Molder Only Runs One Mold with Fast Servo Motor— Instead of Two

When one of its customers approached B A Die Mold with a request to redesign an existing mold for a pressure vessel in order to reduce cycle times, the company knew that its proprietary Programmable Electric Rotating Cores system would fit the bill.

According to B A Die Mold Principal Alan Petrucci, the existing molds used a conventional hydraulic cylinder and rack, and hydraulic motor unscrewing system. The mold also was oversized for the customer’s press capacities—forcing them to farm the molds to another molder with larger molding presses.

Dale Malmer, Director of Engineering Services, elaborates. “The customer was using an old hydraulic method where they had a hydraulic motor, switches and a lot of electromechanical-type controls on the mold,” he explains. “Their customer decided to come up with a new part design that would strengthen the part. They had some mechanical issues with the part. When they redesigned the part it gave them the opportunity to retool the mold. They approached us and asked us to investigate the possibility of using PERC for their part.”

Petrucci notes that the mold has two threads in each part, a large-diameter buttress thread (approximately 5 inches in diameter) and a smaller, standard 60-degree thread in the center of the part that measures about 1½ inches. “These two different unscrewing cores each have a different pitch and different-type threads in each cavity,” he elaborates. “And, the larger thread on the inside of the part had to be timed at a specific point for start and stop, and the hydraulic system didn’t always register exactly where it was supposed to be. In other words, the thread’s start inside the part was critical to positioning the part on the vessel it went on. The thread’s start was critical in relation to the part. The hydraulic system our customer was using with a hydraulic motor wasn’t always repeating the start position of the thread, which created problems for their customer—the end user. Because it is computer-controlled, the PERC system is super accurate, and thus eliminated this problem.”

In addition to solving its customer’s imminent problem of accurate core positioning, B A Die Mold’s PERC system also resulted in reduced cycle time by 40 percent—via improved cooling and faster unscrewing times—and allowed the molder to run its mold in-house due to the smaller size. The original cycle time was approximately 106 seconds. Now it is 76 seconds. Petrucci explains, “This totally new design replaced an existing mold, and gave our customer more flexibility—via more press choices due to smaller mold size and no need for hydraulic core pull—more power and a lot more reliability in the control due to exact positioning and faster rotating core speed utilizing just one drive. We made two molds for them and they are only running one because the mold runs so fast!”