Teaching Introductory Lean Process Design

Teaching Introductory Lean Process Design

Sharon A. Johnson, Arthur Gerstenfeld, Amy Z. Zeng,

Boris Ramos, Saumitra Mishra

Department of Management

Worcester Polytechnic Institute

Worcester, MA 01609

Abstract

Lean thinking has transformed process design in organizations, using a systematic approach that eliminates waste by creating flow dictated by customer pull [12]. In this paper, we describe an introductory course designed to present lean process design to engineering and management majors. Traditional course topics in operations design were linked through the lean concepts of value, flow, demand pull, and perfection. In addition, we developed a set of laboratory exercises based on a physical simulation of clock assembly called TIME WISE. The physical simulation assisted students in ‘discovering’ theory, including concepts related to layout, capacity, inventory, and quality improvement.

Keywords

Process design, lean manufacturing, lean thinking, engineering education.

1. Introduction

Lean process design is an integral part of operations planning and improvement in most organizations today. Because lean thinking plays such a central role, we believe that industrial engineering (IE) students should be given a holistic view of lean principles early in their academic careers. Management majors and engineers in other disciplines, who may take only one operations-focused course, should also have exposure to these ideas.

In this paper, we describe a new course that integrates lean process design with hands-on laboratory exercises and with student research projects. The course is an introduction to the planning, analysis, and design of production systems. Because more than two thirds of the U.S. workforce is engaged in services, and because many of our graduates will also be involved with services, we focus on service as well as manufacturing applications in the course. The application of lean process design to service industries is less well-developed and thus an important emphasis. Our objectives for student learning include: (1) to develop students’ ability to apply lean design principles, (2) to develop students’ ability to analyze data, and (3) to increase student understanding of fundamental process dynamics and variability.

The overall course structure, the research projects, and the lean laboratory exercises are presented in this paper. Traditional topics covered in introductory industrial engineering and operations courses, such as line balancing and material management, are linked to lean concepts of value, flow, demand pull and perfection. The laboratory exercises are based on a physical simulation of a clock assembly called TIME WISE, which was developed by MEP-MSI and is used by Manufacturing Extension Partnership (MEP) programs in several states to teach lean principles to employees at small- to medium-size manufacturers. In adopting the simulation to an undergraduate course, we wanted to provide students with more opportunities to ‘discover’ theory, by generating and analyzing data that could be used to support decision-making.

We have offered the laboratory sessions once at Worcester Polytechnic Institute (WPI), and provide observations about the teaching experience and student learning. We also briefly describe our evaluation plan and present sample results.

2. Literature Review

In order to create a competitive advantage it is necessary to have an understanding of how the operations function contributes to productivity growth [4]. Introductory courses should be integrated with the contemporary issues faced by organizations. In industrial engineering and operations, one contemporary concern is streamlining supply chains to increase responsiveness and eliminate waste. Supply chains have many stages, often involving different firms, which require coordination and synchronization [9]. The design process is complicated because in reality not all waste can be eliminated. To be effective designers, students need to understand how variability affects process dynamics and to combine this knowledge with analysis of process data.

2.1 Teaching Process Design and Lean Principles

We examined Introduction to Industrial Engineering courses at a number of schools. Many schools have created such introductory courses in the engineering disciplines to reduce attrition rates by linking traditional mathematics and science topics to applications [1]. While such courses in IE have provided an effective overview of the discipline, course materials and textbooks do not focus on process design or the impact of lean ideas (see, for example, [11]). Project-based courses that focus on process design are generally aimed at senior-level students (see, for example, [8]). A few universities have developed a separate course focused on lean topics, also geared to upper-level undergraduates or graduate students. More typically, traditional courses have been revised to address the individual tactics associated with lean design, usually as an add-on topic (for example, in production planning and control, one might add a session on kanban). We had traditionally taken this piece-meal approach at WPI. As a consequence, we observed in that students completing capstone design projects in industry often could not articulate the underlying principles of lean design (at least initially), and they failed to understand the links between various tactics and the conditions necessary for their success.

In contrast, many universities have established partnerships with industry to teach and apply lean ideas. These problems often use classroom instruction supplemented with hands-on applications, plant floor exercises, and live simulations. The continued interest in and success of such partnerships provides evidence that the ability to apply lean topics is important to industry. We wanted to take advantage of these methods and materials.

2.2 Discovery Learning

Evidence suggests that students’ design and problem-solving abilities are improved in courses that use active and collaborative learning [10]. The course project and laboratory activities that we describe in this paper were designed to engage students in their learning, setting the high expectations, cooperation and faculty/student interaction consistent with good practice in undergraduate education [5]. Discovery learning seeks to connect students to knowledge. In this approach, tools and information may be provided by a faculty member to solve the problem, but it is the responsibility of students to “make sense” of them by drawing conclusions based on his/her own experience and knowledge.

