Calculating Standard Time in Production Operations

The question asks us to determine the standard time for a production job, given the mean cycle time, worker efficiency, and allowances.

Understanding the Concepts

• Observed Time or Mean Cycle Time: This is the average time taken to complete one cycle of the operation based on direct observation. In this case, it is given as 10 minutes.
• Performance Rating or Worker Efficiency: This factor adjusts the observed time to account for the worker's pace. If the worker performs faster than normal, the rating is > 1 (or > 100%). If slower, it's < 1 (or < 100%). Here, the worker is performing at 90% efficiency, which means the performance rating is 0.90.
• Normal Time: This is the time a trained worker would take to complete the job cycle, working at a normal pace, without any interruptions or fatigue. It is calculated by adjusting the observed time using the performance rating.
• Allowances: These are additions to the normal time to account for personal needs, fatigue, and unavoidable delays. In this problem, allowances are given as 10% of the normal time.
• Standard Time: This is the total time allowed for a worker to complete one cycle of the job, working at a normal pace, including time for allowances.

Steps for Calculation

To find the standard time, we first need to calculate the normal time, and then add the allowances to the normal time.

Step 1: Calculate Normal Time

Normal Time is calculated using the formula:

\(\text{Normal Time} = \text{Observed Time} \times \text{Performance Rating}\)

Given:

• Observed Time = 10 min
• Performance Rating = 90% or 0.90

Calculation:

\(\text{Normal Time} = 10 \text{ min} \times 0.90\)

\(\text{Normal Time} = 9 \text{ min}\)

Step 2: Calculate Standard Time

Standard Time is calculated by adding allowances to the Normal Time. The allowances are 10% of the Normal Time.

\(\text{Allowances Amount} = 10\% \text{ of Normal Time}\)

\(\text{Allowances Amount} = 0.10 \times 9 \text{ min}\)

\(\text{Allowances Amount} = 0.9 \text{ min}\)

Now, add the allowances to the normal time:

\(\text{Standard Time} = \text{Normal Time} + \text{Allowances Amount}\)

\(\text{Standard Time} = 9 \text{ min} + 0.9 \text{ min}\)

\(\text{Standard Time} = 9.9 \text{ min}\)

Alternatively, we can use the formula:

\(\text{Standard Time} = \text{Normal Time} \times (1 + \text{Allowance Percentage as Decimal})\)

\(\text{Standard Time} = 9 \text{ min} \times (1 + 0.10)\)

\(\text{Standard Time} = 9 \text{ min} \times 1.10\)

\(\text{Standard Time} = 9.9 \text{ min}\)

Summary of Calculation

The calculated standard time for the job is 9.9 minutes.