Need better explaination of "Re-cut" geometry option

[wild mouse]

I'm finding it difficult to understand how to use the re-cut option. According to the current popup description it will "generate an extended cut over the first cut section". What exactly is the value specifying? Is it some kind of threshold for what flatcam considers a meeting of lines? Does it specify an overlay width that will be cut away? I have experimented with a few different values, but it looks like the same paths are being generated (just from looking at the plot area, I have not run the gcode on my CNC yet). I have noticed that this option produces very different results than the Passes isolation routing option, which seems to avoids intersections. Is Re-cut a bit like the opposite behavior?

[Marius Stanciu]

Hi,

re-cut feature was added to make sure that isolation of a trace is done completely. While isolating, when finishing the isolation the milling bit is returning to the start point but there is a possibility that where the starting point and ending point meet, there may be still copper residues not removed.

Using the re-cut feature actually creates a new path in the sense that when the milling bit reach the isolation end-point (which is the actual isolation start-point) it does not stop. What it does is to continue the isolation along the same path for a little bit more therefore making sure that the isolation is complete.

How much will be the extra isolation, the overlap? It depends. The actual isolation path is made from multiple segments. Circles are approximated with a number of lines. Squares are simply made out of 4 lines.
So if the re-cut is checked but no value is provided then the overlap will be until the the next vertex is met.
If the end of the isolation is a over a circle area (or an arc) then the next point will be quite close to the meeting point of the isolation start and isolation end (basically it’s the same point but I wanted to make it clear what I am saying). The next point it is close so the re-cut length is small because the interpolation of arcs is done using about 32 lines (or more) so a small pad have those 32 vertexes very close one to another.
On the other hand, if the meeting point is a vertex of an square then the next vertex can be quite far away. So using no value for re-cut creates an uncertainty regarding how long will be the re-cut.

If the re-cut is checked and a value is provided then the overlap length will be the specified value.

I hope that now is clear the reason for this parameter and how is supposed to work.
Best,
Marius

[wild mouse]

Hi Marius,

Yes, that really clears things up and I greatly appreciate the detailed explanation.

Many thanks,

mouse