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Considering lean manufacturing for your welding shop

PRACTICAL WELDING TODAY® SEPTEMBER/OCTOBER 2005

October 11, 2005

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If your welding shop hasn't implemented lean manufacturing initiatives, it's only a matter of time, the experts say. Learn and brush up on your understanding of lean manufacturing to see what tools might help boost your productivity and efficiency.

If you aren't lean in your welding shop, it's just a matter of time, experts say.

Every day several companies report success through implementing lean manufacturing initiatives.

HEI Inc., Minneapolis, and Charlotte, N.C.-based EnPro Industries Inc. attributed fourth-quarter 2004 growth to its lean initiatives.

In 2003 HEI, a manufacturer of microelectronics, subsystems, and software for medical OEMs, identified five categories within its manufacturing processes that could benefit from lean manufacturing: quality, regulatory, service and operations, cost leadership, and partnership. Within six months of implementing lean changes, the company reported the following percentages in improvement:

  • Response to customers: 57%
  • Productivity: 23%
  • Inventory management: 58%
  • Use of floor space: 58%

"One of our company's primary business goals in fiscal 2004 was to improve our manufacturing processes. We wanted to more efficiently meet our customers' individual needs and really focus on better quality, faster delivery times, and competitive costs," said Mack Traynor, CEO and president of HEI.

EnPro, a manufacturer of industrial sealing products, bearings, air compressors, and engines, expects that lean manufacturing will continue to help the company's success this year as well as it did in 2004.

"Increased volumes, combined with the benefits of our lean manufacturing initiative, restructuring activities, new facilities, price increases, and the disciplined execution of our operating strategies, should result in higher profits in 2005," said Ernie Schaub, president and CEO.

As these companies' stories suggest, lean manufacturing experts say it's not a matter of if lean will work for you, but what tools will work.

How Lean Applies to Welding

Several lean manufacturing tools and concepts are available. The trick is to learn about them and decide which ones are best and how to implement them.

"The choice is not whether, it's about how. There are certainly some tools that apply more easily, but they all apply to some degree," said Gary Conner, Lean Enterprise Training, Newport, Ore. (See "Lean Manufacturing: Common Terms and Definitions" for a list of lean manufacturing tools and their definitions.)

Conner suggests using the 80/20 rule when considering different lean manufacturing concepts.

"First you do the PQR: your product, quantity, and routing analysis," Conner said. This information will show what most of your operations (80 percent) consist of so you can figure out what types of lean manufacturing to apply. "You can't look at the 20 percent of jobs that don't fit and say, "Well, lean manufacturing won't work for me because of these oddballs.' In a job shop, there will always be 20 percent of the jobs that are hard to manage."

Although all welding businesses have similarities, the 80/20 concept differentiates job shops from production shops that basically make the same parts every day, said Joe Slattery, project manager at the Northwest Wisconsin Manufacturing Outreach Center, Menomonie, Wis.

"One of the things that immediately comes to mind [in any welding environment] are the [lean] tools; specifically, setup reduction, because in a lean environment we're trying to run more parts more often, and that's predicated on being able to do fast changeovers," said Slattery.

In general, a welding facility should take the following three steps when incorporating lean manufacturing, according to Rick Harris, president of Harris Lean Systems, Murrells Inlet, S.C.:

  1. Create a current-state and future-state value stream map. The current-state value stream map diagrams all of the actions—value-added and non-value-added—currently used to take a product through the two main flows essential to every product: the production flow from raw material to the customer and the design flow from concept to launch.

  2. Create the flow for your future-state map, starting with the pacemaker process—the process farthest downstream and closest to the customer, such as a final assembly cell.

  3. Revamp your materials flow to make sure you're turning materials into products as efficiently as possible. Continuous flow, in its ideal state, means items are processed and moved directly from one processing step to the next.

But first you have to consider your facility's situation, whether your shop is making the same part all day, every day or producing several different products for many customers.

Either way, Harris said, you must have two basic tools: a 5S system—a method of workplace organization—(see "Common Terms and Definitions") and a willingness to change.

