In the past several years, advancements have been made in electropolishing technology that has allowed metal removal to be controlled to within .0001″. This control over stock removal together with the ability of the process to work on complex geometries has opened new applications in part sizing. On complex or fragile components where final sizing is difficult or expensive, electropolishing can be an economical procedure. Sizing can be of special importance in the following areas:
Parts made oversize by operator or machine error, growth from heat treating or other unexpected cause can be brought to finished size with electropolishing. While secondary grinding, lapping or other processes are often used to reduce an oversized part, most of these processes are useless once a part is in finished form or already hardened. Sizing can be performed regardless of hardness and the process will preserve most part geometries. Bores or holes can be enlarged while simultaneously reducing thicknesses on other surfaces or journals.
Many fragile stampings or machined parts do not fit into traditional sizing operations because of the potential of damage, special tooling or introduction of surface stresses or contaminants. Parts requiring critical final sizing that do not fit well under these circumstances are excellent candidates for electropolishing. In addition, short lots or prototype runs are often sized economically as compared to secondary machining or grinding operations where long lead times or high set-up costs are a concern.
High tolerance stampings or blankings made from specially ordered raw material should be considered. In these cases, the extraordinary costs and lead times in getting special thickness material can be avoided by ordering standard gauge material slightly thicker than final requirements. The parts can be blanked or formed as normal, and electropolished to final thickness. The reduced material costs and delivery times of the standard material often more than cover the cost of the electropolishing operation.
Parts requiring unique or special tapering, precise weight control or simultaneous deburring and sizing are often electropolished. The process is well-suited for bringing special “matched set” components to specific size or weight often at less cost than other traditional metal removal processes.