477. Chemical Milling on Apollo and Saturn Gore Segments

Paper

Abstract

Chemical milling is being used extensively in the fabrication of Apollo and Saturn hardware. This exciting design tool has now been applied to thicknesses and physical sizes and is achieving tolerances that were inconceivable only a short time ago. The work described in this paper shows the application of the new techniques for chemical milling extremely complicated parts for three separate phases of the Saturn V, the system which will soon be sending men to the moon and back.
The original concept, ‘chemical milling applies to shallow cuts on thin sheets,’ has been completely outmoded by the recent work on the ‘or segments’ of 33-foot diameter fuel and oxidizer tank bulkheads, where the depths of cut exceed one half inch. Thickness variation in the starting blank no longer limits finished part tolerances, through the use of chemical sizing techniques. Facilities have been scaled up to 30 feet long by 30 feet deep etching tanks. Large stainless steel parts are being chem. Milled to tolerances of plus or minus .001 inch on a production basis, reducing gages from nearly a tenth of an inch to .008 inch! Another dramatic chemical milling accomplishment has been the development of an effective etchant for aluminum alloy 2219 in the T-37 heat treat condition.
These, and other contribution to metalworking technology, are examples of how chemical milling is helping the nation’s space effort, and is ever expanding the concepts available to weight engineers so that they may fulfill their roll in this effort.