Starting a cut part way through the program

[loriny]

Hi
Is there a way to stop my bit from dropping into the material when I have to return to a project part way through after breaking a bit. I don't know what the line # is so I guess and when the router goes to that part of the file the bit starts to lower and digs into the wood.
thanks

[robredick]

Here is the easiest way for me.

Use "Part File Edit"

After the first few lines of the program, delete all lines on the front of the program to the nearest J3 at safe z.

ie
If you died at line 4225 and line 4200 is a J3 with the Z at your safe height, delete from the 0,0 line to there.

You have to run a few lines cutting air, but, it keeps you from having to think too hard about it.

Mostly you should fix the problem of the breaking of bits. The most common reason is heat and shabby bits. The heat is caused by bad chip loads (router/spindle running too fast while cutting too slow). It took me a while to grasp that faster bit speed does not mean better cut. Try a single flute Spiral Vs a 2 flute. The Onsrud Super O changed my life.

A way that I try to explain this to my fellas is
Think of drilling into metal, If your drill is on high it rips through that first hole, but you can really tell the difference on hole 2. However, on slow, the bit is consistent through the first 10 or 20 because it doesn't get hot...

Bla Bla...

I hope that this helps...

[myxpykalix]

A couple things i do before starting a file. I do a c3 find my 0,0 on the lower left corner.

Run my bit to the center (where my 0,0 is) on my material.

Write down those numbers from the control software.

Zzero my bit there (or lower left on material).

Start my 3D file. If I am staying in the shop then i will keep an eye on what line it is on and write that line down when i check it trying to keep a mental note as to where it is on the material.
If I have a break in the file then i know relatively close to where it was. If you break a bit you will have to reZ with a new bit then move it over to approximately where it stopped and follow procedures for restarting the file.

Your problem is you are trying to start from 0,0 and when you input a line and position designation for restarting that might be at a low point in the 3D file and it is going right where you tell it to go.

The problem is Ted hasn't figured out a way to put a pair of eyes on a bot yet so it can see it is going to crash into your part.

[rhfurniture]

With 3d ballcarve work, one thing I always do when starting from any line number partway through a file is to first jump the machine to the x y value in the line I am starting from. This makes the first move pure Z, and prevents unexpected cuts through "angling in" with an M3 move.
R.