A Phased, Data-Driven Approach to Eliminating the 5 Major Wastes in Die Casting Operations

This technical brief is based on the academic paper "Elimination of Wastes In Die Casting Industry By Lean Manufacturing: A Case Study" by Sumit Kumar Singh, Deepak Kumar, and Tarun Gupta, published in the IOSR Journal of Engineering (IOSRJEN) (2014). It is summarized and analyzed for HPDC professionals by the experts at CASTMAN.

Keywords

• Primary Keyword: Lean Manufacturing in Die Casting
• Secondary Keywords: Waste Elimination in Casting, Die Casting Defects, Gap Analysis in Manufacturing, Toyota Production System, Process Improvement Case Study, Poka-yoke and SMED

Executive Summary

• The Challenge: A high-pressure die casting company was struggling with a high rejection rate and hidden operational wastes, including defects, excess inventory, and process delays, which directly impacted profitability and competitiveness.
• The Method: Researchers conducted a case study using a systematic gap analysis to compare the company's current state against lean manufacturing benchmarks. They then used an expert-driven scoring system to identify, quantify, and prioritize the root causes of five major types of manufacturing waste.
• The Key Breakthrough: The study produced a data-driven, three-phase implementation plan to tackle waste. The plan prioritizes actions by starting with low-cost, high-impact solutions like improving documentation and optimizing machine setup procedures before moving to more capital-intensive changes.
• The Bottom Line: Adopting a structured, phased lean manufacturing approach provides a clear and effective roadmap for any die casting operation to significantly reduce waste, cut costs, and improve overall efficiency.

The Challenge: Why This Research Matters for HPDC Professionals

In today's fiercely competitive market, manufacturing operations are under constant pressure to increase productivity, reduce lead times, and lower costs. As the paper highlights, the goal is "to satisfy the customer with the exact product, quality, quantity, and price in the shortest amount of time." However, many facilities struggle with hidden inefficiencies that manifest as waste.

This case study focuses on "Company X," a manufacturer of aluminum-based alloys via high-pressure die casting, which faced a major problem with high rejection rates due to various casting defects. The complexity of the die casting process, where a defect can arise from multiple interacting factors, made it difficult to pinpoint the original cause. This research addresses the critical need for a systematic approach to identify and eliminate the root causes of waste, moving beyond simple trial-and-error fixes.

The Approach: Unpacking the Methodology

The researchers employed a robust, multi-step methodology to diagnose and create a solution for the company's waste problem.

1. Gap Analysis: The first step was to compare the existing shop floor status against the requirements of lean manufacturing. This analysis identified significant gaps in five key areas: Defects, Inventory, Excessive material movement, Delays due to waiting, and Inappropriate processing (Table 1).
2. Expert Elicitation: A cross-functional team of ten company experts—including managers, supervisors, operators, and mechanics—was assembled. This ensured that the analysis was grounded in real-world experience.
3. Systematic Scoring: The experts developed a generalized approach to evaluate potential solutions based on three critical factors: Cost of removal (Low, Medium, High), Ease of removal (Easy, Not Easy, Difficult), and Effect on other areas (Positive or Negative). A quantitative scoring scale was created to convert qualitative expert opinions into hard data (Table 2).
4. Root Cause Prioritization: Using this scoring system, the expert team evaluated numerous root causes of waste. The cumulative scores, compiled in Table 3, provided a clear, data-driven ranking of which problems to tackle first for the greatest impact.

The Breakthrough: Key Findings & Data

The study's systematic approach yielded clear, actionable insights into the facility's most critical sources of waste.

• Finding 1: Quantified Gaps in Lean Performance: The initial gap analysis (Table 1) confirmed that significant "HIGH" or "MEDIUM" gaps existed across all five waste categories. For instance, both Inventory and Delays due to Waiting were identified as having a "HIGH" gap between the current state and the lean ideal of "zero."
• Finding 2: Prioritized Root Causes: The expert scoring process (Table 3) successfully identified the most damaging sources of waste. Among the highest-scoring (i.e., most critical to fix) problems were:
  • Scrapping of product that deviates from drawing specifications (Cumulative Score: 69)
  • Extra copier/excessive information (Cumulative Score: 63)
  • Poor record keeping and retrieval (Cumulative Score: 55)
  • Human error on passing on instructions (Cumulative Score: 52)
  • Storage is away from the production shop (Cumulative Score: 51)
• Finding 3: A Phased Implementation Plan: Based on these scores, the researchers developed a three-phase implementation plan (Table 4). This plan intelligently groups solutions, ensuring early wins and building momentum for continuous improvement.
  • Phase 1: Focuses on high-impact, low-cost, and easy-to-implement changes, such as improving record-keeping, addressing human error in communication, and optimizing machine setup procedures.
  • Phase 2: Involves moderately difficult and more costly measures, such as implementing inventory control techniques, addressing absenteeism, and improving the system for setting process parameters.
  • Phase 3: Tackles the most complex and capital-intensive issues, including machinery and equipment upgrades, major layout changes, and addressing deep-seated cultural issues like worker motivation.

