real world success

Moldflow Software Helps Dolav Determine Strength of its KitBin Product

By Laura Carrabine, Editor

Dolav Dvir-Lahav Plastic Products (www.dolav.com) was established in 1976 and is located in southern Israel. The company specializes in producing large, structural foam injection molded products. The largest product manufactured today weighs 106 pounds in one shot, and its maximum injection capacity exceeds 155 pounds. The plant uses advanced technologies and tailor-made equipment to manufacture heavy-duty, multipurpose box pallets and waste carts. The main advantages of Dolav plastic bins are their unique high-impact strength, heavy duty performance, resistance to corrosion, durability, long life and light weight.

According to Moshe Dotan, design engineer for Dolav, "We use structural foam, a high density polyethylene, with a blowing agent that causes an aerated effect to our products. Using structural foam enables us to produce products that are highly impact resistant. Using conventional injection molding practices, molders typically use a method called 'pack and hold' that applies residual trapped stresses to the injected products, which tend to be relieved under high impact and high heat conditions by cracking. Whereas, we use a blowing agent in the resin that causes the material to locally generate small bubbles and thus fill up the mold without requiring us to apply high pressure. This process enables Dolav bins and carts to face high impact energy and to be cleaned with powerful steam jets."

The KitBin project

Dolav designed and recently began manufacturing a completely new type of bin called the KitBin - a modular, bulk storage, multi-part shipping container. Dotan adds, "We learned that there is a tremendous need among shippers to reduce costs associated with shipping empty containers back to manufacturers for reuse. Traditionally, once crates are unloaded at their destinations, they are stacked one on top of another and shipped back to the manufacturer. It costs a lot of money, and the individual units take up a lot of space to reship empty crates. On the other hand, the foldable bins that have been available in the marketplace present a problem in that if any part is damaged, normally the whole bin becomes unusable. We decided to offer a strong, user friendly bin that can be disassembled into stackable components to help reduce the volume of the return shipment, while retaining the hallmark Dolav strength and durability."

Once Dotan and his team designed the KitBin, they presented it to Gal Sherbelis, a flow and structural analysis expert at GS Design. Dotan says, "At that time, we knew we had a wealth of experience designing and manufacturing one-piece crates, but this KitBin was a totally new product. We didn't want to introduce the product unless we were confident that it would withstand the rigors of disassembly, stacking, long distance hauling and reassembly."

Moldflow nonlinear stress capabilities

Sherbelis used Moldflow Plastics Insight^TM molding simulation software from Moldflow to perform structural analysis. "When the Dolav team approached me, they were pretty sure that the KitBin would perform successfully in the real world; however, they wanted to be completely sure," says Sherbelis. "Using Moldflow, we didn't locate any design faults or anything that needed to be changed. The analysis gave them the confidence that, indeed, the product would resist any harsh conditions such as long distance commutes and rough handling."

Sherbelis used Moldflow's nonlinear stress module. The results of his analysis were "uneventful." He explains, "The software analysis showed that the KitBin will not fail under the prescribed conditions, and no redesign was necessary. The outcome of the simulation work allowed Dolav to release a dynamic and innovative new product to the marketplace that will perform well."

"Using the software, we simulated various handling aspects such as forklift loading conditions, loading from different sides and angles, stacking the KitBin and storing the product on racks. In addition, we simulated strength and durability when the KitBin was filled with water. None of these real-life conditions affected the strength of the KitBin."

The physical test of the bins was conducted after the simulation, and it proved to be a solid confirmation of the simulation test. "We physically stacked 10 bins inside what used to be the space of three traditionally configured containers. The KitBin helps our customers reduce the volume of empty shipments by two-thirds. The longer the distance, the more economical it is for shippers to use KitBins," adds Dotan.

The simulation portion of the project took about two weeks. Dotan says, "As a result of the analysis, I was able to sleep at night. The Moldflow simulation assured us that our KitBin design exceeded our expectations." Today, the KitBin is shipping worldwide. The product can be easily assembled and disassembled manually by one operator. The product is ideally suited for agricultural, food processing, assembly, automotive, consumer goods, transportation, leasing companies and waste and recycling applications.