Chapter D, Problem 7E

To determine

Manufacturing Cycle Time:

The time taken from ordering raw material inventory to putting it in manufacturing production process to producing the finished goods . this can be categorized into following components as below

1. Process Time : The actual time taken in processes where the raw material is converted into finished goods . This is also called value added activity which can be reduced by using various techniques like kaizen which is continuous improvement technique
2. Inspection Time : The time taken for inspection of quality of raw material , work in process at different process end and finished goods . This is part of non value added activity
3. Move Time : The time taken for movement of raw material and work in process goods and people between different process . This is part of non value added activity
4. Wait time : The time taken between getting the production order and ordering the raw material inventory and actual arrival at production floor and during the process . This is part of non value added activity

The formula to calculate manufacturing cycle time is given below

  $\begin{array}{l}\text{Manufacturing Cycle time = (Process Time + Inspection Time + Move time + Wait Time)}\\ \end{array}$

Manufacturing Cycle Efficiency:

This is ratio which calculated the total time spend on value added activity from the total manufacturing cycle time and is represented in percentage terms

The formula to calculate manufacturing cycle efficiency is given below

$\text{Manufacturing Cycle Efficiency = (Value added activity /Total manufacturing cycle time) x 100}$

The manufacturing cycle time

Answer to Problem 7E

The manufacturing cycle time is 50 hours

Following information is given

• Process time is 16.0 hours is also value added activity time
• Inspection time is 3.5 hours
• Move time is 9 hours
• Wait time is 21.5 hours

The formula to calculate manufacturing cycle time is given below

  $\begin{array}{l}\text{Manufacturing Cycle time = (Process Time + Inspection Time + Move time + Wait Time)}\\ \text{Manufacturing Cycle time = (16 hours + 3}\text{.5 hours + 9 hours + 21}\text{.50 hours)}\\ \text{Manufacturing Cycle time = 50 hours}\\ \end{array}$

The manufacturing cycle time is 50 hours

The manufacturing cycle efficiency

The manufacturing cycle efficiency is 32%

Following information is given

• Process time is 16.0 hours is also value added activity time
• Inspection time is 3.5 hours
• Move time is 9 hours
• Wait time is 21.5 hours

The formula to calculate manufacturing cycle time is given below

  $\begin{array}{l}\text{Manufacturing Cycle time = (Process Time + Inspection Time + Move time + Wait Time)}\\ \text{Manufacturing Cycle time = (16 hours + 3}\text{.5 hours + 9 hours + 21}\text{.50 hours)}\\ \text{Manufacturing Cycle time = 50 hours}\\ \end{array}$

The formula to calculate manufacturing cycle efficiency is given below

$\begin{array}{l}\text{Manufacturing Cycle Efficiency = (Value added activity /Total manufacturing cycle time) x 100}\\ \text{Manufacturing Cycle Efficiency = (16 /50) x 100}\\ \text{Manufacturing Cycle Efficiency = 0}\text{.32 x 100}\\ \text{Manufacturing Cycle Efficiency = 32\%}\end{array}$

The manufacturing cycle efficiency is 32% which shows 68% time is spend on non value added activities which should be reduced to bring more efficiency in the production process and resulting in faster delivery to customer

The revised non value added activity time

The revised non value added activity time is 4 hours

Following information is given

• Process time is 16.0 hours is also value added activity time
• The manufacturing cycle efficiency is 0.80 or 80%

To calculate the total manufacturing cycle time by using the formula of manufacturing cycle efficiency as given below

  $\begin{array}{l}\text{Manufacturing Cycle Efficiency = (Value added activity /Total manufacturing cycle time) }\\ \text{where}\\ \text{Manufacturing Cycle Efficiency = 0}\text{.80}\\ \text{value added activity = 16 hours ( which is the process time)}\\ \text{Putting the value in the formula we get}\\ \text{Manufacturing Cycle Efficiency = (Value added activity /Total manufacturing cycle time)}\\ \text{or Total manufacturing cycle time = (Value added activity /Manufacturing Cycle Efficiency) }\\ \text{Total manufacturing cycle time = (16 /0}\text{.80) }\\ \text{Total manufacturing cycle time = 20 hours}\end{array}$

