In reality all offsets are simple basic math. Although it has the tendency to confuse some, a bit of experience negates the confusion. The software and machine are not capable of making a math mistake, only the operator.
FixitMike wrote:Myself, I zero to the corner or center of the material after I clamp it down. My machine does not have a machine zero, so using that is not an option for me.
I haven't needed to use an offset, but I might if the toolpath size was small and the actual material was large. A small 3D carving in a large piece would be an example.
I have locating bars on my table that have been cut to be parallel to the X and Y axes. The material is located against one or both before I tighten the clamps so I know the material is sitting square.
Yes, the fact that VCarve saves some of what was last used the next time it is used can cause problems. Even for me, although I am the only one who uses mine.
TReischl wrote:I won't be using the technique of programming all my parts from machine zero, ever.
First reason: My y-zero is in front of the spoilboard outside the frame of the machine. That is so I can attach a vertical fixture for doing dovetails, etc.
Second reason: I often surface warped,twisted,cupped boards on the machine. To do that the machine has to be able to cut beyond the edges of the workpiece.
Third reason: The zero point of the z axis is a line down the center of the spindle. All cuts would have to be a little more than the bit radius away from the board edges.
Fourth reason: I use one or two vises on my machine, it would not be possible to mount them in such away to be able to use them at all.
Fifth reason: When designing/programming sometimes the zero is best in the center. When I use the vises the zero point is in the upper right corner.
Sixth reason: I have a laser attached to my machine. It is offset from the spindle centerline.
Seventh reason: There is a rotary axis on my machine.
There are lots of reasons to use offsets.
TReischl wrote:Russel: Maybe you did not notice that I use fixtures all over on my machine, one out the front, a rotary and vises? Setting a machine zero that is inside of the actual machining limits would not help with those items one bit, so I have to use offsets. The vises are rarely in the same spot, sometimes they are spread apart sometimes pretty close together.
rscrawford wrote:No, I did notice that. I do the same, and I use offsets often. It just seems weird to have your machine zero in a spot that you rarely use as your zero, but its probably because you do not use your machine for processing sheet goods. With pop up pins, I guess its just natural to use that corner as machine zero, because sheets index with the pins into that corner every time.
When I use fixtures, I have dedicated spots for them (indexed spots) and I have each of those zeros saved as home positions in WinCNC (under the name of the fixture, I have at least 20 saved at the moment). So I just select each fixture I need and the machine automatically zeros where I need it to.
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