Computer-Aided Manufacturing

This is an encore of an article Michael Chusid wrote over 20 years ago. Since then, computer-aided manufacturing has become widespread. Of course, now it is driven by BIM, not CAD.

Computer-aided manufacturing (CAM) is the use of computerized systems to help manage manufacturing operations, CAM encompasses techniques such as numerically controlled fabrication (in which geometric coordinates control automated cutting tools or other machines similar to the way a CAD plotter works), automated control systems, robotics. and programs for production scheduling. inventory control. quality assurance, accounting. and information management. Proponents claim that CAM can increase productivity and enable a manufacturer to respond more quickly to changing conditions. In an automated factory. for example. information about a firm's resources and products may be stored in a common database. When an order is entered, the CAM system would help the people operating the plant to schedule the flow of materials and resources in coordination with other orders in the shop. notify suppliers when materials or components must be delivered. and provide cutting, hatching. or assembly instructions for automated equipment. In addition, CAM could be used to help monitor operations and make necessary adjustments. This "factory-of-the-future" is already operating. to varying degrees. in manufacturing plants around the world.

CAD-CAM is the logical connection between the computer aided design (CAD) system used in the design of a product and the CAM system used in its production. CAD CAM allows design data to be used directly in the manufacturing process. For example, the same dimensions used to draw a product can be used to drive a numerically controlled machine tool. In addition, CAD-CAM can make it easier for a designer to incorporate manufacturing considerations, such as the availability of critica1 resources, into design decisions.

There is a widespread assumption, based on the differences between "real estate" and "personal property." that construction is so different from manufacturing that management techniques used in one may not apply to the other. But since the dawn of the industrial revolution, construction has been successfully borrowing ideas from manufacturing. As early as 1851, for example, Joseph Paxton employed basic manufacturing techniques such as standardization and assembly lines to the design and construction of the Crystal Palace. More recently.manufacturing concepts such as critical path scheduling and just-in-time delivery have moved from the shop floor to the job site. The time has come to appraise manufacturing experience with CAD-CAM to apply its benefits to construction.

AEC opportunities for CAD-CAM
The difference in the structure of the construction and manufacturing industries creates the first hurdle for CAD CAM in the AEC world. In the manufacturing environment. marketing design, engineering, purchasing, and production all take place within one corporate structure. But in building, separate corporate entities - developers, architects, suppliers, general contractors, subcontractors. etc. -are each responsible for separate facets of the total process. In reality, the conflicting departmental concerns within many industrial firms are just as hard to coordinate as the fragmented construction process. And like architects trying to coordinate their work with facility managers and consultants. manufacturers must integrate their CAD-CAM systems with those of their customers and suppliers. But before CAD-CAM can reach its potential in architecture, and construction.the building industry needs to establish information protocols so data can be freely passed throughout the building team.

A simple first step wards CAD CAM would be for designers to distribute construction documents to bidders and contractors on electronic media. This could allow contractors and suppliers to extract information from the design documents more efficiently and will become increasingly attractive as architectural drawings evolve into intelligent graphic databases. Unfortunately. liability concerns about claims for erroneous data may prevent most architects from venturing into this area of expanded service. Large building owners, who stand to gain the most from increased construction productivity, may have to take the lead and insist upon the sharing of electronic data.

A seminal example of CAD-CAM communication between a building designer and builder is the new Beckman Institute for Advanced Science and Technology at the University of Illinois at Urbana-Champaign designed by Smith, Hinchmann & Grylls. The building is clad in intricate patterns of colored bricks produced in special sizes and shapes. The architect's CAD drawings went beyond the customary elevation drawings to provide detailed layouts for each brick pattern and special condition. Because of the time and cost to, draw brick details manually, in the past an architect may have provided only minimal drawings and left the mason to figure out coursing in the field. CAD-CAM gave the designer better control over the building's appearance and provided the contractor with easy- to- follow installation requirements and more accurate information about quantities and dimensions.

Another area of CAD-CAM innovation has been the sharing of electronic data between architects and building product manufacturers. New computerized tools are being developed that will link an architect's design vision directly to a producer's manufacturing operations.

CAD-CAM will enlarge the sire of the architectural palette. Rather than manufacture large quantities of uniform products to be put into inventory, many producers now find it more economical to manufacture on order and are switching to more flexible manufacturing systems. This trend, together with CAD-CAM integration, will enable custom produced building materials to be more economically manufactured in smaller quantities and with shorter lead times.

Lead time will also be reduced because CAD-CAM systems will simplify project administration. For example, shop drawings are now required for a manufacturer to demonstrate his understanding of the architect's construction documents. But if the construction documents were produced using software supplied by the manufacturer. the need for shop drawings might be reduced or even eliminated. Electronic data exchange between designers and manufacturers will mean simplified order-entry procedures and faster quantity surveys and bidding. A unified database of design and product information can also expedite construction.

The Immediate future
Consider the following CAD-CAM examples which are already available or under development:
A pre-engineered building system manufacturer provides its dealers with an interactive design program. The program allows dealers to quickly evaluate design and structural options and takes clients on fully animated video walks through their proposed buildings. The dealer's electronic file is then transferred directly into the manufacturer's production schedule for fabrication.

A floor covering manufacturer is developing a program that can be used by interior designers to design custom patterns and color combinations. In addition to encouraging design experimentation, the software will enable designers to insert their design into a 3D CAD visualization program. The custom design  will then be used by the manufacturer to fabricate actual samples in far less time than is currently required to manually program special production runs.

System furniture manufacturers offer design programs that prepare electronic bills of material for direct order entry. The program also assigns each component in a project an  ID number. When components arrive on the job site, they are bar coded to assist the contractor with assembly and the owner with inventory control.

Techniques similar to desk-top publishing are being developed to offer designers unprecedented abilities to create ornamental treatments that can be economically produced by numerically controlled graphic and milling machinery.

New techniques for desk-top manufacturing enable three dimensional prototypes to be constructed directly from computer data. In these systems, a laser "draws" an object onto a photosensitive or heat-fusible polymer. The laser causes a thin film of the polymer to harden, and the three dimensional shape is gradually built up layer by layer. While the initial applications for this equipment will most likely be complex machine tool parts, costs will likely come down to a point where architects can use it to design and manufacture custom ornaments or building accoutrement like door knobs or plumbing trim.

CAD-CAM is part of the trend towards higher levels of integration between computer programs. The building industry is entering unexplored territory in which traditional methods and relationships will be reexamined. While there will be many false starts and other risks, the journey appears worth taking. CAD-CAM is likely to lead to new levels of design and construction productivity and provide new outlets for architectural imagination.

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By Michael Chusid
Originally published in Progressive Architecture, Copyright © 1990