Case Study: Six-Station Machine Tending Using Kawasaki Robot
| By: Lilly Keyes, Kawasaki Robotics, Marketing Specialist
Manufacturers use automation to take their operations to the next level. Whether it is increasing throughput or decreasing labor costs, the integration of robotics gives enterprises of all sizes the opportunity to expand their business and eliminate pain points in their processes, which oftentimes has a ripple effect of unforeseen benefits.
When Battery Builders, LLC. (BBI), a Naperville, IL based industrial lead-acid battery manufacturer, decided to upgrade their facility, it seemed like an obvious choice to include their six-station COS (Cast-On-Strap) machine in those upgrades. They worked with robotic integrator MAC Engineering from Benton Harbor, MI, to install a Kawasaki large payload robot with robotic cell consisting of 6 process stations. Almost immediately after installing their robot, Battery Builders saw a more consistent product – a benefit that will likely have a huge impact on their business.
- Precise, versatile robot needed to tend multiple stations
- Decrease number of operators needed
- Increase throughput and product quality
BBI had a hefty checklist of must-haves for their new system. The robot needed to have a high payload and high repeatability in order to lift and align the battery plates accurately. They also needed to be able to rely on their robot and peripheral equipment to meet production goals of 1,000 battery cells per day – more than double their current daily production – using less manpower.
Top Priority: Reliability
BBI was plagued by frequent machine breakdowns from their manually run COS machine, which they’d had for over 25 years. The antiquated machine was causing costly delays in production – BBI was experiencing four to five hours of downtime a week. Growing frustrated by this detriment to their efficiency, BBI needed to find a reliable solution that could provide continuous production.
Health & Safety Risks
The company’s old COS machine posed other risks, not related to production. The process of manually stacking battery plates and loading plates into jars generated more airborne lead dust, which posed a greater risk for exposure than if the process was automated. The older machine also required employees to lift heavier loads, resulting in a greater risk of injury. “We have seen significant drops in exposure air monitoring results and we anticipate lower blood lead levels over time from the reduction of airborne lead dust concentrations,” BBI’s Environmental Health and Safety Specialist said. It was important for BBI to see the positive impact of automation reflected in their employees’ work environment - not just on their bottom line.
One Robot, Six Stations
In order to properly create their lead-acid batteries, BBI needed to install a workhorse precise enough to consistently align 300 lbs of battery plates up to 500 times per day. The robot also needed to be able to brush off the end connectors on the batteries, dip them into molten lead, and package them in a plastic jar, among other tasks. In order to accomplish this diverse list of detailed tasks, they needed a versatile robot to tend different types of machinery.
Streamline Operations & Minimize Menial & Hazardous Tasks
One of the manufacturer’s primary goals for automation was to increase their overall plant efficiency and increase their battery cell production numbers. The old COS process they targeted for automation required nine or ten employees to operate, and they were looking to decrease that number. BBI also recognized that their employees could be more useful in other areas of the manufacturing plant.
- One ZX300S robot moves product through entire six-station COS process
- Plate alignment, brushing, flux process, tin dipping, molten lead dipping, and casing
- Two operators load batteries and cases, one oversees the cell and changes grippers
Almost immediately, Battery Builders saw the advantages of their newly installed Kawasaki robot reflected in the quality of their end product.
“We have seen a visible change in the product quality,” BBI’s Assistant Manager said. “It’s not only the robot that’s precise in its movements, it’s all of the equipment around it, too. Everything is automated together, and the combination makes for a more accurate product.”
The number of laborers needed to man this process has gone down from seven to five. One employee is needed to move the battery plates from a pallet to a conveyor using a hydraulic lift. Two employees then stack the battery plates horizontally, align the lugs and load into another conveyor to feed the robot battery plates. Next, one employee loads the plastic battery cases into the case-out station conveyor. The fifth employee oversees the overall operation and changes robot tools and machine specifications, depending on the battery type.
The robot steps in after the battery plates have been manually slid onto the conveyor to align the plates and ensure they are even and flush. During this new process, operators no longer have to lift the plates from the ground – they move of the plates laterally onto a conveyor. This type of movement is more ergonomically friendly, and poses a lower risk of injury.
From here, the robot picks up the plates and runs them over a large bristle brush to remove any lingering debris from the end connectors, also called lugs. Next, the robot runs the product through a flux process, which prepares the metal lugs by removing metal oxides that could form beads when heated. The lugs are then dipped into tin to establish a stronger connection, and then dipped again into molten lead to connect the plates and establish the positive and negative posts. Last comes the case out process, where the robot places the battery plates into their plastic casing.
During this multi-step process, the robot doesn’t have to change tooling – the tooling only needs to change when the battery type is modified. When it’s time for a different battery type to go through the COS process, an operator will manually change out the gripper on the robot, and the MAC Engineering mold station brings in the correct battery mold type.
Although Kawasaki’s ZX300S robots are capable of carrying payloads of up to 300 kg, they combine a long reach arm with a minimal amount of dead space for a wide work envelope. They also have a high repeatability of ±0.3 mm, making them ideal for applications that require precision and heavy lifting. When combined, these features created the perfect solution for BBI’s setup, which required the robot to be able to reach multiple machines at varying heights, while generating a more consistent and accurate product.
Kawasaki’s newer large payload robots, the B and CX series, large have even higher repeatability, ranging from ±0.06 to ±0.08 mm. Both series have a hollow arm structure, which allows for internal dressing of the robot. This feature simplifies installation by reducing the amount of time needed for manufacturing line builds and digital engineering, and minimizes the risk of interference with other robots or peripheral equipment.
- One ZX300S robot covers entire six-station COS process
- Number of operators needed for battery assembly has decreased
- Product quality and consistency increased significantly
- Throughput will increase by 150%
For BBI, working with their new robot has been smooth sailing. “The robotics part of this process was very easy. Installing the robot was no problem at all, it was very simple, and learning to work with it wasn’t too complex,” BBI’s Assistant Manager said. “I’d tell people not to be afraid of bringing robots in.”
In order to get up to speed on operating and programming their new robot, two BBI employees attended a four-day Operations & Programming class at the Kawasaki Robotics Training Center in Wixom, MI. They took what they learned during the course back to BBI, where they were able to train the operators on robot functions necessary for day-to-day operation.
BBI chose MAC Engineering from Benton Harbor, MI because the high quality and performance of MAC's battery-making equipment has made them one of the world's most popular integrators for this type of application. After supplying more than 4,500 machines in over 80 countries to date, MAC is continually looking to the future to develop new products. For example, MAC’s remote access technology allows their customers to troubleshoot problems remotely, which cuts production downtime significantly when issues arise. Kawasaki robot controllers enable this type of functionality, making it easy for customers to utilize time-saving remote access.
Since replacing their old, breakdown-prone COS machine, BBI has seen a better, more consistent product quality using fewer man hours. The employees who used to operate their old machine are now working in the battery assembly department – allowing BBI to put more man hours toward the final stages of battery assembly and ultimately improving the overall quality of their batteries. Automating the battery manufacturing process decreased current operators’ exposure to airborne lead dust and the amount of heavy lifting their role requires, resulting in a significantly safer work environment. Once all of the integration is complete, they will be able to increase production from 400 to 1,000 battery cells per day – more than double the output they saw prior to automation.