The SIMO Chart (Simultaneous Motion Chart) is a detailed and specialized tool used in
micromotion study to record and analyze simultaneous motions of both hands (or limbs) in a
time-precise manner. It is particularly useful in highly repetitive manual operations where
efficiency and ergonomics are critical.
Definition
SIMO (Simultaneous Motion) Chart is a graphical representation used to record the therbligs
(basic motion elements) of both the left and right hands (or limbs) simultaneously, against
time (usually in hundredths or thousandths of a minute).
Components of a SIMO Chart
•
Two parallel columns: One for each hand (or limb).
•
Time scale: Along the vertical axis (in time units like microns or seconds).
•
Therbligs: Symbols or codes representing basic motions (e.g., search, grasp, hold,
transport).
•
Horizontal lines: Indicate simultaneous or sequential activities.
•
Idle time: Easily spotted when one hand is waiting.
Use of SIMO Chart
•
To study rapid and repetitive jobs, e.g., assembly line tasks.
•
To balance hand movements for improved productivity.
•
To eliminate unnecessary motions.
•
To help in designing tools, jigs, and workstations ergonomically.
Benefits
•
Highly detailed: Down to fractions of seconds.
•
Accurate comparison of hand activities.
•
Helps identify asymmetries or inefficiencies.
•
Used as a basis for standardizing and training.
Example Scenario
An operator assembling a small component:
•
Right hand: Reaches, grasps tool, moves, positions, releases.
•
Left hand: Picks up part, holds, aligns, releases.
•
SIMO chart would show these actions on a time scale, highlighting overlaps and
imbalances.
Principles of Motion Economy
The Principles of Motion Economy are a set of guidelines developed primarily by Frank and
Lillian Gilbreth to optimize manual tasks in industrial settings. These principles aim to
minimize the effort and time required to complete a task by eliminating unnecessary
movements and designing efficient work environments.
A. Principles Related to the Use of the Human Body
1. Both hands should begin and complete their motions at the same time.
→ Avoid idle time by balancing work between both hands.
2. Hands should not be idle at the same time except during rest periods.
→ Reduce unproductive time and increase efficiency.
3. Use the momentum of the body to assist work.
→ Let natural body movements contribute to the task.
4. Continuous curved motions are more efficient than straight-line motions with
sharp changes in direction.
5. Rhythmic and smooth motions are more efficient.
6. Minimize the number of motions involved in a task.
B. Principles Related to the Arrangement of the Workplace
1. Tools and materials should have a fixed place.
→ This minimizes search time and movement.
2. Materials and tools should be located close to the point of use.
3. Gravity feed bins and containers should be used to deliver materials close to the
point of use.
4. Provide proper seating to reduce fatigue.
5. Height of workbench and placement of tools should permit good posture and easy
reach.
6. Use jigs, fixtures, and templates to reduce manual effort.
C. Principles Related to the Design of Tools and Equipment
1. Use tools that can be operated with minimal hand motions.
2. Use tools that can perform multiple functions or actions.
3. Design handles to fit the hand comfortably and securely.
4. Use mechanical aids (e.g., foot pedals, power tools) to reduce manual effort.
5. Automate repetitive tasks when feasible.
Benefits of Applying Motion Economy Principles
•
Increased productivity
•
Reduced operator fatigue
•
Enhanced safety and ergonomics
•
Improved job satisfaction
•
Basis for method standardization
1. Basic Time
This is the time required by a worker to complete a task using a standard method and working
at a standard pace, without any interruptions or fatigue allowances.
Formula:
Basic Time = Observed Time × Performance Rating Factor
2. Allowances
Allowances are added to the basic time to account for unavoidable delays, fatigue, personal
needs, and other interruptions. These ensure that the standard time reflects realistic working
conditions.
Types of Allowances:
1. Relaxation Allowance
o
Compensates for physical and mental fatigue.
o
Includes personal needs (e.g., restroom breaks).
o
Typically around 5% to 7% of basic time.
2. Contingency Allowance
o
Covers small, infrequent delays or work variabilities.
o
Added when the job involves occasional interruptions.
3. Special Allowance
o
Given for specific reasons like handling toxic materials or extreme weather
conditions.
o
Determined case-by-case.
4. Interference Allowance
o
Relevant in machine-manned operations where one worker controls multiple
machines.
o
Accounts for idle time when the worker waits for one machine while working on
another.
3. Standard Time
Standard Time is the total time allowed to complete a job, including all necessary allowances.
Formula:
Standard Time = Basic Time + Allowances
Or,
Standard Time = Basic Time / (1 - Total Allowance %)
Example:
If Basic Time = 100 seconds
Total Allowance = 15%
Then:
Standard Time = 100 / (1 - 0.15) = 117.65 seconds
Importance of Standard Time
•
Used for workforce planning, cost estimation, and incentive schemes.