Practical Implications for Your HPDC Operations

The findings from this paper offer a practical blueprint that can be adapted by any die casting facility looking to implement lean principles.

• For Process Engineers: The structured, three-phase plan presented in Table 4 provides a logical template for initiating a continuous improvement program. By focusing on Phase 1 items first, such as "Scrapping of product" and "Human error on passing instructions," engineers can achieve quick wins that justify further investment in more complex Phase 2 and 3 projects, like tackling "Wrong setting and determination of parameters."
• For Quality Control: This research emphasizes a shift from reactive inspection to proactive prevention. The high scores for issues like "Poor quality of inputs" and "Poor record keeping" (Table 3) demonstrate that robust upstream process controls, standardized work, and accurate data management are more effective at eliminating defects than simply catching them at the end of the line.
• For Operations Managers: The gap analysis and expert scoring methodology is a powerful tool for building consensus and allocating resources effectively. By involving a cross-functional team, managers can ensure buy-in from the shop floor and use the resulting data to make a compelling business case for lean initiatives. The study proves that a systematic, data-driven approach is superior to arbitrary or gut-feel-based decision-making.

Paper Details

Elimination of Wastes In Die Casting Industry By Lean Manufacturing: A Case Study

1. Overview:

• Title: Elimination of Wastes In Die Casting Industry By Lean Manufacturing: A Case Study
• Author: Sumit Kumar Singh, Deepak Kumar, Tarun Gupta
• Year of publication: 2014
• Journal/academic society of publication: IOSR Journal of Engineering (IOSRJEN)
• Keywords: Lean Manufacturing, Die casting, Wastes.

2. Abstract:

As the competition in market is growing at a very fast pace, one can survive in today's industrial world by adopting the philosophy of Lean Manufacturing. In order to stay competitive, producing cheaper products at a faster rate Lean Manufacturing would help the industry. This paper represents a case study of Die casting industry. This case study is used to illustrate the steps in implementation of lean manufacturing providing actual and very positive results. The implementation plan is based on five major areas of wastes including Defects, Inventory, Excessive material movement, Delay due to waiting and Inappropriate processing in a die casting industry. The suggested implementation plan is being sub divided into three phases.

3. Introduction:

The introduction establishes the significant benefits of lean manufacturing, such as 35-75% improvements in production lead time and 10-25% reductions in production costs. It frames lean manufacturing as a comprehensive approach to minimize all forms of waste, including excess production, inventory, movement, waiting, over-processing, and rework. The goal is to achieve an efficient production system that satisfies customer demands in the shortest possible time.

4. Summary of the study:

Background of the research topic:

The research is set within a high-pressure die casting facility ("Company X") that produces aluminum-based alloys. The company faces a significant business challenge due to a high rejection rate of its components caused by various casting defects. The paper notes that diagnosing the exact cause of defects is difficult because they can result from a single cause or a combination of factors.

Status of previous research:

The paper defines lean manufacturing by citing established sources like the Toyota Production System. It presents multiple definitions that converge on a core idea: a systematic philosophy to shorten the timeline from customer order to shipment by continuously identifying and eliminating waste (non-value-added activities).

Purpose of the study:

The primary purpose is to identify the causes of various casting defects and other wastes that arise during the die casting process and to propose a structured plan to eliminate them using lean manufacturing principles.

Core study:

The core of the study is a case study methodology applied to "Company X." It involves a gap analysis to identify weaknesses, the formation of an expert panel to provide practical insights, the development of a scoring system to quantify and prioritize problems, and the creation of a phased implementation plan based on the results. The study analyzes five major waste areas: Defects, Inventory, Excessive material movement, Delays due to waiting, and Inappropriate processing.

