Reflection Final Paper

LEAN AND CLEAN VALUE STREAM MAPPING

Value stream mapping is a Lean process-mapping method for understanding the sequence of activities

used to produce a product. During the Green Suppliers Network technical review, you will use value

stream mapping to identify sources of non-value added time or materials; identify opportunities to

increase efficiency; and develop a plan for implementing improvements. Value stream maps serve as a

critical tool during the review process and can reveal substantial opportunities to reduce costs, improve

production flow, save time, reduce inventory, and improve environmental performance.

Conventional value stream mapping can overlook environmental wastes, such as:

• Energy, water, or raw materials used in excess of what is needed to meet consumer needs • Pollutants and material wastes released into the environment, such as air emissions, wastewater

discharges, hazardous wastes, and solid wastes (trash or discarded scrap) • Hazardous substances that adversely affect human health or the environment during their use in

production or presence in products. The Green Suppliers Network incorporates both “lean and clean” elements into its mapping techniques to

help you:

• Recognize where environmental impacts occur in a product line. • Quantify raw materials used by processes and compare it to materials actually needed to produce

the product. • Identify pollution and wastes generated by the production activities. • Identify root causes of wastes and inefficiencies.

VALUE STREAM MAPPING TECHNIQUES Use Icons There are a number of common icons used in value stream maps, but icons can also be customized to best

serve a value stream map. Icons help distinguish different elements of a product line from another. For

example, different arrows should be used to distinguish between product and information movement. The

figure below contains commonly used icons in value stream mapping.

WK

I

Process

Input

Output

COMMON ICONS FOR VALUE STREAM MAPPING

Product Movement

Inventory

External Movement (information or materials)

Signal Kanban1

Withdrawal (pull of materials from stock)

Process Leg Frames

Truck Shipment

Starburst (identifies improvement opportunity)

External Source (suppliers and customers)

1 The Japanese refer to Kanban as a simple parts-movement system that depends on cards and boxes to take parts from one work station to another on a production line. Kanban stands for Kan- card, Ban- signal. The essence of the Kanban concept is that a supplier or the warehouse should only deliver components to the production line as and when they are needed, so that there is no storage in the production area. Work stations located along production lines only produce parts when they receive a card. In case of line interruptions, each work station will only produce enough components to fill the container and then stop.

Record the “Current State”

When reviewing a product or process line, the first value stream map you develop should record the

current state of the line. Remember, conventional value stream mapping tends to focus at a facility-wide

level. The current state map should take a snapshot of the current practices and materials usage rates for

all processes. A current state map should also record where environmental impacts occur in the product

line. The following processes typically have environmental impacts:

• Metal Fabrication (Milling, Welding, Stamping, and Machining) • Parts Washing • Surface Cleaning • Plastic Forming (Extrusion and Molding) • Metal Finishing • Surface Coating • Chemical Formulation • Hazardous Materials Handling • Waste Management • Wastewater Treatment

A current state value stream map should also establish baselines for all inputs and outputs including, but

not limited to, the 10 Green Suppliers Network environmental metrics, which are presented below.

Inputs Pounds of materials used Pounds of hazardous materials used Gallons of water used Gallons of water consumed Watts of energy used BTUs of energy used

Outputs Pounds of solid waste generated Pounds of hazardous waste generated Pounds of air pollution emitted Gallons of wastewater treated

Other inputs and outputs that conventional value stream maps identify include changeover and cycle time,

labor, and rework. Exhibit 1 illustrates a conventional value stream map, shows how to denote process

inputs and outputs, and provides example of where Green Supplier Network environmental metrics may

exist in the product line.

Compare “Use” Verses “Need” Using a Materials Line

In the past, value stream maps would examine the time it takes to produce a product and the proportion of

that time that is value added─or the time spent actually working on the product. The timeline was a

graphic representation that compared the two, but didn’t focus on the resources consumed and waste

generated in making the product.

A materials line is a variation of a timeline and can be developed for any type of resource (e.g., water,

energy, total materials, and/or a critical substance used in the product). A materials line, located on the

bottom of a value stream map, shows the amount of raw materials used by each process in the value

stream and the amount of materials that end up in the product and add value from a customer’s

perspective.

For example, the materials line illustrated below compares the amount of water used and needed in the

milling and parts washing processes in a product line.

Milling Parts Washing

2K gal

800 gal

150K gal

90K gal

Water Used = 152,000 gallons Water Needed = 90,800 gallons Water Wasted = 62,200 gallons

Top line: Amount of

water used

Bottom line: Amount of water needed

Once you collect data for the materials line, you may notice large differences between the amount of

material used and the amount needed for the product. This exercise can help you target the largest sources of

waste for prioritizing improvement efforts.

Exhibit 2 presents a value stream map with a materials line that focuses on water usage. You can also

create separate maps that address other inputs such as hazardous materials or energy use.

Visualize an Improved “Future State”

Future state maps are created to show what a product or process line would look like after improvements

are made. Future state maps should be drafted by the Green Suppliers Network review team following the

completion of a current state map. Green Suppliers Network practitioners play a vital role in developing

future state maps, as they can help suppliers identify areas where environmental improvements can be

made. More often than not, future state maps look closer at process level improvements. Facilities cannot

typically make changes to the order in which processes take place in a product line, but they can

implement changes to specific steps of a process. Opportunities for process improvement can be shown

on a value stream map with a starburst as illustrated in Exhibit 3. Starbursts can identify processes that

need to be examined closer, such as in Exhibit 4.