As described by Bicknell- Holmes and Hoffman [2], there are five basic methods associated with discovery learning, several of which we employed in our curriculum design. In case-based learning, students learn through stories that illustrate the effective application of knowledge, skills or principles. In learning by exploring methods, students ask a faculty member or other students about a particular topic or skill. The faculty member tries to direct the interaction in a particular conversation or a topic. In simulation-based learning, an artificial environment that is close to the real environment is created so that students have the advantage of developing and practicing a complex set of skills.

3. Course Description

The goal of this course in our IE curriculum was to provide a process design foundation early, embedded in the contemporary business context that includes lean ideas. Project-based courses that build repeatedly on core ideas in a ‘spiral curriculum’ have been successfully implemented in other engineering disciplines at WPI ([6],[7]). We thus revised our traditional introductory operations and industrial engineering course, titled “Production System Design”, which is required for IE majors. IE students take this course early in their program, and it serves as a foundation for more advanced courses. The course is also taken by management majors at WPI to fulfill their operations management requirement, as well as students in related engineering disciplines such as manufacturing and mechanical engineering. For these students, it may be the only operations and industrial engineering course that they take.

The overall course plan is shown in Table 1, which identifies topics covered in the lecture portion of the course as well as related hands-on laboratory experiences. Undergraduate courses at WPI are delivered during a 7-week term; there are 4 such terms during the academic year. In this course, students attended two 2-hour lecture sessions a week, as well as a 2 ½ hour laboratory. Over a 7-week term, there are 14 sessions; the sessions not described in the table were reserved for exams and student project presentations. Guest lecturers present some topics. For example, we had speakers from General Electric speak about their six-sigma approach as part of the quality management session.

Table 1: Course Outline for Lean Process Design

• Traditional process includes large lot sizes, unbalanced and insufficient capacity, poor layout
• Play for 3 shifts, switching roles so students can observe the process from several viewpoints
• Student Assignment: Summarize performance measures (e.g., capacity), identify process problems

• Introduce 7 step problem solving method developed by Center for Quality Management [3].
• Examine process variability and capability, review TAKT time and capacity calculations
• Use the 7 step method to define a root cause and improvements that can be made to TIME WISE

• Students present improvement suggestions for simplifying flow, line balancing
• Revise TIME WISE setup to reflect suggestions
• Play 2 rounds to measure process performance and suggest additional improvements

• Introduce additional product to examine robustness
• Students present designs for a demand pull system, visual controls, and 5S activities
• Revise TIME WISE setup to reflect suggestions
• Play 2 rounds to measure process performance and suggest additional improvements

• Examine the impact of distance and variability in the supply chain on system performance

• Introduce customized products
• Explore the advantages of a postponement strategy

3.1 Laboratory Format and Topics

In the laboratory exercises created using the TIME WISE simulation developed by MEP-MSI, students assemble two types of clocks, using a 4-stage process. In addition to assembly personnel, the simulation requires production planners, material handlers, quality inspectors, warehouse clerks, and inspectors. The simulation is carried out in a large group, with each group member assigned a different role. One simulation takes 15 minutes, and corresponds to a work shift. We ran two sections of the lab in Fall 2002 with 15 and 18 students respectively, and are running sessions with 21 students in Spring 2003.

The Massachusetts Manufacturing Extension Partnership (MEP) uses TIME WISE as part of one-day seminars that provide a foundation for understanding the principles of lean manufacturing. Employees of small- to medium-size firms attend the seminars. There are several differences between our laboratory sessions and the seminars conducted by MEP that required some adaptation of TIME WISE. First, participants in MEP seminars typically have been working for several years, often many years. They bring to the seminar an understanding of manufacturing operations, and can tie what they learn to their own work context. Students taking an introductory course at WPI are usually sophomores and juniors, who typically have little work experience in engineering or operations (they are more likely to have worked service industries, including retail, restaurants, and computer services). The TIME WISE simulation provides them with a context for exploring lean principles, but we need to spend more time understanding basic process dynamics and relating issues to other examples. Second, we have significantly more time available (approximately 15 hours of lab time versus about 4 hours spent on TIME WISE in MEP seminars). With this additional time, we ask students to collect data on the process and use more structured methodologies (e.g., assembly line balancing, calculating capacity based on the bottleneck) to suggest solutions. We also explore problem-solving approaches, and experiment with proposed solutions to see how well they work. Finally, we explore additional scenarios to examine the impacts of product customization and distant suppliers.

