What is Power Cord capacity (measured in finished SurAn 333 units per week), Internal Wiring capacity (measured in finished SurAn 333 units per week), Final Assembly capacity (measured in finished SurAn 333 units per week), and Calibration and Test capacity (measured in finished SurAn 333 units per week). Assume a 40-hour productive work week.


Universal Instruments designed and manufactured sophisticated scientific instruments for surface analysis. UI's worldwide customers considered its family of product lines to be "firstclass" in precision measurement and product reliability. Little growth in aggregate product sales was expected over the next year; the demand for any given product could, however, be quite volatile and thus difficult to forecast accurately. UI was constantly upgrading its product lines. There were 10 core product families, each with multiple, featured variations and functionalities. In addition to the sales of final products, 15% of UI's sales were for subsystem units sold to existing customers choosing to upgrade previously purchased instruments. Universal Instruments' manufacturing operations were divided into four departments: (1) electronics manufacturing, (2) precision machining, (3) precision assembly, and (4) final systems integration. Each department operated somewhat independently from the others, like small factories within a larger plant. A computer-scheduling and inventory-management system helped coordinate activities across departments and with UI's suppliers. The Electronics Manufacturing Department (EMD) produced the major electronic controller subsystems used in UI's products. Typically, these subsystems consisted of a few major components or subassemblies: external metal panels (front, side, and back), a steel box-frame chassis, multiple special-function printed circuit boards, internal wires, and a power cord. EMD produced the electronic subassemblies and then assembled, calibrated, and tested all final electronic subsystems. The electronics manufacturing department built 250 distinct controller subsystem units for use in UI's end products, and many of these subsystem units were also sold directly to custome choosing to upgrade their instruments. These 250 controller subsystem units shared few common components or subassemblies. The highest-volume controller subsystem produced by EMD was the SurAn 333, the electronic controller unit in the UI product used to control and monitor air pressure during surface-analysis testing and measurement. More than 70% of the SurAn 333 units were sold directly to customers who wished to upgrade or modify a previously purchased UI instrument. In the Electronics Manufacturing Department, subsystem production was planned for units to be built in batches whose size varied with annual demand. For example, the SurAn 333 was built in a monthly batch of 20 because, on average, 20 units either were sold directly to customers or were needed in final assembled products each month. Some low-volume electronic units were built in a monthly batch size as small as five. The aggregate demand for all 10 core product families was high enough that the EMD ran at capacity. The Precision Machining Department (PMD) fabricated the small precision metal parts for the final product's optical and mechanical subassemblies, using processes requiring a variety of machine tools and highly skilled machinists. Work-in-progress components/subsystems from suppliers and from EMD and PMD were inventoried in the stockroom and delivered in kits to the plant's assembly departments. The Precision Assembly Department (PAD) and the Final Systems Integration Department (FSID) conducted their activities in controlled "clean-room" environments to minimize contamination from dust and other airborne particles. Electronics Manufacturing Department The Electronics Manufacturing Department was organized into five processing areas that were physically as well as organizationally separate: (1) power cords, (2) internal wiring, (3) printed circuit boards, (4) final subsystem unit assembly, and (5) calibration and test. The physical layout is depicted in Exhibit 1. Typical processing times, equipment, and number of employees for each area are given in Exhibits 2A and 2B. EMD was staffed for one nine-hour shift per day, five days a week. Excluding lunch and two breaks, eight hours remained for production each day. Power Cords Every electronic subsystem unit required a power cord. Producing power cords involved drawing cable from the proper reel, cutting it to the specified length, and attaching a plug at the ends. Power cords were produced in planned batch sizes on a monthly basis. Because reels of different cable types were mounted above each operator's bench, no setup was involved in changing over production from one type of power cord to another. Batches of power cords, once completed, were stored as a batch in the stockroom until the batch was needed for final assembly