How to calculate capacity of a machine?

Question: I have a question, need your help. In an article about calculating machines, I just found "how to Calculate Machine Productivity" But can you explain more for me about how to calculate the capacity of the machine? (For example: How many products can be made in one shift if use 1 type of machine?)

 

Answer:

Thank you for asking this question. I want to address all kinds of questions related to garment manufacturing. I am happy to answer this question in this post. 

Definition of machine capacity:

Production capacity is defined as maximum production or output, which can be produced in the production line with the help of available resources. The capacity of a machine is calculated over days or weeks or months. The measurement is done in a way that we can adjust our production capacity according to the demand.

The capacity of a sewing machine or any other machine is calculated using the following variables.

• Process cycle time (operation’s cycle time),
• total shift time (Machine used time)
• machine allowances
• machine idle time

A machine is available for full-time to be utilized. But there are a few constraints that may limit the capacity of a machine.

• There would be some time loss due to machine breakdown.
• Unavailability of feeding (work input)
• Machine stoppage due to preventive maintenance
• And production rate from the machine will depend on the operators’ performance rate. Using the same machine one can make, 3-4 shirts in a day. And a skilled person can make 8-10 shirts in a day.

To accommodate all these constraint, normally allowance is added to the cycle time. It is between 10%-20% percentage.

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Related post: How to calculate the production capacity of a factory?

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Steps for calculating machine capacity:

The process cycle time can be measured through time study. In case you already have operation SAM, you can directly use the operation SAM (standard time of the process) to calculate machine capacity.

The formula would be as follows:

= ((Shift time in minutes – Machine idle time) / (Average operation cycle time x Allowance percentage)) x Operator efficiency

OR

= ((Shift time in minutes – Machine idle time) / (Operation SAM)) x operator’s efficiency

Example-1: 

Let’s say you have one lock stitch machine. An operator is working on the machine and stitching shirts. Operation SAM is 2 minutes. Let’s consider, the machine was idle for 30 minutes and the operator skill level is 80%. Therefore, machine capacity would be.

= ((480 minutes – 30 minutes)/2) x 80%
= (450/2) x 0.80
= (225 x 0.80)
= 180 pieces

For this case, you see machine capacity is 180 pieces per day. The capacity of the same machine would vary if you do an operation of different SAM and a different operator work on that sewing machine.   

Example-2: 

To calculate machine capacity from the operation cycle time, you need to first calculate average operation cycle. Check this post to know average cycle time calculation. Then follow the above formula to calculate machine capacity.

Let’s say, the average cycle time of an operation is 1.2 minutes. Allowance – 20%, Operator efficiency – 80%. Average cycle time after allowance – 1.8 minutes.

Machine capacity

= ((480 – 30) /1.8) x 80%
= (450 / 1.8) x 0.80
= 250 X 0.80
= 200 pieces.

In the case of an automatic machine (with continuous feeding), there would be more accurate machine capacity.