Messages

361

General Mach Discussion / Re: servo encoder ?

« on: April 29, 2012, 12:49:54 PM »

You will need new motors, encoders, new Geckos (G320X instead of whatever you have), almost certainly new power supplies, and you'll have to add belt or gear reducers to all axes.  The BOB is about all you'd be able to re-use.  Why on earth would you want to do that?  What "problem" are you trying to solve, other than perhaps having too much money in your bank account?

Regards,
Ray L.

362

General Mach Discussion / Re: motor settings vs kernel speed

« on: April 22, 2012, 08:25:36 PM »

There is *ZERO* benefit to running kernel speed any higher than necessary to achieve the rapid speed you want.  By my calculation, 25kHz will do that for you (I get a bit over 22kHz max pulse rate for 15000mm/min @ 90steps/mm).

Regards,
Ray L.

363

General Mach Discussion / Re: Auto tool measuring and offsets

« on: April 11, 2012, 01:54:07 PM »

FWIW - I used to to tool length that way, but switched some time ago to just doing it off-line using a digital height gauge.  I find it MUCH faster and more convenient, as I don't have to swap out all the tools.  I can measure a dozen tools in maybe 2-3 minutes, where it would take 10 minutes to do using the machine.  Might be a different matter with a PDB....

Regards,
Ray L.

364

General Mach Discussion / Re: max power from vfd

« on: April 01, 2012, 11:41:05 AM »

Not necessarily.  If you're torque or power limited, then perhaps.  But with smaller tool, very likely higher RPM will allow higher feedrates, but you won't be torque or power limited.

Regards,
Ray L.

365

General Mach Discussion / Re: max power from vfd

« on: April 01, 2012, 11:10:19 AM »

It produces the same torque at any speed below its base speed, which means power below base speed falls off with RPM.  Above base speed, power is constant, which means torque falls off as speed increases.  So, you'll have full torque at any frequency up to 50Hz, and decreasing torque above that speed.  At 100 Hz, torque will be half what it is at 50Hz.  If it's a 1HP motor, it will deliver 1 HP at 50Hz and above, but only 1/2 HP at 25Hz.

Regards,
Ray L.

366

General Mach Discussion / Re: max power from vfd

« on: April 01, 2012, 10:53:23 AM »

A 3-phase motor driven by a VFD will have constant torque up to the motors base speed, and constant power above base speed.

Regards,
Ray L.

367

General Mach Discussion / Re: Smooth steppers

« on: March 31, 2012, 08:19:53 PM »

Great.  I have been considering the Warp9 Tech?  Any brand better/more compatible with mach3 than others?

There is only one.  They all come from Warp9.  Greg there is the designer/programmer.  All the other sellers are simply re-sellers.

Regards,
Ray L.

368

General Mach Discussion / Re: Smooth steppers

« on: March 31, 2012, 07:59:39 PM »

SmoothStepper works great, and provides a VERY clean pulse train.  I ran mine for a couple of years on a 500 MHz PC with no performance-related problems.  Get the new Ethernet one, rather than the USB.

Regards,
Ray L.

369

General Mach Discussion / Re: touch off pad

« on: March 31, 2012, 12:02:08 PM »

I would STRONGLY urge you to spring for a copy of MachStdMill:  http://www.calypsoventures.com/machstdmill/overview.html  This will give you a wide array of very robust probing functions.  You CAN get this working on your own, but it often results in a lot of frustration, and MachStdMill provides a LOT of very useful probing functions that would take you forever to develop on your own.  For the very low cost, it's a real bargain.

Regards,
Ray L.

370

General Mach Discussion / Re: run from here takes forever

« on: March 31, 2012, 11:58:44 AM »

Yeah the part would be scrap but at least you wouldn't have to re-zero, I make lots of identical parts on fixtures.  Thanks for clearing it up for me guys!

That's where accurate home switches and fixture offsets come in handy.  If you lose position, you simply toss the part, re-home the machine, and get back to work, losing only a few seconds.  If you don't have home switches, then I suggest using probing to zero the machine - also takes just a few seconds per axis.  You just have to make sure you always have appropriate reference surfaces, on the part, fixture, or vice, to zero to, even if the part has been partially machined.

Regards,
Ray L.