A2 series (20 bit
and load sensing) for $439USD. I presume that does not include shipping but for genuine quality servo and drives, quality
to which I can personally attest, these are very sharp prices.

Craig

1815

Mach4 Plugins / Re: Galil plugin compatibility

« on: January 05, 2020, 02:07:42 AM »

Hi,
Mach4 is and cannot be a feedback controller, the PC on which Mach runs IS NOT NOR CAN EVER BE REALTIME.
Its not because no one can be bothered or lack of imagination or anything else, but a limitation of PC hardware
or rather Windows operating software.

If you demand a feedback controller there is LinuxCNC.

If you want to stick with Mach4 and use linear scales then you must either use a feedback capable motion
controller, that is Gallil, Hicon Integra or maybe CSMIO/A......OR use load sensing servos like the Delta's.

Even the cheapest feedback motion controller (CSMIO/A) is 600 Euro....so they are not cheap. The CSMIO/A
must operate analogue servos, it cant mix and match step/direction and analogue, its one or the other.
Who wants to spend money on old school analogue servos? They are so last century, even the cheapest crappiest
Chinese AC servo BLOWS all that old analogue stuff into the weeds!

I personally think that load sensing AC servos are the better option, the servo/servodrive manufacturer builds all the
smarts into their products....you don't need to be a feedback control engineer just to get them to work. Note also that
load sensing could be a linear scale, an LDVT or an interferometer cell.

because there are serious limitations to the accuracy that can be achieved using leadscrews even with ground precision types like I have

I don't know what you are using but my existing C5 20mm dia. 5mm pitch ballscrews suffer NO backlash whatever.
The ballscrews I have bought for my new build, also C5, suffer from no backlash whatever. They are guaranteed within 18um
per 300mm and more importantly less than 0.8um cyclic, that is within one rotation. When I say I don't need linear scales its
because my ballscrews, support bearings and linear rails are sufficiently good that I can rely on sub micron accuracy
by knowing the angular position of the servo alone.

I've already got SureServo AC Servos, so it's not economic to change those

How many axes require linear scales? If you have two axes then two load sensing AC servos like the A2 series Delta cost
$500 each. A Galil controller will cost over $2000, and a Hicon Integra with servo activations $1200.
By my calculation it may be cheaper to sell your existing servos, which no doubt would attract significant buyer interest
and use those funds toward two of the A2 Delta's.

Craig

1816

Mach4 General Discussion / Re: M0 (M00) Issue

« on: January 04, 2020, 03:36:42 PM »

Hi,
I've been trying to replicate the problem you've described but cannot.

My laptop has an earlier build than yours, 4162.

I loaded a known good Gcode file, a PCB etch file and it loads and draws the toolpath normally.
Then I made a copy of that file but with the addition of several m0 lines interspersed throughout.
It also loads and draws the toolpath normally. When the file runs it stops as expected when it encounters an m0.
The file restarts at <Cycle Start>.

While I use an ESS on my machine, I use Sim(ulator) as active motion control on my laptop.

I recall there was a setting in Mach3 that determined whether M codes were ignored on loading. If there is a similar
setting in Mach4 I cant find it. All I can tell you is that the m0's ARE ignored when loading and drawing the
initial toolpath.

One thing I would like to point out to you, not that I believe it relates directly to your problem, but can and does cause grief
amongst newcomers.

Mach4's Gcode interpreters reduces all uppercase letters to lowercase and strips out leading zeros and whitespace.
G01 X0.88 y42 Z0.001  becomes
g1x.88y42z.001.

In the vast majority of cases Mach will successfully translate what you have written to a string of Gcode that performs
as you expected. There are a few circumstances when it does not......and that can create a real mystery, that can
be devilishly hard to diagnose. May I suggest that you get into the habit of writing Gcode in the exact manner that
Mach expects, it reduces errors. I personally tend to include whitespace in Gcode to make it more human readable
and usually leave a leading zero in a decimal fraction for the same reason.

