Customers often ask what the difference is between the gravity method used in our lead parts casting machines and other casting techniques.

Unlike with pressure die casting, where the metal is injected into the mold and continuously pressed until it solidifies, gravity casting allows for the alloy to flow downwards by its own weight, slowly filling the mold. This is why the metal must always be poured from above, and the molds should be designed accordingly to maximize efficiency, so that the molten metal can reach every corner of the cavities.

All things considered, pressure die casting is more complex, more expensive, and requires more automation. Pressure die casting molds are also more expensive and can be easily damaged.

Gravity casting, on the other hand, is a slightly slower method, but also more cost-efficient in most use cases. Gravity casting products may not be as smooth as injection products, but the slower process prevents the formation of bubbles inside the metal, ensuring low porosity and heat treatment compatibility. It is particularly suitable for lead alloys and for thicker parts like poles, terminals, bushings, straps connectors and other battery components.

Alongside with inter-cell welding, heat sealing and acid filling, gravity casting is one of our main areas of expertise. BTS has over 30 years of experience with this technology, which is preferred by most Asian battery makers — and, increasingly, by customers in countries as diverse as Kenya or Argentina. That experience allows us to automate most processes, while keeping the costs lower — compared to pressure die casting. We also offer additional features like an integrated leak test that can inspect the finished products right as they are cast.

Special attention is given to the molds, which are carefully designed in close cooperation with our customers. They are manufactured using high-class German and Japanese materials and technologies, and thoroughly tested in our factory.

Send us your drawings to find out if this method is suitable for your needs. Our casting specialists will be glad to share their insight on how to improve your battery terminals' design.