In apparel manufacturing, “Production capacity” is one of
the most important criteria used for vendor selection by the buyers. It is
because; the production time of an order is directly proportional to vendor’s
production capacity. So it is very important that marketing and planning
personnel should aware about the production capacity of their production units.
The capacity of a factory is primarily expressed in terms
of total machines factory have. Secondly, how much pieces the factory produces
on daily for the specific products? In general, total numbers of machines in a
factory mostly remains same for a period. But factory may produce various types
of the product during the season. According to the product (style) category,
machine requirement may change and daily average production in each style may
vary. So to be specific during booking orders, a planner should know exactly
how much capacity he or she needed to procure the order in a given time period.
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| Sewing Floor (Image Credit: Shahi Exports Pvt. Ltd. via Facebook page) |
A factory’s capacity is presented in total minutes or hours
or in pieces (production per day). The method used to calculate capacity has
been explained in the following. To calculate Daily production capacity (in
pieces) one needs the following information.
1. Factory capacity in hours
2. Product SAM
3. Line efficiency (Average)
1. Calculation of factory capacity (in
hours):
Check how many machines factory has and
how many hours’ factory runs in a day. For example, suppose,
Total number of machines = 200
Shift hours per day = 10 hours
So total factory capacity (in hours) =
200 × 10
hours = 2000 hours
2. Calculation of Product SAM (SAM):
Make a list of the product category
that you manufacture and get standard minutes (SAM) of all products you make
from work study engineers. If you don’t have product SAM then calculate the SAM. Or you can use average SAM of the products. Suppose you are
producing a shirt and its SAM is 25 minutes.
3. Factory Average Efficiency:
This data is collected from the
industrial engineer. Or calculate it with historical data. Suppose average line
efficiency is 50%. Read the article - How to calculate efficiency of a production line or
batch?
Calculation of production capacity (in
pieces):
Once you have above information use
following formula to calculate production capacity.
Production capacity (in pieces) =
(Capacity in hours*60/product SAM)*line efficiency
For Example: Suppose a factory has 8
sewing lines and each line has 25 machines. Total 200 machines and the working
shift is 10 hours per day. Total factory capacity per day is 2000 hours (200
machines * 10 hours). If factory is producing only one style (Shirt) of SAM 25
minutes and used all 200 machines daily production capacity at 50%
= (2000 × 60 / 25) × 50% Pieces
= (2000 × 60 × 50) / (25 × 100) Pieces
= 2400 Pieces
[Note: Production will vary according
to the line efficiency and during learning curve or in the initial days when
style is loaded to the line]
Production (capacity) planning is
normally done based on sewing capacity. Having knowledge of the capacity in
other processes (internal or external) is also very important. Otherwise, the
planner may fail and will not be able to meet the dead line. Other departments
such as cutting room capacity, Finishing room capacity, Washing Capacity and
capacity of the value-added jobs.
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