Six-station robotic machine tending boosts productivity

When Naperville, USA-based industrial lead-acid battery manufacturer Battery Builders (BBI) decided to upgrade its facility, it seemed like an obvious choice to include its six-station COS (Cast-On-Strap) machine in those upgrades. It worked with robotic integrator MAC Engineering to install a Kawasaki large payload robot with a robotic cell consisting of six process stations.

BBI had been plagued by frequent machine breakdowns on their manually run COS machine, which they 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.

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. For BBI, it was important to see the positive impact of automation reflected in their work environment - not just on their bottom line.

In order to properly create its lead-acid batteries, BBI had 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, BBI needed a versatile robot. 

One of the manufacturer’s primary goals for automation was to increase its overall plant efficiency and increase its battery cell production numbers. The old COS process it targeted for automation required nine or ten employees to operate, and it was looking to decrease that number. BBI also recognised that its employees could be more useful in other areas of the manufacturing plant.  

Almost immediately, BBI saw the advantages of its newly installed Kawasaki robot reflected in the quality of their end product. The number of labourers needed to man this process has gone down from seven to five.

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 which is a more ergonomically friendly move.

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, called lugs. Next, the robot runs the product through a flux process. The lugs are then dipped into tin, and dipped again into molten lead.  Last comes the case out process, where the robot places the battery plates into their plastic casing.

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.

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 minimises the risk of interference with other robots or peripheral equipment.

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.

BBI chose MAC Engineering because the high quality and performance of MAC’s battery-making equipment has made it 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.

Since replacing their old, breakdown-prone COS machine, BBI has seen a better, more consistent product quality using fewer man hours, and created a significantly safer work environment. 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 its batteries. Once all of the integration is complete, it will be able to increase production from 400 to 1,000 battery cells per day – more than double the output it saw prior to automation.