in EMD. Internal Wiring The Internal Wiring area was responsible for laying out and completing an assembled set of electrical wires for each unit. Different unit models required different wire types, connectors, and wiring-layout configurations. Operators referred to a specification sheet and sketches of the wiring-layout plan to determine which wires to include, how long each should be, and how they should be configured. Plastic fasteners were used to hold wires in the appropriate patterns on a large table, and connectors were attached to the ends of each wire. Each worker's wiring activities were performed at the worker's individual table, with all employees working collectively on the same batch of a given wiring pattern until it was completed. The setup time required at each table for any particular wiring pattern was approximately 30 minutes. Every batch of product required a new setup at all five tables. All completed batches of internal-wiring assemblies were sent to the stockroom until they were needed for final assembly in EMD. Printed Circuit Boards Printed circuit boards (PCBs) were the critical functioning elements of electronic control and monitoring units. Because each subsystem unit had different functional purposes and features, each contained different PCBs. In total, this area produced nearly 300 different PCB designs. Each SurAn 333 unit, for example, contained 5 different PCBs. There were five steps in the production of each PCB (see Exhibit 2B). All electronic components (e.g., capacitors, resistors, transistors, microprocessors, and integrated circuits) needed to produce a batch of PCBs were received from raw-materials inventory and prepared for insertion into the boards. 1. Preparation involved cutting and shaping the lead wires of individual electronic components so that those wires could be inserted into the holes of the blank PCBs. Direct labor time for component preparation for a single unit with five PCBs was 30 minutes (6 minutes of labor time for each PCB in the unit). No setup time was required for this step. 2. After preparation, the components were inserted (by hand) into the appropriate predrilled holes on each board. Purchased boards arrived from a supplier that had drilled the correct pattern of holes for each distinct PCB design. Direct labor time for component insertion for a unit with five PCBs was 120 minutes (24 minutes per PCB). No setup time was required for this step. 3. To fasten the components onto the boards permanently, the component-loaded boards were sent through an automatic soldering device known as a wave solderer. Inside this machine, a continuously moving wire-screen belt carried PCBs across a bath of molten solder. An operator at the front end loaded boards onto the moving belt. An operator at the other end unloaded the boards, and stacked them in preparation for a special wash. The washing machine could hold 50 boards at a time. For equipment-design reasons, partial loads were not allowed. Rather than run a wash group of fewer than 50, the operator would wait until a full load accumulated before beginning the wash. The average elapsed time, from the loading of a board onto the wave solderer until it emerged from the wash, was 40 minutes. Most of this time was spent in the wash. For each group of 50 boards emerging from the washer, the two operators typically would have spent a total of 10 minutes in presoldering and postwashing activities (loading and unloading). The workers performed these tasks for each new batch while the wave soldering and washing machines were processing other batches. 4. Washed boards were then transferred to the touch-up station, where they were examined and, if necessary, manually re-soldered. In addition, components that could not be wave soldered were hand-inserted and manually soldered here. Touch-up required eight minutes of labor per PCB. 5. After touch-up, a technician electronically tested each board. The test required eight minutes of labor per PCB. Following the testing of all PCBs in a batch, the boards were sent to the stockroom for storage until they were needed for final assembly in EMD. Final Subsystem Unit Assembly The power cables, wiring harnesses, PCBs, chassis, and exterior panels needed to produce the planned batch of a particular controller model were sent from the stockroom to the Final Subsystem Unit Assembly area, where the assembly process occurred. Assembly required 240 minutes of labor for each SurAn 333. Calibration and Test Assembled electronic controller units were sent directly to the Calibration and Test area. Units were calibrated and tested on steel holding racks. Each unit was calibrated and run through a series of initial tests by a technician. This initial test required 60 minutes per unit. Each unit was then run through a "burn-in" test (unattended by the technician) for an additional 48 hours to test for defective electronic components. The length of the burn-in test was