Messages

61

Newfangled Solutions Mach3 Wizards / Re: Tool pauses at X axis while cutting circles or threading?

« on: May 24, 2009, 04:48:25 PM »

You have the Exact Stop checked!
Check the Constant Velocity instead. Make sure you don't have any G61 in your g-code.

62

General Mach Discussion / Re: CV distance

« on: May 24, 2009, 07:14:54 AM »

Yes, you can even set it to a decimal value like 0.3 if you like. You probably should set it to a value like 0.05 or something like that if your units is inch and you don't want it to "cut" your corners to much.

63

Newfangled Solutions Mach3 Wizards / Re: Tool pauses at X axis while cutting circles or threading?

« on: May 23, 2009, 01:19:42 PM »

CV mode?

Me think also.

64

G-Code, CAD, and CAM discussions / Re: Need help with 4th axis continuous motion code

« on: May 21, 2009, 05:24:39 AM »

I'm a newbie here.
As I understand it Mach has no ability to do a true continuous movement or rotation of any axe. Workarounds is possible but this doesn't give ideal results. One limitation is that the rotation of the "continuous rotation" axe has to stop between every line of g-code. If your tool end of movement isn't in air then the stop of rotation will happen with your tool still into the work piece.
Say you want to face of a work piece with an end mill while the work piece rotates, leaving a circular "edge" in the center. You do something like this: X50 A3600. Your end mill feeds 50mm across the work piece while the work piece rotates 10 full turns. However you want the work piece to rotate one full turn after the X feed stops. Your next line of code will be: A360. And there is no way to retract the end mill from the work piece before the rotation stops after this line of code. So the rotation stops and your next line may be X0. This lead to the end mill "resting" against the edge of the work piece, with the spindle running, for a short moment before it moves off. This may produce a mark on the edge of the work piece.

Here is two topics which may be of interest for you.
http://www.machsupport.com/forum/index.php/topic,11438.0.html
http://www.machsupport.com/forum/index.php/topic,11422.msg72469.html#msg72469

65

General Mach Discussion / Re: VFD Input Voltage

« on: May 02, 2009, 01:53:12 AM »

It is no problem using a VFD to power a 240V motor in a 400V system with a 400V VFD. You set up the VFD with the motor name plate parameters. The VFD ,simply explained, put out a voltage in linear relationship to the Hz. That is a 240V 50Hz motor shall have 120V at 25Hz, 216V at 45Hz as two examples. This setup also allowes for "oversyncronous" operation, that is operation above 50Hz without loss of torque. At 70Hz the VFD puts out a voltage of 336V. This can be done because the supply voltage is 400V and the motor is only 240V.

However a 400V VFD can not be connected to a 240V supply voltage. The reason for this is that the low supply voltage alarm would immediately be activated and the VFD most likely wouldn't even try to run the motor.

66

Third party software and hardware support forums. / Re: +X, -X axis moves in same direction. Why?

« on: April 30, 2009, 02:02:45 PM »

Are you sure your direction pin for the X-axis is correctly configured in ports and pins, and all your connection cables for the X direction signal is correctly connected?

67

General Mach Discussion / Re: Steps (chugging) around radius.

« on: April 29, 2009, 01:44:09 AM »

When you look at your G-code, does your arcs consists of many short straight lines or many short arcs?

Have a look on here http://www.machsupport.com/forum/index.php/topic,11310.msg71822.html#msg71822

And here http://www.machsupport.com/forum/index.php/topic,11310.msg71911.html#msg71911

68

General Mach Discussion / Re: Axis Home question

« on: April 28, 2009, 02:08:12 PM »

Ok, thanks Hood 

69

General Mach Discussion / Re: Axis Home question

« on: April 28, 2009, 12:13:18 PM »

What is the meaning with the line: "Sleep (100)"?

70

General Mach Discussion / Re: smooth pulses for Laser

« on: April 28, 2009, 11:31:14 AM »

What is CV feedrate ?

CV feedrate is, as I have found, the maximum allowed feedrate in "corner cutting mode", that is in the exact parts of the cutting where CV feedrate/CV distance is working. CV feedrate is working at the end and beginning of line and arcs segments.

CV distance is how far from the start and end of a line or arcs segment where "corner cutting" is allowed. A high value or not turned on gives deviation from the original toolpath on a relatively long section at the intersection of two line or arcs segments. A low value gives a short distance where the actual toolpath deviates from the original toolpath, but at the same time lower feedrate in those same sections.

You may want to set the CV distance to a low value like 0.1 to 0.3 when you need reasonably sharp corners. Such a low CV distance value gives nearly as sharp corners as exact stop mode but still considerably higher feedrate. When more rounded corners is allowed a higher value like 0.5 to 2.0 may be adequate. A CV distance of 180 gives very large deviations from the original toolpath when the feedrate is high and/or acceleration is low.