PRB Plant – Robert Bernard Group

Mandate

To meet growing demand and improve its competitiveness, the Robert Bernard Group’s PRB plant enlisted glm conseil to optimize production processes at the retreaded tire assembly station (Premold Builder). The goal: to significantly increase the production rate while reducing quality errors, in order to boost the plant’s capacity and enhance customer satisfaction.

The customer

The PRB plant is part of the Robert Bernard Group, a major player in Quebec's tire industry. The plant specializes in cold retreading (pre-mold process), a demanding manufacturing process that combines precision assembly with a sustained production rate.

Challenges

Increase production capacity at the Premold Builder station to meet demand, while eliminating recurring quality issues that were affecting customer satisfaction.

Initial findings

Significant waste: frequent trips to restock sole rolls; preparation tasks performed after the machine has stopped instead of being done in advance.
The machine is idle 38% of the time, almost exclusively while waiting for the operator.
Operator identified as a bottleneck: The operator's workload far exceeded the automatic machine cycle time, causing prolonged downtime.
Recurring quality issues: improperly installed soles, tire contamination, and handling errors leading to rework, material waste, and additional costs.
Production capacity is insufficient to meet the company's goals, with a production rate of 65 tires per builder per shift.

Objectives

Increase productivity: go from 65 to 95 tires per builder per shift.

Eliminate quality defects: reduce errors related to incorrect soles and contamination to zero.

Increase the machine utilization rate: from 62% to 80%.

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Expected results:

Improving the quality of the product delivered to the customer the very first time.

Shorter delivery times thanks to increased capacity.

Reduction in mandatory overtime.

Improving profitability by reducing waste and rework.

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Interventions

Diagnosis

Detailed human-machine analysis: 176 tasks observed over a period of 2 hours and 10 minutes, with 45 changes in machine state.

The operator spent 43% of his time on activities that did not add value (travel, cleaning up contamination, corrections, etc.).

There is significant variability in machine downtime, primarily due to model changes and movements to the storage area.

Systematic identification of issues with the team: buffer problems, contamination, defective scrubbing, sole supply, and frequent model changes.

Key actions

Introduction of a helper shared between two machines: a third resource handles setup tasks while the machine is running, reducing downtime to an absolute minimum.

New optimized work procedure: definition, testing, and implementation of an operational sequence tailored to a three-resource setup, with a clear division of tasks between the primary operator and the helper.

An implementation plan structured in four phases: correcting the fundamentals, helper-builder synchronization, standardization and training, and then continuous improvement.

Implementation of daily monitoring: briefings at the start of each shift, debriefings at the end of each shift, posting of results, and systematic counting of production.

Maintain a buffer stock of rolls at the workstation to eliminate unproductive movement.

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Results

Productivity increased by 45%: from ~130 to 188 tires per shift (two machines), or ~26.9 tires per hour compared to ~18.4 previously.

Average stopping time per tire was reduced by 54 percent: from 137 seconds to 63 seconds.

Machine utilization rate improved by 15 percentage points: from 61.7% to 77.2%.

66% of stops now last less than 45 seconds, compared with just 14% before the intervention.

The proportion of the operator's time spent on value-added activities rose from 57% to 89%: the operator now devotes more than 4 out of every 5 minutes to tasks that directly contribute to the quality and progress of the product.

Elimination of long stops: The maximum stop time has been reduced from 5 minutes and 32 seconds to 3 minutes and 59 seconds.

Benefits

Improved quality delivered to the customer: fewer assembly errors ensure that the correct tire is delivered the first time, thereby strengthening customer confidence.

Shorter delivery times: Increased production capacity allows us to fulfill orders more quickly.

Reduction in mandatory overtime: Increased daytime productivity reduces the need for overtime, particularly during periods of high demand.

Increased operational flexibility: the ability to eliminate the need for night shifts by operating with two day shifts and two evening shifts during peak periods.

A culture of continuous improvement has been established: a monthly review cycle, documented and audited work standards, and the potential to reach 217–230 tires per shift through subsequent optimization phases.

Improved profitability: reduced costs associated with rework, material waste, and suboptimal use of resources.

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