set using a timer, which automatically ended the test after 48 hours. For all practical purposes, Calibration and Test had access to an unlimited number of holding racks. Lean Manufacturing Work Cells In mid-2005, a Continuous Improvement Team, headed by Production Planning Manager Ken Jeansomme, began to examine how the process flow in the Electronics Manufacturing Department might be improved. The team's analysis uncovered processes characterized by large batch sizes, high in-process inventories in the stockroom, excessive handling of subassemblies to/from the stockroom, long throughput times, scheduling inflexibility, and occasional quality problems that were not identified during production. For example, the throughput time for a SurAn 333, within EMD (i.e., ignoring the lead times for parts from other internal departments or outside suppliers), was eight weeks. This time, according to Connie Tsu, was typical for UI products in EMD. To eliminate or alleviate some of these problems, the Continuous Improvement Team's concept was to reorganize EMD into product cells. Each cell would complete a substantial portion of the processing, subassembly, final assembly, and test activities for a particular electronic controller model or family of models. Every operation required to build a complete unit would be incorporated into every cell (except for some equipment; specifically, power-cord production and PCB wave soldering and washing would be shared by the multiple cells within the department). The cells would, in theory, be designed so that the work was evenly divided across the activities in a cell. Furthermore, the workers would run their cell with Lean Manufacturing principles: electronic control units would function according to single-piece flow, and each operation would deliver its output to the next operation, neither earlier nor later than required, but just-in-time. A pilot cell was established, and the high-volume SurAn 333 was chosen as the major model to be produced in that cell.1 The layout of the pilot production cell is depicted in Exhibit 4. At one end of the U-shaped cell, a small stock area was set up to hold components unique to the work cell's products. There were five workstations in the cell: (1) PCB preparations (component preparation and insertion), (2) PCB touch-up and test, (3) internal wiring, (4) final subsystem unit assembly, and (5) calibration and test. These tasks were the same as those performed in the Electronics Manufacturing Department operating in its traditional layout. Each workstation in the cell was a miniature version of each of the larger processing areas, except that it was dedicated to the SurAn product family. PCB wave soldering and washing, as well as power-cord production, would remain outside the cell because these activities could not be performed efficiently on a small scale. Four workers were recruited for the pilot Lean Manufacturing cell. They received the necessary cross-training to allow them to work in all five workstations. In August 2005, the pilot Lean Manufacturing cell began production of SurAn products. After some experimentation and refinements, the following materials-handling procedures were instituted: Once each week, the cell ordered all the components needed for a week's production schedule. The schedule was planned by the Production Planning Manager based on current orders. The stockroom order was triggered by sending an empty parts rack to the stockroom. The ordering process differed fundamentally from the old system, under which the stockroom "pushed" parts onto the factory floor as dictated by the computerized production schedule—whether EMD was ready to use them or not. With the new material handling procedures in place, the Lean Manufacturing cell carried an average of 1 unit of work-in-process at each work station, and 1 unit of work-in-process waiting before each work station. After three months, the pilot cell was running smoothly as a Lean Manufacturing product cell and results looked promising. Throughput time decreased and product quality improved; defects were down by more than 50%

 

Electronics-Manufacturing Department: SurAn 333 Processing Times, Department Staffing and Equipment SurAn 333 were produced in batches of 20 units Area Power Cords Internal Wiring Final Assembly Calibration & Test Minutes Set-Up 30 per table Minutes Labor Time for One SurAn 333 20 70 240 60 Number of Workers Available in Department 2 5 22 7 Equipment 2 benches 5 wiring tables work tables holding racks for 48 hours of burn-in Workers were permanently assigned to one area (e.g., five workers were assigned to Internal Wiring). Within their area, they could perform the necessary operations on any unit. 'In Internal Wiring, 30 minutes were required for each of the five tables set up for the assembly of a particular wiring pattern in a batch. This setup involved locating the required wires and leaders, and organizing a wire assembly table