Messages

4531

General Mach Discussion / Re: stepper or drive problem

« on: June 27, 2010, 10:20:14 AM »

Could this be the drives or steppers?
-Steppers can get finiky when run at too hiigh curent setting or when they get hot.

Sounds like you are running near the limit of what the x axis will do, so if the Z drops down ( for whatever reason ) you
get additional demands on the X axis and it skips. Maybe lower the velocity and accel some.
Long files means longer running  time which means increase in stepper temp depending on amp and volts provided to them.

RICH

4532

General Mach Discussion / Re: Relationship of Velocity/Accel to G0...

« on: June 27, 2010, 09:56:04 AM »

Stan,
A SS will provide for an increase in the number of pulses that can be provided to the drives. The question is ....... are the drives and motors capable of using the pulses. The SS is generating the signal and not the PC/PP. The signal quality may be better at higher rates than from the pc and motor preformance will be improved.

The problem I am having is that you are trying to make a correlation of how a stepper motor will preform  running unloaded as to compared to one
loaded ( hooked to something ). That makes no sense at all from a practical point or theory. There is a world of difference. And depending on the application you should care about velocity and accel at this time. Well maybe not, since you already have the motor and you got what you got. You could use a motor sizing program and quickly see what the affects of varing  conditions provided you have known motor characteristics ( which you don't have ) and would see how velocity and acceleration comes into play at a given load.
Why do you think manufactures provide preformance motor curves?

Like Gerry, I get  the same performance in motor tuning and running g-code also.

Unloaded motor  you are mention IPM, yes relative is a sense only, since when a load is attached you will find that if your operating the stepper motor past some point of say max power the feedrate is no longer linear  because the torque is decreasing and as such the feedrate will no longer be linear
and any addition increase to the feedrate will be less than commanded. In fact you can almost generate a curve for your motor until it stalls based on the load!

RICH



 
  

4533

General Mach Discussion / Re: I seem to be gaining steps...

« on: June 26, 2010, 07:52:54 PM »

tap tap tap noise after 20+ hours running

- what's the temperture like after 20 hours of running since steppers can start to act funny when they get hot

feedrate was set to 2mm/minute

- thats around .001" / sec or one "clonk" / pulse per second
- the slowest feedrate i ever tried running my steppers with a G201 was 1 "tik" / sec........
  I was just fooling around to test a peck drilling cycle, but they just tiked like a clock and left them run like that for a half hour time.
  Sounded just like a clock and in perfect harmony with the stop watch. ( good grief what i do when i get bored )
Never experienced what you experienced so don't know what to say. Maybe take Hood up on his offer to try a different drive.

Sound is a good indicator and you know what's right when you hear it.
Sorry don't know what to tell ya......
RICH

4534

General Mach Discussion / Re: Closed loop system, encoder connected to mach3

« on: June 26, 2010, 02:14:55 PM »

I've seen steppers stall - period - but never have I seen one miss the occasional step

The missed step is a tough one. My experience in all this time on missed steps can be counted on one hand and i really can't clarify a simple single missed step as all is not as it seems. In the few times that a stepper "skipped" the outcome was that axis movement was such that the axis went off with a mind of it's owne, like just cutting some random path thru the metal, or you could hear the skip ( but maybe extremely short - say just a few steps / fraction of a second) and it kept the pathing of the code but was off somewhat in location. Very , very infrequent / unusual if your motor tuning &  application is proper for what you are going to do.

We tried finding magical lost steps using custom high end equipment which would count and compare steps out of the PP to the actual steps provided to a stepper along with measured distance. The counting accuracy was in parts per million and although the equipment said  there were a few in the comparison we never heard or experienced a problem in the stepper motor movement. In one case it identified that the lost steps were due to belt tension ie; the steppers were turning appropriately as pulsed....movment was lost in the timimg belt which made it appear like lost steps.  SO looking for a needle in the hay stack that may not even exist is difficult.

So i agree with ya, Ian.  Steppers are very accurate and reliable when used properly, and they either work or don't, and there is a world of difference between stalled/skipped/ lost step.

