Simple CNC control.

[Michael Simpson Virgina]

I have used the cnc to cutout complete parts. I had a project where I needed to work a piece with a little more manual control. I needed to make a 45 degree cut so the piece would fit on the outside of a corner.

I had used my table saw in the past but wanted to see if I could do the cut with the CNC. So I created a 45degree jig shown here with the cut piece in place.

177212

(FYI, I used the CNC to make the parts for the jig.)

I did the first one by hand but I wanted to automate the process a little. So I wrote a little Gcode generator that would let me plug in a couple values and it woud generate att the passes needed to make the cut.

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You set the feedrate, spindle speed, pass depth, and stepover and it will gen all the gcode needed to cut the pocket out.

Here is the file loaded into MAch3.

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I normaly use Corel then convert to Cut2D and then import into Mach3. But this is a bit much for a simple groove or cutout. Also this method is a bit more manual so I can use the CNC to position the bit to where I want the extents to be and just enter the values into the program.

It will output directly to mach3 so it saves me lots of steps. Since it worked so well I think Im going to add a graphic representation of your your cut as well as a pre cut test at the safeZ setting. I also plan on adding circles, lines, archs and splines.

Keep in mind I dont use these all at once. The program is jus tment to cut a single geometric shape to particular depth.

I also want to try cutting the V by moving the bit at 45 instead of using a jig. No sure how well that would work with a straight bit though.

[Mick A Martin]

Good job, it looks like you are handy with Mach3 it will same some time rather than converting it from CoralDraw.

Mick

[Michael Simpson Virgina]

Its not so much with mach3 as it is with gcode. I purchased the book "CNC Programming HandBook" awhile back and have read it through a few times. I figured it was time to put it to use.

Its been a learning experiance. For instance I generate a raster type pattern. Well I discovered this is not the cleanest way to cut a pocket as it leaves little marks at the end of each raster. So now I am in the process of adding a final pass feature.

I have found a few issues. For instance MAch3 defaults to seconds with the Dwell (G04 P2000) command. Needless to say it did not work. I later found a setting in Mach3 that let you set it to Milliseconds.

I need a delay after I set the spindle speed as I use a closed loop system (Super PID) with a damping delay. Once MAch3 locks on Im golden. It wont vary more than a few RPM unless I overload the router.

[Gerry Grzadzinski]

If you only set the spindle speed when you turn on the spindle, just set a spindle delay in Ports and Pins, Spindle tab.

I use a Super-PID sa well, and just use a 5 second delay when I turn on the spindle. My g-code is typically:

S10000 M3

Which starts the spindle, and the delay waits for 5 seconds before any movement occurs.

[Michael Simpson Virgina]

Very cool. I will try that.