Omega Plastics utilizes GROB & Merrifield to automate mold manufacturing
The right mindset, the right five-axis technology and an intuitive approach to palletization help Omega Plastics extend automated control to the majority of its high-mix work.
Machining scaled up along with workholding, both in terms of size and sophistication, Mr. Arbic says. The first major change was from a three-axis VMC to one with a two-axis rotary table that enabled 3+2 machining. This eliminated the need for manual setup adjustments to provide spindle access to multiple part faces. However, he says that machine’s rotary table, spindle housing and other components left no room for larger parts like mold bases and base plates, particularly when mounted on pallet stacks. The model in place now, Grob’s G350, suffers no such restrictions, offering the ability to accommodate blocks even larger than the 18-by-18-by-3-inch plates for the largest, standard quick-change frames. With an auto-opening door, a feature requested by Omega and incorporated by Grob, the machine can also be integrated with the robot. That’s a contrast with previous models that required human operators to swap pallets in and out of the table chuck.
The machine’s spacious workzone is thanks largely to its horizontal spindle, which retracts back into the enclosure (including for toolchanges), as well as its one-sided trunnion table, which can flip a full 180 degrees. These two features allow the shop to machine mold base waterlines as deep as 22 inches by drilling to half depth, then flipping the part to bore the rest of the hole from the other side, Mr. Arbic says. Along with carefully programmed 3+2 machining routines, this configuration also makes complex features more accessible than ever before, he adds. That facilitates the use of shorter, more rigid tool assemblies to achieve tighter tolerances and smoother finishes. The machines’ 202-tool-capacity automatic toolchanger (ATC) also prevents tool availability or breakage from limiting lights-out capacity. He adds that the combination of a 26,000-rpm, HSK63A spindle and 63 Nm of torque provide versatility for both heavy material removal and fine finishing operations.
Grob and Grob dealer Merrifield Machinery Solutions (Pontiac, Michigan) deserve much of the credit for getting the machine up and running in the way the shop prefers, Mr. Arbic says. For instance, few users request smooth worktables with nothing but a specific chuck style (a choice that provides a mild chip evacuation advantage while also evidencing the shop’s confidence in its manufacturing strategy).