The Economics of Burrs and Deburring
The Economics of Burrs and Deburring
As the only known publication in print dedicated to understanding the costs of burrs, this book is written for manufacturing engineers, managers in piece part manufacturing, vendors exploring sales potentials, and economists.
|ABOUT THE AUTHOR
LaRoux Gillespie has studied burrs and deburring since 1966 gathering documents and facts along the way and reporting on advances in the technology at technical conferences around the world. In his 40 years of work, which included a search for data for a doctoral dissertation, Gillespie has found no published work with a clear picture of the cost of burrs. The competitive market place limits published information of burrs, particularly economic data. To compile information for this book Gillepie used insight gathered from forty years of experience in manufacturing and the assistance of experts such as John Kittredge as well as published literature gathered with the help of librarians at Linda Hall technical library. In his pursuit for accurate information, Gillespie welcomes constructive criticism and suggestions that can add to public knowledge of this important topic. Case studies on burrs and costs or surveys not mentioned in this book are particularly welcome.
excerpts from the first page of each chapter
| Chapter 1|
Many shops have only a superficial understanding of deburring economics and few are aware they have 122 different deburring processes to select from. Despite 40,000 pages of information on burrs and deburring finding useful information on deburring economics is difficult. This book is directed at a clear understanding of the economics of burrs and their removal. It does not describe how the processes work, the side effects of deburring or...how to reduce burr size. It does provide the basic information about burr prevention, but only as a prelude to how that impacts deburring costs. In all cases the reader is directed to other excellent works ... This is a book that allows the reader to make actual economic comparisons and estimates.
Cost is not the only consideration in deburring, but it is a major decision making consideration. A rational approach for deburring consists of the steps shown in Figure 1-1. While Figure 1-1 illustrates several steps, the details for each one of those steps are already defined in one of the several recent publications in easy to follow examples. The truth is that there is no reason for not climbing the pyramid shown there to reach a mastery of burr technology knowledge. The information exists and each company can delve as deeply as they find appropriate
In any on-going operation reducing the cost per part is a daily need. The cost per part for deburring, however, is not an issue that most shops have closely studied. Lean manufacturing is a common issue for all plants and one closely studied in many. Lean manufacturing focuses on reducing the time between operations, reducing operation time, and reducing the need for operators (deburring personnel). That improves costs and operations, but is not the same as knowing how much costs are reducing. Time reductions are important since they greatly affect costs, but knowing how to calculate accurate costs is also important.
Throughout this book the emphasis is on deburring costs, but the real objective in manufacturing is to reduce total part cost. That means manufacturers must understand not only the cost of machining and the cost of deburring but the economic tradeoffs between the two. Many of us have seen the machining cycle greatly improved at the cost of higher deburring. That may be the best answer for many applications, but the total part cost should not go up as a result. Sockman (2000) provides an example where a cutting tool change reduced tool costs, but the deburring costs greatly increased as a result. Probably most of those who have worked in the shop have experienced the same unintended effect. Many years ago machinists would not change HSS tools timely because tool change was a time consuming effort and near shift end it was just easier to let it run. When that happens with stainless steel parts the burrs become horrendous and the deburring time will go from minutes per part to sometimes hours per part. It was not a problem for the machinist - he met his parts per shift goal, but the deburring department paid a terrible price.
This chapter focuses on how the economics for an entire deburring department, section or room are calculated. Chapter 2 looked at the cost of individual parts. In this chapter the focus is on understanding where the costs within a department truly are and how much they are. It looks at the broader picture.
The fourth step in a rational approach to improving plant wide deburring is to understand the cost of burrs within a plant site. That includes the deburring equipment costs, labor costs, space costs, costs of parts scrapped for burrs/excessive deburring, warranty costs of field failures due to burrs not adequately removed and others ... Once those costs are defined the next obvious step for many plants is to understand the drivers for those costs ...
...there are many considerations for picking the "best" finishing process...Economics are critical... The "best' deburring processes may involve requirements, but it is not the only criteria ... Other strong drivers for 'best" include least rejections, quickest throughput, best visual appearance, or least impact ...
You are part of a $30 billion annual burr issue. That is the opportunity companies have for growing new business. That is the impact for those who have not solved their burr issues. In this chapter we will explore those national and international opportunities by using several boundary limit calculations. ... readers can document the trends of burr reduction and other manufacturing efforts that reduce (or increase) deburring costs.
...Several key assumptions must be made and much of the data generated provides more of a 'boundary" picture to expenditures than a true cost estimate. ..This chapter will show how the results were determined and the reader can make any other assumptions readers needs for their application. The approaches discussed here to estimate costs are very simple. ..These approaches, however, do provide the reader with simple to follow fundamental means to establish cost boundaries...
WHAT CAUSED THE REDUCTIONS IN COSTS?
Since the mid 1970's eight aspects of technology have impacted the world of edge finishing and the burr. Each will continue to be key means of reducing plant costs of burrs. They include:
This chapter will discuss how companies, individuals and technology has reduced the cost of burrs and deburring. While it is presented in a historical context, readers need to note that each issue presented here is the same solution for their specific part or specific plant needs. Stated differently, Chapter 1 presented a format for solving burr issues (see Figure 5-1), while this chapter presents the technology changes that reduced costs and continue to be the basis for today's cost reductions.
History of Processes
Manual Deburring on a Drill Press
Abrasive Belt Deburring
Rolled Edge Finishing
Manual Abrasive Belt Deburring
Handheld Portable Tool Deburring
Hand Deburring w/o Motorized Tools
Hand Deburring of Plastic Parts
Loose Abrasive Tumbling Processes