Household survey design

Next, the items that you have decided to keep need to have a specific home. Determine where these items should be located in your work area. Make it obvious where they belong. Use visual techniques such as signs, lines, labels, and color coding to help easily locate the correct items (see Section 2.2.1, “Visual Workplace”). If you use the item every day, it should be kept close to your work area. If you use it once a week, it can be placed a little farther away. If you use it only once a month, it can be kept even farther away or in another area. Set up a system for how many to have on hand, when to replenish, and who is responsible for ordering more.

Having the correct items in the correct location when you need them reduces or eliminates much of the waste in a work area. By ensuring that every appropriate item in the work area has a specific home and that it is in the right location when needed adds to good discipline.

A rule of thumb for having world-class “Set in order” is that anyone in your work area can find an item in 30 seconds or less. This means that the items are clearly marked and labeled.

3. Shine

5S is much more than just cleaning. Shine is the process of inspecting while cleaning.

Look for safety hazards, loose wires, poor connections, and bad hoses, basically anything that could cause a breakdown or potential problem if not attended to. Divide up the work among the team members. Decide what to clean, when to clean, how to clean, what you need to clean, and how long the cleaning and inspection should take. Remember, everybody cleans and inspects. Plan ahead so that the proper cleaning supplies are readily available. Having a portable Shine cart or station makes this easy. Clean and inspect from top to bottom and get everything in a like-new condition. Start with large items first and do the floors last. People start to take ownership and have pride of their area because of Shine. Look for ways to prevent the dirt, dust, and grime from accumulating in the first place. Replace any worn, defective, or unsafe components or equipment.

A clean work area is safer, a more pleasant place in which to work, and more efficient. It also produces better quality and impresses customers. If people resist participating in Shine by saying “I wasn’t hired to clean!” remind them that they weren’t hired to make a mess either.

The discipline of touching one’s equipment, tools, and work area makes a person a better operator after all, who knows the work area better? With Shine, small problems can be spotted before they become big problems, like a breakdown or safety incident.

4. Standardize

Have the teams in the work area establish the guidelines, policies, or rules for Sort, Set in

order, and Shine. Many organizations pursuing 5S say that they failed at sustaining their efforts (the 5th “S”), but it’s more likely that they failed at Standardize. When you standardize, you make up the rules, but then you have to follow and enforce these rules.

An important element here: Don’t create a rule that no one will follow.

Examples for standards might include the following:

 Sort: what information goes on the red tag, how to perform the 5S Red Tag Technique, and rules to disposition items in the 5S Red Tag Holding Area

 Set in order: where and how much inventory or supplies should be kept on hand, visual standards such as color coding

 Shine: visual standards for Shine, how should people clean and inspect, how often should cleaning and inspection be done, and what items should be cleaned and inspected

5. Sustain

The fourth and fifth “Ss” are the two functions that, without proper attention, will result in tasks being performed the “old” way.

To maintain these efforts, the team must use creative methods to share their lessons learned and to encourage the continued process of 5S. Sustaining efforts may include additional training, communication with bulletin boards or newsletters, reward and recognition, benchmarking tours, and so on. Many organizations use 5S audits to ensure that standards are not slipping back or deteriorating.

The key here is to keep the 5S efforts going and to make it part of everyone’s daily work life. 5S should not be something additional or something that management tells the employees to skip because there is no time. Once the standards are in place, everyone has to support the program to make it last.

Discipline

5S is a discipline as in “control” not as in “punishment” Having a strong 5S system will help bring the good discipline needed to build a strong, lean organization. 5S allows us to utilize other aspects of lean that need a very robust discipline, like standardized work or kanban. It sets the stage for a well-run total productive maintenance program.

5S is having a clean, neat, organized and safe workplace. It reduces waste, time spent searching for items, and stress. The foundation of a lean company, 5S sets the stage for how you want your organization to be; it is a foundation of improvement (Galsworth 1997). By employing the 5S principles you are creating a culture of lean.

2.2.2. LOT SIZE REDUCTION

In traditional mass production operations, large lots, or batches, of product are created and moved to the next process, regardless of whether the product/part/documentation is needed. At this point, the product waits in a queue as work-in-process (WIP). This is known as push production.

Push production is creating large batches of product at the maximum rate of the process, normally as a result of a forecasted customer demand. The product is then moved to the next downstream process or stored. Push production does not take into account the actual pace of work (cycle time) in the next process or actual customer demand (takt time). The

traditional push production method makes it almost impossible to institute the smooth flow of work from one process to the next process, which is the trademark of lean. All we are really trying to accomplish is to get one process to make only what the next process needs, when it needs it, as the customer demands it (Rother and Shook 2009, 37).

With push production, most manufacturing and service departments find it easier to have long runs of one type of product or service scheduled in order to avoid changeovers. These longer runs of a single type of product cause lead times to expand. It becomes difficult to meet a customer’s demand for a product or service that is different from the batch currently being worked. This requires organizations to create finished goods inventories to have the product on hand to meet those customers’ needs when they place an order.

