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Five-Year Plan

Continuing its trend of opening a block & paver plant on five-year intervals, Sims Stone has made Bowman, S.C., its latest stop. The producer entered

Continuing its trend of opening a block & paver plant on five-year intervals, Sims Stone has made Bowman, S.C., its latest stop. The producer entered concrete masonry in 2000, adding a production line at its Tuscumbia, Ala., headquarters, where the flagship Sims Bark landscape materials bagging business had evolved from a family-owned nursery (Barking up the right tree, Concrete Products, June 2001). A Woodbury, Georgia, building and hardscape unit operation followed in 2005.

The South Carolina plant was assigned an aggressive timetable. Purchased in June 2009 and placed in operation by year's end, it enabled Sims Stone to realize benefits of the ROL Tax Law, extended as part of President Obama's February 2009 stimulus program. Expanding demand for concrete masonry products, combined with stepped-up Southeastern Coastal region sales efforts, convinced Sims Stone that the best way to serve this important market was through a dedicated Carolinas site. Like Tuscumbia and Woodbury, the Bowman plant is equipped for concrete masonry production and landscape materials bagging, netting a product combination suited to big box and independent landscape retailers.

The flagship plant's success with a Hess RH 2000 large-board (1400 _ 1100) machine compelled company president David Sims to enlist Hess Machinery to design the South Carolina site around a similarly configured RH 1500-3 model, coupled with a fully automated finger car, walking beam conveyors, and packaging line for high-quality, high-volume throughput. The new operation is also equipped with a face mixing system, positioning Sims Stone to bring the market a full range of new product now under development.

The RH 1500-3's Variotronic Vibration system allows amplitude and frequency to vary across the pre-, intermediate-, and main-vibration cycles. A more densely and evenly filled mold cavity is achieved over a range of product heights and shapes. The machine enables plant staff to change unit molds and mix designs from product to product in under 15 minutes. This feature gives Sims Stone the ability to react quickly to market demands and more efficiently manage inventory.

The RH 1500-3 allows us to maintain the high standards of quality with a high level of product throughput, all at a very economical cost, says Bowman Plant Manager Eduardo Aleman. The machine's Oil Bath Vibration System, he adds, will simplify maintenance and reduce operational costs.

The Oil Bath, Hess officials note, provides a maintenance-free vibration table: Vibrator shafts are mounted in individual enclosed housings; filled with oil, they assure uniform lubrication during operation. Through a spray channel, the oil reaches all areas of the bearings, while a reservoir at each housing's base prevents dry runs. Damage due to lack of lubrication is eliminated.

ACTION PLAN

Hess engineers configured the plant for a cycle-time balance between the production (wet) and the handling and packaging (dry) sides. This affords maximum output performance for a range of products at the lowest unit cost. The plant is also equipped with an advanced safety system running on integrated controls. All machine functions are controlled and managed by a Siemens S7 operating system. A diagnostic program assists the operator in monitoring critical functions, and an interface program connects the diagnostics to the Hess technical team for 24/7 support.

With a 1400 _ 1100 board size, the RH 1500-3 machine can use existing molds from the headquarters plant's RH 2000 Û an option that helped in the South Carolina facility's budgeting and rapid deployment. In addition to molds on hand, Sims Stone ordered Hess XD Molds for the new shapes it plans to introduce in the Southeastern Coastal region.

Hess Machinery technicians coordinated the Bowman start-up with Advanced Concrete Technologies (ACT) counterparts, who were commissioning a MobilMat Twin Mixer concrete batch plant. A Wiggert HPGM 2250 high shear planetary counter-current mixer produces base mixes, an HPGM 750 high shear planetary model the face mixes. A W∏rschum COM 70-3 granular-color pigment-metering system is fully integrated, while the Siemens S7 control automates production, including calls for concrete from the ACT batching and mixing, PC-based PCS Control system.

The ACT MobilMat batch plant features three discharge hoppers below each mixer, allowing automatic mixing of three different colors for greater mix flexibility in value-added units. The PCS allows fully automatic, unattended operation. Clicking and selecting a programmed product code will download all production parameters including mix designs, pigment recipes, and color mix feed parameters. An ACT Hydromat water-metering system uses a microwave moisture probe in each mixer to automatically maintain the targeted water/cement ratio. A Hydrotester moisture probe, installed in the sand bin, automatically maintains batch yield, even as the aggregate moisture varies.

The W∏rschum COM 70-3 color-metering system provides automatic granulated pigment dosing of virtually any earth-tone hue from four primary colors, plus pneumatic dispensing from three separate conveying vessels. Supplied by suspended, labor-saving super sack color pigment bags, the closed-loop system operates dust-free.

The high-speed, computer-controlled operation enables Sims Stone to be a low-cost source of a wide variety of building and hardscape units. The producer is concentrating initial capacity on pavers, segmental retaining wall units, and other value-added product. Û Concrete Products staff with information provided by Hess Machinery