Summary: |
A Digital Fabrication Production System (DFPS) is a concept describing a set of processes, tools, and resources that will be able to produce an artifact according to a design, fast, cheap, and easy, independently of location. A DFPS project is a complex assembly of custom parts that is delivered by a network of fabrication and assembly processes. This network is called the value chain. The workflow concept of a DFPS is the following: begin design process with a custom geometric form; decompose it into constructible parts; send the part files for fabrication to various locations; transport all parts at the construction site at the right time; finally, assemble the final artifact. Conceptually it means that based on a well structured value chain we could build anything we want, at anyplace, at controllable cost and quality. The goals of a DFPS are the following: custom shapes, controllable lead time, controllable quality, controllable cost, easiness of fabrication, and easiness of assembly. Simply stated this means to build any form, anywhere, accurately, cheap, fast, and easy. Unfortunately, the reality with current Digital Fabrication (DF) projects is rather disappointing: They take more time than what was planned, they get more expensive than what was expected, they involve great risk and uncertainty, and finally they are too complex to plan, understand, and manage. Moreover, most of these problems are discovered during production when it is already late for correction. However, there is currently no systematic approach to evaluate difficulty of production of DF projects in Architecture. Most of current risk assessment methods are based on experience gathered from previous similar cases. But it is the premise of mass customization that projects can be radically different. Assembly incompatibilities are currently addressed by building physical mockups. But physical mockups cause a significant loss in both time and cost. All these problems suggest that an introduction of a DFPS for mass customization in architecture needs first an integrated theory of assembly and management control. Evaluating feasibility of a DF project has two main problems: first, how to evaluate assemblability of the design; second, how to evaluate performance of the value chain. Assemblability is a system’s structure problem, while performance is a system’s dynamics problem. Structure of systems has been studied in the field of Systems Engineering by Network Analysis methods such as the Design Structure Matrix (DSM) (Steward 1981), and the liaison graph (Whitney 2004), while dynamics of systems have been studied by System Dynamics (Forrester 1961). Can we define a formal method to evaluate the difficulty of production of an artifact if we know the artifact’s design and the production system’s structure? This paper formulates Attribute Process Methodology (APM); a method for assessing feasibility of a DFPS project that combines Network Analysis to evaluate assemblability of the design with System Dynamics to evaluate performance of the value chain. |