|
Why Use Rotational Molding?
Many advantages make rotational molding the best choice. One of the greatest advantages is the reduced cost of tooling. The cost of having a mold built for rotomolding is significantly less than for most other plastics processes.
Molds can be machined, cast or fabricated from materials such as stainless steel or aluminum. Cast and machined molds are best when exacting tolerances or cosmetic finishes are important to the finished product. Cast molds offer a wide range of finishes from wood grain to a mirror finish. Fabricated molds are more economical than cast or machined molds, but offer less options for finish.
Other benefits of rotational molding include:
- Design flexibility to meet specifications
- One-piece seamless construction
- Metal inserts and fittings as integral parts
- Uniform wall thickness
- Resistance to corrosion
- Variety of colors and finishes
- Lightweight
- Excellent load-bearing properties
- U.V. resistance
- Molded-in graphics, such as logos, and embossing
- Product longevity
Rotational Molding vs. Other Molding
Rotational molding offers many benefits over other types of molding such as injection molding, blow molding and thermo-forming:
Greater design flexibility
Rotationally molded pieces can be designed and manufactured to fit just about any space available. Often parts that are assembled from multiple pieces can be consolidated into one rotomolded part. That improves design possibilities. And the fewer parts, the fewer chances for part failure.
Dramatic cost savings
Because there is no interior core to manufacture, tooling for rotational molding parts is less expensive than tooling for other types of molding. When compared to most durable metals, plastics are substantially more cost effective.
Consistent wall thickness
Traditionally, metal components are weakest at the corners - the exact areas where the parts endure the most stress. With injection molding or blow molding, it's difficult to achieve total consistency in wall thickness. With rotomolding, the constant rotation allows the resin to coat every surface evenly.
Superior strength
A number of factors contribute to the superior strength of rotomolded parts: durable new plastics, consistent wall thicknesses, one-part construction and corrosion-resistance.
Shorter production times
We can usually design the piece, tool it and begin production in fewer than 3 months. Compare that to the minimum lead time of 6 months for injection molding, and it's easy to see that rotomolding brings your finished product to market dramatically sooner.
Easier to modify
Because of the relative simplicity of the tooling, minor alterations can be made to an existing mold to accommodate your changing production needs.
Ability to do small runs
With less expensive tooling, rotomolding makes it possible to do smaller runs on products. In fact, many of our customers find it economical to do runs as small as 10 pieces.
|
What Is Rotational Molding?
Rotational plastic molding is an extremely versatile and economic process that relies on gravity and heat to produce parts with exceptional strength. The finished result is a stress-free, lightweight and seamless design that is very durable.
A variety of plastic resins are available to use, depending upon the product specifications, strength requirements and resistance to other substances required. Materials that may be selected include polyethylene, nylon, polycarbonate, polypropylene, polyvinylchloride (PVC) and custom formulated compounds,
The flexibility of RDP's process allows for a wide range of shapes and sizes to be manufactured. RDP also offers products in a wide range of colors, with graphics molded directly into the part.
Steps in the rotational molding process:
- After the type of resin is selected, a premeasured amount of plastic resin is placed into a mold.
- The resin melts and fuses in a three-stage process. After the resin is loaded into a mold, the mold is inserted into an oven and rotated on two axes at low speed until the resin coats the inside surface of the mold cavity, fusing into a uniform wall thickness.
- While still rotating, the mold is removed from the oven and is cooled gradually.
- The rotation ends when it reaches the temperature that the part can be safely removed from the mold.
|
