9 steps to custom metal fabrication excellence

Applying operational excellence or lean manufacturing can be difficult in any circumstance, but especially in the highly variable environment that is a custom fabricator. Fab shops have various job routings, frequent setups, variable processing times, and significant swings in demand, just to name a few of the challenges.

If you manage a job shop and want to implement lean methods, you first need to fully understand current conditions. You also must have a deep understanding of lean concepts so you can adapt them to your low-volume, high-product-mix environment.

All this requires time. Flexible, adaptable manufacturing does not happen by chance, but by design. But implementing lean concepts successfully will uncover significant benefits for your long-term business strategy.

Are you willing to put in the necessary effort to take your organization to the next level? Here are nine steps that can help.

Step 1: Identify Product Families

Review the equipment requirements and processing times for each product. After doing so, you may find that the products you fabricate have a lot more in common than you first believed. Lessons learned from developing product families will help you look through the complexity and see your business through a “simpler set of lenses.”

How you define a product family depends on your operation and product mix. A product family need not be limited to a specific customer. You can identify product families in various ways. Some may share similar customers, processing requirements or times, product designs, materials, demand characteristics, quality requirements, or any combination.

Wherein lies the truly significant difference between products? You may be able to design production cells for specific product families, which can help improve flow significantly. You also may uncover opportunities to simplify routings.

For example, one custom fabricator combined three finishing operations into a single station with three different machines, each operated by cross-trained associates. This simplified the product routings and part flow and improved flexibility for handling a variety of parts.

Step 2: Value Stream Map Key Product Families

Value stream mapping (VSM) has been called the assessment and planning tool of lean practitioners. It depicts how the enterprise operates, its current state. The map shows how material and information flow, from quote to cash. Information includes quotes, orders, and various transactions within scheduling and purchasing. The material aspect involves material receipt through production and shipping. The map has icons or symbols that help you develop “eyes for flow” and “eyes for waste.”

Next, develop a future-state VSM that shows how information and materials could flow in significantly improved ways. Identify which improvement tools should be applied and the potential benefits of doing so. This gives you a road map.

Step 3: Create Capacity-planning Tools

Custom fabrication faces varying demand, so you need to use tools that can help you regularly monitor demand and available capacity. You need to understand the rate of demand, or takt time, even if it’s ever-changing.

Over the years many job shops have learned to adapt the concepts of takt time to high-product-mix environments. It helps determine what resources are needed to meet demand and identify and proactively address bottlenecks or constraints.

To realize these benefits, you need to find a meaningful expression of takt time. The time could be expressed as it relates to units produced, dollars, or even certain processing metrics of a constraint process.

A takt time is often a very specific measure that relates solely to a specific business. For instance, say you work at a stainless steel fabricator that is falling behind too often. You identify polishing as a constraint process in one or more product families. You know how long it takes to finish a certain amount of linear feet. After all, you use this calculation during quoting, so the information is readily available. Once you understand that takt time—that is, how long it takes for our current resources to polish that many feet of material—you can start measuring demand by monitoring the polishing time for all incoming orders.

For other product families, you find that the band saw is your constraint process. In this case, you find that the number of pieces the saw can cut is the appropriate measure for takt time. That is, you can saw this many pieces in this amount of time. All this allows you to identify upcoming demand surges that exceed the takt time, and plan for it by authorizing overtime, adding shifts, or, if possible, hiring temporary workers.

Finding the right approach to takt time is like finding the Rosetta Stone; it allows your organization to get a handle on its demand. Once in place, such planning helps direct sales activity when capacity becomes available. It also leads to robust sales and operations planning, as we will discuss in Step 9.

Step 4: Address Information Quality Issues

Working at a custom fabricator, you depend on information accuracy. After all, you are not making repetitive, simple products. Details matter, and it starts with quoting.

The current-state map you develop (refer to Step 2) often reveals a significant lack of complete, accurate information. It’s easy to explain this away as a natural, unavoidable part of the custom fabrication business. But inaccurate and incomplete information can cost a business dearly, so you really must address the problem.

First, establish a robust process to identify customer needs upfront. This often means developing more of a partner relationship with the customer. Internally, enact processes that ensure you can communicate with customers effectively. Identify and address the manual transfer of information among multiple systems. You can turn to mistake-proofing techniques like check lists, visual cues in customer documentation, and, yes, even software.

Step 5: Implement 5S and Total Productive Maintenance

Working at a custom fabricator with a lot of moving parts, you need to stay organized, both in production and in the office. You need reliable equipment, and you need to avoid the all-too-common “run it ’til it breaks” approach.

Use 5S to get and stay organized—a place for everything and everything in its place. More than just housekeeping and safety, 5S seeks to achieve a functionally organized work environment, not just the appearance of being organized. You need to shorten time spent searching for and retrieving tools, parts, fixtures, information, materials, supplies, and more.

