Tools for Motion Study and Methods Analysis
Several charts and diagrams are used to analyze and record the various motions involved in a work operation process. These charts are called process charts. Some of these charts are described below
1. Flow Process Charts. A flow process chart is a graphic presentation of the sequence of operations involved in a work process. It shows the relations between various elements of the process. It is used to record activities of the worker, flow of materials and time covered in various elements of the process. it is also called flow diagram and it serves as a map of the work process. A typical flow process chart is given on earlier article. The meaning and result of various symbols used in this chart are as Operation, Inspection,
Transportation and Storage.
A flow process chart has been defined as “a graphic representation of the sequence of all operations, transportation, inspections, delays and storage occurring during a process or procedure and includes information considered desirable for analysis such as time required and distance moved”.
A flow process chart may very well disclose inefficiencies hidden in the production process and may suggest rearranging of work stations. Systematic visualization of each element in the production process in a summarized and compact form makes room for possible improvements. It may point out elimination of backtracking and unnecessary handling.
2. Machine tool record card. This card contains illustration of the equipment and provides information about capacity, space, power needs, handling devices, etc. It is also known as machine data card.
3. Flow diagram. It is a diagram showing the sequence or flow of materials in the manufacturing process. It provides a sketch or map of the work area (floor plan) indicating the location of various equipment. It is used to an the arrangement of facilities and to visualize the possible improvements for eliminating backtracking or long hauls of materials. It is drawn to scale and the path of each material is represented by a single line. It indicates the point of origin, route through which materials move and their destination.
A careful examination of the flow diagram gives an idea of the adequacy of the arrangement. If it reveals inefficient flow of materials, alternative arrangement might be attempted.
4. Operation flow chart: This chart is prepared in relation to systems procedures. It depicts a flow (sequence) of operations in a particular job. If it is found that a sequence involves operations which impede or delay the flow of work, it should be charged to remove causes of bottlenecks in the work flow. The object of such a chart is simplification of work. Therefore, it is also known as a work-simplification chart.
Thus, an operation process chart is a graphic depiction of the various operations involved in the production process.
5. Travel chart: It is in the form of a two-way table or matrix. The number of backward movements are shown below the thick diagonal line xy and the forward movements are indicated above the line. This chart represents the movements of materials as they travel in the process of being converted into finished products. It shows the origin of movement, the direction of movements and the destination of materials. It represents visually useful data for methods study and plant layout.
6. Operator Process Chart: Such a chart shows graphically the movements of the operator’s hands. Activities of left hand are shown in one column and those of the right hand in another column. This chart is also known as `right hand left hand chart’ as it shows simultaneous movement, of both the hands. When a time scale is also used, the chart is called ‘simo chart’ . Operator process charts are useful in analyzing and improving the motions of a worker to increase productivity and reduce physical strain.
7. Man-machine Chart: This type of chart shows simultaneously the activities of both the operator and the machine. It is a graphic view of the operations carried out by man-machine system. It is also known as multiple activity chart. It may be in tabular or circular form. A man-machine chart is helpful in securing optimum use of both labor and machinery.
8. String Diagram. A string diagram indicates the paths taken by men and materials during the course of work. Pieces of string are used as connecting links indicating the path of operations involved in a task and total distance traveled during an operation. Sometimes, work positions are marked with pins.
9. Cyclographs. Cyclograph was developed by Gilbreth as an addition to the range of photographic aids. Small electric bulbs are attached to the fingers of the operator and a photographic plate is exposed to the scene for a period of one cycle. The spots of light trace out movement of the hands on the exposed plate. A variation of this is the chronocyclograph in which interrupted light in the form of regular flashes is used. With its help speed can also be estimated from the pear shaped spots of light on the photograph.