The time you will notice this feature is if you write your own M codes to replace or take precedence over the built in M code,
m3 for example. There may come a time that you wish when turning on your spindle that you may wish some particular sequence
of events, checking the 'tool in place' circuit for example, and so you will write your own m3 macro. When an m3 macro
is encountered by the Gcode interpreter it searches for the macro starting in your profiles macro folder. If you have written
an M03 macro for instance and Mach is searching for an m3 it may ignore your macro and carry on its search until it finds
the built-in m3 instead.

Craig

1817

Third party software and hardware support forums. / Re: XHC Pendant WHB04B-4

« on: January 03, 2020, 01:52:30 PM »

Hi,

Surfing around Machsupport website i discovered the CSMIO/IP-M by CS-LAB which is not that expensive (EUR 229+VAT) and should be a kind of professional product... the 5 and 6 axis brothers are way more expensive thou.

My opinion of CSMIO products is somewhat tarnished. CSLabs had a market leading reputation for build quality and support.
In more recent times that support has diminished greatly, maybe change of personal. Another possibility is that they are developing
their own CNC software solution and their support for Mach has taken a back seat. Their Mach3 plugin is pretty complete
and that is a  viable solution. I think however you will be disappointed in the restricted feature set of the CSMIO/M.
If you are going to consider Mach4 then CSLabs lack of commitment to creating a bug free Mach4 plugin is very evident.

Notwithstanding the build quality which remains high I think the diminished support and buggy Mach4 plugin make CSMIO
hard to recommend at the prices demanded by them. Other manufacturers, Warp9TD, PMDX, PoKeys and CNCDrive all
produce cheaper boards with excellent support and a demonstrated commitment to Mach4.

Craig

1818

Mach4 General Discussion / Re: Index pulse and Spindle RPM?

« on: January 03, 2020, 05:52:29 AM »

Hi,
my understanding is that in order to calculate the spindle rpm the time between index pulses is measured and
the inverse calculation is done to arrive at the rpm.

Given that the index pulses happen very rapidly it is not possible for Mach to do that measurement, remembering that
a PC is not and cannot be a realtime device. That interval measurement must be done by the realtime motion controller.

I use an ESS as it alone has the speed and resolution to make the measurement. I presume the CSMIO does the same.
It must also be said that CSLabs have been very slow, you might almost say reluctant, to add and/or debug realtime features
for their Mach4 plugin. I think an email to CSLabs seeking clarification about the interval measurement capability
of the CSMIO is in order.

Craig

1819

Third party software and hardware support forums. / Re: XHC Pendant WHB04B-4

« on: January 03, 2020, 01:26:45 AM »

Hi,

there are lots of plugins of good stuff, like a professional 4 axis controller for about 250 EUR....

if you buy on price you'll get stung again.

If you must buy another controller buy one that has a Mach4 plugin. They are:

Ethernet SmoothStepper by Warp9TD
UC100, UC300, UC400 by CNCDrive (watch out for cheap Chinese fake UC100's, get genuine or don't bother)
57CNC,57CNCdb25 by PoKeys
PMDX-411, PMDX-424 by PMDX
Hicon Integra by Vital Systems
DMC40x..., DMC41x... by Galil

CSMIO by CSLabs, note the Mach4 plugin is buggy and the company have 'gone off song' and don't appear to be to fussed
about fixing it. Given the price, hard to recommend despite excellent build quality.

XHC make a Mach4 ready controller....buggy as hell, avoid like the plague!

Craig

1820

Third party software and hardware support forums. / Re: XHC Pendant WHB04B-4

« on: January 02, 2020, 02:35:08 AM »

Hi,
why the P4? That's the most expensive pendant they make.

I have a P1A, the one WITHOUT the LCD screen, and it works perfectly and $159USD list verses $289USD for the P4SE which
has an LCD and a keypad. Thankyou, but I don't need an LCD or a keypad as I already have a PC!!!

Craig