Lean practices in the metal finishing industry

William W. Corcoran

Abstract of Article presented at the 2010 Aluminum Anodizers Counci Conference, Montreal, QC, Canada:

Lean practices are production practices that target the expenditure of resources for any goal other than the creation of value for the end customer. Therefore the practice works to identify and eliminate wasteful activities and focus on the value creation process. The objective in the practice is to focus on value creation by working smarter and preserving value with less work.

From the perspective of the customer who consumes a product or service, "value" is defined as any action or process that a customer would be willing to pay for. The essence therefore is to achieve maximum efficiency by evaluating production processes and identifying anything that is being done that a customer will not pay for. For example, waiting for the parts to start a production process on the finishing line is not something the customer will pay for if the company tries to "bill" for wait time.

All anodizers can use lean practices to work smarter and be more profitable without a large capital investment. The investment is in and with the people that work in the shop; identifying bottlenecks, inefficient flow, lack of resources and steps that do not have value to the customer.

"Lean" as used in manufacturing and particularly metal finishing is a state of mind. By this I mean that it is not a plan or prescription that you can acquire and give to the plant manager and expect implementation and results. Lean is a company wide, top down commitment to a philosophy and a never ending, ongoing process like the institution of comprehensive quality program.

Lean is about eliminating "waste".

"Waste" is traditionally defined (when addressing "lean" concepts) as anything that does not add value to the end product, but has attendant cost, and for which the customer would be unwilling to pay. "Value Added" activity is one that increases the market value of the product or service. "Non Value Added" does not add market value to the product or service and is therefore unnecessary. The concept of "value added" can vary according to who is looking at the operation or activity. There are many examples of "non value added" activities for which the customer is willing to pay. Take for example, compliance testing for certification to a specification that is required by the customer. The testing does not change the part that has been anodized or coated. The part is done; the process is over. By our definition the testing of coupons for compliance adds no value to the physical part yet the customer wants the assurance and will pay for the "required" non-value-added service. Therefore, the essence of "lean" is to measure all activity from the customer's point of view.

The typical examples are:

Excess Inventory; too much finished goods held in inventory and therefore representing unproductive use of capital.
Over Production; tied to excess inventory, over production represents the use of production resources when they could be used for a product that is in demand and salable currently.
Transport; the unnecessary or excessive movement of parts or components both internally (in the shop) and externally (via freight carrier or truck).
Process; this refers to excessive process steps or unnecessary handling, paperwork, dealing with customer caused problems (i.e. unnecessarily dirty parts).
Scrap and Rework; parts that fail inspection due to process errors are extremely costly and time consuming. This is an area of great opportunity for committed anodizers who understand proactive vs. reactive management.
Waiting; there are many reasons why people wait; for material, tools, inspections, information from management, engineering, etc., equipment cycle times.
Motion; this is a waste category that refers to people in the shop and how the work flows through their work area and how efficient that flow is. If workers need to look for tools or parts it is wasted motion.
Underutilized people; watching the process running with nothing else to do.

The examples of waste listed here are symptoms of inefficiency and lack of control of the operations. Recognizing waste leads to identifying the "root cause" of the problem. Underlying any waste is the systemic problem that reflects on the people, materials, machines, operating systems and information used in the operation.

How do I make my metal finishing shop a "lean" operation?

Embracing Lean requires a company-wide, top-down commitment to a philosophy of change for the better of everyone that works for the company. That's why it is a "state of mind". The implementation takes great commitment but more importantly, the continuation of that commitment must be relentless. In order to carry out this implementation one must acquire certain skills or tools of "lean" to be successful.
The tools have familiar names but usually people without familiarity with lean disciplines have only a superficial understanding of the exact disciplines. They are:

Standardized Work
5S System
Visual Controls
Plant Layout

1. Standardized Work is the implementation of standard processes that have been proven reliable, repeatable, safe and applicable to all tasks or processes in a sequence that is known to be successful; and done by the best combination of material, machines, methods, and people. The latest thinking in this area revolves around "process control". This is the creation of process standards that take "operator controlled variables" out of the equation. The fewer decisions or judgments people have to make, the more uniform the process becomes. People are not removed from the decision making process, it is just accomplished before the work hits the floor. Everyone should participate in creating the best process and then when it is established, follow it. Don't permit improvisation.

