spline mode nurbs mode

Has anyone used spline or nurbs mode?
I am having trouble getting it to work for me.

The reason I am trying to use these modes is because
when cutting a 3D surface using G64 at 80 IPM
the surface quality is not very good.But is very
smooth at much slower speeds(5 to 10 IPM).I can't
understand why I can't attain a performance
level that is well below what I know the latest version
(16.6)
CamsoftCNC Pro is capable of.

I have new ballscrews and new yaskawa drives and motors.

Anyone's input would be appreciated.

Thanks
Gary

G64 issues SMOOTH ON. I used it with great success on a small part that had 1000s of lines of Gcode. All very small moves and low feedrate. Just reading the manual on this command tells me you'll need the great techs. at camsoft for this one. I'm not sure its used for larger moves where you can have high feedrates.

Just look at all the cautions in this section of the manual:

SMOOTH
This command produces non-stop motions between positions by disabling the in-position check routine between moves. The SMOOTH command has one mandatory and two optional parameters. The first parameter is either ON or OFF and is the mandatory parameter. The ON parameter produces non-stop moves between positions. This helps to reduce the ratcheting effect caused by the in-position check routine. The SMOOTH command nullifies the BLEND factor while it is in effect and may produce feed rate changes at undesired positions because the computer may actually be ahead of itself while reading in the G code program. The side effects are that the graphics display window and G code display window could be ahead of the actual machine position. This effect will also kick in any new feed rate change or M code immediately that it reads from the program until the SMOOTH effect is canceled by one of the following reasons: a SMOOTH OFF, STOP or DECELSTOP command is encountered; the user aborts or ends the program; or the CYCLE START is pressed. It is recommended that a G61 be used to turn SMOOTH OFF and a G09 be used to turn SMOOTH OFF with a decelerated stop. Whenever you use G61 or G09 to turn SMOOTH OFF, always issue a G61 or G09 before a G01 on the same line of the last move of the spline. The user issues a G08 to turn SMOOTH ON without buffering or G64 to turn SMOOTH ON with buffering. There is a second optional parameter, which can be one of the following: BUFFER, FASTMODE, SPLINE and NURBS. When BUFFER is used, it dumps the entire smoothed profile to the motion card all at once into the buffer and runs from the motion card's buffer until a SMOOTH OFF is encountered. FASTMODE has the same effect as BUFFER. However, in FASTMODE there are some restrictions such as the graphic display, dynamic feed and bitmapping of the G code window will all be suspended until a G61 is encountered. In addition, there should be no macros, no M codes, no feedrate, no spindle speed changes and no other G codes except a G61 are allowed between starting the FASTMODE contour and the end of the contour. All moves between the beginning and end of the contour are assumed to be linear G1 type moves consisting of no more than 3 axes.
SPLINE adds more positions between the original positions while fitting a parametric curve through the original positions. NURBS adds more positions between the original positions while fitting a bspline curve. Caution, the bspline curve will not pass through the original points. The SPLINE and NURBS modes have the same restrictions as FASTMODE. In SPLINE mode, an R code is needed and will reflect a value from 1-10 to specify the smoothness. A value of 1 cutting a triangle has the smallest effect while the value of 10 will cut a curve closer to a full circle. In NURBS mode the R code is the weights and the K value represents the knots. A message will appear in the G code window to notify the user when FASTMODE, SPLINE or NURBS is in effect suppressing and replacing the actual G code display to provide the quickest response. A third optional parameter may be used to specify how many moves to buffer ahead of the current position. If the third parameter is not specified, the buffer ahead option is handled automatically.
EXAMPLE: SMOOTH ON;BUFFER;500

Hey Karl T,

Thanks for your reply.
I have read that part of the manual.A have been discussing this with Camsoft.
They said the type of toolpath I am running is better ran in G1 mode with
DECELSTOP
GO x;y;z;a;b
-----G1

I attached two pictures, top one was cut at 80IPM in fast mode(G64)
the bottom one was cut with smartpath on but in slow motion and
has the surface I was hoping to get.

I can't figure out why I am only able to get slow motion when the
finishing cut is running which is many small moves but the rough
routine looks great when cutting.And with smartpath running the
motion looked the same.I played with the BLEND and tried different
values -100 to -500.

I am wondering if my computer is the bottle neck?
It seem that my iron is good I have new yaskawa dives
good software.I built the pc with low end pc components
from newegg.com 1.7Ghz 1 Gig of ram.


Thanks
Gary

If you use your machine for general machining you're not going to want that DECELSTOP in there for your G01. You'll get a witness mark at the end of every G01 move. Use a different Gcode like G10. I think that's the default.

I would certainly try a computer swap.

I think G10 is the same as G01 with DECELSTOP

Quote:

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Originally Posted by Karl_T

If you use your machine for general machining you're not going to want that DECELSTOP in there for your G01. You'll get a witness mark at the end of every G01 move. Use a different Gcode like G10. I think that's the default.

I would certainly try a computer swap.

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