Messages

5191

General Mach Discussion / Re: Pulse Frequency

« on: February 23, 2018, 03:26:26 AM »

Hi,

In the MACH3 videos, this pulse frequency is important for the proper operation of the MACH3 software.

That is true for a Mach3 parallel port buy not an external controller like yours.

Can you take some screen shots of the plugin setup pages. Maybe some of Machs Port &Pins pages too.

Craig

5192

General Mach Discussion / Re: Limit Switches Hard and Soft

« on: February 23, 2018, 12:35:51 AM »

Hi,
soft limits rely on the machine being referenced or homed. How does your machine do that?

Craig

5193

Mach4 General Discussion / Re: I'm stuck

« on: February 23, 2018, 12:33:39 AM »

Hi,
great news. May I suggest wiring and testing small bits before continuing to others.
My observation is that many people try to get everything going at once and end up with a number of problems. It can make diagnosing and fixing problems
very difficult instead of identifying, understanding and solving each problem as it ocurrs.

1) One axis at a time, configure and test with jog commands and MDI BEFORE moving on to the next axis.
2) Home switches, again one axis at a time
3) Soft limits
4) Limit switches, commonly in series therefore all axes at once.
5) Test all motion...jog...MDI...Gcode
6) Test all motion...jog...MDI ...Gcode
7) Test all motion...see above!
NOW have a go at the spindle, first just get it to turn on and off. If you really need it get it to reverse (personally I think a reversing spindle is a waste of time except
     in special circumstances). Now try speed control.

Craig

5194

General Mach Discussion / Re: Pulse Frequency

« on: February 22, 2018, 06:47:48 PM »

Hi,
I thought the NVEM controller was a USB connected external motion controller?

If it is then the pulse frequency is set by the board manfacturer not you. It is recommended that you set the kerenl
frequency of Mach to 25kHz but it wont really affect the controller.

Craig

5195

General Mach Discussion / Re: Spindle orientation on a Bridgeport...

« on: February 22, 2018, 05:49:40 AM »

Hi Dave,
that was profiling, probably 25% step over. My machine starts flexing before the power limit of the servo is reached.

The essential concept of field oriented control is that the  applied field is calculated and phased such that it is 90 degrees to the magnetic field of the rotor
and therefore produces the highest torque for a given current. If instead the applied field is at a greater or lesser angle then a fraction of the applied field
will either reinforce or oppose the rotor field. Should the rotor field be weakened in this manner then the motor will produce a smaller back EMF at rated speed
or alternately a greater speed for the same back EMF.

A servo operated in this fashion might produce 10Nm at rated speed of 2500rpm but with field weakening produce 7.5Nm at 3500rpm, ie you can trade torque
for speed, very clever. You may have noted that some industrial machine specifications might list a maximum traverse speed of 36m/min but a max cutting speed
of 20m/min. What they are referring to is that with field weakening its possible to get higher speeds but not retain the torque and thrust to cut.

I'm not sure you aren't doing the cheap imported servos a disservice by suggesting they are not capable. Commonly you'll see a servo with a maximum speed limit
well in excess of its rated speed. Such a servo has the capacity to use field weakening. I suspect that the quality and reliability of the drive will come under pressure
well before the servo wilts.

Craig

5196

General Mach Discussion / Re: X Y axis move togehter with Arrows key

« on: February 22, 2018, 03:39:10 AM »

Hi,
you need to check that your step and direction pins are correctly assigned, it sounds like you have both X and Y step inputs being feed from a single signal.

Craig

5197

General Mach Discussion / Re: Spindle orientation on a Bridgeport...

« on: February 22, 2018, 03:36:12 AM »

Hi Dave,
could you not try it direct rather than all the expense and shagging around to gear it?

Of course there is nothing so permanent as a temporary thing.....

May also be possible to push the 2500 rpm. You may have read about 'field weakening', an extremely clever means of manipulating the back EMF constant to
achieve higher rotational speeds for a given input voltage.

I have not seen it mentioned in any servo drive manuals that I've read but you can be sure that my Vickers servo (3000rpm rated, 4000rpm max) drive will have it!

Craig

5198

General Mach Discussion / Re: Spindle orientation on a Bridgeport...

« on: February 22, 2018, 03:28:37 AM »

Hi Dave,
its 6Nm and 3500 rpm in a baby (X,Y,Z = 200,200,200) bed mill. I have taken 6mm deep cuts with a 16mm endmill in steel with cooling but my machine is flexing
and dancing but throwing chips like its going out of fashion, really impressive.

Prior to getting this Allen Bradley unit I bought a 2.6kW 12Nm 3000rpm Vickers unit, again second hand. When it turned up I would say it was new or maybe
re-manufactured. The date on it suggests 1994. Only downside is it has a 4 pole resolver which severely limits my choices of drive. My interest is electronics so I
decided to make a Field Oriented Control drive for it. Still working on it, been a long learning curve!

As it turns out this is a big servo, too big for my machine, I think it would topple over and my machine can't really handle it all anyway. My plan is to use it as a lathe
spindle motor.

If a hobby is measured by what you learn in the pursuit of it then this servo and drive is a very VERY good hobby, I've had to learn all sorts to stay on track!

Craig

5199

General Mach Discussion / Re: Spindle orientation on a Bridgeport...

« on: February 22, 2018, 02:35:58 AM »

Hi Dave,
I recently bought a second hand 1.8kW Allen Bradley AC servo and drive for a spindle. I needed a spindle motor with some decent torque at slower speeds for steel.
This servo has turned out great. The main reason I went with a servo is that they are the most powerful/torque-y motor for the size.

Its the first time I've really ever played with a modern AC servo and I am impressed, very, very impressed! They are extremely capable and while it was not even
on the radar, stopping the spindle to line up the drive dogs is trivial with a decent servo. My 'zero window' is 4 counts of an 8000 count encoder ie 10.8 arc min!
Easily good enough to line up surely!

I had always been put off by the cost of servos but after playing with one I wont be looking for any other solution anytime.

Craig

5200

General Mach Discussion / Re: computer

« on: February 22, 2018, 02:17:14 AM »

Hi,
if I were buying another platform I'd try this:

https://www.dfrobot.com/product-1585.html

The Enterprise Windows 10 is like Windows 10 Pro, you can turn Windows updates off which is highly recommended.

My biggest Gcode jobs are PCB isolation routing files of about 5MB. Such a file will occupy my machine for about 10 hours. A 60GB drive would give me
about 13.7 years continuous...probably enough for me, your 2TB drive will run for 456.3 years continuous!

Craig