Time-Based Demand-Pull Production Workflow
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Solution Overview
Problem
High-variety production environments face challenges in inventory management, as traditional Kanban methods are ineffective due to the infrequent production of individual parts, leading to inefficiencies in replenishment and inventory control.
Innovation Solution
A demand-pull system that uses a computerized workflow control system to analyze work orders (WOs) across production facilities, identifying the next WO to authorize based on priority-setting rules and comparing arrival times to processing needs, ensuring just-in-time production by matching flow times with downstream demand requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional Kanban methods are used for inventory replenishment, then inventory control is simplified, but they become ineffective in high-variety production environments where individual parts are produced infrequently
Solution Approach 1:
The patent transforms the replenishment trigger from quantity-based (traditional Kanban) to time-based parameters. By calculating flow times and comparing arrival times against need times, the system adapts to high-variety production where each part may only be made once, making traditional batch-based Kanban ineffective.
Solution Approach 2:
The patent replaces the mechanical card-based Kanban system with a computerized workflow control system that automatically calculates and compares time parameters. This substitution enables handling of high-variety production scenarios through automated time-based authorization rather than manual card tracking.
2Productivity
If more inventory is maintained to ensure availability, then production continuity is improved, but inventory investment and holding costs increase
Solution Approach 1:
The system performs preliminary time-based calculations to determine exactly when work orders will arrive at downstream work centers. By authorizing upstream work orders based on these calculated arrival times matching downstream need times, the system ensures materials are available precisely when needed without requiring excess inventory buffers.
Solution Approach 2:
The system continuously monitors and compares flow times against need times, creating a feedback loop that dynamically authorizes or delays upstream production. This real-time feedback mechanism ensures production continuity by triggering replenishment exactly when downstream demand arises, eliminating the need for safety stock.
3Reliability
If production is synchronized by stopping upstream operations when downstream stops, then quality is enhanced and costs are reduced, but production flexibility is limited
Solution Approach 1:
The patent implements dynamic time-based authorization that adapts to varying production conditions. Instead of rigid synchronization that stops all upstream production, the system dynamically calculates arrival times and authorizes work orders flexibly based on real-time flow conditions, maintaining quality through controlled pacing while preserving adaptability.
4Ease of manufacture
If batch-based replenishment is used, then setup times are reduced through economies of scale, but cycle times increase due to waiting for batch accumulation
Solution Approach 1:
The system implements periodic time-based authorization intervals rather than continuous or batch-based triggers. By authorizing upstream work orders at calculated intervals that match downstream consumption rates, the system maintains setup efficiency while eliminating batch waiting times through continuous small-lot replenishment.
Data Source
AI summary
Work at each Work Center in a production system is authorized by a demand-pull system. The demand-pull system can be based on the time for the oldest unauthorized work order in upstream adjacent WCs to get to the next WC and whether that WC will be ready to receive it.