Continuous improvement: Do you have a handle on flow

One simple explanation of lean can be summed up in four words: Eliminate waste, create flow. Waste gets lots of attention, but flow is an equally important and powerful part of the lean equation. Let’s focus on flow.

One of the best ways to assess operational performance is to evaluate flow critically. Unless flow is purposely planned, it most likely will “evolve” over time.

Evolutionary flow presents problems and opportunities.

Product Versus Information Flow

Think of flow as the path the product or information takes as it winds through the operation. This path defines direction, distance, potential stopping points, and locations of congestion.

Product flow usually is obvious, because you can see the widgets (physical objects) moving through the operation, from the receiving dock to stock to work-in-progress (WIP) to finished goods to the shipping dock. If you have continuous flow, then the widgets never stop once they start. In streamlined flow, they move through an effective path with minimal hand-offs and short distances between manufacturing steps. Still, once you stop and do an objective evaluation, you might observe that the reality of the product flow is far from this ideal.

Information flow is the path information takes in the business. You can look at information flow beginning at the point of customer contact (request for quote or order placement, for example) to the design, the creation of a shop order, making the product, shipping, and, finally, invoicing and collecting cash. The information flow is intangible, hard to see, not easily measured, and crosses many organizational boundaries. Hence, it’s easy to overlook lots of potential problems.

Both products and information have flow. Flow will happen regardless, whether by design or by evolution. That said, do you have a handle on your flow?

How Does Flow Evolve?

Layouts, processes, and the resulting flows happen for lots of reasons, planned and unplanned. It’s the unplanned flows that create problems and cause the flow to evolve on its own over time. How exactly? Consider the following four examples.

1. Machine landed and grew roots. A new machine is delivered to your shop, and you have to find a space. In the hustle of keeping everything else running and shipping products out the door, you accept the most reasonable space available at the time. Once it lands, it is very difficult to move, simply because you need to manage ongoing operations. Before long, you’ve moved on to the next problem.

2. Batch-and-queue approach drives a need for buffer space. That buffer space ebbs and flows like a giant lung. This creates variability that affects your ability to have predictable WIP, consistent use of floor space, and streamlined flow. The buffer space becomes a symptom for much deeper problems, and the variability creates opportunities for confusion and disruption.

3. Use of a functional layout. Over the years many plants have followed a functional layout where like machines and processes are grouped together. The traditional logic was that the functional layout was more efficient and provided greater flexibility: cutting machines in one department, press brakes in another department, welding in yet another. This logic has been proven false and counterproductive. Undoing the functional layout to create flow takes a commitment of resources. It is particularly challenging to execute on that commitment when you are fighting to keep up with customer orders, quality expectations, and cost targets.

4. Information handed off across departments. This includes the department-to-department flow with multiple hand-offs and deep in-baskets, both physical and electronic: a buried customer order, a production order, an engineering change, and the like. Weaknesses in information flow create mayhem. Once an organization gets control of its physical processes, the information flow problems usually become apparent.

Most of you probably have more examples specific to your operation. The point is that evolutionary flow happens, and our plants pay a price for all the disruption that follows. Create your own list of evolutionary flow examples, make it relevant to your company, and help get traction for action.

Actions to Improve Flow

So what do we do to create effective flow? Let’s explore several specific actions. Effective flow comes from targeted and disciplined work from people across your business. These examples present a range that starts with the most basic and ends with a longer-term systemic approach to enhance flow.

Walk the process. A great starting point is to simply walk the process to make sure you really understand the flow. Make sure “you know what you know” (not what you think you know) about the process. A detailed process walk includes lots of observations and talking to process stakeholders such as supervisors, operators, material handlers, and engineers. All this will illuminate flow improvement opportunities. This is a wonderful application of “go see.”

Draw a spaghetti diagram. Draw a spaghetti diagram of the process to show movement and flow. You can draw a “micro” spaghetti diagram that shows movement within a particular work center or cell. This highlights operator or material handler movement that is non-value-added, such as parts not presented effectively, going outside the cell to chase down parts, or tooling not in the correct space.

You also can use the spaghetti diagram to analyze the “macro” flow, such as dock-to-dock flow. Take a plant layout and start from the first point you apply work. In some cases, this might be the receiving dock, and in others it might be kitting from raw material and the component inventory warehouse. Then follow the product all the way through the operation. How many feet … or miles … does the product travel from start to finish? Does the product backtrack in the flow? Are there congestion points or intersections that create flow issues and (even worse) safety problems?

Create manufacturing cells. These locate different operations together. With a good cell, you have line-of-sight management, no need to batch, short travel distances, and clearly defined flow. This can apply to light-duty operations where changing the flow means moving around some benches and tooling. But it also can apply to a series of operations ranging from stamping and forming to welding and finally packaging for shipment. Don’t underestimate your opportunities to apply cellular flow, regardless of what type of operations and processes you use.

Create future-state map for flow. For a given product or family of products, document and analyze the current state of flow. Then step back and create a future-state flow that accounts for streamlining, one-piece flow, minimal transportation, and the use of cells. Make sure the future-state analysis pushes the boundaries of possibilities. It is much easier to think about the ideal and then ratchet back to “aggressive reality” rather than to merely accept incremental improvement that keeps you close to the status quo.

Make a master plan layout. Another way to get a handle on flow is to create a master plan for the facility layout. This allows you to get a long-term perspective on space utilization and product flow. The master plan should minimize those short-term, suboptimal decisions that drive evolutionary flow in the first place.

Flow With Purpose

So, do you have a handle on flow? Whether your company is just starting its improvement journey or has been on the journey for years, flow is an important concept that requires attention and upkeep. The ideas here serve as a starting point.

The key is to get the appropriate stakeholders in your company to assess the condition of flow and to develop a plan for remediation, if necessary. Be sure to apply flow concepts not just to physical products but also to the information about those products, your machines, and your business. A deep in-box in the front office can be just as wasteful as a deep pile of WIP on the shop floor.

Don’t accept evolutionary flow. Make your flow have purpose and discipline.