How to Make an Operation Bulletin for a Garment?

Creating an Operation Bulletin (OB) for a garment is an essential step in the sewing and production process of apparel manufacturing. It serves as a roadmap for stitching operations, helping optimize production, maintain consistency, and control costs. 

An Operation Bulletin (OB) is one of the most essential Industrial Engineering (IE) tools used in garment manufacturing. It helps set up a production line with the correct number of machines and manpower, ensuring balanced workflow and optimal efficiency.

Before you start preparing an OB, you must understand three fundamental concepts:

1. How to determine operation SMV (Standard Minute Value)

2. How to calculate machine requirements

3. How to make an operation breakdown for a garment

Once these are clear, follow the steps below to prepare an effective Operation Bulletin.

Step #1: Prepare an OB Format

You’ll need a computer with a spreadsheet application (like Microsoft Excel) to make the OB format and perform automatic calculations.

At the top (header) of the sheet, include basic information such as:

• Style No.

• Buyer Name

• Order Quantity

• Garment Description

• Fabric Type

• SAM (Standard Allowed Minutes)

• Target Efficiency (%)

This helps anyone reading the OB understand the key production details at a glance.

Step #2: List the Garment Operations

Break down the garment construction into a sequence of individual sewing operations — from the first stitch to the last.
Each operation should be written in a clear and logical order following the actual production flow.
Example operations might include:

• Join shoulder seams

• Attach collar

• Close side seams

• Hem sleeves

• Attach main label

Step #3: Identify Machine Types and Work Aids

For each operation, specify:

• The machine type required (e.g., Single Needle, Overlock, Flatlock)

• Any special attachments or folders needed (e.g., binder, edge guide, trimmer)

This ensures the line is equipped properly and operators have all necessary tools.

Step #4: Assign SMV (Standard Minute Value)

For every operation, input the SMV — the time required for a skilled operator to complete one cycle of that task under normal working conditions.
You can determine SMV through:

• Time Study (stopwatch method)

• Predetermined Motion Time Systems (PMTS) such as GSD or MTM

Accurate SMV helps in line balancing, capacity planning, and costing.

Step #5: Calculate Targets and Machine Requirement

Use Excel formulas to calculate:

• Operation-wise hourly target

• No. of machines/operators required

• Cumulative SAM and total manpower

Example formula for target per hour:

Target per hour = (60 / SAM) × Efficiency (%)

Example formula for total machine requirement:

Total Machines = Total SAM × Target Output / (60 × Efficiency)

Step #6: Finalize the OB Sheet

Your OB should now look like this:

Step #7: Review and Use in Production

• Review the OB with the IE and Production teams before implementation.

• Adjust based on pilot run feedback or style variations.

• Use the OB for:

  • Line setup

  • Operator allocation

  • Target setting

  • Performance monitoring

Here is a detailed explanation of how to set up an Operation Bulletin (OB) in Excel with formulas for auto-calculation of all necessary fields. You can use this as a guide when creating or enhancing your OB sheet.

Basic Components of an Operation Bulletin

An Operation Bulletin (OB) is a document used in garment manufacturing to define and plan operations required to complete a garment. Here's how each element should be addressed in the sheet:

1. Daily Working Hours

• Purpose: To define how many hours an operator works per day (e.g. 8 hours).

• Cell Example: B2

• Usage: Base for calculating capacity and targets.

2. Target Output per Day / per Hour

• Per Day Formula:
  Target Per Day = Working Hours × Target Per Hour

• Per Hour Formula:
  Target Per Hour = 60 / SMV @ Target Efficiency

3. Total SMV

• Components:

  • Sewing SMV

  • Non-Sewing SMV

• Formula:
  Total SMV = SUM(Sewing SMV, Non-Sewing SMV)

4. OB Prepared By

• Entered manually (e.g. Engineer Name).

5. Job Code / Style Code

• For factory tracking; manually entered.

6. Operation Description

• Line-wise description of each operation; entered manually.

7. Machine Description

• Machine type used for each operation; manually entered.

8. SMV @ 100% Efficiency

• Enter the calculated SMV for each operation.

• Cell Formula Example (if SMV = 0.50 @ 100%):
  0.50

9. SMV @ Target Efficiency %

• Formula:
  SMV @ Target = SMV @ 100% / Target Efficiency %

• Example:
  If SMV is 0.50 and target efficiency is 70%,
  =0.50 / 0.70

10. Calculated Production Per Hour

• Formula:
  Production Per Hour = 60 / SMV @ Target

11. Folder/Attachment Used

• Note whether any folder, guide, or attachment was used.

12. Calculated No. of Machines

• Based on target per day/hour and SMV:

• Formula:
  No. of Machines = Total SMV × Target Per Day / (Daily Working Hours × 60)

13. Actual No. of Machines

• Enter actual allocation on the line.

14. Estimated Production per Unit Hour

• Formula:
  Estimated Production = Target Per Day / (Working Hours × 60) × Total SMV

15. Remarks

• For any additional comments or concerns.

16. Machine Summary List

• At the end of the OB sheet, generate a summary of all machines used, with counts.

• You can use functions like COUNTIF() or pivot tables for summarization.