In a project with a goal to implement the Future Value Stream Map, the primary objective was to reduce lead time from order to final product delivery. This goal was pursued by decreasing the amount of in-process inventory, freeing up space in the production layout to increase the density of value-added activities, and thereby improving both productivity and the production capacity of the plant.
Welcome to our 'Lean in Action' series, where we bring you real stories from the field about the transformative power of value stream mapping (VSM). While we’ve taken care to keep identities confidential, the insights, successes, and lessons shared here are authentic accounts from lean experts and industry professionals across various sectors.
Material Supply Reorganization
A crucial step in this process was the reorganization of material feeding for an assembly line consisting of 20 workstations dedicated to producing industrial machinery. In this line, the layout previously relied on large containers of bulky materials placed beside the assembly line, while smaller or customized components were transported on kitting carts that followed the product through the various assembly stations. Additionally, painted chassis were loaded at the start of the line directly from the buffer between painting and assembly.
Workstation Optimization
The initial phase focused on analysing assembly operations to identify time spent on non-value-added activities, such as moving materials from the line edge to the assembly point. Workshops based on the 5S methodology helped optimize workstation layouts, simplifying operational flow and setting the foundation for redesigning workstation equipment.
At the same time, the logistics team and process engineering team classified materials into three main categories:
- Class C: Small, low-cost components.
- Class B: Standard materials used across multiple products, non-bulky.
- Class A: Expensive, bulky materials or those with many variants.
Specific material feeding models were defined for each category, with further subdivisions for Class A components depending on whether they were sourced internally or externally.
Material Feeding Models
Class C: Small Components
Class C components were transferred to manageable bins with a capacity suitable for average daily consumption. These bins were stored on flow racks with gravity rollers at the workstations.
- Replenishment Process: When a bin is emptied, it is placed in a collection area. Once a day, a logistics operator gathers the empty bins, which serve as a "Kanban signal" to trigger replenishment.
- External Management: The entire replenishment and bin-filling process was outsourced to a third-party logistics provider, simplifying operations for the purchasing department.
Class B: Standard Materials
Class B components followed a similar logic to Class C but used standardized containers and racks designed to hold a sufficient daily stock. However, replenishment occurred every two hours through a logistics operator performing a milk run. This operator collected empty bins, delivered them to the central warehouse, and replenished the racks with full bins.
- Central Warehouse: Empty bins were taken to the warehouse, where an operator refilled them using materials from supplier containers. This double-handling process, though seemingly inefficient, centralized materials, freeing up line-side space and improving overall efficiency.
Class A: Bulky and High-Variant Materials
Class A materials were managed with two distinct approaches:
- Internally Sourced Components
Painted components were sequenced directly from the painting line, which operated according to the assembly sequence planned for the next two hours. Materials followed a FIFO (First In, First Out) lane, eliminating the intermediate buffer. - Externally Sourced Components
The central warehouse prepared containers based on the frozen production sequence for the next two hours. These containers were loaded onto a logistics train that supplied the assembly line.
In both cases, containers were designed to hold only the quantity required for the next two hours.
Synchronization Between Painting and Assembly
A critical improvement was the elimination of the in-process inventory buffer between painting and assembly, replaced by a FIFO lane. The production sequence was communicated daily to the painting supermarket and confirmed two hours before entering the assembly line. This change achieved:
- Reduction of intermediate inventories.
- Increased space: Freed up to extend the assembly line and boost production capacity.
- Just-in-time availability: Ensuring materials were available precisely when and where needed.
The described activities led to the following outcomes:
- Lead Time Reduction: Synchronization ensured that materials arrived at the assembly line only when needed, avoiding unnecessary stockpiling.
- Increased Usable Space: Bulky materials were centralized in the warehouse, freeing up line-side space and improving workstation ergonomics.
- Productivity Improvement: Reducing non-value-added activities increased the cycle time dedicated to productive tasks.
- Enhanced On-Time Delivery: Synchronization eliminated material shortages, ensuring a consistent and predictable flow.
This synchronized material feeding system, designed based on the Future Value Stream Map, optimized the entire production flow, improved plant performance, and enhanced responsiveness to customer demand.
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As you can see, the benefits of value stream mapping go far beyond the theory—it’s about real results that drive impactful change. Our lean professionals have helped countless organizations streamline operations, eliminate inefficiencies, and achieve measurable gains. Ready to see what VSM can do for you? Book a meeting with our experts today to discuss your unique challenges and get hands-on with our VSM software. Let’s start mapping your path to lean success.