• Innovative Applications of Computer Technology on the Factory Floor

UCF researchers continue to identify computer technology applications for the modular factory floor.  Research efforts during this reporting period, focused on real time production labor data collection. While labor represents a relatively modest fraction of production cost, typically 10-15%, it has a profound impact on operations, including product quality, cycle time, material waste, and labor productivity.

Except for the slower winter months, experienced labor is a scarce resource.  Even if labor is sufficient in the aggregate, it may not be positioned where it is most needed at a particular moment in time.  Competitive pressures are resulting in an increasing mix of custom features, increasing the likelihood of "floating bottlenecks" in production.  Quality and safety can suffer as undermanned crews rush to complete custom features (i.e., fire-rated walls or a hip roof).  If a crew cannot keep pace, the line slows, production rate drops, overtime is required, and delivery dates are missed.

In the past, the sheer number of production activities, lengthy cycle times, and extensive product customization have discouraged manufacturers from accurately estimating labor needs and using this information to plan and control production.  Instead they have responded by controlling labor at the overall plant level, attempting to maintain labor at a historical target value stated as a percentage of overall production cost or sales revenue.  This approach seldom reflects the actual labor content in the product, particularly during times of increasing customization.  To address the problem of shifting bottlenecks, many manufacturers use flexible resources termed "utility workers, flex workers, or expediters."  However, the decision to deploy these workers often is made with minimal planning, after a problem has impacted the line.

Figure 25. Schematic of the Status Tracking and Control System (STACS).

The Status Tracking and Control System (STACS) is a real time labor data collection and reporting system. A schematic of the STACS system is shown in Figure 25. Production workers using wireless laser scanners, verify their current work assignment, including employee number, module number, and activity number with these scanners.  The scanned information is transmitted immediately to a base station and then to a local laptop, where it is verified and temporarily staged.  Information is periodically transmitted via wireless LAN to a central database computer where it is stored and used for reporting purposes.

STACS reporting provides both real time manufacturing status and summaries of historical production performance. Historical results can be used for a variety of analytical and management purposes:

• The development of analytical labor estimating models to estimate labor requirements for product costing, production scheduling, and labor planning.
• As a baseline for continuous improvement efforts.

Figure 26. Testing alpha prototype of STACS

An alpha prototype of STACS was completed and tested at Avis American Homes. (Please see Figure 26.)  Test results in framing and set indicated that manufacturing workers could operate the system effectively and that the system accurately captured scanned activity. (Please see Figure 27.) During the next reporting period, researchers expect to test an enhanced version of the system on a larger scale and develop labor models using linear regression and neural nets.

Figure 27. STACS alpha prototype results

• Lean Production of Precast Concrete Panels

UCF researchers continued efforts to improve quality, reduce costs, and increase energy efficiency as Arvida, a large Florida builder, transitions from concrete block to precast concrete panel construction. In 2002, UCF researchers completed a full analysis of the precast panel operation and presented those findings to management.

In 2003, value stream mapping identified activities that contributed value to the customer and activities that added little or no value. Material handling and rework were primary contributors to the 47% of labor consumed by non-value added activities. Once started, the flow of value-added activity was routinely interrupted.  Poor access to materials and tools, rework, ill-defined process flows, and workforce/first line supervision issues were contributing factors to work flow interruptions.

To address these issues, UCF researchers utilized lean production principles - challenging non-value added activities and removing the obstacles to continuous production flow.  Researcher recommendations addressed organization/communication, structured procedures and continuous work flow, material handling, and off-line sub-assembly issues. (Please see Figure 28.)

Preliminary estimates indicate that labor may be reduced as much as 60% and cycle time by 25% if these recommendations are implemented. The research team plans a full-scale operating test of the recommendations in Year 5. If these recommendations are accepted, researchers will assist Arvida and their primary contractor, Trinity, in detailing the design of the insulated panel walls and in the design of a new precast plant to serve the north Florida market.

Figure 28.  Summary of typical daily production schedule using continuous flow.

Figure 29. Pouring precast panels.	Figure 30. Setting precast panels.

UCF researchers are currently collaborating with FSEC colleagues to develop an order of magnitude energy savings in modular housing and to develop insulation strategies for precast concrete walls for the north Florida market.  (Please see Figures 29 and 30.)  Trinity currently uses no wall insulation in their concrete walls for central and south Florida.