How a Tier-1 Automotive Supplier Cut Line Stoppages 50% Without Replacing Its AS/400

Client Overview

The client is a Tier-1 automotive parts supplier operating three production plants across North America. The company manufactures stamped and assembled components for automotive OEMs and works against strict just-in-time production schedules.

Its assembly lines are managed through a modern Manufacturing Execution System (MES). The MES tracks production activity in real time, including the movement of units across stations, material consumption, production status, and inspection results.

The company also relies on an AS400 environment as the system of record for inventory, bills of material, work orders, and customer orders. These records are stored in DB2/400 tables and supported by business rules that have been refined over more than two decades. Together, the MES and the AS/400 form the core of the client's production and inventory operations.

Business Challenges

Inventory Records Lagged Behind Production

Materials were consumed on the line, but the AS/400 was updated hours later. Planners were therefore working with outdated stock figures, which led to emergency purchases, unnecessary reordering, and higher inventory costs.

Replenishment Could Not Respond in Real Time

The MES could detect a low feeder bin immediately, but the AS/400 could not receive that alert. Replenishment requests were delayed, causing avoidable line stoppages even when the required material was already available in the plant.

Traceability Was Split Across Systems and Paper Records

Production and material records were stored across the MES, the AS/400, and paper documents. When an OEM requested traceability details, the quality team had to piece the information together manually, turning a minutes-long task into several days of work.

Approaches Considered

Both the MES and the AS/400 were performing their core functions effectively. The issue was the delay in transferring production information from the shop floor to the inventory system. To address this gap, two integration approaches were considered.

OPTION 01

Scheduled Batch Synchronization

Data would be exchanged between the MES and the AS/400 every 15 or 30 minutes using file transfers or staging tables.
This would reduce the delay, but inventory figures would still lag behind actual production activity.
Low line-side material levels could not trigger an immediate replenishment request.
A failed batch could affect an entire synchronization window and create additional reconciliation work.
Since the client needed inventory and replenishment updates as production events occurred, this approach was not considered sufficient.

OPTION 02 - RECOMMENDED

Real-Time Event-Driven Integration

A lightweight, event-driven integration layer would connect the MES and the AS/400.
Shop-floor events such as material consumption, unit completion, scrap posting, and low material alerts would reach the AS/400 within seconds.
Messages would be retained and replayed if either system became temporarily unavailable, reducing the risk of lost or duplicated transactions.
The client could retain its existing AS/400 logic, historical data, and business rules.
The solution could be piloted on one production cell before being expanded across the remaining lines.

We recommended this approach because the client's main problem was latency. A real-time design would remove the delay rather than simply reduce it.

Solutions Implemented

01 / Connectivity

Enabled Real-Time Communication with the AS/400

The existing inventory, bill-of-material, and order routines on IBM i were exposed through REST services connected to the relevant DB2/400 tables. The core AS/400 logic was not rewritten or replaced. The integration simply gave the MES a secure way to send and receive information from the existing system.

MES

Unit Complete

Rest Services

Secure. Real-Time

IBM i/ AS400

Existing logic
unchanged

02 / Reliability

Built a Reliable Event Backbone Between MES and IBM i

Important shop-floor events, such as material consumption, unit completion, and low-bin alerts, were sent through a durable IBM MQ. If either system was temporarily unavailable, the events remained in the queue and were processed once the connection was restored. This prevented transactions from being lost or processed twice.

Shop-floor Events (From MES)

Material
Consumption

Unit Completion

Low-Bin Alert

IBM M1 (Event backbone)

Durable Queue
No Loss/ No Duplicates

IBM i/ AS400

Events are processed when connection is available

03 / Automation

Automated Inventory Consumption and Replenishment

When the MES confirmed that a unit was complete, the related components were automatically deducted from the AS/400 inventory using the existing bill of material. Low-bin alerts also created replenishment requests before the feeder ran out of material. Goods-receipt updates were sent back to the MES so the production schedule reflected current stock availability.

MES

Unit Complete

AS/400 Inventory

Inventory Updated

Replenishment
Request

Request Created

Low Bin Alert

04 / Traceability

Improved Lot Traceability and Exception Management

Each finished serial number was linked to the raw-material lots used during production and recorded in IBM i. Quality teams could trace a finished part back to its material lot in minutes instead of searching through multiple systems and paper records. A supervisor dashboard also highlighted failed validations and unmatched transactions so they could be resolved quickly.

Material Lot

Captured in MES

Trace & Search

Across Systems

Visibility

Quick Resolution

05 / System of Record

Kept the AS/400 Updated as the System of Record

Approved backflush deductions and cycle-count adjustments were written back to the AS/400 through the same integration layer. Each transaction included a complete audit trail, while planners retained the ability to review or override it before posting. This allowed the AS/400 to remain the single, accurate system of record without requiring employees to enter the same information manually.

Transactions

From MES

AS/400

System of Record

Audit Trail

Complete & Accurate

Implementation Roadmap

1

Discovery and AS/400 Interface Audit

The team mapped the DB2/400 tables, shared data objects, field structures, units of measure, and ownership rules for each system.
2

Service Enablement on IBM i

The required RPG and DB2 routines were exposed through REST endpoints. Reads and writes were then validated in a production-like staging environment.
3

Event Backbone and Middleware Development

IBM MQ was configured as the event backbone. The integration layer was built with the transformation, validation, idempotency, and audit controls required for reliable event processing.
4

Pilot on One Assembly Cell

Real-time backflush and replenishment were introduced on a single assembly cell. The existing manual process remained in place temporarily as a safety net while the team compared results from both processes.
5

Multi-Line Rollout and Hardening

Once the pilot was validated, the integration was extended across the remaining production lines. Genealogy and exception dashboards were added, and the integration was optimized for performance, throughput, and resilience.
6

Monitoring and Continuous Optimization

Ongoing reconciliation monitoring was established to identify transaction issues quickly. The team also introduced a repeatable method for adding new events, workflows, production lines, and business units to the integration layer.

Business Impact

50%

Fewer Line Stoppages

15%

Lower inventory carrying costs

<5 sec

Shop-floor-to-inventory latency

Days → Minutes

OEM traceability response

Zero

Manual double-entry

Looking Ahead

With a stable real-time connection between the MES and the AS/400, the client now has a foundation for further operational improvement. The same integration layer can support predictive maintenance, supplier-performance analytics, OEE-based scheduling, and the gradual modernization of the wider IBM i environment.

Nalashaa continues to support the day-to-day reliability of the AS/400 environment while helping the client plan future integration and modernization initiatives.

"For years the AS/400 ran our plant, but the shop floor always moved faster than the data. Now the two finally speak in real time. My planners trust the numbers on their screen, and we've stopped chasing stock that was in the building all along."
â€” Plant Operations Manager, Tier-1 Automotive Parts Supplier