Need Help!- Cutting a Long Piece in Multiple Sections

[Mr.Chips]

I am thinking about making my second CNC and like many others using my first to make the second. My first machine is a fixed gantry and the movable work table is not large enough to cut some of the pieces to the new CNC in one cut. It will be necessary to cut one section, move the material and cut the next section, repeating this until the entire length is done. Naturally supporting the overhanging parts and insuring that when the table moves to it’s extremes it doesn’t punch a hole in the wall.

Here is my impression as to what I need to do. Please let me know where I have the wrong assumption.

1. Screw the AXIS GUIDE onto the table and take a skim cut, thus insuring that the alignment edge is square to the Axis travel.
2. From the Gcode make an index hole in the in the left side of the table.
3. Clamp the piece to be cut against the AXIS GUIDE.
4. Make an index hole in the left and right side in the material.
5. Remove the material and install guide pin in table.
6. Replace the material and place over guide pin and clamp in position.
7. Cut all cutouts in section one, making a guide pin hole on the right to be the new index hole.
8. Unclamp and move material to section 2 and engage with index pin.
9. Cut all cutouts in section two and repeat as necessary for additional sections.

The part I’m not sure about is, when I draw the part and generate the Gcode it must be generated in as many sections that are required with a PAUSE between sections to reposition the material to the next section.

Is this correct? Or is there an easier method that would be as accurate??

Thanks

Hager

[acondit]

Hager,

Take a look at posts #113 and #114 in my thread http://www.cnczone.com/forums/showthread.php?t=10425 to see how I did my long ribs. I don't know whether your table is long enough to do this or not but it might give you an idea.

Alan

[Mr.Chips]

Originally Posted by acondit Hager, Take a look at posts #113 and #114 in my thread http://www.cnczone.com/forums/showthread.php?t=10425 to see how I did my long ribs. I don't know whether your table is long enough to do this or not but it might give you an idea. Alan

Alan,

Since your pieces were symmetrical you could draw half of the part and cut it, then flip it over and position and run the same code again. That is the simplest way.

I think the max cut length on my table is 28” that would enable me to cut a symmetrical piece 56” long. That should be longer than I need. Since I don’t have it totally designed I not exactly sure it will be symmetrical yet. If it turns out that it won’t be then I’ll post again

Thanks for the tip Alan.

Hager

[Mr.Chips]

Alan,

Did you cut a little extra in the corners (see drawing) at the bottom of the notches where the pieces interlocked together so that they would fully seat when they were put together?

Hager

[ger21]

You want to drill the index hole for the second step during the first operation, so it will be properly aligned. Then the 3rd hole during the second step, etc.

You can also make separate programs for each section, or if it's repetitive, run the same program over and over. Trying to combine it all into one program would probably be more confusing.

[Mr.Chips]

Originally Posted by ger21 You want to drill the index hole for the second step during the first operation, so it will be properly aligned. Then the 3rd hole during the second step, etc. You can also make separate programs for each section, or if it's repetitive, run the same program over and over. Trying to combine it all into one program would probably be more confusing.

Gerry,

Sounds like separate programs may be the bast way to go and using the index holes as reference points in drawing each layout.

Thanks
Hager

[acondit]

Originally Posted by Mr.Chips Alan, Did you cut a little extra in the corners (see drawing) at the bottom of the notches where the pieces interlocked together so that they would fully seat when they were put together? Hager

Hager,

Yes, I do. I use a 1/8" bit to make it small and I just cut directly into the corner at a 45° angle. I use the formula for the distance ((Sqrt(2)-1)*r) to calculate how far to cut.

Alan