Plunge to surface after CR

[sbd1]

I was wondering if anyone has ever experienced this when running a CR or table resurfacing?

After finishing the cut my Z returns home then plunges (fast) to zero while the router is still running before turning off the router. It's quite unnerving watching a rapid plunge touch the surface of a freshly surfaced table. I've looked through the file & can't see why it's doing this.

Here's the code in my surfacing file:
---------------------------------------

IF %(25)=1 THEN GOTO UNIT_ERROR 'Check to see software is set to inches
SA 'Set program to absolute coordinate mode
VC,2.75,,,,,15
JZ,1.00 'Jog Z axis to safe height
JA,2.00 'Jog A axis to safe height
J3,0,0,1 'Jog to start position
SO,1,1 'Turn on router 1
PAUSE 2 'Give router time to reach cutting rpm
MZ,0
CR,97,49,T,1,4,0,1,2,1
JZ,1
SO,1,0 'Turn off router 1
END
'----------------------------------------------------------------
UNIT_ERROR:
C#,91 'Run file explaining unit error
END

[wayne_walker]

Daren, When I surface my table, I use the CR mode and it does plunge back to zero. I did not really notice that it is at a rapid rate. I am using a PC router and I just turn it off before it gets to that point. When I run the CR file, I set it up to plunge from Zero, so the tool is already at Zero. Then the tool returns to where the file was started. Just my 2 cents. I will be following this thread and learn something. I'm sure one of the regulars will know. Wayne

[beacon14]

Instead of using CR to surface your table, you can create a pocketing toolpath in PartWorks or Aspire, and have much more control over the tool movements, without the return to Z0. Even better would be to draw a back-and-forth set of vectors and use a Profile toolpath, so you can surface using just back-and-forth motions instead of a pocketing motion. Fewer changes of direction means less ramping and faster surfacing.

[sbd1]

It appears that this "plunge at end" is a known feature of CR, but it's something I'm not comfortable with. So I've been looking into Paco's 'surfacing_along_XorY_axis.sbp' file after reading about it's virtues & it seems like a good alternative to CR. I believe that you (David) said in one thread that it was one of your most commonly used files. I look forward to trying it for surfacing next time.

I've already tried testing it with some air cuts though & it's not cutting as expected. Here's what's happening:
- I tell it to cut (a rectangle the size of 12" X by 6" Y) along the X axis.
- It cuts one pass 12" along the X axis & stops (then asks if I want to cut another [which if I said yes, would be deeper but in the same X path]).
- It seems to be missing the stepover command somehow (which I set at 80%).
- It does the same thing if I reverse the 'cut along' axis from X to Y.

I've looked at the code & believe it's coming from this section, but would appreciate some help identifying exactly what to change as I'm still fairly new with editing files. The file I have says "'PACO - 2007" at the top so maybe it's not the latest version. Thanks.

==========================================

X_AXIS:
BEGIN_X:
PRINT "Now at "; &depth; " of an inch deep."
J3,&start_x - &tool_radius,&start_y,0.03 - (&depth - &stepdown)
M3,&start_x + (2 * &tool_diam),&start_y,-&depth / 2
M3,&start_x - &tool_radius,&start_y,-&depth
LOOP_X:
MX, &start_x + &x_size + &tool_radius
&yvalue = %(2) + &tool_stepover
IF &yvalue > &y_size THEN GOTO FINISHED_X
MY,&yvalue
MX,&start_x - &tool_radius
&yvalue = %(2) + &tool_stepover
IF &yvalue > &y_size THEN GOTO FINISHED_X
MY,&yvalue
GOTO LOOP_X
FINISHED_X:
JZ,%(28)

[srwtlc]

Daren,

Here's the version I've used in the past, maybe there's something missing in yours, but this one worked with what I think were your settings.

2.75 diameter cutter at 80% stepover (just going by the VC setting in your first post)? Perhaps you have a value that is larger than your rectangle y size so it thinks it's done.

[sbd1]

Thanks Scott. I compared every line in your file with mine & they're basically the same (it looks like you have spindle speed lines that I don't). So then I re-ran mine a few more times & figured out what works & what doesn't.

You're correct, I'm using a 2.75" dia. bit with 80% stepover.

If I tell the file to surface an area 12" X by 10" Y it does one pass & then ends (my original problem). But if I tell it 12" X by 20" Y then it works as expected. I also tried changing the bit dia. to 1", but that didn't make any difference. So I still don't know what the problem is, but at least I get to see it working.