5. Research Methodology

Research Design:

The research is designed as an industrial case study. It follows a structured, multi-stage process:

1. Gap Analysis: Compare the existing state with lean manufacturing requirements.
2. Expert Panel Formation: Assemble a team of 10 employees with diverse roles.
3. Factor Identification: Brainstorm and define key factors for evaluating solutions (Cost, Ease of removal, Effect on others).
4. Quantitative Scoring: Develop a scoring scale (Table 2) to convert expert opinions into numerical data.
5. Data Collection & Analysis: Experts rate root causes of waste, and the scores are compiled and summed to create a priority list (Table 3).
6. Implementation Plan Formulation: Group the prioritized solutions into a three-phase plan (Table 4).

Data Collection and Analysis Methods:

Data was collected via a "Performa" (questionnaire) filled out by the 10 experts. They provided qualitative ratings (High, Medium, Low) for each root cause against the defined factors. These qualitative ratings were then converted into quantitative scores using the scale in Table 2. The final analysis involved summing the weighted scores for each root cause to determine its overall priority, as shown in the "Cumulative score" column of Table 3.

Research Topics and Scope:

The research is scoped to a single die casting company. It investigates the root causes of five specific types of manufacturing waste and develops a generalized, phased implementation plan for waste elimination that could be applicable to other die casting industries.

6. Key Results:

Key Results:

The key results are presented in a series of tables:

• Table 1 (Gap analysis): Shows that "Inventory" and "Delays due to Waiting" have "HIGH" gaps, while "Defects," "Excessive material movement," and "Inappropriate processing" have "MEDIUM" or "HIGH" gaps, confirming significant room for improvement.
• Table 3 (Responses of Experts): Provides a ranked list of root causes based on their cumulative scores. The highest-scoring problems are procedural and systemic, such as "Scrapping of product" (69), "Extra copier/excessive information" (63), and "Poor record keeping and retrieval" (55).
• Table 4 (Suggested Implementation Plan): Organizes the solutions into a logical, three-phase approach. Phase 1 contains the highest-scoring, easiest-to-implement solutions. Phase 2 contains moderately difficult solutions, and Phase 3 contains the most complex and costly ones.

Figure Name List:

• Fig.1. Die casting hot chamber machine
• Fig.2. Die casting cold chamber machine

7. Conclusion:

The study concludes that a phased implementation plan is the most effective way to introduce lean manufacturing in a die casting industry. Phase 1 should focus on low-cost, easy-to-implement provisions that have a positive effect on the organization. Phase 2 involves more difficult and costly measures requiring budgetary approval. Phase 3 includes hardcore technical changes to machinery and tooling that require substantial capital investment. The paper also briefly introduces other essential lean tools for waste reduction, including poka-yoke (error-proofing) to achieve zero defects and SMED (Single-Minute Exchange of Die) to reduce setup times and enable smaller batch production.

8. References:

• [1] Shingo, S., 1987. The Sayings of Shigeo Shingo: Key Strategies for Plant Improvement. Productivity Press, Cambridge, MA.
• [2] Black, J.T., Hunter, S.L., 2003. Lean Manufacturing Systems and Cell Design. Society of Manufacturing Engineers, Dearborn, MI.
• [3] Conner, G., 2001. Lean Manufacturing for the Small Shop. Society of Manufacturing Engineers, Dearborn, MI.
• [4] Jordan, J.A., Jr., Michel, F.J., 1999. Valuing Lean Manufacturing Initiatives. Society of Manufacturing Engineers Technical Paper No. MS01-104, pp. 1-15.
• [5] M. Brian Thomas, Laboratory exercises for teaching lean enterprise, Proceedings of ASEE Conference and Expo, 2007.
• [6] Joseph Chen, Ronald Cox, Win-Win-Win Curriculum in Lean/Six Sigma Education at Iowa State University, Proceedings of ASEE Conference and Expo, 2007.
• [7] www.leanproduction.com.
• [8] Jim Parrie, (2007). Minimize Waste With the 5S System. Retrieved from www.pfmproduction.com/pdfs/PFMP.../PFMPSpring07Waste.pdf.
• [9] Jones D., and Womack, J., (2003), “Seeing the Whole – Mapping the extended Value Stream”, The Lean Enterprise Institute, Brookline, USA
• [10] Lean Manufacturing and the Environment .(2010). Cellular Manufacturing. Retrieved April 26, 2010, from http://www.epa.gov/lean/thinking/cellular.htm.
• [11] Taiichi, Ohno. (1988). Toyota Production System - beyond large-scale production. Productivity Press. 25-28.
• [12] Womack J., Jones D. T. & Roos D. (1991). The machine that changed the world – The story of lean production. HarperPerennial, New York.
• [13] Kenney, M. and Florida, R. (1993). Beyond Mass Production. Oxford University Press, Oxford.
• [14] Koskela, L. (1997). "Towards the Theory of Lean Construction." Proc. 5th IGLC Conference, Gold Coast, Australia.
• [15] Melles, B. (1994). "What do we Mean by Lean Production in Construction?” Proc. 2nd Workshop on Lean Construction, Santiago, in Alarcon 1997.
• [16] Seymour, D., Rooke, J., and Crook, D. (1997). "Doing Lean Construction and Talking about Lean Construction." Proc. 5th IGLC Conference, Gold Coast, Australia.
• [17] A. Sahoo, N. Singh and R. Shankar, (2008). "Lean philosophy: implementation in a forging company." The International Journal of Advanced Manufacturing Technology 36(5): 451-462.
• [18] A. Badurdeen (2007), “Lean manufacturing basics", http://www.leanmanufacturingconcepts.com.
• [19] Feld, William M., Lean Manufacturing: Tools, Techniques and How to Use Them. Boca Raton, FL: St. Lucie Press, 2000
• [20] Cua, Kristy O., Kathleen E. McKone & Roger G. Schroeder (2001). Relationships between implementation of TQM, JIT, and TPM and manufacturing performance. Journal of Operations Management, Vol. 19, pp. 675-694.
• [21] Karlsson, C. and Åhlström, P., (1996), “Assessing changes towards lean production”, International Journal of Operations & Production Management 16, pp 24-41.
• [22] Wilson, L. (2010), How To Implement Lean Manufacturing. New York: McGraw-Hill.
• [23] Basic concepts of Lean Manufacturing- WWW.TWINETWORK.COM.
• [24] Tom Gust- "Leading the Implementation of Lean Manufacturing”, Athabasca University December 2011.

