Define Phase Blog

Containment to Prevent Automotive Steering Column Electrical Failures

Define Phase

Date: 7 February 2016

Introduction 

The aim of this project is to put a containment in place to prevent foreign metal debris in a steering column assembly causing short circuits on the steering column electronic. The issue the team are focusing on is one related to several field failures as a result of shorts within the steering column electronic (SCE). Detailed analysis and investigation revealed that the root cause was determined to be foreign metal debris from the steering column assembly which was attracted in particular to the two Hall IC's on the electronic. Their close proximity to magnets located on the bottom side of the printed circuit board was the main reason for this.The Hall IC's have conformal coating protection applied to them, however this was not sufficient, primarily on the bend of the leads to protect against metal debris causing shorts. Hence the need to come up with a containment solution as soon as possible to prevent further field failure, and also to ensure that this design flaw would not reoccur in any future redesigns.

Conformal coated Hall IC's                    Metal debris short across Hall IC

The first step in the Six Sigma process was to form a project team , the one chosen was one individual from each relevant department ; each would bring invaluable knowledge and experience to the table.

The next step was to create a project charter which was an invaluable tool in that it gives a simple
overview of the complete project from start to completion .

Project Charter

A SIPOC diagram was generated to chart the process flow of product through the conformal coating stage .

SIPOC diagram

Subsequently , I went on to hold a brainstorming session with the team members to go through the potential causes of the lack of conformal coating in the steering column electronic(SCE).From this information I then created a Cause and Effect diagram to visually display all potential causes of this problem. I found this an exceptional tool for organising all the possible causes of a known effect in a clear and organised way .I also found the brainstorming session itself to be a very positive experience as it gave much more insight into the process than I would have previously encountered .

Cause and Effect diagram

A Gantt chart was formed to display project milestones ie define, measure, analyse, improve and control in a much more visible format. This six sigma tool also helped identify all essential tasks and whether they could be performed parallel to each other or had to be performed sequentially .

Gantt Chart