Neptune Technology Group benefits from customized automated pouring.

Like many metalcasters, Neptune Technology Group, Tallassee, Ala., a manufacturer of lead-free brass water meters, sought to reduce its operating costs to enhance its competitive position. It was determined that increasing casting yields through automation was a key way to reduce costs.

But Neptune needed to determine which of its production processes could best benefit from automation. The melt shop was already highly automated with a computerized control system, and the molding system, a continuously molding inline cope and drag flask design, operated efficiently with minimal manpower required.

This left pouring and cleaning. Of these, pouring was targeted as the best candidate for automation. "Our casting yields were running at about 50%, and we knew we could do better," Patton said. The firm selected Inductotherm Corp., Rancocas, NJ., to install a new pouring system.

Neptune's continuously moving mold line proved a challenge in developing an automatic pouring system. Inductotherm's existing pouring technology was designed to work with a flask or flaskless indexing mold production system, not with a continuously moving line. With an indexing line, the entire line is motionless as a mold is being produced and only moves when the new mold is pushed into the line. It is while the line is motionless that the automatic pouring system fills a mold.

To work with Neptune's continously moving molds, the system Inductotherm designed consisted of three parts:

* the existing 12,000 lb. (5,443 kg) capacity pressure vessel with 225 kW induction power supply to hold the molten brass at a precise temperature in an inert gas (nitrogen) atmosphere. Metal flows directly from the melting furnaces into this holding vessel via launders;

* an automatic pouring mechanism with a stopper-rod system to provide greater speed and precision. The stopper-rod pouring mechanism is computer controlled and fully programmable by the operator;

* a PLC-controlled pouring shuttle that moves with the mold.

The moving shuttle enables the system to pour automatically on a continuously moving mold line. The shuttle, consisting of a wheeled frame holding a pre-cast launder, is mounted on rails between the stationary stopper-rod pouring nozzle and the moving mold line. A pouring nozzle is cast into the forward end of the launder on the shuttle.

As the spree on the moving mold passes below and is aligned with the stopper-rod nozzle and the shuttle nozzle, the stopper-rod opens and the automatic pour begins (Fig. 1).

The shuttle begins to move, tracking with the moving mold and keeping its nozzle directly above the sprue on the mold. Although the metal flowing from the stationary stopper-rod nozzle is no longer aligned with the nozzle on the shuttle, it continues to be captured by the moving shuttle's extended launder and flows through that launder and into the mold.

Just before the mold is completely filled, the stopper-rod closes and the remaining metal in the shuttle tops off the mold. The empty shuttle returns to its starting position as the next mold moves into place under the pouring unit.

"This sytem consistently provided precise pours, without over or under filling molds, even while we were adding metal to the pressure furnace," Patton reported.

With a rated pouring capacity of 400 molds per hour, the Inductotherm system keeps pace with Neptune's current production needs (Figs 2-3). "We are now producing from 210 to 290 molds per hour, depending on the casting being made," Patton said.

Fig. 2. Yields improved 30% with the new equipment while
productivity increased almost 40%.

                         Mold Yield    Production (Molds/Hr)

Old Pouring Equipment       ~50%                180
New Pouring Equipment        65%                250

Note: Table made from bar graph.

Fig. 3. A marked reduction in scrap rate was felt in 2000,
the year Neptune installed the stopper-rod pouring system.

Scrap Rate

1998           12.5%
1999           10.1%
2000            6.4%
2001           11.0%
2002            7.6%
2003            8.2%
2004            5.0%
2005            4.2%

Note: Table made from bar graph.