High-Speed Molding for Brake Discs

A high-volume iron foundry has made a process switch to elevate its throughput while maintaining its product quality standards. Letec Automotive Co. is a specialty manufacturer of automotive brake discs, brake drums, and automotive engine flywheel assemblies in Qixia, Shandong, China, which it supplies to European automakers. With a total annual capacity of 45,000 metric tons, the foundry currently produces about 30,000 metric tons/year of finished castings.
The change involves a new vertical molding machine built by DISA, a part of the Norican Group, and a globally recognized developer of automated molding processes for metalcasting.
“The main reasons for choosing the Disamatic C3-X-350 was its high production efficiency and the low, spare-parts consumption of its simple, robust design,” recalled Yongqiang Sun, vice general manager. “Disamatic vertical lines are trusted worldwide and we could see there were already many C3-X-350 machines running very successfully in the Shandong area.”
The Disamatic C3-X-350 supports Letec’s brake-disc production program with high uptime, low scrap, and high molding speed. It’s able to complete 300 molds/hour with cores, or up to 350 molds/hour without core setting. That speed, combined with its large-format mold capability – 535×750 mm – makes it possible for Letec to maintain its output of up to 30,000 metric tons/year of castings per line.
“The greatest attraction of the Disamatic C3-X was that its mold size was exactly the same as our existing molds,” Sun explained. “It’s the perfect size for producing brake disc castings.”
The C3-X machine’s mold thickness is adjustable from 120 mm to 395 mm, which maintains a sand-to-iron ratio of around 5.5:1. That keeps casting quality reliably excellent while minimizing sand consumption – and cutting scrap and material costs.
The new Disamatic system requires a sand plant of just 40 to 50 metric tons, which significantly reduced the foundry’s capital-investment cost.
Letec chose to outfit the C3-X-350 with two auxiliary capabilities: an automatic core-setter (CSE) and a quick pattern change unit (QPC.) The CSE is a simple and reliable feature that uses a light curtain and an “auto-acknowledge” capability that makes the placement of sand cores ten times faster than a manual process, according to DISA. It avoids broken and/or dropped cores, and the results are consistently accurate.
The QPC makes changing pattern plates easy, fast, and less dependent on the operators’ skills or performance. Because a pattern-change sequence can be completed in less than two minutes, the C3-X-350 is also well-suited to shorter runs of different castings. Together with its high accuracy and production speed, the C3-X was a good choice for producing the ventilated brake discs that Letec supplies.
“The vertical molding application for brake disc production has more than 30 years’ history behind it,” according to Alen Chen, dean of DISA China Foundry Institute. “You only need to remember the simple rule: Keep the pouring time short and the iron melting flow slow. Then you can easily control brake disc production on a vertical molding line.”