2. 5S System:

Sort to eliminate clutter: if it isn't needed, get rid of it.
Set in order: Organize and label everything; have a place for everything.
Shine: Clean the whole building inside and out.
Standardize: Keep everything maintained and in good repair.
Sustain: Maintain discipline throughout the organization and support this culture.

Workplace organization is the objective of the 5S System. In an organized workplace, people know where things belong and can visually understand when things are in order. It affects workers very positively, reduces accidents, improves efficiency, reduces wasted motion because search time is reduced, reduces contamination (chemical, biological, etc.), provides visual workplace control and becomes the platform for other improvements.

3. Visual Controls: Simple visual signals give shop workers information to make the right decisions. They are efficient, self-regulating, and worker managed. This is management of the processes in the shop by using "sight" of signals that alert workers and permit quick, automatic action. Examples include color coding of tools, masking materials, traveler folders and papers, work areas, lining the work floor to delineate use of certain areas. These techniques permit ease of understanding, support a diverse workforce, support workplace safety, and permit both workers and managers to assess the workplace quickly and accurately.

4. Plant Layout: Plant layout can affect efficiency in a number of ways. By co-locating processes that integrate easily, one reduces the movement of people, materials and work in process, which permits a better flow of production. Additionally it facilitates better communication and maximizes floor space utilization and shortens material handling.

Implementation:

1. Begin the implementation process with the last step above; with the plant layout. First create an accurate drawing or representation of the shop floor beginning with receiving and inspection all the way through to final inspection and shipping. Create a large drawing if possible on the wall of a conference room. Every station or location on the shop floor where parts are handled or worked on should be on the drawing. From this drawing, teams can identify and discuss work flow and start to develop a clear picture of the current state of work flow. From this the desired future state can start to be visualized. People should look for "waste"; bottlenecks, delays, duplicate steps (inspection, part count, etc.). Identify the obvious problems first but don't be satisfied with just a few problems identified.

2. Next do a spaghetti diagram of the work flow. This requires that you follow a job through the plant and record exactly where the parts go and then draw the route on a copy of the plant layout. Examine where parts go without interfering. Learn what really happens on the shop floor notwithstanding what you are told in the conference room.

3. In addition to the plant layout, create a work flow analysis spread sheet on excel which shows the linear flow of work with side lines that identify when interruptions in the flow are required. An example of this could be a requirement for measurement of tight tolerance parts. This interrupts the flow and could be viewed as waste, but if the customer has specified dimensional tolerances then he should be prepared to pay for the service.

4. Next, use the plant layout drawing and the work flow spread sheet to do a "point of use" analysis. In a point of use analysis, one examines the physical tools and materials needed to move parts along the process trail. These include hand tools, racking tools, masking materials, carriers, clamps, etc. Everything should be readily available. This applies to "physical tools" as well at the "intangible tools", i.e. correct and detailed information. Specifically this focuses on your router or traveler. It the traveler is incomplete it leads to either process errors or delays while people seek the information. Develop a replenishment system for tools and physical materials and review your information system to satisfy yourself that anyone reading the work papers can understand what to do and be informed enough to do it correctly.

Why POU?

It will reduce non-value added activities such as sorting, moving, transporting of parts and tools,
It allows the identification of quality issues in a timely fashion
It simplifies physical inventory tracking, storage and handling

Quality at Source:

Quality at source is one of the best elements of "lean" available. Rejects and process errors are the most costly of all waste in the metal finishing industry. When one has to repair rejects, the cost can be three times higher than it would have been originally if the work was done correctly.

