Tech Update: Near-Net Shape Mold Formation

Sept. 12, 2005
Gets simpler, more consistent with new matchplate machine

In concept, metalcasting has not changed much over the past several decades, except in terms of what metalcasters aim to do to improve product quality or process efficiency. In this sense, moldmaking has progressed in various ways to meet the needs of metalcasters. One of their objectives is near-net-shape casting.

Hunter Automated Machinery Corp. has been developing technologies for making and handling green-sand casting molds for the past 40 years. Recently, Hunter introduced several advances in moldmaking, as well as some refinements on current practices, and the company claims it’s making it possible for metalcasters to produce molds in high volumes for regular casting of near-net-shape products.

The new XL Series of horizontal matchplate molding machines that Hunter recently introduced offers several advances for the process, and some refinements, that directly address the problem of mold shifting. The Schaumburg, IL, company claims it’s making it possible for metalcasters to produce near-net-shape castings more efficiently thanks to regular, high-volume production of molds.

The XL Series applies several new developments by Hunter to maintain cope and drag alignment without variation in repeatable, high-volume production. For example, it uses no roller lifts, platen swivel bearings, draw pins, or seats, all of which contribute to mold shifts and misalignments.

The XL Series incorporates a rigid platen and zero-clearance linear bearing system that precisely maintains positive alignment of the cope and drag throughout operations at the squeeze station.

When elevated, the platen, drag flask, and cope flask, guided by the linear bearing system, traverse the squeeze station on these hardened stainless steel pillar guides, matching the drag flask to the cope flask in perfect alignment when closing and squeezing the mold. These pneumatically-controlled detent cylinders are integrated with the rigid platen and lock the drag flask into alignment with the platen to eliminate the possibility of mold shift.

After a pattern change, a new Autolock hydraulic pattern-clamping system eliminates the need to bolt down a pattern. The result is drop-in pattern changes that take just a few minutes according to Hunter. An inverted hose-tracking system creates additional clearance for removing and inserting patterns during changes.

The XL Series has been designed for simpler maintenance and higher reliability than earlier matchplate machines. And, its HMI operator control system simplifies machine operation and management thanks to its built-in Foundry Floor Network capability. Coupled with Hunter’s optional Network Bridge Controller, this creates a seamless connection to existing Ethernet business networks for production data and machine condition reporting.

Even prior to the Hunter XL Series’ introduction at CastExpo 2005 in May, it had been installed at the Francis-Nygren Foundry in Chicago. That operation reports a notable increase in mold quality, along with diminished scrap and lower maintenance costs. Other orders for XL systems have been received from A.Y. McDonald Mfg. in Dubuque, IA, Bremer Foundry, Elkhart Lake, WI, and Lethbridge Iron Works in Lethbridge, AB, and those installations are expected soon.