To manage garment stitching quality on the sewing floor, we use various methods of checking garments and reporting operator-wise quality performance. I have explained the different types of quality inspections in another article. In today’s post, I will cover the Traffic Light System (TLS) for garment inspection
What is Traffice Light System in Garment Quality Management?
The Traffic Light System is widely used in garment quality inspection. This system helps stop defects at their source. It is a random inspection technique and is often more effective in controlling shop-floor quality than other tools because of its visual communication format. At the same time, it measures the operator’s quality performance level.
TLS acts as a direct feedback mechanism to sewing operators regarding their stitching quality. No operator wants to be identified as a low-quality performer; therefore, they naturally pay more attention to quality when TLS is implemented.
The TLS format is used for both displaying and recording audit results. It is simple to understand and use. The format is printed on a slightly thick A4 sheet and hung on the sewing machine. In this system, a quality auditor visits each operator’s workstation four times a day (in an 8-hour shift), inspects stitched garments, and fills the circles with color according to the inspection results.
Objectives of the Traffice Light System
- Quality control through operator-wise and operation-wise inspection
- Faster identification of defects and immediate feedback to operators
- Understanding training needs through TLS data analysis
- Explaining style-specific quality requirements to operators
- Reducing DHU levels in inline and end-of-line inspections
- Increasing Right-First-Time (RFT) or First-Time-Right (FTR) output
- Improving floor productivity by improving quality
- Documenting the quality process as part of the factory’s quality control system
History of Traffice Light Inspection system
In the initial phase, when this format was introduced by J.C. Penney for their suppliers, auditors were instructed to inspect 7 pieces. If the auditor found any defective garment, the respective circle was filled with RED. Whenever a red mark appeared, all stitched pieces had to be checked by the auditor, and the operator was briefed about the quality requirements and how to achieve them. In some cases, operators needed additional practice to produce defect-free pieces.
Later, factory Quality Auditors (QAs) modified the sample size, rating criteria, and introduced the yellow color for intermediate scoring. The sample size was reduced because auditors often did not find 7 pieces at a time at many workstations due to low Work-In-Process (WIP) in single-piece or low-buffer systems.
Recently, I visited a factory in Delhi where TLS is followed. The TLS format is attached to all sewing workstations, usually hung from the thread stand. Their criteria were as follows:
Standard TLS Criteria Used by the Factory
Sample Size: 5 pieces
Inspection Frequency: Every 2 hours
Color Marking Rules:
- GREEN: If no defect found in the checked garments (garment parts)
- YELLOW: If found 1 defect
- RED: If found 2 defects. Stop production.
TLS inspection method
The format is used for a single operator or workstation. One sheet is used to record the entire month’s data for that operator. On the first day of the month, the auditor fills in:
- Operator name
- Operation name
- QA name
- Line number,
- Floor number
- Inspection Month.
Inspection instructions have been given on the format itself with rating procedures. The format is displayed in two sections to cover 31 days (whole month). Write the date in the cells of the top row. Each column contains 4 circles, represents four inspections in a day.
After inspection is conducted, fill the respective circle (date and number of inspection of the day) according to the rating criteria. At the end of the day quality auditor has to sign the report on below the circles.
Video on showing how factories modifying raffice light system:
Frequestly Asked questions:
A: Normally 5 or 7 garments are checked by the quality checker.
Q: What if the factory follows a single-piece flow system and doesn’t have 5–7 pieces available?
A: In that situation, auditors usually check the maximum available pieces (even if fewer than 5) and note the limitation. Many factories reduce the sample size for single-piece flow workstations.
Related Articles:
What is Inline Inspection in the Garment Industry?
17 Simple Tips to Improve Garment Quality