High-mix, low-volume (HMLV) manufacturing refers to industrial operations that produce many different products or components in relatively small quantities. These companies all engage in a make-to-order production strategy based on sporadic and often changing demand from their customers. Beyond these general characteristics, there is no one-size-fits-all definition of an HMLV manufacturer, as they could perform: medical device assembly for highly specific, high-price pieces of equipment; component or part manufacturing for larger industrial companies that produce their own finished goods, such as machine builders or automotive companies; or be a contract packager in spaces such as food and beverage that must meet the demands of mass customization by packing out many different stock keeping units (SKUs).
By specializing in specific domains, HMLV manufacturers can operate most efficiently. Moreover, because many HMLV manufacturers are subcontractors, the reshoring of manufacturing operations has benefited them. Particularly in industries such as automotive and medical device manufacturing, there is growing interest in working with suppliers who are as geographically close as possible—not only to shorten lead times, but to avoid supply chain disruptions and maintain better oversight of quality.
To better address their customers’ often changing requirements, many HMLV manufacturers are adopting increasing amounts of automation. The issue for HMLV manufacturers is that traditional, fixed automation products are either too expensive or don’t satisfy their needs. For those in the HMLV space, flexibility, modularity, a compact footprint, and mobility are paramount. Enabled by increasing onboard software intelligence, lighter-weight and more responsive hardware, and the proliferation of low-code/nocode code applications, several major automation suppliers are moving to fill this gap in the market for HMLV manufacturers.
Flexible material handling
Helping HMLV manufacturers address the proliferation of SKUs in food and beverage packaging are flexible conveyance technologies that allow manufacturers to manage various product combinations and packaging formats on one line without the need for mechanical changeovers.
An example of this technology is Beckhoff’s Extended Transport System (XTS). The XTS is made up of reconfigurable motor modules assembled into a continuous track, which can be circular, rectangular, or follow a complex, curved geometry, based on the needs of the application. Individual movers affixed to the track can brake, accelerate, and adjust their speed independently of one another. The movers can also form groups capable of merging, diverging, or stopping together at varying speeds, and are synchronized with other assets such as traditional conveyors to ensure harmonious operation.
According to Jeff Johnson, product manager for mechatronics at Beckhoff, the XTS’s configurable track saves significant floor space, which is important for manufacturers attempting to process a higher mix of products without expanding the size of their facilities.
The XTS also allows for software-based changeovers. With this capability, an application involving the filling of different size bags with nuts or candy, for example, can be accomplished by using grippers on two movers to grip the bags on opposite ends. By gripping bags with an independent XTS mover on each side of the bag, differently sized bags can be filled on the same line by varying the amount of space between the individual movers.
As an example of how XTS can be used to address specific HMLV packaging applications, Johnson mentioned work Beckhoff did last year with Brenton, a machinery OEM. Brenton needed to make a cartoner for a pizza packaging application that could quickly switch from packaging pizzas in boxes to shrink-wrapping them in plastic. At the time, the machine Breton’s customer was using required a 30-minute changeover to handle the different packaging types. Using XTS, Breton was able to design a new machine that allowed them to combine three machines into one pitchless machine that could handle random in-feeding of frozen pizzas in different shapes, orientations, and SKUs. This new XTS-based machine can handle 41 different SKUs and up to 27 cases per minute. Changeover time has been reduced to five minutes, and the equipment footprint has been reduced by 50%.
When it comes to job shops—small industrial subcontractors that use CNC equipment and other machining techniques to produce parts and components for larger companies—collaborative robots (cobots) are increasingly becoming a go-to technology. In contrast to food and beverage packaging operations, these businesses are not necessarily interested in producing multiple products in the same workcell. Instead they prefer to keep production running more continuously without the need for extensive manual supervision.
In addition to the growing customer demands job shops face with greater product customization, they are also encountering increased cost pressures due to rising raw material prices. Because of this, they must simultaneously expand their capacity, optimize production, and increase efficiency. However, this can be challenging given the nature of their business model. For one, the unpredictable nature of make-to-order production means that typical methods of planning, which require some degree of regularity, are not possible. And fixed automation technologies designed to handle standardized, unchanging processes are of little use for CNC based manufacturing. On top of all of this, labor shortages make it difficult or impossible for these companies to expand their staff. As a result, the only way for them to increase their capacity is by asking employees to work overtime, which further raises costs and does little to solve the long-term issues.
According to Joe Campbell, senior manager for strategic marketing and applications development at Universal Robots, cobots that assist in machine tending have proven effective at navigating this scenario for several reasons. First and foremost, they are available at a lower price point than traditional automation technologies, placing them within the grasp of smaller companies that may not be able to take on a large upfront capital expenditure. Beyond that, the low weight of cobots (less than 100 pounds) means they can be placed on mobile carts or manually carried from one CNC machine to the next depending on the production demands and number of available employees on a given day. Furthermore, increases in onboard intelligence allow Universal Robots’ cobots to be more easily configured without specialized programming and engineering skillsets that small HMLV manufacturers lack.
All-Axis Machining, one of Universal Robots’ customers, was able to significantly grow its production capacity by adopting cobots to tend the CNC machines overnight.
Campbell said All-Axis Machining was really suffering because they couldn’t keep up with their customer demand, so the owner doubled down and bought more cobots. “That allowed him to spread out his man-power across multiple shifts, and even have some entirely unmanned shifts,” he says. “In the evenings, he would wheel a cobot up to the machine, set it up with 500 or 100 blank parts, start the automated process, and then just go home.”
As software innovations enhance and expand the capabilities of the various types of hardware used by HMLV manufacturers, online application marketplaces such as Bosch Rexroth’s ctrlX Store have begun to play an increasingly important role in reducing the time needed to deploy advanced automation applications. By making an ecosystem of turnkey automation applications available, the CtrlX Store can reduce the challenges associated with the configuration, programming, and design required to set up a new line or build out automation applications for tasks such as winding and sealing, says Rob McArdle, vice president and general manager of assembly technology at Bosch Rexroth. The CtrlX platform allows applications to be programmed in a variety of languages including C++ and Java, as well as low-code methodologies such as Google's Blockly visual programming environment. Not only does this make the deployment of automation applications faster, but it reduces the barrier to entry for smaller companies who may not have strong digital or software expertise on staff.
“A lot of third parties are vying to develop applications [for CtrlX], and it’s going to be a game-changer when it comes to customers programming their machines with our controls. They don’t have to start from scratch every time they want to do a conveyance line, sealing, or folding application,” McArdle says. “In the past, if someone developed code for a machine and then left the company, no one knew what the heck he wrote, how to change it, or how to build off it. With [the CtrlX Store], anyone can go in, see what was done, download the latest and greatest version, and make changes. They won’t have to rewrite it from scratch.”