Techniques to keep equipment in good condition are also part of 5S, but more is typically needed in this area. This is where total productive maintenance (TPM) plays an important role.

A robust TPM program can provide important stability and predictability to a job shop. As one component of TPM, preventive maintenance (PM) is scheduled along with all other work. Make it part of the capacity planning described in Step 3.

However, TPM goes beyond calendar or usage-based maintenance, which PM represents. TPM also involves condition-based maintenance, which monitors equipment conditions via objective, measurable means: sensors and other devices measuring and analyzing vibration, temperature, particles in oil, and more. Such monitoring allows you to schedule maintenance based on the equipment’s actual condition, well before a breakdown occurs and not just when the calendar dictates.

Step 6: Achieve Quick Changeover

Quick changeover promotes flow and reduces costs, especially in an equipment-intensive custom fabricator, so it’s essential that you closely examine the various changeover or setup processes throughout the operation. By doing this, you’re likely to shorten changeover times by 40 percent or more.

If you’ve made it to this step, you’re probably halfway there. About half of the reductions in changeover time come from just being more organized by applying 5S (described in Step 5), as well as defining standard work for the various types of setups that operators perform.

Other opportunities involve equipment, fixture and tooling modifications to facilitate changeover, maybe even eliminating a changeover altogether. Modern fabrication machines are designed for rapid setup, though you actually may find that your operation isn’t taking advantage of the equipment’s full capabilities. Equipment vendors can help educate associates about what their machines can do, but people also must resist doing things because “that’s the way we’ve always done it.”

Step 7: Revise Office and Shop Layouts to Support Flow

Although it’s no small task, effective layout provides important benefits to a custom fabricator. The right layout can accelerate material movement from receiving through production.

Of course, no ideal layout, one that will work 100 percent of the time, really exists in the job shop. Nevertheless, if you can design a layout that efficiently accommodates 80 percent of jobs or more, then go for it.

As described in Step 1, some job shops have designed highly flexible, and successful, flow lines or cells. A cell’s flexibility depends on many variables, but it is remarkable what can be achieved with some ingenuity. You may be able to make some equipment mobile so that workers can move it in and out of the cell. Some machines in a cell may be idle at times (gasp!) when jobs do not require them.

Also consider “machine watching time,” and ask operators to perform other tasks during machine cycles. Combining multiple operations, particularly manual and automated ones, can boost part flow velocity significantly.

Step 8: Establish Pull Systems

There is no quicker way to lose the benefits of lean practices than to continue with the old “push” approaches to part flow. Continuing to load the shop to keep machines and people busy doesn’t mean more orders will ship. If jobs are just going to pile up somewhere, then why push them to the shop floor? Work-in-process (WIP) will increase, take up limited floor space, wreak havoc on workplace organization, and impede flow.

Pull, or kanban, systems do just the opposite. Job shops have successfully implemented pull systems to control flow between resources, which are typically shared. However, it is a sequential pull rather than the “supermarket” approach.

While the supermarket approach centers around the flow of products, the sequential approach focuses on the flow of orders. Orders are pulled in sequence to meet the demands of production. For instance, the welding department pulling the next order triggers events like order releases, purchase orders, and upstream processes like cutting and bending. The result: All components for a job flow quickly from one workstation to the next, and arrive at final assembly at just the right time.

The specifics depend largely on the job shop’s customer and process mix. Still, the underlying idea remains the same: What to work on next hinges on the actual flow of jobs.

A pull system is a decision-making system. Once you identify proper decision-making regarding the release of work to and the movement within production, you can incorporate them into the pull system and give associates a powerful method to control flow.

Step 9: Continuously Improve

At this point the focus moves to continuously improving performance of key metrics: throughput (typically measured in dollars), on-time delivery, inventory turns, order-to-cash lead time, quote conversion rates, and more. But be advised, after an initial bump, improving these metrics isn’t easy for a custom fabricator. Leaders must be diligent. Job mix and other conditions change quickly.

Moreover, new business development must align with a custom fabricator’s capabilities. Sales should not chase after new business that a fabricator cannot handle efficiently and effectively. If they do, performance will suffer. There is no such thing as infinite capacity or infinite flexibility.

This is not to say that the system will be static over time. You need to review and revise the system if a new business strategy warrants it. Until that time, everyone needs to maintain discipline and focus to keep sales and operations working together—with everyone working for the benefit of the entire organization.

“How Can We Make That Work Here?”

I have worked with many make-to-order companies, including custom fabricators, throughout the 1990s and into the 2000s. You might say that I cut my lean teeth in the custom world.

Learning what works for your circumstances will come only through experimentation. For every successful lean manufacturing initiative that I have witnessed, business leaders never said, “That won’t work here.” Rather, they asked, “How can we make that work here?”