Emerging technology offers dramatic new options in mold
design that will allow more complex plastic components.
The centerpiece of the new approach is conformal cooling, which refers to curving channels that allow better control of hot spots, reducing cycle times and improving quality. In traditional mold manufacturing, channels are drilled in straight lines.
GF AgieCharmilles is partnering with EOS to demonstrate a nearly automatic process for creating injection and blow mold tooling with conformal cooling channels.
In a demonstration at the International Manufacturing Technology Show, an EOSINT M 270 direct metal laser-sintering (DMLS) system created a mold for a plastic, blow-molded golf ball, complete with conformal cooling channels and the fixturing needed for all successive stages of machining.
The insert is made from EOS MaragingSteel MS, which is a pre-alloyed ultra-high-strength steel in fine powder form. Its composition corresponds to U.S. classification, 18 Maraging 300; European, 1.2709; and German, X3NiCoMoTi 18-9-5.
The mold then moves through a secondary process chain that includes a GF AgieCharmilles HSM 400U LP high-speed milling machine, an FO 350MS die sinking EDM and a Cut20P wire EDM. The wire EDM cuts off the fixturing, and the HSM 400ULP cuts the parting lines for a flash-free (no leakage) surface, leaving the mold ready for use.
In the production scenario envisioned at the ITMS, the DMLS process produces a near-net shape part. Single fixturing is then used for all secondary operations to reduce manual benchworking and generate surface finishes accurate to within three to five microns.
Conformal-cooled molds generally reduce part-production cycle times 17 to 20 percent and, in some cases, as high as 45 percent. The extra cost is justified only for demanding parts.
Click here to watch a video that shows the conformal cooling process.