Motion and Time Study: Design and Measurement of Work, 7 Edition
John Wiley and Sons
Chapter 6. Work Methods Design - Developing a Better Method
Eliminate, Combine, Rearrange and Simplify steps are used at the level of process, operation and Motion.
At the level of analysis of the processes, it is operations which are subjected to ECRS.
At the level of operation, it is elements which are subjected to ECRS.
In motion study, individual motions are subjected to ECRS.
If the technology of manufacturing a product is divided into processes, ECRS can be applied to even processes.
Eliminate all unnecessary operations/elements/motions/work
The Procter and Gamble has found this step so profitable that is has established a formal procedure for the "the elimination approach."
1. Select the cost for questioning: Major costs must be selected first in order to get the greatest money returns. Labor costs, material costs, clerical costs, and overhead costs of all kinds are possible subjects for elimination.
2. Identify the basic cause: Find the basic cause which makes it necessary for doing the process/operations/element that results in the cost. A basic cause is the reason, purpose, or intent on which the elimination of the cost depends. The basic cause is the factor which controls the elimination of the cost. The key question is, "This could be eliminated if it were not for what basic cause?" At this stage we do not ask the question "Why is this operation necessary?" This question is avoided because it tends to justify and defend the job's existence. Operation for which, there is no basic cause can be eliminated at once.
3. If the basic is identified, it can be questioned in two ways.
a. Disregard the basic cause:
b. Apply "why?" questioning:
Packing Lettuce in Cartons: In packing lettuce, ice was interspersed between the layers of lettuce in wooden crate. In the changed method, fiberboard carton was used and it was quickly cooled to 36 to 38 degree farenheit in a vacuum cooling plant. No ice is required and it saved $3 per box. The fiberboard carton was also cheaper than wooden crate.
Code Dating Cartons: Four dates were being stamped on the each carton of soap. The reason for it is know when the carton of soaps was manufactured. Only one date is sufficient and rest three were eliminated.
Splicing Insulated Wires: In the cables of the Bell system 250,000,000 splices were done between wires. The earlier method was to skin the insulation of the two wires to be connected, twisting the two bare wires together and slipping an insulation sleeve over the twist. In the revised method, a pneumatic tool is used that flattens and connects the two wires along with a phosphor-bronze tang. Skinning and twisting the bare wires was totally eliminated.
B. Combine Operations or Elements
Normally it is thought more efficient to break down a process into many simple operations. But, this division of labor may have been carried too far resulting in excessive handling of materials, tools and equipment. Such situations can be identified and corrected by simply combining two or more operations by making some changes in the operations.
An operator was loading the input Wood at input side of the molding machine. At the output end another operator was collecting the output and loading them in the truck. Two short conveyors were installed that made it possible for one operator to take out and incoming material and load the outgoing material on the same truck. For facilitating this, in the truck four parts were made and only three were loaded with raw material. This arrangement reduced the number of trucks needed and also saved floor space.
C. Change the Sequence of Operations
When production is scaled up, the original method may still be retained even though it can be improved. For this and for other reasons it is desirable to examine and question the order in which the various operations are performed.
In one plant, small assemblies were made on semiautomatic machines in department A, were stored in department B, 10% of the assembles were inspected in department C, and were packed for shipment in department D. Whenever there were more defects found in 10% inspection, all the stock was inspected till the production system was adjusted to eliminate the defect.
The system was modified, and the inspectors were placed in department A at the end of each line and were asked to inspect 10% as production is coming out of the line. Whenever excessive defects were found, the line was corrected immediately. This simple arrangement was easy and inexpensive and saved the company tens of thousands of dollars in inspection and also reduced the number of scrapped parts.
E. Simplify the Necessary Operations
Question every thing about the job being done in the operation under investigation. The design of the product, the material being used, tools and equipment, machining processes used, jigs and fixtures, speeds and feeds, the working conditions, the operator and the manual motions used.
Which equipment is being used?
Who is doing the job? Who could do it better? Can a person with less skill do the job? Can we change the job so that less skilled person can do the job?
How is the work done? Eliminate, combine, rearrange and simplify motions.
(See for more details - Operations Analysis - http://nraoiekc.blogspot.in/2012/04/operation-analysis.html )
Case Study Papers
PRODUCTIVITY IMPROVEMENT THROUGH ECRS METHODOLOGY
August 2012 Blog Post
ECRS’s Principles for a Drinking Water Production Plant.
IOSR Journal of Engineering, May. 2012, Vol. 2(5) pp: 956-960
Improvement of Efficiency in Biodegradable Packaging Process
2010 conference paper
Updated 12 June 2016, 3 Sep 2013