The formula to calculate manufacturing cycle time can be re-written as below

$\begin{array}{l}\text{Manufacturing Cycle time = value added activity time + non value added activity time}\\ \text{Non value added activity time = Manufacturing Cycle time - Value added activity time}\\ \text{Putting the values in the formula we get}\\ \text{Non value added activity time = Manufacturing Cycle time - Value added activity time}\\ \text{Non value added activity time =}20\text{ hours - 16 hours}\\ \text{Non value added activity time = 4 hours}\end{array}$

If the manufacturing cycle efficiency is 0.80 or 80% and value added activity time is unchanged then the non value added activity time should be 4 hours to achieve the desired manufacturing cycle efficiency

Explanation of Solution

Following information is given

• Process time is 16.0 hours is also value added activity time
• Inspection time is 3.5 hours
• Move time is 9 hours
• Wait time is 21.5 hours

The formula to calculate manufacturing cycle time is given below

  $\begin{array}{l}\text{Manufacturing Cycle time = (Process Time + Inspection Time + Move time + Wait Time)}\\ \text{Manufacturing Cycle time = (16 hours + 3}\text{.5 hours + 9 hours + 21}\text{.50 hours)}\\ \text{Manufacturing Cycle time = 50 hours}\\ \end{array}$

The manufacturing cycle time is 50 hours

The manufacturing cycle efficiency

The manufacturing cycle efficiency is 32%

Following information is given

• Process time is 16.0 hours is also value added activity time
• Inspection time is 3.5 hours
• Move time is 9 hours
• Wait time is 21.5 hours

The formula to calculate manufacturing cycle time is given below

  $\begin{array}{l}\text{Manufacturing Cycle time = (Process Time + Inspection Time + Move time + Wait Time)}\\ \text{Manufacturing Cycle time = (16 hours + 3}\text{.5 hours + 9 hours + 21}\text{.50 hours)}\\ \text{Manufacturing Cycle time = 50 hours}\\ \end{array}$

The formula to calculate manufacturing cycle efficiency is given below

$\begin{array}{l}\text{Manufacturing Cycle Efficiency = (Value added activity /Total manufacturing cycle time) x 100}\\ \text{Manufacturing Cycle Efficiency = (16 /50) x 100}\\ \text{Manufacturing Cycle Efficiency = 0}\text{.32 x 100}\\ \text{Manufacturing Cycle Efficiency = 32\%}\end{array}$

The manufacturing cycle efficiency is 32% which shows 68% time is spend on non value added activities which should be reduced to bring more efficiency in the production process and resulting in faster delivery to customer

The revised non value added activity time

The revised non value added activity time is 4 hours

Following information is given

• Process time is 16.0 hours is also value added activity time
• The manufacturing cycle efficiency is 0.80 or 80%

Conclusion

To calculate the total manufacturing cycle time by using the formula of manufacturing cycle efficiency as given below

  $\begin{array}{l}\text{Manufacturing Cycle Efficiency = (Value added activity /Total manufacturing cycle time) }\\ \text{where}\\ \text{Manufacturing Cycle Efficiency = 0}\text{.80}\\ \text{value added activity = 16 hours ( which is the process time)}\\ \text{Putting the value in the formula we get}\\ \text{Manufacturing Cycle Efficiency = (Value added activity /Total manufacturing cycle time)}\\ \text{or Total manufacturing cycle time = (Value added activity /Manufacturing Cycle Efficiency) }\\ \text{Total manufacturing cycle time = (16 /0}\text{.80) }\\ \text{Total manufacturing cycle time = 20 hours}\end{array}$

The formula to calculate manufacturing cycle time can be re-written as below

$\begin{array}{l}\text{Manufacturing Cycle time = value added activity time + non value added activity time}\\ \text{Non value added activity time = Manufacturing Cycle time - Value added activity time}\\ \text{Putting the values in the formula we get}\\ \text{Non value added activity time = Manufacturing Cycle time - Value added activity time}\\ \text{Non value added activity time =}20\text{ hours - 16 hours}\\ \text{Non value added activity time = 4 hours}\end{array}$

If the manufacturing cycle efficiency is 0.80 or 80% and value added activity time is unchanged then the non value added activity time should be 4 hours to achieve the desired manufacturing cycle efficiency