A Lead Paste Case Study
Solving quality and efficiency challenges with Mate Gauge
Understanding the lead paste manufacturing process
The battery plate consists of a lead grid of wires, approximately 150 mm square, where each wire is spaced by 10 mm. During the pasting process, the plate gets coated with lead-oxide slurry that later cures and hardens.
You can make a battery without paste but it wouldn’t provide as much power or last as long. The paste is where the bulk of the electrochemistry happens. The resulting electrical energy passes through the grid and eventually to the battery terminals.
Why pasted plate thickness matters
The ideal plate is flat (or close to flat) with paste applied evenly from top to bottom and from left to right. When the paste is applied unevenly, errors begin to stack up. Plates are grouped into cells, so are susceptible to stack-up error. In particular, during the COS process (where the plates are inserted into the battery case) when the paste application is uneven, the group of plates won’t be able to fit into the case, causing machine jams, scrap, and downtime.
Measuring plate thickness is the only way to monitor and ensure paste is being evenly distributed across the plate. Measuring weight alone doesn’t provide this vital information.
Why weight measurement alone is not enough
Historically, weight has been the preferred control parameter when manufacturing lead paste plates. It’s easy to take weight measurements and, from a chemistry perspective, battery designs are based on the active dry material weight (the weight of the paste in the plate). However, one of the main reasons weight measurement has been traditionally used was because there was no viable way to measure thickness.
Weight measurement doesn’t give you the whole picture. When you weigh a plate, you weigh the entire plate. You get one result but you have no idea how the weight is distributed across the plate.
The benefits of thickness measurement
Even paste distribution across the plate matters! Weight measurement alone doesn’t inform your operators when the product is in or out of spec. (It’s possible for plates to be within spec for weight but out of spec for thickness.)
AGM batteries, in particular, need consistent paste application. They require plates and separators to be kept under a level of compression in the cell. This keeps the glass-mat material in near-uniform contact with the plates to ensure consistent electrochemical performance at the boundary. It also keeps the compression of the glass-mat within spec, as that ensures the proper amount of acid is included in the battery.
Adding thickness measurement to your manufacturing process helps ensure plate conformity and consistency. Everyone wants to produce the best product, with the least waste, in the most efficient way. When you’re producing millions of plates per year (roughly 72 plates per battery and often, depending on the factory size, 1 million+ batteries annually), quality matters.
The Mate Gauge solution
Battery manufacturers need a solution that uses accurate thickness measurement tools to minimize non-conformance, is easily maintained and calibrated, enables real-time monitoring and reduces the training and time required by operators. That’s where Mate Gauge comes in.
Non-touch measurement technology with dual-laser sensors
Pasted lead plates are soft and compressible, making them difficult to measure using touch methods (micrometers, vernier calipers, and drop-down dial indicators). On the other hand, our laser (non-touch) sensors are ideal for measuring this type of surface.
Dual-laser sensors scan across the pasted surface and capture the full cross-sectional thickness profile. Our software then reports the thickness based on the full center-line average or only by first extracting the peak regions of the plate and reporting a thickness of the peaks.
In addition, our sensor design is resistant to dirt accumulation and temperature fluctuations. They don’t get dirty quickly and, when they do, they’re easy and fast to clean.
Continuous real-time measurement and monitoring
The plates aren’t touched so they can freely move, allowing them to be measured on the active manufacturing line (with typical line speeds of 75+ feet per minute).
Continuous inline measurement allows more plates to be measured while freeing up the operator (no more manual measuring of sample plates). The operator simply observes the thickness and shape of the plates (by referring to the easy to read and interpret real-time monitoring screens) and makes machine and process adjustments to counteract any conditions that may be causing the plates to drift from their target thickness.
Why Mate Gauge?
Mate Gauge has been providing laser thickness measuring systems for lead paste manufacturing since 2009 and currently has systems just like this in over 22 countries around the world. Manufacturers rely on our technology and our team to provide them with the best solution for their lead acid battery production.
The Mate Gauge MG3 system is a traversing laser thickness measurement system designed to be implemented directly into pasting lines. Our engineers will help you understand the best location for installation. Mate Gauge also works with leading paste manufacturers, for example, MAC Engineering and Wirtz Manufacturing for additional line integration.
The MG3 is designed to counteract temperature drifts and is resistant to external dust and debris. It includes an easy-to-use touchscreen display that can be mounted close to the pasting machine operator. Our software includes product recipes and advanced features such as “Belt Scan” (which simplifies setting up and measuring plates that travel on conveyor belts).
The Mate Gauge MGX benchtop solution brings the benefits of non-contact thickness measurements off-line, in a fully-featured, plug-and-play system that's been designed to work out of the box. The MGX gives operators and quality assurance engineers complete flexibility to perform thickness measurements both on the factory floor and in the testing lab.
Based on our field recorded data, our systems prevent approximately 20,000,000 pounds of lead from unnecessarily entering car batteries every year, something that not only benefits our customers but also the planet.
Want to learn how we can help you overcome your lead paste measurement challenges? Contact us today!
Web Demos Available!
We can walk you through use and features of out benchtop scanning thickness gauges.