How Hindustan Pencils Achieved 99% Accurate Wooden Slat Inspection with Jidoka

Using Jidoka’s AI-powered Kompass vision inspection system, Hindustan Pencils automated wooden slat quality control reducing manual inspection escapes, eliminating operator variability and enabling high-speed inspection at 125 parts per minute.

How Hindustan Pencils Achieved 99% Accurate Wooden Slat Inspection with Jidoka

Industry

Stationery / Pencil Manufacturing

Result 1

99% defect detection accuracy

Deployments

Kompass (AI) Vision System with Multi-Camera + Laser Measurement Integration

Result 2

125 parts per minute inspection speed

Overview

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Hindustan Pencils Pvt. Ltd., India’s largest pencil manufacturer and a cornerstone of the Indian stationery industry, produces millions of pencils that demand consistent quality and flawless finish.

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A critical stage in pencil manufacturing is the inspection of wooden slats—the foundation of every pencil. Surface defects such as cracks, knots, pin holes, bends, and dimensional inconsistencies directly impact downstream processes and can result in 2–5% defective pencils during later production stages.

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Opportunity

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Ensuring consistent slat quality at high production speeds presented several challenges:

Manual inspection variability between operators affected detection reliability
Defect escapes led to rework and downstream production inefficiencies
Required inspection of multiple surfaces (top, bottom, sides) within a single station
Manual dimensional verification could not reliably keep pace with high production speeds.
Required real-time decision-making integrated with the existing PLC system

The goal was clear - eliminate manual dependency and create a high-speed, zero-down time inspection system.

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Jidoka's Approach

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Multi-Camera Vision Architecture

Jidoka deployed a four-camera inspection system to ensure complete surface coverage:

Top Camera: Captures high-resolution images of the top surface to detect cracks, knots, chips and pin holes.
Bottom Camera: Captures multiple images (15 mm field of view per frame) as the slat passes through the inspection gap. The system stitches images together to create a full bottom-face view.
Side Cameras (2): Inspect both edges to detect bends and structural irregularities.

The wooden slat field of view spans up to 200 mm × 100 mm, ensuring comprehensive inspection of critical surfaces.

AI-Powered Defect Detection

All captured images and sensor inputs are processed through Jidoka’s deep-learning Kompass engine.
The system automatically detects and classifies: cracks, knots, chips,pin holes, bends, width & length deviations, thickness variation
Defects are categorized into critical, major and minor with predefined thresholds, enabling standardized decision-making without human subjectivity.

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PLC Integration & Automated Rejection

Image capture is triggered by Jidoka’s PLC in sync with inspection cycles.
Inspection results (OK/NOK) are communicated in real-time to the machine.
Eight reject gates ensure accurate segregation of defective slats.
Electrical interlocks integrate seamlessly with the conveyor and station controls.
OK parts continue downstream without interruption.

This ensures zero inspection downtime while maintaining continuous production flow.

BIG WINS

Real-Time Control, Reliable Outcomes

Zero Downtime Inspection

Fully synchronized PLC integration ensures uninterrupted production flow.

Reduced Defect Escape & Rework

‍‍Significant reduction in downstream rejection and production loss.

125 Parts Per Minute

High-speed inspection aligned with production takt time.

Enhanced Brand Reliability

Strengthened product consistency supporting supply assurance and customer confidence.

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With Jidoka’s Kompass-powered AI inspection system, Hindustan Pencils transformed wooden slat quality control from a manual, variable process into a standardized, high-speed and highly accurate automated operation. The implementation delivers 99% defect detection accuracy at 125 parts per minute reducing defect escape, improving throughput and reinforcing the company’s commitment to quality excellence.

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