Project background
A manufacturer of bearings for use in agricultural, mining, air and material handling and marine applications purchased a manufacturer of ball bearings and all operations were moved for cost reasons. However production rates for the acquired business were too low, a backlog of orders accumulated and sales were lost due to poor delivery performance and quality issues with an external defect rate of 15,000 ppm. The variation in both processes and operators was too high. Kaizen activities alone were unable to fix the root causes or implement sustainable control mechanisms. Therefore, a decision was made to assign a Black Belt to the project in order to reduce variation and improve output.
Problem
Productivity was not high enough to meet customer demand resulting in excess overtime of €114,000. The Black Belt discovered that the ball insertion, seal and slinger tools were ineffective. Output expectations from distribution to manufacturing were not clearly defined. Using unskilled operators who had not transferred to the new owner were causing reducing throughput, and there was excess tooling and inventory on the assembly line.
The team’s micro maps and failure modes and effects analysis and process capability studies also found bearing clearance defects, wrong parts, wrong specifications, poor tooling design and maintenance, inadequate training and 17 individual key process inputs that did not have documented operating procedures or work standards. The gage study found that the gage consumed 45% of the tolerance.
Solutions
Amongst the many solutions implemented, an air booster was installed to increase the force to deflect outer ring for easier insertion of balls. A positive stop was added to vice blocks to reduce the possibility of cracking outer rings. A positive stop was also added to seal and slinger tools to ensure the correct depth of seal/slingers, reducing the need for rework and improving part quality. Tools were organised and colour coded to aid setup time and location of the correct tool for the task. A 5S system was developed for the area, along with a training plan, training matrix and Standard operating procedures to ensure all operators functioned at the required skill level. The Black Belt also guided development of visual factory to aid 5S, SOPs and output expectation for the newly acquired company. SMED activities were performed on the sizing station.
Business benefits
Productivity increased initially from 6.4 to 9 units per man hour and later doubled to 12 units per man hour. Overtime costs were reduced by €93,000 per annum. Set- up time was reduced by over 90% and run time by 55%.
