Stellantis Reduces Tightening Rejects by 90.5% with Inbolt’s Vision-Guidance at their Trenton Plant

Customer: Stellantis
Location: Trenton, United States
Return on Investment: 12 months

Challenge

Stellantis’ Trenton plant, which produces the V-6 Pentastar upgrade engine, was facing a critical issue with the production line. Despite the presence of a lift and locate system to index the engine to the station, there was a reject rate of 2.55% for bolt run down. This meant that the robotic system could not always correctly locate and tighten the bolts during assembly because of a non-repeatable engine position. As a result, an operator was required at the end of the line to manually tighten any missed bolts, which introduced inefficiencies and added labor costs.Key Issues

• Tool non-engagement rate of 2.55%, where the robotic system failed to engage and tighten bolts properly.
• The need for an operator to manually tighten missed bolts, which led to higher labor costs and inefficiencies.
• The lift and locate system required significant infrastructure changes on the line and increased the station total cycle time
• Traditional fixturing systems such as crowders or lift and locate fail to be 100% reliable and become increasingly unrepeatable over time due to wear and tear or stacked up tolerances, contributing to misalignment and inefficiencies in bolt tightening.

Impact

The non-engagement rate of 2.55% led to inefficiencies in the production line, requiring an operator to manually tighten missed bolts. This added labor costs and disrupted the flow of production. Additionally, the lift and locate system imposed infrastructure costs and required slowing down production to position the engine, further reducing overall efficiency.

Solution

Inbolt deployed their real-time vision-guidance technology. Unlike traditional lift and locate systems that require costly infrastructure changes, Inbolt’s system integrates seamlessly into the existing production line, eliminating the need for any interruption to the production process.Here’s how Inbolt’s solution worked:

• The vision-guided robot system was deployed without requiring any changes to the existing infrastructure.
• The AI-based solution dynamically adjusted to any position change (x, y, z, yaw, pitch, roll), enabling the robot to engage the bolt at any orientation, even in difficult-to-reach positions.
• This eliminated the need for constant rework down the line

Success Metrics

• Non-engagement rate reduction: The non-engagement rate dropped from 2.55% to 0.24%, showcasing a significant improvement in robotic accuracy.
• Part rejections: Overall part rejections were reduced by 90.5%, improving product quality and operational efficiency.
• Scalability: Stellantis is now deploying Inbolt’s solution on other production stations, expanding its benefits across the plant without the need for costly new infrastructure.
• Operator satisfaction: While the operator still remains at the end of the line, they are now able to perform their tasks more effectively and with less frequency, improving their working experience.

"Streamlining our engine tightening process meant fewer adjustments, and more consistent results on the station."
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— Manufacturing Engineer, Stellantis Trenton plant.

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