Consultants in Lean Manufacturing Á Manufacturing Strategy

Consultants in Lean Manufacturing & Manufacturing Strategy

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Value Stream Mapping

Symbols & Icons 

Process Symbols

customer/supplier

Customer/Supplier

This icon represents the Supplier when in the upper left, the usual starting point for material flow. The customer is represented when placed in the upper right, the usual end point for material flow.

Dedicated Process-vsm symbol

Dedicated Process

The dedicated process icon is a process, operation, machine or department, through which material flows. Typically, to avoid unwieldy mapping of every single processing step, it represents one department with a continuous, internal fixed flow path.

In the case of assembly with several connected workstations, even if some WIP inventory accumulates between machines (or stations), the entire line would show as a single box. If there are separate operations, where one is disconnected from the next, inventory between them and batch transfers, then use multiple boxes.

value stram mapping symbol-shared process

Shared Process

The shared process icon represents a process operation, department or workcenter that other value stream families share. Estimate the number of operators required for the Value Stream being mapped, not the number of operators required for processing all products.

vsm symbol-data box

Data Box

The data box goes under other icons that have significant information/data required for analyzing and observing the system.

Typical information placed in a Data Box underneath FACTORY icons is the frequency of shipping during any shift, material handling information, transfer batch size, demand quantity per period, etc.

Typical information in a Data Box underneath MANUFACTURING PROCESS icons:

C/T (Cycle Time) - time (in seconds) that elapses between one part coming off the process to the next part coming off.

C/O (Changeover Time) - time to switch from producing one product on the process to another.

Uptime- percentage time that the machine is available for processing.

EPE (a measure of production rate/s) - Acronym stands for "Every Part Every___".

Number of product variations.

Available Capacity

Scrap Rate

Transfer Batch size (based on process batch size and material transfer rate)

value stream mapping symbol-workcell

Workcell

Cellular Manufacturing is an important part of VSM and Lean operations. The workcell symbol indicates that multiple processes are integrated in a manufacturing workcell. such cells usually process a limited family of similar products or a single product. Product moves from process step to process step in small batches or single pieces.

 

Value Stream Mapping symbols are not standardized and there are many variations. Here are the most common symbols. You may also create your own symbols for specialized applications.

Material Symbols

inventory

Customer/Supplier

These icons show inventory between two processes. While mapping the current state, the amount of inventory can be approximated by a quick count, and that amount is noted beneath the triangle.  If there is more than one inventory accumulation, use an icon for each.

This icon also represents storage for raw materials and finished goods.

value stream mapping-shipments

Shipments

This icon represents movement of raw materials from suppliers to the Receiving dock/s of the factory.  Or, the movement of finished goods from the Shipping dock/s of the factory to the customers.

push arrow

Push Arrow

This icon represents the "pushing" of material from one process to the next process. Push means that a process produces something regardless of the immediate needs of the downstream process.

supermarket

Supermarket

This is an inventory 'supermarket" (kanban stockpoint). Like a supermarket, a small inventory is available and one or more downstream customers come to the supermarket to pick out what they need. The upstream workcenter then replenishes stocks as required.

When continuous flow is impractical, and the upstream process must operate in batch mode, a supermarket reduces overproduction and limits total inventory.

kanban pull

Material Pull

Supermarkets connect to downstream processes with this "Pull" icon that indicates physical removal.

fifo lane

FIFO Lane

First-In-First-Out inventory. Use this icon when processes are connected with a FIFO system that limits input. An accumulating roller conveyor is an example. Record the maximum possible inventory.

value stream mapping safety stock symbol

Safety Stock

This icon represents an inventory "hedge" (or safety stock) against problems such as downtime, to protect the system against sudden fluctuations in customer orders or system failures. Notice that the icon is closed on all sides. It is intended as a temporary, not a permanent storage of stock; thus; there should be a clearly-stated management policy on when such inventory should be used.

truck shipment

External Shipment

Shipments from suppliers or to customers using external transport.

Information Symbols

production control symbol

Production Control

This box represents a central production scheduling or control department, person or operation.

manual information

Manual Information

A straight, thin arrow shows general flow of information from memos, reports, or conversation. Frequency and other notes may be relevant.

Electronic Information

Electronic Info

This wiggle arrow represents electronic flow such as electronic data interchange (EDI), the Internet, Intranets, LANs (local area network), WANs (wide area network). You may indicate the frequency of information/data interchange, the type of media used ex. fax, phone, etc. and the type of data exchanged.

Production Kanban

Production Kanban

This icon triggers production of a pre-defined number of parts. It signals a supplying process to provide parts to a downstream process.

Withdrawal Kanban

Withdrawal Kanban

This icon represents a card or device that instructs a material handler to transfer parts from a supermarket to the receiving process.  The material handler (or operator) goes to the supermarket and withdraws the necessary items.

signal kanban

Signal Kanban

This icon is used whenever the on-hand inventory levels in the supermarket between two processes drops to a trigger or minimum point. When a Triangle Kanban arrives at a supplying process, it signals a changeover and production of a predetermined batch size of the part noted on the Kanban. It is also referred as "one-per-batch" kanban.

Kanban post

Kanban Post

A location where kanban signals reside for pickup. Often used with two-card systems to exchange withdrawal and production kanban.

sequenced Pull

Sequenced Pull

This icon represents a pull system that gives instruction to subassembly processes to produce a predetermined type and quantity of product, typically one unit, without using a supermarket.

Load Leveling

Load Leveling

This icon is a tool to batch kanbans in order to level the production volume and mix over a period of time

Value Stream Mapping symbol-MRP

MRP/ERP

Scheduling using MRP/ERP or other centralized systems.

go see

Go See

Gathering of information through visual means.

verbal information

Verbal Information

This icon represents verbal or personal information flow.

General Symbols

Kaizen Burst

Kaizen Burst

These icons are used to highlight improvement needs and plan kaizen workshops at specific processes that are critical to achieving the Future State Map of the value stream.

Operator

Operator

This icon represents an operator. It shows the number of operators required to process the VSM family at a particular workstation.

Other Stuff

Other Stuff

Other useful or potentially useful information.

Timeline

Timeline

The timeline shows value added times (Cycle Times) and non-value added (wait) times. Use this to calculate Lead Time and Total Cycle Time.

Extended VSM Symbols

Rail Shipment

Rail Shipment

Delivery by rail.

Air Freight

Air Freight

Delivery of material by air freight.

Extended Value Stream Mapping-expedite

Expedited

This symbol shows deliveries of product or information that are always or usually expedited.

Milk Run

Milk Run

A "Milk Run" vehicle makes multiple stops to pick up or deliver items at multiple locations. Milk runs often, but not necessarily, follow a fixed route. The advantage of a milk run is that it does not require a full load for each delivery to be economical.

Warehouse

Warehouse

The Warehouse icon can represent an internal or external warehouse. It may also be used in lieu of the Customer/Supplier icon.

vsm-cross dock

Cross-Dock

In Cross-Docking inbound and outbound trucks are closely coordinated so that materials move directly from inbound trucks to outbound or, at least, with only a brief staging.  

Order Input

Orders

This icon represents conventional sales orders or purchase orders.

phone 

Phone

The telephone represents some type of telephone communication and is often used for telephone orders.  

Batched Kanban

Batched Kanban

Kanban cards or signals sent or received in batches.  

control Center

Control Center

Control Center icon for centralized kanban control

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