In the manufacture of metal products and parts, a common production method is to cast such products or parts from molten metal. A particular form of casting is the manufacture of investment castings such as turbine blades for gas turbine generators, jet engines, or the like. Such casting processes create raw castings which are often out of tolerance from required specifications, i.e., castings that fail to meet necessary dimensional ranges for such products. Dimensional variations in various metal products and parts can also be experienced after such parts are heat treated for durability purposes. Dimensional corrections must be made before the parts can be used or the parts are discarded. Accordingly, it has been common practice in the metal casting industry, as well as for other treated metal products, to correct such out of tolerance products or parts prior to sending such products or parts on for final machining.
In the past, the correction of dimensional variations in out of tolerance metal products and parts has primarily been accomplished through manual straightening or bending practices. Such methods are inaccurate and unreliable at best, and failed to provide any precise, controlled method which would correct such parts on a consistent basis.
A common manual correction method included manually pressing the part to be corrected or engaging the part by hand with a hammer on an anvil. This accomplished a rough, crude type of bending correction. If twist correction was necessary around a defined axis within the part, it was usually made by clamping the part in a vice and manually twisting a free end of the part with a T-bar or similar tool. In each case, these methods were very time consuming, typically inaccurate, and most often produced poor correction results. Especially when manual methods using a hammer were utilized, it was very difficult to produce small, minor corrections because manual hammer strikes typically produce significant impact and/or could not be properly controlled. Therefore, the manual correction of a wide variety of manufactured metal parts, produced by casting or otherwise, such as gundrills, slides for vehicle sun roofs, springs for vehicle transmission shafts, medical implants, drill bits and/or saw blades often encountered high rejection rates due to the inability to make proper corrections in the rough parts resulting from initial manufacturing processes. Consequently, significant expense was added to the production of a desired number of parts or products.
In addition, in those metallic parts manufactured by investment casting such as turbine blades, where both bending correction and twist correction around a longitudinal axis is critical, it has been experienced that correction of the longitudinal bow or straightening of the part can itself induce a certain amount of twist in the part during such correction. Correspondingly, correcting the twist in a manufactured metal part can often induce the need for bow correction or straightening.
Accordingly, a need was encountered in the metal and cast metal parts manufacturing industry for a device enabling an initially manufactured or treated part to be held precisely during bow correction or straightening, twist correction and/or bow and twist correction with a press in a controlled manner for reliable, accurate and precise correction of the part.