The TachythermTM mold making process
The TachythermTM mold making process was conceived by inventor and company founder Robert Szokolay in 2005. It was intended as a means of creating fast-cycling molds for the plastics industry.
It begins with electroforming the mold cavity walls and parting line surface in nickel or a nickel alloy. Those not familiar with electroforming are directed here for more information on this process. The electroformed nickel shell is backed by a somewhat thicker layer of pure copper, also electrodeposited, atop the nickel. Because the nickel and (especially) the copper are more thermally conductive than conventional tool steels, this nickel-copper composite has a thermal conductivity approximately eight times that of a comparable thickness of tool steel. Using a long-established but little-known trick, the electroform is used as an EDM electrode to erode a closely conforming pocket into a block of conventional tool steel.† At the interface between the tool steel and the copper, the optimized cooling circuit is milled, or otherwise conventionally machined, into the tool steel. The electroform is then sealed to the tool steel blank, through a means appropriate to the temperature regime the mold will see in service, and the sealed assembly is then brought to finished dimensions as one piece, to complete the mold plate or cavity insert. See illustrations below.
This process accomplishes several things. First, by creating the mold cavity with nickel and copper, the electroformed shell is essentially a high thermal conductivity envelope comprising the mold cavity. Secondly, because the copper of the electroform serves as one of the walls of the cooling circuit, it is in direct contact with the water flowing through the cooling circuit, virtually sucking heat from the cavity walls. Thirdly, because the electroformed shell corresponds to the shape of the mold cavity, the channels of the cooling circuit are automatically conformal to the cavity shape, despite the complexity of the part being molded. The high conductivity envelope around the cavity conducts thermal energy from the resin to the coolant very efficiently. This synergistic combination of judiciously selected materials and unconventional assembly makes molds produced by the TachythermTM process thermodynamically superior to other molds on the market (consider that the tool steel used in this system is a relative insulator, whereas in conventional molds it is the primary heat conductor). Because cooling is both faster and more uniform in a TachythermTM mold, both cycle time and part distortion are reduced.
A TachythermTM mold makes a better part, faster, and with less energy. Thatís how a TachythermTM mold saves you money.