An overview of each laboratory session is provided in Table 1. Each lab lasted approximately 2.5 hours and was focused on a particular topic. The format of the labs was similar. Using data collected from previous labs (e.g., lead time, work in progress, quality data), students were asked to propose solutions for continuous improvement using tools introduced in class. For example, in session 3, one focus of the lab is better balance among the various assembly tasks. In the course lectures, students have reviewed assembly line balancing and now have an opportunity to apply it. After students present one or more solutions, we then set up the lab to experiment and see what improvements can be made to the solution.

3.2 Team Projects

Students also completed team projects as part of the course requirements to emphasize the importance of teamwork as well as to give them the opportunity explore the supply chain and lean ideas in a specific industry. We encouraged students to select service industries, and had teams of about three students researching lean operations in fields such as: airlines, financial services, health care, mail and freight delivery, railroads, recycling, and waste management. Each team was required to analyze competitive forces in the industry, present a general map of the supply chain, and to suggest how lean ideas have or might be applied to improve supply chain performance. Teams could develop their analysis using one or more companies as case studies. To support their conclusions, students were required to do an extensive literature review (with at least half of their sources not from the web), as well as some interviewing or other form of data gathering. The literature review supported their competitive analysis, as well as the discussion of the supply chain and the application of lean ideas, specific to the industry they selected.

4. Observations and Results Related to Student Learning

Our objectives in introducing the lean laboratory exercises were to improve students’ ability to apply lean concepts, to improve students’ ability to use data to support decision-making, and to improve student understanding of process variability and dynamics. We are using student surveys, course evaluations and reviews of student work to establish our success in achieving these objectives. Data was collected from a course section taught with our traditional format in Spring 2002 (which focused on process design topics, with a separate chapter on lean and without laboratory sessions) to compare to our first delivery of the new course in Fall 2002. We also plan to interview students who have taken these courses after a year to try to evaluate the impact on longer-term learning.

We used student surveys to examine student confidence in their learning in a variety of areas, including their understanding of lean principles, supply chain activities, and calculation and understanding of process measures. We gathered data at the beginning and end of each course. In general, students expressed greater confidence about their knowledge with the introduction of the laboratory exercises, particularly in their ability to understand and apply lean concepts. Figure 1 shows a sample result, related to process measures. Students felt confident in their understanding of process measures when taking the course without the lab exercises in Spring 2002 as well as when the lab exercises were included in Fall 2002. However, students expressed significantly more confidence in their ability to calculate process measures when the course included the lab exercises.

Figure 1: Students’ Confidence in their Ability to

Understand and Calculate Process Measures

In addition to such student surveys, we collected student responses to essay questions on exams and have started evaluating them in relation to our objectives. We broke each objective into smaller aspects, then created rubrics to score student work relative to that aspect of the objective.

Because later laboratory sessions depended on the data and solutions that students developed, we also observed that students learned a number of ‘real-life’ lessons about process improvement and lean design. For example:

• A balance must be struck between optimization and gathering data. Prior to the third lab session, students were asked to redesign and balance the assembly process, eliminating non-value added tasks and potentially rearranging other tasks. Students had data about overall process times, but initially did not have any data on the sub-tasks making up major assembly steps. Students came to realize that collecting data on sub-task times and defining standard work procedures, which theoretically was needed for assembly line balancing algorithms, was quite time-consuming. They wanted more and better data, but had to estimate in order to get a solution.
• Some experiments fail! After students presented their balancing solutions, we set up the simulation to reflect their recommendations. In one session, students had done a lot of analysis to create a good balance, but the proposed solution did not work as well as expected in practice. The students had forgotten to include material handling and other small tasks.
• Today’s solution may not be good tomorrow. One student group developed a solution with a dedicated line for each of the two initial products, which resulted in greatly improved performance. In the fourth lab, however, a third product was added to the mix and students observed that the dedicated design was not as flexible as others that had been proposed.
• Information flow can be as problematic as material flow. In the final lab sessions, customers are allowed to customize their clock orders. Students grasped that it was important to move the assembly tasks related to the customization to the end of the process (postponement), but did not anticipate how much more difficult tracking the customer orders would be. Additional effort was required to develop better coordination between the final assembly steps and the warehouse, which shipped the products to the customers.

5. Conclusions

This paper describes our experience with teaching lean process design as part of an introductory IE and operations course. We have shown in this paper how the integration of a laboratory as well as research papers gives the students a full learning experience. The six laboratory exercises, based around a physical simulation of clock assembly called TIME WISE, encouraged students to experiment with theoretical concepts and critically examine process results. Students who took the course with the added laboratory exercises expressed significantly more confidence in their ability to understand and apply lean ideas, as well as to calculate process measures. They were also overwhelmingly positive about the laboratory activities in student evaluations.