Future state maps should represent the product or process line in a perfect state or fully optimized and

highly efficient. It should not be restrained by cost. The future state should include the best available

technologies and equipment, and estimated waste reductions should be included where appropriate. For

example, if a surface coating line could reduce solvent use by installing a solvent recycler, the future state

map should represent that improvement.

The materials line that should be included on a current state map can be a good indicator of where

improvement opportunities exist. If a process showed a large difference between the amount of a material

used and the amount of material needed, Green Suppliers Network practitioners should question why the

difference exists. Inefficiencies are the root cause of most wastes. Efficient production lines will have

little to no difference between the amount used compared to the amount actually needed to produce the

product.

Exhibits 5 and 6 show the difference between a current state and a future state parts washing line. Current

and future state process maps can be generated for one or many processes that occur in a facilities product

line.

Exhibit 1: The Current State with Inputs and Outputs

Milling Parts Washing

Surface Coating

Assembly Packing/ Shipping

Welding

Sales and Purchasing

WK

Raw Materials Fluids Water Energy

Transport Packaging

Time Labor

Welding Consumables

Degreasers Detergents Solvents Acids Water

Solid Waste Haz Waste Wastewater

WK

Coatings Energy Solvents

Air Emissions

Wastewater

Solid Waste Haz Waste Air Emissions

Solid Waste

Customer Supplier

Some processes will not have environmental

inputs and outputs but all have time and labor

inputs such as cycle time and man hours

Damaged goods from packaging and shipping can cause unnecessary wastes.

Exhibit 2: Water Use Materials Line

Milling Parts Washing

Surface Preparation

Rinsing Assembly

Water Source 2

State

45K gal 1K gal 90K gal 250K gal 0 gal

10 K gal 30K gal 1K gal 75K gal 125K gal 0 gal

Metal Finishing

I

Water Source 1

Wastewater Treatment System

Federal

Local Regulations

500 KGPD

Effluent

30K gal

Water Used = 416,000 gallons per day Water Needed = 241,000 gallons per day Water Wasted = 175,000 gallons per day

Exhibit 3: Opportunity for Improvement with Inputs and Outputs

Supplier Customer

Receiving Shipping

Milling

Raw metal Fluids Process water

Solid Waste Wastewater Haz Waste

Welding Parts Washing

Surface Coating

Assembly

10 lbs 5 lbs 12 lbs 0 lbs 0 lbs

60 lbs 2 lbs 2 lbs 2 lbs 0 lbs 0 lbs

Hazardous Materials Used = 107 lbs Hazardous Materials Needed = 66 lbs

Welding Consumables

Water Acids Detergents

Packaging

Solid Waste Haz Waste Air Emissions Wastewater

Haz Waste

Packing Consumables

Solid Waste

80 lbs

Incoming Raw Exhibit 4: Surface Coating with Inputs and Outputs Materials

Surface Prep or

Pretreatment

Spent Solvents VOC Emissions Solid Waste Hazardous Waste Used Rags Wastewater

Part Washing or Degreasing

Drying Oven (optional)

Alkalines Acids Emulsifiers Solvents

Water Solvents Degreasers Detergents

Spent Solvents Wastewater Spent Rags

Watts of Energy

VOC Emissions

Quality control can greatly reduce the amount of rework a facility performs. Rework generates

unnecessary wastes. Operational personnel are the most likely to

know how to dramatically improve quality and reduce rework.

Increased quality control can be included in a future state.

Base Coating or Priming

HAP, PM & VOC Emissions Paint Arrestors (filters) Gun Cleaning- Solvent Masking Unused Coating Solid Waste

Coating Quality Check

(optional)

Curing Oven

VOC Emissions

BTUs of Energy

If part fails inspections

Intermediate Sanding or

Surface Prep

Sanding Materials Solvents

Spent Solvents VOC Emissions Solid Waste Hazardous Waste

Curing Oven

VOC Emissions

BTUs of Energy

Rework

Solid Waste Solvents VOC Emissions

Blasting Material Stripping Material

Quality I Check

Finished Part

Top Coating

Coating

HAP, VOC & PM Emissions Paint Arrestors (filters) Gun Cleaning- Solvent Masking Unused Coating Solid Waste

Exhibit 5: Current State Parts Washing for Rust Removal with Inputs and Outputs

Drying Rack Incoming part w/ oxidation and rust

Opportunity to reduce acid use

through recycling

Opportunity to reduce water use through cascade

rinsing

Rinsing Dip Tank

Acid Wash Dip Tank

Freshwater Acid

Acidic- Wastewater Acid Fumes

Freshwater

Acidic- Wastewater

Washed Part

I

Exhibit 6: Future State Parts Washing

Filtered Vapor Recovery Unit

Recovered Acid Washed Part

Evaporative water and acid mist

Acid Wash Dip Tank

Rinse Tank #1 Incoming part with oxidation and rust

Acid Regeneration

Unit

Spent Acid Fresh Acid

I

Rinse Tank #2 Final Rinse Spray / Fog

Fresh water

Overflow water

Outputs: Iron Oxide Iron Hydroxide

I