Lean Manufacturing: Common Terms and Definitions

Pull/Kanban System. Pull/kanban systems control the flow of resources in a production process by replacing only what has been consumed.

Cellular/Flow Manufacturing. Cellular/flow manufacturing links manual and machine operations into a combination of resources to maximize value-added content while minimizing waste.

Total Productive Maintenance (TPM). TPM is designed to help you maximize your equipment's productivity for its entire life.

Quick Changeover/Setup Reduction. This process can help you design no- or low-cost systems to reduce changeover time.

5S. This series of activities is designed to improve workplace organization and standardization. The five activities are:

  1. Sort. Remove all unneeded items.
  2. Set in Order. Set limits and create temporary location indicators.
  3. Shine. Clean everything, use cleaning as inspection.
  4. Standardize. Implement visual displays and controls.
  5. Sustain. Keep in place through training and total employee involvement.

Value Stream Mapping. A value stream map diagrams the material and information flow for any manufacturing or administrative process.

Facility Layout. This process combines analytic tools and computer software to evaluate and restructure the manufacturing environment.

Equipment Selection. Modernizing your manufacturing processes by selecting and implementing the most cost-effective manufacturing machinery can help you meet your lean manufacturing objectives.

Sources: Illinois Manufacturing Extension Center, Northwest Wisconsin Manufacturing Outreach Center, Wisconsin Manufacturing Extension Partnership

Production Welding

In general, lean manufacturing in welding leads to smaller batch sizes and an increase in welding uptime, Harris said. Much streamlining in a welding environment involves tooling changeovers.

Lean manufacturing also relates to parts assembly, Slattery said.

Making a value stream map is just one part of the process, he said. First, it's critical to get everyone involved.

"We try to get together with the people who are involved in the lean effort," Slattery said. "Primarily we want to involve management people and production people. The management people can make the changes, but they don't know what to change. The production people know what needs to be changed, but they look to the management to make those changes."

The next step in the process is to put together a value stream, a group of products or customers that have the same components in common. Find out what the customers want, determine how much time it takes to make the product, study the information flow, and learn about the state of your processes today.

Then make a flow diagram in which you illustrate how you want to achieve a better future state. This diagram becomes your company's road map to the future, which then becomes a list of objectives to accomplish.

For production welding shop owners, Harris advises calculating the number of parts required in a day and dividing it by the time available to make the parts. Also, calculate how much time is required per part to ascertain how much labor you need to produce the number of parts you aim to manufacture. After making the proper calculations, take them to the shop floor and determine which processes, equipment, and equipment layout can do the job most efficiently.

The key differences between production welding shops and job shops are the types of product being made, the time needed to make the products, and the customers' requirements.

"In production welding, they're making stock, not make-to-order, items," Harris said. "We set the processes up to make the part flow from one part of the shop to another. For example, Toyota knows every footstep of every worker every day. What do you know? In a production welding shop, it's all about production flow and making sure you know how many welds are required and how many welds are performed."

Job Shop Welding

Another important distinction is that a job shop focuses more on how the customer's order flows through the facility, so the delays in the process often are caused by how order information is received and how it's processed from the time the order is taken to when the customer receives the product, according to Slattery.

Although job shops differ, the same steps used to implement lean manufacturing in a production welding shop are used in a job shop.

"Everything's the same except for takt time," Harris said, referring to the rate of customer demand calculated in a production welding shop. For a job shop, takt time is takt image, or the amount of time required to produce a product.

"You have to create the takt image; you have to look at your daily requirements," Harris said, rather than considering the demand for a single product as in a production environment. Takt image also is sometimes described as the management time frame.

Whether your company is production- or job shop-based, the main idea in lean manufacturing is to increase the amount of time a welder's welding, Harris said. A welder should be spending time welding, not moving throughout a facility to find what he needs to weld or what he needs to complete a project.

"The only time we make money is when the welder's welding," Harris said. "We have to make sure every welding rod is within the welder's reach."



Stephanie Vaughan

Contributing Writer

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