(continued)
Cosmetic Appeal
Addressing at least 25-30 different conversion opportunities during their meeting, the Finn/MOD engineering teams are reviewing a host of other parts such as fenders, clutch guards, slides, hatches and covers. All of these are flat pieces that are currently made from hot rolled steel to handle the constant abuse in the field. The fenders covering the tires, for example, are often used as a makeshift workbench and for climbing atop the machine with steel-toe boots. The fenders also block road debris flying at high speeds from reaching the wheels and the machine’s interior. Similarly, the straw blower’s feed system, a steel slide where hay bales are placed en route to being mulched, is subject to frequent scraping from the steel hooks contractors use to handle the heavy straw bales. This daily, metal to metal contact gradually scrapes away the paint and invites rust and discoloration. These examples demonstrate the challenge Finn and MOD face in balancing the needs for strength and visual appeal to achieve the ideal combination of fit, form and function with a plastic part.
To enhance visual appeal and prevent rust on these areas, Reichert recently revamped his in-house painting and coating process and has already seen improvement. Yet he was intrigued by the idea of rotationally molding some of these parts to capitalize on MOD’s ability to mold the same color throughout the part. If parts molded in Finn’s red or beige colors, for example, were ever scratched or chipped over time, the part would maintain its color without inviting rust formation. “It’s important to help our customers present a clean image without expecting them to repaint their machines,” says Reichert. “Plus, this would allow us to skip painting entirely and speed up assembly and delivery.” Although nearly any color can be matched, Girard cautions the hue of a molded part might differ slightly from a painted steel part, and in some cases, painting the plastic may be a viable alternative depending on the importance of the color to the project. “We’ve matched the brown for Steven Spielberg’s E.T. and we could match UPS’s brown and IBM’s blue,” says Girard. “We’ve worked with color enough to feel confident recommending the most effective, cost-efficient way to use it, whether it’s rotational molding or an alternative method like painting or painting with fluorination.”
It is this track record of experience that Reichert finds invaluable and one reason their relationship promises to continue growing. “Everyone at MOD has been interested in listening and learning about our operation,” says Reichert. “That isn’t common among vendors and I feel the deeper we involve them in our plans the more they can do to assist us in reaching our goals.” Adds Girard, “Jeff has a definite plan of action. He is willing to let us be the expert supplier and he has given us free reign to be creative problem solvers. When we have creative license, as any engineer will attest, everything becomes a lot of fun.”
When It Makes ‘Cents’ To Convert
Converting metal parts to rotationally molded plastic may seem to make perfect sense in many cases but much more is required than simply making the existing parts out of plastic, especially if costs are to be considered. According to Bob Dunne, vice president, sales, Meese Orbitron Dunne Co., Saddle Brook, New Jersey, the following issues may need to be addressed when considering a conversion:
Part Size
Rotational molding excels with large parts. Although it is capable of producing tiny medical bulbs and other small parts, if the product is as big as a bread box or up to seven feet tall and four feet wide then a conversion is likely to make financial sense.
Part Consolidation
Rotational molding often eliminates the need for several small parts, along with their fasteners and adhesives, in favor of one or more plastic parts. If the parts are made from either sheet metal, wood, hand laid up fiberglass or welded aluminum then you’ll likely save money in materials and assembly with a conversion. The operating conditions, types and amounts of stress it will be under, aesthetics and other factors must be considered.
Complexity
Rotational molding is ideal for producing complex parts requiring double or multiple walls, foam filling and/or hollow sections to tight tolerances. Engineers who use this process to upgrade an entire product typically get more bang for the buck vs. converting a single part from one material to another.
Initial Cost
Rotational molding tooling costs approximately 10% to 20% of the cost of injection mold tooling. This means producing parts in limited quantities is often cost-efficient.
Lead Time
With cost-efficient short run production and speedy tooling fabrication, it’s common for skilled rotational molders to bring new products from drawing to market in four to eight weeks.
For more information or an estimate on your project, contact Bob Dunne, 1.800.772.7659; bob@modroto.com.
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