ROBOTICALLY ENHANCED ADVANCED MANUFACTURING CONCEPTS TO OPTIMIZE ENERGY, PRODUCTIVITY, AND ENVIRONMENTAL PERFORMANCE

Abstract

In the first phase of the REML project, major assets were acquired for a manufacturing line for follow-on installation, capability studies and optimization. That activity has been documented in the DE-FC36-99ID13819 final report. In this the second phase of the REML project, most of the major assets have been installed in a manufacturing line arrangement featuring a green cell, a thermal treatment cell and a finishing cell. Most of the secondary and support assets have been acquired and installed. Assets have been integrated with a commercial, machine-tending gantry robot in the thermal treatment cell and with a low-mass, high-speed gantry robot in the finish cell. Capabilities for masterless gauging of product’s dimensional and form characteristics were advanced. Trial production runs across the entire REML line have been undertaken. Discrete event simulation modeling has aided in line balancing and reduction of flow time. Energy, productivity and cost, and environmental comparisons to baselines have been made. Energy The REML line in its current state of development has been measured to be about 22% (338,000 kVA-hrs) less energy intensive than the baseline conventional low volume line assuming equivalent annual production volume of approximately 51,000 races. The reduction in energy consumption is largely attributable to the energy reduction in the REML thermal treatment cell where the heating devices are energized on demand and are appropriately sized to the heating load of a near single piece flow line. If additional steps such as power factor correction and use of high-efficiency motors were implemented to further reduce energy consumption, it is estimated, but not yet demonstrated, that the REML line would be about 30% less energy intensive than the baseline conventional low volume line assuming equivalent annual production volume. Productivity The capital cost of an REML line would be roughly equivalent to the capital cost of a new conventional line. The unit raw material cost for REML (through-hardened bearing steel) is somewhat greater than raw material cost for the conventional line (case-hardened bearing steel). However, changeover time, tooling costs, gauging costs, utilities and energy costs, and manning of REML are less than the conventional line. Since REML supports near single piece flow, work in process inventory and work flow time are much less on the REML line than on the conventional line. REML allows the reduction in inventory of source steel tube sizes from several hundred to a few dozen. As a result, the business model indicates that the costs incurred on the manufacturing line are less with the REML line than with the conventional line for low manufacturing run volumes. Environment The REML line, when processing through-hardenable steel, requires far less hydrocarbon and other process gases than the conventional line when processing case hardenable steel. The REML line produces fewer greenhouse gas emissions and less liquid and solid waste materials. Broad Applicability The REML benefits will in general be extendible to the manufacture of non-bearing, heat treated and finished machined metal parts in the United States.