Process and apparatus for wire electrode trimming using a laser

A process for dressing a tip of an electrode used in combined laser and spark erosion hole drilling wherein the electrode includes a substantially flat ended tip which is periodically eroded from a flat end configuration to a tapered end shape the improvement comprising:

• sequentially forming a plurality of holes in a part by first directing a laser beam against the part to form a rough hole therethrough and then directing the substantially flat ended tip of a wire electrode through the rough hole and applying a predetermined current pulse from the electrode to the part to spark erode the rough hole to a precision shape;
• and
• noncontact dressing the wire electrode when a taper is eroded at the end of the wire electrode at intervals during the sequential hole formation to reshape the wire electrode to form a flat surface tip thereon without the formation of burrs or whiskers at the periphery thereof.

Apparatus for drilling and dressing parts comprising:

• means defining a laser source;
• means including a spark erosion wire electrode having a substantially unworn flat tip thereon for forming holes by spark eroding material from a part and the flat tip erodable to a tapered end during hole formation;
• and means for selectively diverting a laser beam from the source and focusing the diverted laser beam on the taper end of the wire electrode for dressing it to its original substantially unworn flat tip configuration.