Tolerance Specification and Related Issues for Additively Manufactured Products
Gaurav Ameta, Robert R. Lipman, Paul W. Witherell, Shawn P. Moylan
Additive manufacturing (AM) has gained increased attention in the last decade as a versatile manufacturing process for customized products. AM process can create complex free-form shapes, internal cavities and lattices, which are either not feasible or highly costly with traditional manufacturing processes creating new challenges in maintaining and communicating dimensional and geometric accuracy of parts produced. In order to manufacture a product that meets functional needs, the specification of those needs through geometry, material and tolerances is necessary. This paper surveys the current state of and needs for tolerance specification mechanisms for AM that are available to a designer through specification standards such as ASME Y14.5 and ISO 1101. Emerging AM-related GD&T challenges are identified, and a potential plan of action is put forth for addressing these forthcoming challenges. Various issues highlighted in this paper are classified as (a) AM-driven specification issues and (b) specification issues highlighted by the versatility of AM process. AM-driven specification issues include build direction, layer thickness, support structure related specification and scan/track direction. Specification issues highlighted by the versatility of AM process include, region based tolerances for complex free-form surfaces, tolerancing internal functional features, tolerancing lattice and infills. Basic methods of solving these specification issues are also highlighted in this paper.
35th Computers and Information in Engineering Conference (CIE)