BTW, two different steppers, all things equal, can require different steps per unit ( lost steps ....not really, variation in constructed quality)
unusual, but true.

BUSTING THE MYTHS........

RICH 

4535

Show"N"Tell ( Your Machines) / 7X14 MINI LATHE - CNC CONVERSION

« on: June 26, 2010, 11:11:35 AM »

This thread will be about the conversion to cnc for a mini lathe. Don't know how long it will take or when the conversion will be completed.
We are just getting started, so who knows. 

4536

General Mach Discussion / Re: Closed loop system, encoder connected to mach3

« on: June 26, 2010, 08:43:01 AM »

stay with steppers or go servo

A decision only you can make. I have never gone to servos because i have 5 drives for steppers and a bunch of stepper motors.
But, i will get a servo and at least one drive ( one of these days ) for running the spindle on the lathe constantly.
This way there will not be changing torque and have linear speed over the rpm range.

FWIW and depends on the good junk you may already have,
RICH

4537

Show"N"Tell ( What you have made with your CNC machine.) / Re: Extended Wheel Nuts for Shovel, Axe, & Jack Holder for My Prado

« on: June 26, 2010, 08:26:19 AM »

Chris,
I created a thread for the macros here:

http://www.machsupport.com/forum/index.php/topic,15205.msg101682.html#msg101682

I have used them and like you know you can also specify  mutiple holes. I used them for peck drilling
small holes at high speed and at very small feedrates ( F of .05 or less ). Now others  can find them.

RICH

4538

MACH TOOL BOX / MACRO- LATHE & MILL DRILLING MACROS m830 and m831

« on: June 26, 2010, 08:14:16 AM »

The attached file contains  peck drilling macros for the lathe and mill created by Melee.
There is a read me file which explains their use.
Since the referenced download location in the original thread is no longer working i thought i would post them here.
At least they will not get lost.

RICH

4539

General Mach Discussion / Re: lazyturn problem

« on: June 25, 2010, 03:12:39 PM »

Here is info from the manual:

4.0    INSTALLING LAZYTURN

4.1   LazyTurn  ( LT ) currently can be run independently via hard drive, USB stick
     etc as it’s installation can stand alone.

4.2   When installing Mach3 you are asked if you also want to install LazyCam.
The current lockdown version of Mach3 installs LazyCam 3.00.2. If you are using an older version of Mach3 you may need to install the LazyCam 3.00.2 Update. Both versions can be downloaded from
the ArtSoft site. Here is the link:

                   http://www.machsupport.com/downloads.php                 

4.3   You can either update LazyCam 3.00.2 by installing the update or create another directory for a stand alone installation, but both versions must be installed for LazyTurn to work.

                "LazyCam 3.00.2 Update" is a special build that includes additional  required
                 files.

4.4   Now you will need to update the LazyTurn REL 1.1 application file to the most recent version posted. As of  3/14/2010, The latest application file posted is: Re:LazyTurn thread, reply #1349, page 135


                   Download and unzip the above file and copy the LazyTurn application
                  file into the directory you installed Lazycam.  You will replace the existing
                  file that is there.

     Once installed, you can play with LazyTurn by running lazyturn.exe in the
     resultant folder.

RICH

4540

FAQs / Re: dfx to gcode

« on: June 25, 2010, 05:38:26 AM »

MCTROOTS1
Can you attach the dxf file?

CNC FRESHMAN
Attach the dxf file.
In general, to convert an Autocad file to gcode, you would need to save the drawing as a dxf. The dxf file of the drawing is a file which contains info about what was drawn and is then imported by another program. That program, and there are manny them, allows you to add machining information to what was drawn.  The program then converts that file to gcode which can be used by Mach to machine the profile.

SO, we can convert the program to gcode, but know nothing about how you want to machine the drawn piece.

If you want learn more you can just have a look at some of the tutorials in the LazyCam manual or any manual and you will get a flavor of what needs to be done since all programs require the same info and do the same thing in general. Just another learning curve for ya to accomplish.

As Bud mentioned, you can use Gerry's program and convert it directly from AutoCad.

RICH