Researchers were mildly surprised by recent experimental results that showed that the performance of a non-watered copper-alloy core attached to a copper-alloy chill plate was nearly identical to the performance of a normally watered copper-alloy core.
Mold engineers frequently encounter designs where core areas cannot be cooled with the direct application of water. Copper alloys have been used for non-watered core sections of the mold for years, but there are no widely accepted guidelines to aid the engineer.
Researchers at Western Michigan University designed an experiment to measure the performance of various combinations of solid core materials and chill plate materials and compared them to the typical watered core used in the industry. Copper cores and stainless steel cores were each attached to a copper-alloy chill plate and a P-20 chill plate and then compared.
Copper Core With Copper Chill Plate Performed Comparably To Watered Copper Core
The warpage in parts molded using various cooling strategies.Performance of each combination was evaluated by measuring the warpage of the parts as the cooling time was reduced. The figures show the warpage and the cooling time and core temperature for several cooling strategies.
As expected, the solid steel core with secondary cooling was the least effective. Using a copper-alloy core with a chill plate reduced the warpage but not the cycle time.
Copper Alloy Cores Reduce Operating Temperatures And Cycle Times
Cycle time follows core temperatures.Because the combination of the solid copper-alloy core with the copper-alloy chill plate is much more effective than a watered steel core, non-watered cores can be used with confidence in situations where getting water to a core is difficult or impossible.