•
Helps in evaluating worker efficiency and machine utilization.
•
Ensures fair workload distribution.
Job Evaluation and Merit Rating
1. Job Evaluation
Definition:
Job Evaluation is a systematic process of determining the relative worth of various jobs within
an organization to establish fair and equitable wage structures.
Objectives:
•
Eliminate wage inequalities.
•
Establish a rational pay structure.
•
Facilitate promotions and transfers.
•
Improve employee morale.
Methods of Job Evaluation:
1. Ranking Method
o
Jobs are arranged in order of importance or difficulty.
o
Simple but lacks detailed analysis.
2. Job Classification Method
o
Jobs are grouped into predetermined grades or classes.
o
Used in government and public sectors.
3. Point Rating Method
o
Jobs are evaluated based on key compensable factors (e.g., skills, effort,
responsibility).
o
Each factor is assigned points; total points determine job worth.
4. Factor Comparison Method
o
Combines the ranking and point methods.
o
Jobs are compared against key factors using benchmark jobs.
Factors Considered:
•
Skill level
•
Effort (mental and physical)
•
Responsibility
•
Working conditions
2. Merit Rating (Performance Appraisal)
Definition:
Merit Rating is the process of evaluating the performance of individual employees based on
predetermined criteria. It helps in identifying high performers and areas for improvement.
Objectives:
•
Assess employee efficiency.
•
Determine training needs.
•
Support promotion and salary decisions.
•
Provide feedback and motivation.
Methods of Merit Rating:
1. Ranking Method
o
Employees ranked from best to worst.
2. Graphic Rating Scale
o
Numerical rating across various traits (e.g., punctuality, job knowledge).
3. Checklist Method
o
Yes/No checklist of employee behavior or traits.
4. 360-Degree Feedback
o
Feedback from peers, subordinates, superiors, and sometimes clients.
5. Management by Objectives (MBO)
o
Performance assessed based on goal achievement.
Traits Evaluated:
•
Job knowledge
•
Attendance and punctuality
•
Communication skills
•
Initiative and creativity
•
Leadership and teamwork
Key Differences
Feature
Job Evaluation
Merit Rating
Focus
Job
Employee
Purpose
Set wage levels
Appraise individual performance
Frequency Done occasionally Done periodically (e.g., annually)
Basis
Job responsibilities Personal qualities and output
Wage Payment Plans
Wage payment plans are structured methods to determine how employees are paid for their
labor. The objective is to ensure fairness, reward productivity, control labor costs, and motivate
workers.
1. Time-Based Wage System
Definition:
Wages are paid based on the time an employee spends on the job, regardless of output.
Formula:
Wages = Hours Worked × Rate per Hour
Advantages:
•
Simple to administer.
•
Provides income security.
•
Suitable for jobs where output is hard to measure.
Disadvantages:
•
No direct incentive for higher productivity.
•
May lead to idle time and reduced efficiency.
2. Piece-Rate System
Definition:
Wages are based on the number of units produced, not the time taken.
Formula:
Wages = Units Produced × Rate per Unit
Advantages:
•
Encourages higher productivity.
•
Simple to calculate for repetitive tasks.
Disadvantages:
•
May compromise quality.
•
Not suitable for complex or variable jobs.
•
Can lead to worker fatigue.
3. Incentive Plans (Bonus Systems)
These plans combine base pay with additional rewards based on performance.
A. Halsey Plan
•
Basic time rate is guaranteed.
•
A bonus is given for saving time.
Bonus = 50% of time saved × hourly rate
Total wages = Time taken × rate + Bonus
B. Rowan Plan
•
Bonus depends on the proportion of time saved.
Bonus = (Time saved / Time allowed) × Time taken × Rate
Total wages = Time taken × Rate + Bonus
C. Taylor’s Differential Piece Rate System
•
Different rates for efficiency levels:
o
Lower rate for output < standard
o
Higher rate for output ≥ standard
D. Merrick Multiple Piece Rate System
•
3 levels of piece rates based on output percentage.
o
<83% of standard output: basic piece rate
o
83%–100%: 110% of basic rate
o
100%: 120% of basic rate
4. Group Incentive Plans
Wages or bonuses are shared among a group based on collective performance.
Useful when:
•
Teamwork is essential.
•
Output can't be assigned to individuals.
5. Profit-Sharing & Co-Partnership
•
Profit Sharing: Employees get a fixed share of company profits.
•
Co-Partnership: Workers receive shares of stock or become part-owners.
6. Modern Systems
•
Gainsharing: Bonuses tied to improved productivity or cost savings.
•
Skill-based pay: More skills = higher pay.
