Future-proof a shop with high-speed machines and brass

Article by Copper Development Association Inc.

Global competition and high demand for everything from electronics to new transportation infrastructure have propelled manufacturing to rapid advances in productivity not only to keep pace but reduce cost per part and maintain competitiveness. To accomplish this, manufacturers constantly seek ways to keep up within their industry segments, and more often than not, that leads them to acquiring new, advanced high-speed machine tools and taking full advantage of their high-speed machining potential with part materials such as brass – a combination that also makes it even easier for manufacturers to justify the cost of new equipment.

Modern machine tools incorporate more spindles than ever before, enabling the rapid fulfillment of large orders through simultaneous production of multiple parts. Today’s machine tools offer multi-axis capabilities that increase shops' design capabilities exponentially at the same time that they reduce setups and increase accuracy. And, perhaps most importantly, with direct-drive servomotors on rotary axes, these machine tools also offer faster rotation without the backlash that gear-driven systems introduce. Those faster axial speeds further enhance production capacity while the motor technology increases the ability to perform the rapid acceleration/deceleration required for complex parts.

New manufacturing strategies also take full advantage of the capabilities of these advanced machine tools – and meet the ever-increasing demands of customers. Batch production enables shops to take on the smaller jobs that customers increasingly request, especially for products with tight tolerances and stringent specifications. As production strategies shift from the mass quantities of high-volume, low-mix (HVLM) assembly lines to high-mix, low-volume (HMLV) specialization, efficient new equipment with minimized setup time eases the transition to fulfilling orders that may call for single workpieces.

Of course, it’s not just technological advancement that has resulted in these changes. Between 2018 and 2028, manufacturers will need to fill 4.6 million vacant jobs, including 2.69 million positions that open as Baby Boomers retire and 1.96 million created through economic growth. Due to outdated perceptions of manufacturing among young people and a lack of a clear career path into the industry, employers will be unable to find skilled workers to fill 53% of these jobs, leaving 2.4 million of them vacant. These persistent skills shortages could compromise $2.5 trillion in economic output over a 10-year period – unless manufacturers embrace technologies such as conversational programming and innovative human-machine interfaces (HMI) that can make it easier to train up novice machinists.

For these reasons, among many others, investing in new machines gives manufacturers an opportunity to retool for proactivity as well as productivity at the same time they work to “future-proof” their operations. Instead of acquiring only enough new speed and output to continue their current work with a small boost in capacity, manufacturers can look for equipment that will enable them to expand, taking on jobs that formerly lay outside their capabilities.

However, advanced machine tools carry higher price tags than less-sophisticated equipment, leading many manufacturers to doubt the wisdom of these investments. They look at the number of simpler machines they could acquire for the same or less money, capable of producing nearly the same capacity, and they hesitate. If they view initial investment as their sole consideration, however, they take a shortsighted view that may stunt their future growth.

For example, suppose a manufacturer receives an order for 10,000 pieces per year of a connector housing. Should they tool up to produce it on two machines – a 2-axis lathe and a 4-axis mill – or should they acquire a 3-turret 9-axis lathe with dual Y axes that can handle the entire process on one piece of equipment? Both options use the same tooling, feeds and speeds, with a single operator required in each case.

Running seven hours out of each eight-hour day, the dual-machine option costs a total of $180,000 to purchase and produces 10,900 parts in 174 days of operation. To produce the 10,000 pieces required for the new contract, this option carries machine, labor and shop-rate costs that total $231,768, for a cost per piece of $23.18. The contract will take up 56% of the equipment's annual work time.

While the more-sophisticated machine carries a higher purchase price of $600,000, it produces 10,300 parts in only 52 days of run time. Its machine, labor and shop-rate costs for the new contract total $153,296, or $15.33 per piece, which is about 34% lower than the dual-machine option. At only 20% of the machine's annual work time, the multi-turret machine leaves 80% of its availability open for other work – and the production advantages are even greater when factoring in the elimination of part transfers between machines.

In general, increasing throughput can have a greater impact on shops' profitability than a lower machine purchase price, reduced labor requirements, longer tool life and reduced maintenance costs, among other factors. At the same time, the new equipment’s high-speed capabilities also offer the manufacturer another big advantage: the chance to tap into the productivity upside of highly machinable materials like brass that take full advantage of modern machine tool capabilities.

With a machinability rating of 100%, brass lends itself to high-speed machining to a greater degree than perhaps any other metal. Contrary to conventional wisdom, manufacturers can – and should – run brass at the highest speeds and feeds that each machine tool safely allows. If manufacturers follow the outdated recommendations in overly conservative handbooks, however, they will continue to underestimate the productivity of brass by up to 85%, and risk missing profits they could earn through high-speed machining.

In reality, brass readily supports high-speed production on today’s advanced manufacturing equipment, often with little tool wear and excellent chip control, even after long periods of operation, which decreases downtime for tool changes. In fact, an extensive machinability study, published as “High Speed Machining of Brass Rod Alloys” in Modern Machine Science Journal, recently demonstrated the remarkable cutting speeds and metal removal rates that can be achieved on brass rod alloys for practical production periods.

For high-precision parts, brass yields lower costs per part in high-speed, high-volume production with greater machine tool utilization. New machine tools with faster, more powerful spindles can machine brass at those high speeds, enabling shorter cycle times, expanded production capacity and quicker payback periods for capital upgrades.

Brass also offers another profitability edge over other metals, one with an environmental advantage: its significantly higher residual value and recycling efficiency. By comparison, steel and aluminum swarf holds only a fraction of its raw material value and can require additional processing to regain usefulness. Conversely, most post-processing brass scrap holds 75% to 90% of its original value – and brass rod stock is made almost entirely from recycled material.

Manufacturers who want to maximize their ability to respond to changing market conditions as well as to capitalize on new job opportunities need the future-oriented power and performance of modern machine tools to compete for challenging work and accommodate the changing landscape of their workforce. Although these investments in new technology require careful consideration to assure that shops choose the optimal equipment for their workflows, focusing at least some of their attention on brass parts will enable them to take full advantage of their acquisitions.