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Messages - robertspark

72
General Mach Discussion / Re: 4th Axis PID
« on: November 23, 2016, 02:09:26 PM »
Ok, being devil's advocate ....

Why do you actually need an arduino for a 4th axis?
All you do is set mach3 up with an a axis, and set it as a rotary motion in the configuration.

Why do you need pid?

What error are you expecting to have to correct for?

What are you actually going to use the 4th axis for?

Most cnc users even with a forth axis are not actually 3d machining, but index their 4th axis, or use it as a rotary axis.... Sort of a quazi linear rotary axis motion
.. not 3d

Sorry not trying to be critical of anyone's ideas and I appologise if it reads that way.... Just trying to expand on what you plan to do or more so why?

I bought a rotary table (6" / hv6) of Chinese origin, then bought a cnc adapter for a nema 23 stepper from here

http://medw.co.uk/wiki/Rotary+Table+CNC+Options

.. built the 4th axis, and discovered the backlash was well... A lot, and motion was not fast.... I kind of forgot the purpose for me which was a 4th axis for a plasma cutter... Ok... Stop... Time to do some calcs....  Then I bought a 4" Chinese 6:1 4th axis, belt drive, changed the stepper motor, and now have a very fast with fast acceleration 4th axis for the plasma (and a cnc rotary table for the mill....
http://i.ebayimg.com/images/i/251320056397-0-1/s-l1000.jpgL



73
General Mach Discussion / Re: Physical buttons for plasma
« on: November 22, 2016, 04:05:49 AM »
Although its not your manufacturer, if you have a look at the hypertherm 65 manual, it provides additional air pressure (as dave says above) requirements for the longer hose.  https://www.hypertherm.com/Xnet/library/library.jsp?file=HYP115403&format=pdf


Blowback start is simply (yes I'm sure there is more to it than this but) .... a "floating" electrode within the torch tip, so that the air pressure drives the electrode gap, and the high voltage between the electrode and the tip generates the high voltage spark   (think spark plug, but with variable gap). edit: after reading Jim's post, the breaking away of the electode from the tip when the air pressure rises, which creates the spark

Hence the air pressure may be your problem with the longer hose given the floating electrode within your torch may not be moving back enough to trigger the arc or with-stain an adequate arc...... note that the current hyperthem range have an electronically variable air pressure (not the PMX45), so I suspect that the air pressure can be adjusted dynamically given any affects from the cutting surface which may cause some variance in the air pressure as the cutting height varies.

All of the above could however be bull.... so take with a pinch of salt as I'm no plasma industry employee just an owner of two (hypertherm) plasma cutters and have read a lot of the hypertherm manuals

blowback start waffle:
http://www.cnczone.com/forums/hypertherm-plasma/181858-cnc.html

better explanation on the HF + blowback start from Jim Colt:
http://www.tractorbynet.com/forums/welding/211108-plasma-cutter-choices-4.html

74
General Mach Discussion / Re: Physical buttons for plasma
« on: November 21, 2016, 11:08:48 PM »
Is this the machine torch you have?
https://www.amazon.com/Autocut-PA2211-Plasma-Cutting-Trafimet/dp/B01I247GWK#

Which hand torch do you have?

Did you extend the machine torch lead, if so, by how much?

I suspect that if you rejointed the lead the pilot (high voltage) may be tracking.... How did you insulate each core from each other once you remade them off?


Note some of the hand torches are blowback start, not sure about the machine torches though...

75
General Mach Discussion / Re: V.B. programming problem
« on: November 17, 2016, 05:57:10 AM »
Glad you found a solution, sorry couldn't be more help, but that's for reposting as I learnt something (been playing with c, c# for a while, VB requires a brain reboot)

78
Mach4 General Discussion / Re: digital indicator serial port input
« on: November 13, 2016, 06:57:37 PM »
Wow that mm kit is expensive... But meet and prepackaged

Alt solution...
http://www.compendiumarcana.com/caliper/

Maybe an easier suggestion.......  Get yourself something like an arduino due (note they are 3.3v) or maybe a mega if they have multiple rs232 ports.... Then read the caliper and pass the reading via modbus to mach4.... Once breadboarded... You can then cut down on the circuit.... It may be possible with a due to feed in multiple rs232 inputs from multiple caliper....  Or you could do some sort of a multiplexer circuit maybe... If only a few ports...

Mach4 does not have native rs232... Hence you'll need to write a plugin if you want direct interface... Which means you'll need to ask NFS for the SDK for mach4.

79
General Mach Discussion / Re: Mdi is not a MODE
« on: November 13, 2016, 02:58:37 AM »
Couple of things to consider...

You mentioned using version 066, the popular recommended version is 062 as a few bugs were introduced in 066 relative to a mill application (from memory I believe 066 has some lathe functionality or bug fixes). The problem with 066 is I believe motion controller related.  I don't believe I've ever seen a changelog listing 066 bugfixes and updates, and any changelog stops many versions before.  There is also a version 067 too which appears (I guess, no official knowledge) to have been commissioned by CandCNC incorporating elements for their plasma motion controllers https://www.candcnc.com/downloads/


Consider the following:
You bought mach3 from NFS / artsoft.
It has always been developed with numerous bug fixes.  I'm not sure which version is considered a lockdown version as each deals with potential serious bugs (serious by the nature that the software controls a machine automatically (sort of)) and like you experianced there may be potential high energy debris (speed x mass) to cause harm.

You have a motion controller, which requires a plugin developed by another company who have interpreted mach3 plugin coding requirements (good luck with finding volumes of plugin manuals listing all plugin functions in detail along with any subsequent amendments as bug fix versions progress)

Then you potentially have a screenset which mayor may not have been edited by persons unknown who knew nothing of your hardware of software at the time of implemention (ie it was developed on version 043 and your installed 066, but there was no documentation identifing which is the screensets development version or it has a means to loch the screenset to a particular version.

