SODICK A320D - Chapter 7: Wire Offset Description; Understanding and Programming Wire Offsets

Wire EDM Machine Operation Chapter 7
Copyright November, 98 Page 7-1 Sodick Inc.
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An “offset” tells the control how far to keep the wire centerline away from the
programmed surface to be cut for any given pass. If making only one pass to size
(roughing the part right to size), the offset would be equal to the wire radius + the amount
of the spark gap. If making multiple passes, the amount of offset used per pass will be
slightly larger than the wire radius + spark gap. It must be large enough to leave stock on
the part for the next pass.
There are three “G” codes related to wire radius compensation:
G40 - Cancel
G41 - Wire Left
G42 - Wire Right
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The first advantage of this feature allows the operator to input actual part coordinates into
the program with no concern for the wire diameter in the values of the coordinates. The
control will automatically keep the wire a specified distance (the offset value) away from
the surfaces of the part while cutting. This generates the movements necessary to make
the part to the proper size.
The second advantage to using wire offsets is that the same program that machined the
first rough pass can be used for subsequent trim passes. This means you may not have to
develop multiple programs for the various trim passes required to make the part to the
size and finish requirements you need.
The third advantage to using wire offset is that you will be able to incorporate die
clearance into your program with the same set of coordinates that machined the part to
size.
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Now that you know some of the advantages to using wire offsets, let’s look at how you
use it. Wire offsetting requires three steps in the program:
1) Instate wire offset (G41 or G42 codes)
2) Drive the wire through its motions
3) When finished, you MUST cancel offset (G40 code)