Time is money

The manufacturing industry has changed drastically over the past several decades. The golden age of automotive manufacturing saw large production runs of tens of thousands of the same part. However, today manufacturers are moving towards short-run production with a large variety of parts to be machined. The days when you could just turn on a machine and let it run is no longer the standard.

With small batches and just-in-time production, machine shops are saddled with more machine downtime due to multiple changeovers. The ever-increasing challenge is to find production efficiencies, because time is money and money is made when the machine is running. One way to do this is through adopting new workholding solutions to decrease downtime between jobs.

Workholding Selection

There are many different types of workholding solutions ranging from the simplest device to highly customizable pieces. Clamps, chucks, fixtures, jigs and vices all ensure that components are affixed in place in order to machine accurately and efficiently. Regardless of the different approaches to workholding, one constant is the trend towards decreasing machine downtime in order to maximize productivity.

“Standard workholding may be as simple as a vise for a milling machine, a chuck for a lathe or a gripper for a robot,” says Matthew Mayer, CEO of RÖHM Products of America, Inc. “We can offer a customized workholding solution that will enhance a machine’s ability to eliminate operations, provide a more efficient manufacturing process or reduce setup times between operations.”

For the most part, manufacturers focus on finding the right machine and proper cutting tools for a job. What they often overlook is choosing the proper workholding solutions.

Some shops can be successful with standard workholding; however, exploring workholding options and solutions is a great way to ensure the best production practices.

“Manufacturers today are starting to realize that the next area of cost savings is in quick-change fixturing,” says Mark Kubik, product manager at Jergens Inc. “They’ve bought all the best cutting tools, maximized the high-speed spindles to cut the part as fast as possible, the way to get more uptime is to get quick change fixturing, or you’re are going to have to buy new machinery.

“[By incorporating improved workholding], it takes a machine and maximizes it to its highest efficiency levels.”

Workholding requirements differ due to a wide range of factors including material being machined, tolerance requirements, shape and size of workpieces, production run size, frequency of changeovers, and financial investment.

Mass production machining offers a different set of requirements and challenges than a smaller job shop that takes on shorter runs. Maintaining a high level of efficiency, though, is something that all shops should strive for. This is where quick-change workholding can be a great solution.

“The more changeovers, the more a quick-change system becomes user-friendly,” Kubik explains.

Quick-Change Solutions

Although there are obvious implications for quick-change systems in smaller shops, larger companies can also use them to increase their productivity.

“There is definitely a trend towards more quick change options for the customers that are operating these systems like Magna and larger companies that are looking for solutions to reduce downtime and changeover,” says Mark Watson, Canadian national sales manager for Halder Inc.

The truth is no one, large or small, wants to pay for changeovers. It’s the one area of business where manufacturers are not compensated. “Customers are really only compensated when the machine is running,” explains Dean Winkel, Canadian regional sales manager for Hainbuch America Corp.

“So the faster they can get from one job to the next, they’re ultimately more profitable. So whatever device that can help them to do that, that saves time, or can be configured while the machine is running, helps them to absorb the cost a lot more easily…The more the machine runs, the more money you make.”

Because there is such a wide variety of workholding solutions, depending on the application, there is an equally wide range of quick-change options. It is important to choose a system that is suited to the machine’s capabilities as well as the type of work you are doing.

Quick-change systems do tend to have a higher initial investment than traditional fixturing systems. “I’ve been selling these products for over 20 years,” says Sidney Roth, president at Samchully Workholding. “I remember reading a prediction in the mid-1990s saying that in the next 5 to 10 years, 90 per cent of lathes will be equipped with quick jaw change chucks.” It never really happened though, and Roth believes this is because customers are not willing to spend the initial up front cost.

Where you find the savings is in set up time. Roth breaks it down like this: if you figure a job shop will change over two times per day at 45 minutes each time, and there is a $75 overhead rate, you’ve got $112 per day in downtime.

If there are 220 workdays in a year, it works out to a pretty healthy number, around $25,000. The cost savings per year minus the initial cost of the chuck still yields profit, and when you factor in that a chuck can last up to 10 years, it clearly demonstrates the cost benefits of using quick-change systems.

Opting for a standard system because it is the cheap option can end up costing way more in the long run. “[Customers] are really hurting themselves,” he explains.

Almost all experts purport that although these systems have a higher upfront cost, they pay off quickly. “Once you’ve made your initial investment, the addition of more quick change plates is much less,” says Kubik. “We’ve done case studies where the customers have paid for their systems in less than a month. Mostly we see it being paid for in less than six months.”

Changing Production Environment

Traditionally, workholding has had a grip on the way work is scheduled in a shop. The use of quick-change workholding solutions has allowed for a shift in production mentality. It allows orders to dictate what work is on the machine instead of the workholding dictating what order is the next to be processed.

Winkel explains that many shops operate on this premise: we’ve got this workholding on the machine, we don’t want to waste any time taking it apart, let’s do all of these jobs because we can use this chuck. And then we will do these other jobs that require a changeover. “Unfortunately this limits the ability to take the rush jobs because you don’t want to take the workholding apart,” he says.

Quick change options allow for manufacturers to choose the next job in terms of their customers’ needs or by priority. They can quickly change the workholding in minutes and start a job with little downtime.

In today’s manufacturing environment, there are more and more unique machining capabilities and customer requirements. “We are seeing more complex workpieces that require more complex manufacturing processes. When you can combine operations and reduce the number of clampings, you can increase accuracy and reduce scrap,” says Mayer.

So not only do quick-change options reduce time, but they can also save money by decreasing the amount of scrap, which in turn saves time from having to re-machine a piece.

“As more and more manufacturers move toward just-in-time production, the flexibility to change quickly from product to product becomes essential,” says Roth.

If you experience frequent workholding changeovers, whether you are working with clamps, chucks, fixtures, jigs, vices or workholding accessories, be sure to investigate quick-change options. One thing is certain, the machining efficiencies and cost savings makes this option well worth it.