•
Commission-based: Common in sales.
Conclusion
Choosing the right wage payment plan depends on:
•
Nature of the work
•
Measurability of output
•
Organizational goals
•
Worker motivation and fairness
Production Planning and Control (PPC)
Production Planning and Control (PPC) is the process of organizing and optimizing the use of
resources (manpower, machines, materials, and time) to produce goods and services
efficiently. It ensures that production occurs on time, within budget, and at the desired
quality level.
A. Components of PPC
1. Production Planning
o
Deciding what, when, and how much to produce.
o
Involves forecasting, resource allocation, routing, and scheduling.
2. Production Control
o
Monitoring and adjusting production activities to match the plan.
o
Includes dispatching, progress tracking, and corrective actions.
B. Importance of Planning in Production
1. Efficient Use of Resources
o
Planning ensures optimal use of raw materials, labor, and machines, reducing
waste and idle time.
2. Improved Coordination
o
Helps coordinate between departments like design, procurement, and
manufacturing.
3. Timely Delivery
o
Ensures products are manufactured and delivered on time, enhancing customer
satisfaction.
4. Inventory Management
o
Reduces overstocking and understocking by balancing production with demand.
5. Cost Control
o
Minimizes production costs through effective scheduling, batch sizing, and
resource planning.
6. Quality Assurance
o
Helps maintain consistent product quality by planning process standards and
inspections.
7. Flexibility and Adaptability
o
Enables quicker response to market changes, customer orders, or disruptions in
supply chain.
8. Risk Reduction
o
Anticipates potential bottlenecks and allows for proactive problem-solving.
9. Improved Labor Productivity
o
Clearly defined plans provide workers with better understanding of their tasks
and timelines.
10. Capacity Planning
o
Helps align production with market demand by analyzing plant capacity and
workload.
Conclusion
Effective planning is the foundation of successful production operations. It lays out the
roadmap for execution, helps utilize resources wisely, and ensures that production goals are
met efficiently and economically.
Forecasting Techniques
Forecasting is the process of predicting future trends or outcomes based on historical data and
analysis. It is a critical part of business decision-making for inventory management, production
scheduling, and strategic planning.
1. Qualitative Forecasting Techniques
These techniques are used when there is little or no historical data available, and the forecast is
based on subjective judgment, expert opinion, or market research.
A. Delphi Method
•
A panel of experts is consulted individually and anonymously to provide forecasts.
•
The responses are summarized and sent back for further refinement until a consensus
is reached.
B. Market Research
•
Involves collecting data from potential customers through surveys, focus groups, and
interviews to predict future demand.
•
Common in new product development.
C. Executive Judgment
•
Forecast is made based on the opinions of key executives or managers.
•
Often used for long-term forecasts in the absence of historical data.
2. Quantitative Forecasting Techniques
These techniques use historical data to make predictions about future events. They are typically
more accurate than qualitative methods and are used for products or services with sufficient
data.
A. Time Series Analysis
Time series forecasting is based on historical data points over a specific period, identifying
patterns or trends to make predictions.
1. Moving Averages
o
Smooths out short-term fluctuations to identify longer-term trends or cycles.
o
Simple moving average (SMA) and weighted moving average (WMA) are
commonly used.
2. Exponential Smoothing
o
Similar to moving averages, but assigns more weight to recent data points,
making the model more responsive to changes.
3. Trend Analysis
o
Identifies long-term movement in data (increasing, decreasing, or constant).
o
Linear regression is often used to fit a trend line to historical data.
B. Causal Models (Cause and Effect)
Causal forecasting methods establish relationships between the forecasted variable and other
variables that influence it.
1. Linear Regression
o
Predicts the value of a dependent variable based on one or more independent
variables.
o
Used to model and analyze relationships in data.
2. Multiple Regression
o
Similar to linear regression but considers more than one independent variable.
o
More complex but can account for multiple factors influencing demand.
C. Box-Jenkins (ARIMA) Method
•
ARIMA (Auto-Regressive Integrated Moving Average) models are used to predict
future points in a time series by using past values, differences between values, and past
forecast errors.
•
Suitable for non-stationary data with trends or seasonal components.
3. Judgmental and Mixed Techniques
These combine both qualitative and quantitative methods to refine forecasts and improve
accuracy.
A. Naive Forecasting
•
Assumes that the future will follow the same pattern as the most recent period. It’s often
used in stable markets or where little data exists.
B. Consensus Forecasting
•
A combination of different forecasting methods or inputs from various departments
(marketing, finance, etc.) to come up with a final forecast.
Conclusion
The choice of forecasting technique depends on the availability of data, the nature of the
product or service, and the business environment. Quantitative methods tend to be more
precise for established products with historical data, while qualitative techniques are useful
for new products or services.