Quality at source requires the development of "process control". Typical anodizing specifications are MIL-A-8625F and AMS-A-8625. Both specifications require process control documentation and process control inspection. This means that all steps in the processing sequence should be documented. That includes ranges for immersion time and temperature for each step in the process, chemical constituents use with allowable solution control ranges with solution analysis, ranges for temperatures, current density and anodizing time as appropriate for particular alloys. If one wishes to eliminate process errors and rejections, a program of proactive quality management at the source of processing must be adopted.

Educate your work force: give them end-product knowledge so they understand what the final use of the product is supposed to look like and how it is to be used.

Standardize the steps to the process. Develop work instructions for every step along the process line from incoming inspection to final inspection. Have the work instructions reviewed by the people who are to use them. Have them participate in their creation or editing.

Have process documents that require that all steps be recorded and signed off. Flow customer specifications down to the plant floor through the documents. Let the work force become familiar with the customers and their needs.

Communicate: timely feedback to workers and vendors adds tremendous value to their understanding of the business and your customer needs.

One such program is called Six Sigma. Six Sigma originated as a set of practices designed to improve manufacturing processes and eliminate defects. In Six Sigma, a defect is defined as any process output that does not meet customer specifications, or that could lead to creating an output that does not meet customer specifications. Six Sigma focuses on measurable, quantifiable steps in a process that can be recorded statistically so that trend analysis and statistical analysis can help identify weaknesses in a process and predict trouble areas.

With Six Sigma, a statistical picture can be created which reflects the error trends in your process line. Statistical process control (SPC) is the term used to identify the statistical method of gathering data around process or product failures and measuring trends. In it's simplest for, for an anodizing process line, it can identify weak areas and permit focus on appropriate improvements.

Preventive Maintenance:

All manufacturing operations have maintenance requirements. How one approaches maintenance can make a big difference in productivity, quality and waste. When a pump or motor ceases working, the impact is usually idle time or "waiting" by workers. Generally there are three types of maintenance: emergency maintenance, routine maintenance and preventive maintenance.

Emergency maintenance is the least desirable since it occurs without warning and causes disruption to production. Often times production grinds to a halt while maintenance personnel hurry to fix the problem and get the operation back up and running. Consider the idle time of workers in this situation and the measureable waste it produces.

Routine maintenance is the application of simple, small scale activities to regular and general upkeep of equipment, machinery and buildings against normal wear and tear. The logical extension to routine maintenance is preventive maintenance. Preventive maintenance is maintenance of equipment or a system before fault occurs. The primary goal of prevenetive maintenance is to avoid or mitigate the consequences of failure of equipment. It is designed to preserve and restore equipment reliability by replacing worn components before they actually fail. Preventive maintenance activities generally include overhauls at specified periods, oil changes, lubrication and so on. The program should provide information so workers can record equipment deterioration and know when to replace or repair worn parts before they fail. The ideal preventive maintenance program would prevent all equipment failure before it occurs.

Key to success:

Essential to the success of a lean program is the genuine commitment of management, from the top all the way down the line, to the success of the program. This is not the kind of program that one can send out a memo and dictate the institution of a successful lean program. Lean is a focus on excellence at all levels of the organization based on a system wide vision and commitment. Toward that end, think about how much the concept of lean extends (or should extend) beyond the shop floor. This is an opportunity that is significant. When you create your process map, include all of the "soft" connections that affect or are affected by the flow of work; cost analysis/pricing, sales/purchase orders, specifications, engineering review, invoicing and accounting.

Determine which people touch what documents and processes and why they touch them. Determine how much activity is really needed and what can be streamlined. Optimize the physical environment. In some cases it may make sense to move objects and people around in the office and plant to facilitate a more direct and efficient communication and decision-making process. It's ok to have people from different disciplines sitting next to each other. In fact it may improve the flow of information. If information does not reach the appropriate party, people wait and that's waste. Information and the paperwork process is just like the shop floor. The same principals of lean apply.