SI's Lo-Tow Towline Boosts Production Efficiency and Safety for Fortune 500 Company, Increasing Output with No Added Costs

Cummins Inc. produces engines, fuel systems, controls, air handling, filtration, emission control, power generation systems, and trucks, operating globally with over 600 company-owned and independent distributors.
The Challenges
Cummins Inc. aimed to consolidate heavy-duty engine assembly and testing into one towline system, necessitating improvements in size, control systems, safety, ergonomics, flexibility, and ‘fail-safing’ of finished products.
The major challenges were:
  • Maintaining current assembly line operation without impacting product flow and quality.
  • Designing a towline infrastructure with a robust quality assurance system.
  • Designing a flexible system with a wide range of engine assembly functions.
  • Providing real-time shop floor data collection. 
The Process and Solution

Cummins Inc.

Application:  Generator Assembly Operations
Industry:  Vehicle Engine Assembly
Equipment: Lo-Tow® Katchain™ Towline System, NFF (No Fault Forward) technology, RFID

i) Maintaining Existing Production with Zero Interruptions
The new towline systems was installed with transfers between the new and existing systems, ensuring that the former stayed operational during the installation of the new Lo-Tow system to maintain production capacity. 

ii) Quality Control Process:
As a major component of the project, SI Systems created tight quality control measures in the towline system to avoid production delays:
  • RFID tags and readers were installed in the carriers and workstations. The first station established a correlation between the engine serial number and the carrier number, while the assembly control station kept production data and quality control criteria specific to each ID number.
  • Requirements for an engine assembly were transmitted to a touch screen display controller as it enters a workstation.
  • Parts bin lights directed the operator to the correct parts for each engine, and torque values were automatically set for fastening operations.
  • The ‘fail-safe’ I/O structures could be configured to manipulate devices between stations. 
NFF Technology Process:
SI Systems No-Fault Forward™ (NFF) technology prevents incomplete/non-conforming assemblies from advancing to the next workstation until all operations are completed to specification.
  • Non-conforming assemblies were automatically transferred to one of three powered repair spurs, each with four workstations, upon detection of noncompliance.
  • Fixed assemblies were rerouted to the main towline and on to the next station. 
  • The system has a fourth spur with 11 stations near the end of the assembly for low-volume options. 
NFF technology detects non-conforming
operations and automatically transfers
assemblies to a repair spur.
After each operation, the carrier moves the
assembly to the next workstation.
RFID tags on each carrier correlate the engine serial
number to that cart at the first workstation.
The carriers were designed for ergonomic worker
interaction and increased productivity.


The Results
The towline upgrade positively impacted warehouse operations, resulting in simplified logistics, improved quality control, efficiency, safety, and customer satisfaction. Partnering with SI Systems and investing in their Lo-Tow towline system was a wise decision.

Order Cycle Time:  The Lo-Tow Towline NFF technology reduced order cycle time by 30%, enabling the company to handle a higher volume of orders.
System Flexibility:  Keeping the original system as a buffer added previously unavailable handling flexibility.
Overall Efficiency:  Overall assembly efficiency improved by 18%. The upgraded towline system resulted in 100% elimination of mistakes and errors, resulting in zero defects in finished products.
Assembly accuracy:  The 23 repair spur workstations enabled 100% satisfactory assembly by fixing assembly exceptions. This sequential quality control resulted in a 30% increase in process quality.
NFF Workflow Diagram