beg

In manufacturing, a beg is the remnant or stub of material that remains after the main workpiece has been removed from a cast, forging, extrusion, or similar forming process. It is the piece still attached to the runner system, gate, or feed point. The beg must be cut away before the finished part can be used, though depending on material and process, it may be recycled or scrapped.

Begs appear across metal casting, plastic injection molding, and forging operations. In sand casting, the beg includes the portion of metal that solidifies in the feeder head or riser; this metal is typically thicker and may have shrinkage porosity that makes it unsuitable for the final part. In injection molding, the beg is the plastic attached at the gate or along flow channels in the mold cavity. In drop forging or extrusion, it is the flash or stub left where material flowed during forming.

Removal and Reclamation

Begs are removed by sawing, shearing, grinding, or machining depending on material hardness and part geometry. The cost and effort of removal directly affects part economics; thick begs add scrap weight and labor time. Some processes, such as direct squeeze casting or precision molding with small gates, are designed to minimize beg size. The beg material itself, if free of defects or contamination, is often returned to the melting pot or hopper for reuse.

The term derives from the verb sense: the beg is what is left, or what remains to be dealt with, at the beginning of finishing work. In older British foundry practice, "beg" also carried the sense of the solidified metal in the feeder cup itself. Modern usage in manufacturing usually applies the term to any attached remnant that requires removal before a part enters service or final inspection.