Machine Requirement for Garment Assembly Line
Garment Assembly Line:
In garment production, until garment components are gathered into a finished garment, they are assembled through a sub-assembly process. The production process includes a set of workstations, at each of which a specific task is carried out in a restricted sequence, with hundreds of employees and thousands of bundles of sub-assemblies producing different styles simultaneously.
Follow the following steps to estimate how many machines and what types of machines you need to make your garment in an assembly line. The primary information you need to calculate number of machines are –
- Daily production target –it means how many pieces you want to stitch per day.
- Number of hours in a shift –How many hours you plan to work each day
- SMV of each operation –Standard minutes for each operation
- Present efficiency of the factory (in case you don’t aware about present factory efficiency, use 50% efficiency).
Efficiency is required because production will depends on how efficiently workers may do their job.
Step 1: Operation breakdown –Select a garment for which you want to calculate machine requirement. Analysis the operations required to sew the garment and list down operations in a spread sheet in a sequence. For example, see operation break down of a Crew neck Tee in following table.
Step 2: Identify machine type –Observe what stitch class has been used in the operations and according to those select machines against each operation.
Step 3: SMV of each operation –write down SMV or standard minutes at right column of machine type. SMV is the most important part for calculating machine requirement. You can use SAM of each operation from your database. If you don’t have database for standard minutes then calculate.
Step 4: Calculate Theoretical machine requirement –Set your production target for the day (8 hours shift). Example-400 pieces per line. Use present efficiency level of the factory. And now, calculate machine requirement using the following formula. It is called as calculated machine number. Because formula gives you fraction of machine but in real you can’t able to use fraction of machine.
= (Target quantity in pieces* individual operation SMV)/ (8 hrs.*60 minutes*desired efficiency)
= (A*C)/ (B*60*D)
Step 5: Physical machine requirement –Now simply round off the machine number. Or you can club operations those use similar machine class. To do operation “Serge margin” half machine is required and the operation “sew side seam with label” required 1.4 machines. So can use first 4TOL machine to do the second job. Hence you can reduce the machine number and increase machine utilization.