Then you have (I think from reading the post) an external control keyboard, developed and built by persons unknown, relying on the motion controller plugin to correctly send signals to mach3.

Then you have to consider that artsoft / newfangled solutions don't sell any hardware.  So persons unknown have physically built your machine and wired it following instruction manuals from all the various parts manufacturers, software providers using manuals which may not reflect or been tested on the current installed version of either windows, any supporting service packs and libraries (prerequisites, such as c++, VB, .NET framework etc), mach3, motion controller plugin, along with of course any other plugins installed (whether enabled or not as mach3 can assign resources to unenabled but installed plugins).

Then you have to consider such disclaimers that I'm sure all the various component and software suppliers will make, such as that within the mach3 installation manual (page 1-1)

Before You Begin....
Any machine tool is potentially dangerous. Computer controlled machines are potentially more dan-
gerous than manual ones because, for example, a computer is quite prepared to rotate an 8" unbalanced
cast iron four-jaw chuck at 3000 rpm, to plunge a panel-fielding router cutter deep into a piece of oak,
or to mill away the clamps holding your work to the table.
This manual tries to give you guidance on safety precautions and techniques, but because we do not
know the details of your machine or local conditions we can accept no responsibility for the perfor-
mance of any machine or any damage or injury caused by its use. It is your responsibility to ensure
that you understand the implications of what you design and build and to comply with any legislation
and codes of practice applicable to your country or state.
If you are in any doubt, be sure to seek guidance from a professionally qualified expert rather
than risk injury to yourself or to others.

Followed by the following extract from the next page of the manual

Every effort has been made to make this manual as complete and as accurate as possible, but no war-
ranty or fitness is implied. The information provided is on an “as is” basis. The authors and publisher
shall have neither liability nor responsibility to any person or entity with respect to any loss or dam-
ages arising from the information contained in this manual. Use of the manual is covered by the license
conditions to which you must agree when installing Mach3 software.

Then there is consideration of your own competency, testing and training, and appropriate selection and use of personal protective equipment or the use of machine guards and interlocks (given the speed of the tool that broke and it's mass, why did you (or the machine assembler and manufacturer) deem it unnecessary for a fixed guard or shield not to be installed in front of the operator position?

Court decisions are not 50/50 (from my experience), it can come down to your legal representation and their experience, and the expert witnesses and professors you call, given the number of potential defendants given I presume youve not bought an assembled turn key machine, and undertaken their operator training programme chances of success against NFS  would be about 1% (or much lower), and if it was a fully assembled turn key machine, your port of call for litigation would be the turnkey supplier who may or may not sue up the tree after loosing their own initial case to you.

... Only the lawyers get rich out of this process. ...

Install an operator guard of appropriate energy absorption rating if you are unable to remove the risk or correct the coding.

If you are manufacturing a machine for release (which upon rereading you may be), although not practical maybe, have you spoken with supplier s regarding mach3 version compatibility?  Have you documented this in your literature, do you offer training and operator certification (it may not be practical or ever taken up by a purchaser (cost prohibitive to them), but it protects your liability later).  You should offer comprehensive manuals which also inform windows version compatibility and that things such as automatic updates should be turned off as operation cannot be guaranteed should additional software be installed or updated (if you buy a dedicated cnc lathe or mill (Haas etc), there is no opertunity to install other stuff like running a cnc app on a windows PC or laptop.  Operator training should be offered same as site installation anywhere in the world your customer is based, now this does not have to be at a low cost, but an appropriate cost.... Ie. + Include travel and accommodation costs if the customer wants site training, or give them the opportunity to come to you at their own cost but still provide for a structured 5 or whatever day tailored training courses covering installation maintenance and operation, plus refresher training, plus advanced operator / trainer training, any of them they may or may not choose (they may prove cost prohibitive to them, but ensure your rates for local training can be considered reasonable).  If the customer chooses not to pay for this service it provides evidence in your favour should an accident occur in the future.  Ie accident occurs, was the operator trained by you, were they competent... Maybe you trained the owner, but now someone else was using the machine, were they trained by you, or were they trained by the owner, did the owner possess proficiency in using the machine for long enough such that they could train others, were they certified to train others, was the machine and guards maintained, were they in place, was the machine installed in an appropriate location with adequate clearances such that the energy of any projectile would have diminished before leaving the work zone , if not add guards etc etc.

Sorry for the long post.... Just a few ways to look at things from different perspectives.

As a mach3 user it would be very difficult to sue and win against NFS (or any other component manufacturer) because of the sheer number of intercontinental components and variables, likewise as a manufacturer selling complete systems you can protect yourself well even with using many interconnecting components by how you offer the turnkey project (if the customer never takes up the offers or training and installation, provided you offer it at what is considered a reasonable cost and also can demonstrate a structured (documented) training system later even though no customer has ever taken it up)... All about training, certification, records and documentation...  likewise All suppliers should offer this to system integrators .... Even if it is never taken up... It was offered...as can be demonstrated as such.  Eg... http://www.haascnc.com/training.asp#gsc.tab=0

80
General Mach Discussion / Re: Coordinate Spaces - a Guide
« on: October 27, 2016, 03:41:17 PM »
Nice guide.

I'd suggest a bit more explanation on absolute distance mode, maybe add the word "relative" before the word positions at the start of the second line and maybe an example of an absolute move with the tool at x0y50, and a move of g0y100 for both absolute and incremental, if you do an update on the guide in the future. (From a relatively new cnc non native user / enthusiast)