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Offline ger21

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Re: Really need help
« Reply #60 on: August 15, 2009, 11:52:20 AM »


Are Mariss and Marcus the same person?  I had email exchanges with Marcuss Freimanis (may have spelled that wrong), but I ocationally see 'Mariss' mentioned.

Marcus is Mariss' son.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html

vmax549

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Re: Really need help
« Reply #61 on: August 15, 2009, 11:53:04 AM »
COULD BE (;-)  I would set to the highest resolution for the drive. Then adjust MACH as you stated. FUll step mode is KNOWN for midband resonance in SOME applications(not all).

I woulds ALSO eliminate the double iso (;-)

(;-) TP
Re: Really need help
« Reply #62 on: August 15, 2009, 12:20:49 PM »
I'm, sorry, but I don't know what you mean... "double iso"  (duh)

Offline Hood

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Re: Really need help
« Reply #63 on: August 15, 2009, 12:22:12 PM »
I'm, sorry, but I don't know what you mean... "double iso"  (duh)

double isolation

Offline RICH

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Re: Really need help
« Reply #64 on: August 15, 2009, 02:19:04 PM »
Simpson,
1. The logical conclusion is that this is not so simple as it's made out to be.
            Depends on where you are comming from.
            If you start with a clean sheet of paper, then you define what you want the system to do
             and go through all the itinerary steps to arrive at an acceptable design within all the
            constraints  that are placed on doing the task. This is done in a way which utilizes good
            engineering principles, techiniques, judgement and includes past / present / researched  experience.
           The task utilizes all the different disciplines involved in a respected and valued manner. In the end a
           rationalized design is provided in terms of cost, quality and time (CQT).
           CQT is related and requires sacrifice to improve the other.

2. I don't reacall finding any clear advice on exactly how to select a 'quality' component.

The suppliers of material components cover the gamut of required items. There is a lot of choice
to be had and the evaluation of all of them would be mind boggling. User experience of tried items
is invaluable and manny recomendations / suggestions satisfy a general need in the hobbiest arena.Consensus may never be had. We are here to offer suggestions for consideration and not make decisions for someone. In the end is falls back to oneself  to make a decision.

3. Is there some way to be proactive in interpreting a spec, graph, or other perfomance
   documentation?

Yes, and when given, most folks don't full understand it, or, will shy away because it's too technical. For even a simple item a book can be written and probably already exists.
All too often data and application must be related to the system and intended use.

4.What are the caveats to avoid?

Putting it all together and then asking others to fix it for you and challenging their experience.

RICH

Offline simpson36

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Re: Really need help
« Reply #65 on: August 16, 2009, 07:44:55 AM »
YOU are right IF I just wanted to drive around town showing off I would buy the sports car those speeds shure are impressive.

BUT IF I wanted to actually do some work and actually MOVE the dirt I would BUY the dumptruck every time.

Exactly. This is why the whole stepper vs servo argument is meaningless if undertaken out of context.

Certainly the debate is valid in applications where there is overlap . . . dump truck and Firarri will both take you and a friend to the local Blockbuster Video Store to rent a movie. Speed is identical while sitting in a traffic jam . .  etc. i.e. applications wherein the advatages of either are not required nor are the disadvantages of either going to hinder the machine's function.

But as you correctly point out, the objective, winning a race or hauling dirt,  should be the first item of discussion before any recommendations start being passing around. Unfortunately, more often that not, the fur starts flying before anyone knows what the application is. This was pretty confusing to me when I first entered the fray.


Incidentally, is 'VMAX' related to the motorcycle?

Offline simpson36

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Re: Really need help
« Reply #66 on: August 16, 2009, 08:10:40 AM »
I'm, sorry, but I don't know what you mean... "double iso"  (duh)

You should protect your PC from a short that could send motor voltage to fry the PC port or worse.  Since your drives are already isolated, you do not need additional isolation between them and the PC. For example, Gecko drives are isolated, so the BOB I linked you to comes in a less expensive 'Gecko version', that has no isolation on the pins typically used to connect the drives.

My money is on your RF gizmo being the prime suspect, so since you do not need isolation for the drives and you have a no-frills BOB to try our, my vote is to go for it. Worth a try.

Full step vs half step vs micro-step *should* have no bearing of whether the setup functions correctly or not, although there are reports that checking off the 'sherline half step mode' box in Mach does solve certain mysterious lost step problems . . . .  primarily on the Z axis for some reason . . . .even though it shouldn't have any effect.

Mostly I am interested in how the little scope works for you. When I had the Gecko servo drive, I was sniffing around available scopes to use in tuning and I selected this one: http://www.saelig.com/PSPCEL/PSPC019.htm but never bought it as I got rid of the Gecko instaed.

Offline simpson36

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Re: Really need help
« Reply #67 on: August 16, 2009, 08:14:53 AM »
I'm, sorry, but I don't know what you mean... "double iso"  (duh)

double isolation

A common CNC term that describes what happens to husbands who spend too much on their toys  ;D

Re: Really need help
« Reply #68 on: August 16, 2009, 08:21:45 AM »
I'll be sure to buy my wife a gift today!
Re: Really need help
« Reply #69 on: August 17, 2009, 05:15:24 PM »
I got it working!!!

All I did was to change my Slo-Syn spepper controller to half-Step... go into Mach-3 and under motor tuning change the "Units per"  from 50 to 100.
I even took the max motor speeds to to 400  (There are some G0s in the code, so max speed IS executed)

I ran my most problematic profile over and over and EVERY TIME both hand-wheels returned to zero as expected.
I even turned the graphic display for the toolpath ON, and the steppers never skipped a step.

With twice as many pulses, each stepping half the distance, the motors sound better than they ever have.  They just "purr".
I bet my curves are cutting at higher resolution.  Less sanding afterwords... NICE!

My sincere thanks for everybody's help.  You guys are the best!

« Last Edit: August 17, 2009, 05:17:43 PM by TunerTom »