Value Stream Mapping - Future State Map

Developing a Future State Value Stream Map

Overview of Current State

• The presentation discusses creating a future state value stream map for State Street assembly, which requires producing 18,400 steel brackets monthly.

• The production includes 12,000 left-hand drive and 6,400 right-hand drive brackets shipped in trays containing twenty pieces each.

• Daily shipments are based on customer forecasts provided electronically (90-day, 60-day, and 30-day forecasts), along with daily orders.

Production Control and Processes

• The production control department uses MRP to determine weekly schedules across various processes: stamping, spot-welding (two stages), assembly (two stages), and shipping.

• Weekly forecasts are sent to suppliers via fax; Michigan Steel Company supplies steel coils twice a week. Five days' worth of coil inventory is maintained.

Process Metrics

• Each process has specific metrics such as cycle times, changeover times, reliability rates, and work-in-process inventories for both left-hand and right-hand drives.

• Total lead time is calculated from the cycle times and inventory levels; current processing time indicates inefficiencies in the system.

Identifying Problems in Current Operations

Issues with Mass Production

• Observations reveal mass production leads to large lot sizes being pushed through processes independently due to an island mentality among departments.

• This results in significant waste—excessive inventory between processes—and highlights the disparity between value-added time versus total time spent in the plant.

Lean Systems Perspective

• From a lean perspective, overproduction is identified as a primary waste that needs elimination. Other wastes include defects and unnecessary processing or motion.

Transitioning to Continuous Flow

Understanding Flow Dynamics

• The presentation contrasts batch/push processing with continuous flow systems where products move one at a time through interconnected processes.

Tack Time Concept

• Tack time is introduced as the pace at which production should occur to match sales demand. It’s calculated by dividing effective working time by customer requirements per day.

Challenges of Implementing Continuous Flow

Limitations of Continuous Flow

• Continuous flow may not be feasible due to long setup times or distances between processes. Alternative methods like Kanban systems can help manage these challenges effectively.

Supermarket Pull System

• A supermarket pull system is proposed where products are produced based on actual demand rather than forecasts. This involves using Kanbans for signaling movement between upstream and downstream processes.

Coordinating Upstream and Downstream Processes

Functionality of Supermarkets

• Supermarkets serve as buffers that regulate production without scheduling every single process individually. They ensure that upstream processes respond accurately to downstream demands without excess inventory buildup.

Evaluating Process Efficiency

Assessing Current Workstations

• An analysis of workstation timings reveals that current operations exceed tack time; adjustments are necessary for efficiency improvements through potential Kaizen events aimed at reducing cycle times.

Redesigning Processes for Improvement

Creating Efficient Work Cells

• A proposal suggests restructuring workstations into cells where tasks can be combined efficiently while ensuring cycle times remain below tack time thresholds for optimal performance.

Establishing a Kanban System Between Stamping and Suppliers

Overview of the Kanban Process

• Acme Company is implementing an internal withdrawal Kanban system for coils received from suppliers, which will streamline communication with the production control department.

• The production control department uses these Kanbans to order coils based on actual usage by stamping presses, ensuring timely replenishment of materials.

• Discussion includes exploring daily deliveries (milk runs) instead of the current twice-weekly schedule to enhance efficiency in material supply.

Future State Visualization

• The future state includes multiple supermarkets: one between welding and assembly, another between stamping and raw material suppliers, facilitating better inventory management.

• Production control transfers information about coil usage back to suppliers, optimizing the flow of materials needed for production.

Scheduling and Pacemaker Process

Understanding Scheduling Needs

• Emphasis on scheduling only one process within the system to maintain efficiency; this process will dictate overall operations.

• Introduction of the pacemaker process concept, which is crucial for leveling production mix across different products being manufactured.

Production Mix Leveling

• The newly designed welding and assembly process serves as the pacemaker due to its complexity and involvement of multiple workers.

• Daily requirements are established at 920 pieces per day split between left-hand drive and right-hand drive brackets, aiming to avoid batch processing.

Achieving a Balanced Production Rate

Strategies for Balancing Production

• A strategy is proposed where one right-hand drive bracket is produced followed by two left-hand drives in each cycle, aligning production with consumption rates.

• Importance placed on reducing changeover times between different product types to facilitate a leveled production mix effectively.

Determining Production Frequency

• Instructions for when to produce specific items are communicated through a calculated pitch that dictates work increments based on demand.

Calculating Pitch for Efficient Workflow

Pitch Calculation Methodology

• The pitch is determined by multiplying tag time (60 seconds per unit produced in trays containing 20 units), resulting in a 20-minute cycle time for each batch.

Coordination Through Pitch Implementation

• This structured approach allows coordination among various processes involved in manufacturing while maintaining consistent output frequency.

Streamlining Operations with Load Leveling

Operational Flow Management

• Material handlers utilize load leveling boxes to manage product flow efficiently according to set frequencies (every 20 minutes).

Finalizing Product Delivery Processes

• Finished goods are moved from staging areas into trucks for daily shipping based on withdrawal Kanbans established earlier in the process.

Summary of Improvements Achieved

Key Outcomes from Current State Analysis

• Significant reductions observed in non-value-added time due to overproduction; inventory days decreased from 23.6 days down to just 5 days.

Overall Efficiency Gains

• Processing times have improved slightly; however, more importantly, value-added steps have increased relative to total production time.

Conceptualizing Future State Maps

Loop Structures Identified

• Different loops were identified: pacemaker loop focusing on welding/assembly efficiency; stamping loop managing equipment use; supplier loop coordinating raw material flows using Kanban systems.

Conclusion Insights

• The presentation emphasizes creating future state maps that integrate key concepts like tag time, signaling Kanban systems, supermarkets, and pitch calculations into cohesive operational improvements.