Metal fabrication improvement: Manage the gray area between operations

I recently attended both IMTS in Chicago and FABTECH^® in Las Vegas, and you can surely understand my excitement for the technologies that are the lifeblood of manufacturing. But I want to introduce another topic that is not as shiny, fun, or obvious as the technology side of the business, but still represents great opportunity for improvement: the “gray area” between operations.

What Is the Gray Area?

If you have developed process flow or value stream maps, then you probably know the amount of time not spent directly transforming (cutting, welding, assembling, etc.) raw material into a product. If you have done this analysis, you probably recognize that more than 90 percent of the throughput time—that is, the total time it takes to process a customer order from beginning to end—is in that gray area, where nothing productive occurs with the product or information.

I mention “information” because some manufacturing processes are mostly or entirely information-based. Looking at the entire cycle from “get the order” to “collect the cash,” we see that information-based processes might include order entry, assembling production part approval process (PPAP) documentation, preparing material certifications, and invoicing the customer. Like the processes that make the physical product, these information-based processes have gray areas too.

When an operation is complete and the material moves away from the workcell, does it go directly to the next operation for immediate processing, or does it get shunted aside to a storage location—either a formal location like a warehouse or an informal location like an open space somewhere in the plant—to sit and wait? Is it sitting and waiting for quality control to perform inspection, and is QC waiting for someone to bring the material? The wait time, caused by a disconnect between functions in the business, is part of the gray area.

Regarding the “information” gray areas, does the information sit in a queue (like an inbox) waiting for someone to do something? Is the processing step redundant, or could someone else perform it sooner? Does the order, engineering change notice, or first-article request get lost in the “information” work-in-process?

Fixing the gray area is not about making the machine run faster or causing the weld bead to be laid down quicker. The equipment I saw at IMTS and FABTECH certainly addresses such opportunities. Minimizing the gray areas is all about connecting the value-added processes to shorten throughput time and, from the customer’s perspective, improve performance.

Actions to Reduce Gray Area Impact

Addressing the gray area between operations does not require capital investment. Often you simply need to change the way people execute a process or work step.

On the floor, try to create physical workcells where possible. If you group different equipment and workspaces together, products can flow through the sequence of operations without stopping. Think in terms of one-piece flow. A well-designed cell, tight enough so that people can hand workpieces from one operation to the next, will shorten the gray area to almost nothing.

If your process contains monuments—that is, pieces of equipment that cannot be moved because of pits, foundations, environmental requirements, etc.—then consider a logical workcell. In these cases, employees move parts around as if they were in a physical cell, even though machines may be far apart. Employees move a small batch of parts from one operation directly to the next, expecting that this very batch is the next job for the next operation. You will have minimal WIP and minimal gray area. Of course, you will have to use your imagination and have very clear rules about material flow and sequencing.

You also can adjust the production scheduling process. Some plant managers will load the plant floor with orders. Their thinking goes that the more orders there are on the floor, the greater the opportunity for supervisors to make decisions to drive efficiency. For instance, they can combine jobs or move jobs forward or backward based on material or parts availability. They also feel that having a lot of orders on the floor can motivate the workforce because it gives them the security of having a big backlog.

The better solution, which many see as counterintuitive, is to limit the number of orders on the floor. Provide only what is needed to meet the schedule, and you facilitate quicker flow and velocity. This eliminates the confusion caused by the stacks of production orders that, when just sitting there, prolong time spent in the gray area.

Ideally, you can manage the entire value stream rather than individual operations. Perhaps you have a production process that spans multiple supervisors: cutting is in one department, welding in another, and paint and assembly in others. If supervisors optimize their individual operations (metrics that drive inward behavior), then they may be making “the whole” less efficient.

Alternatively, if people manage the entire value stream, balancing the departmental focus and the value stream focus, they uncover opportunities to squeeze out the gray areas. Even better, have individual supervisors come together to create their combined plan to manage and execute the value stream.

An Example

Consider a fabricator that performs laser cutting, press brake bending, welding, painting, and assembly. The shop starts with flat sheet stock and ends with completed product ready to ship to customers. Customer orders come from a combination of Tier 1s and OEMs.

Where are the gray areas? Start at the very beginning, when a customer sends the order. After you receive the order, you do a credit check and make sure the raw stock and parts inventory is available. Once engineering develops, modifies, and/or confirms the design, you issue a production order.

Think about it—all these steps have gray areas before and after them … and you have not even begun making the product. As customer orders sit in queue waiting on answers from customer service, engineering, or sales, precious lead time is lost. Many times this makes those in production late before they even get started!

Once the material has been cut on the laser, the flat stock WIP is placed on skids to be moved for the next operation, at the press brake. Since they are cutting material up to three weeks ahead of the customer ship date, and the press brakes are a capacity constraint, shop employees build up WIP between operations.

Materials are set in open spaces. The four skids that contain the flat stock for a specific customer order get separated and stored in different parts of the plant. When the time finally comes to form the pieces for that order, only three of the skids can be found. Two production people plus the supervisor spend a couple of hours looking for the skid, and finally give up. Where did the parts go? They don’t know. They will probably show up later. In the meantime, a hot production order is created and inserted as the next job on the laser, disrupting the flow. Do you see lots of gray area here?

Finally, it is time for assembly. Parts are gathered to fulfill the assembly order. The materials department pulls the parts and delivers them to the assembly line, which is waiting for the parts. Before the first unit is halfway assembled, the assembler raises the dickens because the materials department has delivered the wrong parts: two sets of right-hand panels instead of one left and one right panel.

The assembly process halts, and a state of emergency ensues. Everyone focuses on sorting out what happened and finding the necessary left-hand parts. This disrupts not only assembly, but also the materials department, shop planning, and the fabrication supervisor. All of this is gray area activity.

Although your specific processes may be very different, the issues are universal. Once you recognize the gray areas and their disruptive (and usually hidden) impact, improvements and solutions become apparent.

Conclusion

As exciting as new technology is in this business, we should never lose sight of the “blocking and tackling” improvements made in the gray areas entrenched between the many manufacturing steps in metal fabrication. They can emerge anywhere in the quote-to-cash cycle, on the shop floor and in the front office—between quoting and engineering and purchasing, as well as between cutting, bending, welding, and assembly.

A balanced continuous improvement effort should attack the gray areas to shorten throughput times and increase responsiveness to customers. Teach everyone to attack the gray areas. Be relentless, and you’ll soon find that you will free up funds for future investment—so at your next FABTECH, you can really go shopping to handle new customer demand.