As previously implied, batch production causes the consumption of raw materials and parts in batches, which expands the WIP inventories for upstream processes. This can result in quality issues, because once the mass production process makes a defect, it is quickly replicated throughout the batch. Potential quality issues are another reason to reduce the batch size in order to reduce the amount of impacted WIP and inventory when a defect does occur. Additionally, with increased inventories there is a risk of not selling the finished product. This results in additional waste associated with transporting and storing the inventory. In some cases, the inventory can become obsolete and must be scrapped, another waste.

Another issue is that large batch sizes lead to an unevenness in flow of product. At times there can be more work than people or equipment (peak conditions; see Figure 2.2.2-1). At other times, there is not enough work and these same operators and equipment sit idle (valley conditions). This unevenness reduces overall efficiency, where the peaks can cause strain on employees and equipment, resulting in a reduction in safety and morale.

To reduce the strain of peak conditions, traditional mass production thinking would size the equipment, employees, inventory, and other resources for these peak conditions. This results in overall efficiency being reduced during nonpeak conditions. As these fluctuations occur with customer demand, the range and impact of the peaks and valleys increase as they move upstream to earlier processes, causing a greater impact. These fluctuations are known as mura.

To eliminate mura, fluctuation at the final product assembly should be minimized. Zero fluctuation is preferred. At Toyota, the final assembly line never assembles the same automobile model in a batch. In other words, each automobile is a batch, or one-piece flow. The final assembly production line is leveled by making first one model, then another model, and then yet another (Ohno 1988, 126). This is known as production

leveling, or heijunka (evening out the work schedule). Successful heijunka (see Section 2.2.3) is key to eliminating mura, which in turn will lead to elimination of muda and muri.

Quick changeover, setup reduction, and single minute exchange of dies (SMED) may be used to implement lot size reduction. (See Section 2.3.7.2 for more information on quick changeover/setup reduction.)

2.2.3. LOAD LEVELING

One of the benefits of reducing the lot size is to be able to level the work schedule, or load leveling. In heijunka, lot sizes are reduced, or made as small as possible. This differs from traditional mass production, where more is considered better, whether it be customer demand peaks or economies of scale. When a final assembly line produces based on smaller lot sizes, the upstream processes naturally conform to its production schedule. This forces processes to perform many more changeovers, which are generally avoided with traditional thinking. However, production leveling requires many changeovers.

Changeovers must be performed quickly in order to provide the flexibility needed for the leveled production (see Section 2.3.7.2, “Quick Changeover/Setup Reduction (SMED)”

for more on how this is accomplished).

Smaller lots and consistent pulling from downstream processes will result in fewer adjustments. Work can be performed evenly and the significant peaks and valleys eliminated. When looking at this from the value stream as a whole, the result is less strain on employees, equipment, suppliers, and customers. An additional benefit is a reduction in inventories needed.

Production leveling has been applied successfully across many different industries, including high- and low-volume production systems. There are three components of production leveling (Figure 2.2.3-1):

1. Total volume 2. Model sequence 3. Model volume

In production leveling, it is assumed that each of these components is held constant (unchanged based on historical customer demand over a given period of time). This is basically the same assumption used with calculating takt time. To apply production leveling, an organization must make progress by addressing customer demand, beginning with an understanding of total production volume, moving to specific details on the demand of individual product/service types (models), and ending with an evaluation of a product/service type (model) sequence of production.

Total Production Volume

The total customer demand may vary from day to day. However, there are usually predictable patterns throughout a specific time period when demand, on average, is relatively constant. The goal is to identify the patterns and time periods and then level the total production volume over each period (Figure 2.2.3-2).

Model Sequence

As the total volume of customer demand varies from day to day, so does the type of product or service. The sequence in which these product or service types are performed affects the time needed to change over the production or servicing from one type to another. Therefore, the sequence of production and servicing has an impact on the overall capacity of an organization, or the number of products and services the organization can perform within a given time period. (See Section 4.3.3.5 for more information regarding sequencing of models [product and service types].)

Model Volume

Even with a constant total production volume demand, immediate response to fluctuations in demand for individual product types can result in waste (Figure 2.2.3-3).

Similar to total production volume, product type volumes often vary from day to day.

However, product types also have predictable patterns and time periods where demand is, on average, constant. The goal is to identify the patterns and time periods and level the product type volumes over each period (Figure 2.2.3-4).

Mixed Model Production

Even with total production volume and product type volume leveled, production still results in batching. The next step is to create a mixed model production system. This requires that the demand per product type per unit of time (e.g., 5 units per hour for Product A, 15 units per hour for Product B, and 10 units per hour for Product C) and the total demand per unit of time be calculated (30 total units per hour for Products A, B, and C). There are a few different scenarios for sequence model production.