Process Optimization

Content

High-mix SMT production introduces frequent changeovers, variable cycle times, and unstable PCB flow.
One of the most common consequences is line blocking, which reduces efficiency and increases operator intervention.

This article explains how to approach line blocking from a process optimization perspective.

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1. Understanding Line Blocking in High-Mix Production

Line blocking occurs when downstream processes cannot accept PCBs at the required pace.
In high-mix environments, this is often caused by:

• Product-dependent cycle time variation

• Frequent inspection parameter changes

• Manual intervention between automated processes

• Insufficient buffering between stations

Blocking is usually a systemic issue, not a single equipment failure.

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2. Root Cause Analysis

Effective optimization starts with identifying where instability originates:

• Which process causes the most frequent stops?

• Is inspection synchronized with production speed?

• Are manual stations creating unpredictable delays?

• Do PCB transfer signals behave consistently?

Without this analysis, optimization efforts remain reactive.

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3. Practical Optimization Strategies

Common and effective strategies include:

• Introducing buffers at critical points

• Separating inspection flow from main production

• Stabilizing PCB transfer logic via SMEMA coordination

• Grouping products with similar cycle times

• Reducing unnecessary operator handling

The goal is not maximum speed, but predictable flow.

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4. Implementation Considerations

When applying these strategies:

• Avoid over-buffering, which wastes space

• Ensure buffer logic aligns with inspection routing

• Coordinate signal timing across machines

• Validate changes under real production conditions

Optimization must be verified at the line level.

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5. When Process Optimization Becomes a Project

If line blocking persists despite local improvements, it often indicates the need for a broader factory upgrade initiative.

👉 Process optimization is frequently part of a larger Factory Upgrade Project, where equipment, layout, and flow are redesigned together.

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