Messages

4271

G-Code, CAD, and CAM discussions / Re: Please help a newbie with cad

« on: September 16, 2010, 05:56:38 PM »

Mike,
To use the lathe module in LazyCam you will need a pro license and that would give you Gcode for the finished profile.
Lazy Turn, in current state, will not do a finish pass yet. You can however get the code for a rough / finish pass, and with some hand work have a smooth surface.

Can you provide a dimensioned sketch of the handle and post it?
Then maybe someone wil quickly draw it in CAD and generate the Gcode for you.

Just a heads up on the LT and LC software.

I know folks in here are using free / shareware CAD programs, I don't use them, so surely you will get a recomendation.

Have fun during the learning curve,

RICH

 

4272

General Mach Discussion / Re: how to set A-axis to move continuously,not in steps?

« on: September 16, 2010, 05:33:28 PM »

- a Stepper ( 1.8 DEG ) REQUIRES 200 STEPS or pulses  to turn one rev
                  ( .9  DEG  )   "               400              "

- So if you have no gearing, or like you describe, attached directly to the the spindle and are micro stepping
 then 200 steps/rev x 4 us = 800 steps / rev for indexing. No more and no less........

- lets say you want to rotate 90 deg, then 800 steps / rev  x 90/360 = 200 steps and you would see the dro indicate 45.00 deg
                       "                       30       "         800 x 30/360 = 66.6666 steps so you will see the dro display 29.*********xx deg and not a
  even number for the degrees. That's becuase you can't  move a fraction of a step like .66 steps.In fact it may be something different than the
  calculated depending on the stepper used.

- The best you will do in movement accuracy, if all was ideal would be 1/800=.00125 of a rev = 0.45 degrees, thus your something less or more
  than a degree. Now if you increase the resolution via gearing then the resolution will improve such that you will get a display which would show 30 deg
  for a commanded G0 A 30. So if you use gearing with a ratio of 10.8 then you will get even steps and the dro will show even deg.

-Now if you use gearing, then the stepper will need to run faster for a given feedrate, and as you increase rpm of the stepper motor, the stepper
  will loose torque and thus you start to limit the max speed you can index at. Because the spindle has drag and that drag increases with velocity then
  the velocity will not linear. Just like a typical stepper curve shows.

So as Gerry (oops...Ian) said, you need gearing to get an true increase in resolution. ie: more pulses to the stepper to move the same axis travel,

RICH
              

4273

General Mach Discussion / Re: how to set A-axis to move continuously,not in steps?

« on: September 16, 2010, 06:53:43 AM »

Usually for indexing the steps per is in steps per degree. If you are using like a linear axis then the steps are step per inch or mm.
In indexing you can just command a large number of degrees and it will run continously until  it achieves the rotational move.
Similar for linear move.
Now you can use the stepper for the spindle / constant turing of the lathe spindle. The steps per unit would be steps / rev. You will need set
spindle pulleys in Mach and some other configuration.

Irrelevant of the above, I suggest you don't use a stepper for turning the spindle since the torque goes way down and the rpm will not be linear.
 
BTW, if used directly as described, then if indexing, you may not get  exact degree displayed in the DRO because of resolution.

RICH

4274

General Mach Discussion / Re: help with motor torque

« on: September 16, 2010, 06:37:22 AM »

skanner,
Simple intial test would be to be to select the lowest current setting and see how warn / hot it gets to the feel in say 5 - 10 minutes.
Work your way up. If the current setting is to high the motor will get hot rather quickly and then drop down by one setting.
 With that setting see if you can move the Z, if not, then you may be able to change the wiring. Go through the currrent testing again if you wire the stepper differently. Go to the Geco site as they have explainations on stepper wiring and how it affects speed and torque.
With the current setting right, now you can test for velocity and acceleration  settings. Too high a current and the stepper may not run correctly
ie; like having it set right on the max.

RICH

4275

General Mach Discussion / Re: CamBam Gcode problems

« on: September 15, 2010, 08:59:52 PM »

Have a look at the ARC MOTION write up in Members DOCS, page 1 &2, relevant, even though it's for the lathe.
Figure 9 on page 6 shows influences which can have an affect.

RICH

4276

CVI MachStdMill (MSM) / Re: G73/G83

« on: September 15, 2010, 08:43:30 PM »

Will just try to help some...... FWIW......
I don't remember a problem using G73 / G83 with version 3.042.032 and if i recall that was with both SS & PP and 1024 ( mill only ).
So the time frame was about a year ago when i was trying peck drilling.
I haven't used the SS since then and only use PP now.
Now about that time, a few folks had drilling problems and Melee posted some peck drilling cycles that i did test on both the lathe and the mill
using the 1024 screen sets and the above version 3.042.032 & also .033. They worked very well / no problem on the lathe and mill.
So, don't know if this time frame and version is a help, but will say that the combination does work for me.
I would think there are enough users out there, that have done peck drilling, thus they can relate a problem to any version of Mach and use of PP /SS.

RICH

4277

Show"N"Tell ( What you have made with your CNC machine.) / Re: Couple of simple gifts...

« on: September 14, 2010, 09:02:38 PM »

Dave,
There is no need for you to spend so much time and effort on my gifts. 
A couple of grand, just like last year, would be appreciated just the same. 

RICH

4278

General Mach Discussion / Re: New PC or Used PC?

« on: September 14, 2010, 08:54:45 PM »

Hmm.....
We have used Dells at work for the last 15 years and they work fine ( hundreds of them ) and I have two at home that are great for everything. 

BUT 

I wouldn't give a penny  ( sorry let me change the wording ) "wouldn't take one for free"  if it was going to be used to be used for CNC / Mach using the PP.

FWIW,
RICH

4279

General Mach Discussion / Re: Acceleration

« on: September 14, 2010, 08:28:56 PM »

Arto,
Why do you need different accelerations?


RICH

4280

G-Code, CAD, and CAM discussions / Re: G code needed for lathe spindle used as rotary indexer

« on: September 14, 2010, 05:43:22 AM »

Bill,
Yes there is a lot  to sort thru. Take a look at replies 125,127,145,193,204 and get the swap axis macro's M940 and M950 that he posted.
I like the idea of doing it via the swap axis board. Haven't tried it all out, eventualy ...... I currently have two configs, one for indexing and another for rotary and use a stepper with gear reduction to temporarily drive the lathe spindle. Stepper use leaves something to be desired since as the motor rpm goes up torque decreases and the rpm is not linear and feedrate becomes limited and feedrate is also not linear. So need to get a servo and drive for the spindle, but that requires mods to my controller and wiring etc , etc......never ends...........

Also try out Phil's screen for the lathe ( you will see why as it is set up for A axis and other things) and also do a search for drilling macro's for the lathe.

RICH