DMAIC Project: Improving the Productivity of Surface Treated ST Products

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Baseline (Define)

At the start of the project, the lead time for the company's surface treatment products varied throughout the surface treatment process. The company has a wide range of products and therefore the analysis was limited to products with sufficient volume and yield. The objective of the project was to improve the throughput (running meters or rm/h) of ST products for surface treatment in the surface treatment process.

Process performance at the beginning (Measure)

The analysis of process performance was carried out over a 6-month period. The process was found to be stable, averaging 496 jm/h, but with a large variation of 180.6 jm/h. Of the production batches, 50.67% was below the target value. Determining the performance clarified the statistical target setting:

• Reduction of dispersion to 100 runningmeter/h -> better controllability of the process
• 70% above target value of 500 runningmeter/h -> better process yield

Improvement measures (Analyze & Improve)

A detailed process description and workshops with employees helped to identify the reasons affecting lead times. Hypothesis testing was used to identify the main causes, with surface treatment, potting and finger break found to have an effect on the average lead time per product, and potting also found to have an effect on lead time dispersion. The development measures chosen to achieve the objective were:

• Improving the quality of finger-joints by developing quality monitoring of the finger-joint line
• Reducing the disturbances caused by punching on the surface treatment line by means of a technical solution

Analysis of the follow-up period on the finger extension line showed that quality defects could be divided into three factors. However, the difference in the number of causes was not large. A regular quality check of the finger-joint was started on the finger-joint line and the number of quality problems per type of defect was monitored using a quality card. A joint training session was organised for staff on the use of the quality cards. The P-card was introduced as an indicator of the change in the total number of defects in the quality table. An action plan was drawn up to be used in the event of incidents. A light mesh dust blower was installed in the light mesh of the punching machine.

Results (Control)

The measures taken, the introduction of a quality card on the finger-jointing line and the addition of dust blasting to the end-jointing process, had a clear impact on the lead time of ST products in the surface treatment process.

• Average runningmeters 450 runninemeter/h -> 579 runningmeter/h
• Above target 49.33 % -> 86.33 %

During the project, continuous improvement skills were transferred to the company's quality manager. A guideline for the company was drawn up based on this project. The purpose of this guideline is to enable the quality manager to further develop the current project and to mirror its development to other process steps in the company.

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This project was a Black Belt training project, which the participant did as part of the training and received a Black Belt certificate at the end of the project.

If you are interested in learning how to improve your processes using Lean and Six Sigma, and earn your Belt Belt certification at the same time, check out the training at the link: Black Belt training.