Conclusion & Next Steps

This research provides a valuable roadmap for enhancing process efficiency in die casting. The findings offer a clear, data-driven path toward improving quality, reducing defects, and optimizing production by systematically tackling waste.

While this paper focuses on Lean Manufacturing principles, the identified defects and process inefficiencies are precisely the problems that CFD simulation aims to predict and solve before production begins. Understanding these real-world production challenges allows for more targeted and effective simulation work.

CASTMAN is committed to applying cutting-edge industry research to solve our customers’ most challenging technical problems. If the problem discussed in this white paper aligns with your research goals, please contact our engineering team to discuss how we can help you apply these advanced principles to your research.

Expert Q&A:

• Q1: What are the five major areas of waste identified in the die casting industry case study?
  • A: The paper identifies five major areas of waste: Defects, Inventory, Excessive material movement, Delay due to waiting, and Inappropriate processing. This is detailed in the abstract and forms the basis for the gap analysis in Table 1.
• Q2: How did the researchers prioritize which problems to solve first?
  • A: They used a quantitative scoring system based on expert opinions. A team of 10 experts rated each root cause on three factors: cost of removal, ease of removal, and effect on other areas. The problems with the highest cumulative scores, as shown in Table 3, were given the highest priority for implementation.
• Q3: According to the study, what was a top-priority, Phase 1 action for reducing 'Defect' waste?
  • A: The highest-scoring issue under the "Defects" category was "Scrapping of product, this deviates from drawing specifications but can be used," which received a cumulative score of 69. According to the implementation plan in Table 4, this, along with "Human error on passing on instructions," were designated as Phase 1 priorities for tackling defects.
• Q4: The paper suggests a three-phase implementation plan. What is the general principle behind this phasing?
  • A: The principle is to start with changes that are less costly, easier to implement, and have a positive complementary effect on the organization. Phase 1 focuses on these "quick wins." Phase 2 moves to measures that are slightly more difficult and costly, while Phase 3 addresses hardcore technical changes requiring substantial capital investment and more extensive trials. This is explained in the conclusion section of the paper.
• Q5: Besides the main implementation plan, what other lean manufacturing tools does the paper mention for waste reduction?
  • A: The paper mentions two other key waste reduction tools in the "Other Waste Reduction Techniques" section. These are poka-yoke, an autonomous defect control system for achieving zero defects, and SMED (Single-Minute Exchange of Die), a method for drastically reducing machine setup times to allow for smaller production batches and reduced inventory.

Copyright

• This material is an analysis of the paper "Elimination of Wastes In Die Casting Industry By Lean Manufacturing: A Case Study" by Sumit Kumar Singh, Deepak Kumar, and Tarun Gupta.
• Source of the paper: https://www.iosrjen.org/pages/v4-i7(version-1).html
• This material is for informational purposes only. Unauthorized commercial use is prohibited.
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