Rotational Molding and Its Advantages
Rotational molding is a technique used in the manufacturing industry to create highly durable and customizable hollow
plastic products. The process allows for double wall construction. It ensures
uniform wall fitness throughout the construction.
Rotomoulding process is ideal
for making large products such as tanks and bins that have to be hollow, and
can be made in one piece. It is also utilized to make complex medical products,
toys, recreational craft, and extremely artistic point-of-sale products.
In comparison with other methods of
plastic molding, rotomolding has many advantages in terms of relatively
low levels of residual stresses in the process and relatively inexpensive
molds.
Rotational molding is also called
roto-molding or roto-casting. Many manufacturers of hollow-type plastics
usually prefer this method in making their products. Another process used in
liquid-vinyl is slush molding, which is also a similar process.
Rotational Moulding process offers
many advantages as compared to other methods of plastic molding such as
injection molding, blow molding, and thermo-forming.
Benefits
of Using Plastic
ü Plastic is
corrosion resistant, it cannot rust. Stainless steel products are subject to
rust in welded parts.
ü Plastic is
chemical resistant. It’s a material that can withstand various chemical
components, which makes it perfect for tanks, intermediate bulk containers, and
other containers.
ü Plastic is a
durable material. It is extremely impact resistant and it does not dent. Plastic
parts can incorporate metal inserts in high-stress areas as well.
ü It is economical.
Plastic is lighter weight than metal, therefore it takes less fuel to operate
equipment with plastic parts. The material is less expensive than metal. Because rotomolding allows for one-piece construction, this reduces assembly costs.
ü Plastic is a
safe material to use. It eliminates sharp corners and burrs, resulting in a
smooth, seamless product. This reduces the risk for injuries for operators.
Advantages
of Rotational Molding Process
Size
Options
Rotational molding can produce any
size from the smallest part to larger sizes, which means the process is
flexible compared to other systems. The process can be used on a small ping-pong ball sized plastic part to 21,000-gallon tanks. Many manufacturers are able to produce a large capacity tank between 0 to 1000 pounds, and as tall as 17 feet.
Different
Designs
With rotational moulding, it is very
easy to design different shapes. This is because when the hot plastic compounds
are placed into a mold, they take the shape of the mold as they melt and then
harden. The process makes it ideal for creativity since manufacturers can make
any shape using the process. While other types of molding processes are inelastic
in nature with few options, rotational molding can provide different varieties of
design in the manufacturing phase.
Inserts
Rotational molding can easily accept
metal inserts while producing the part. It also allows the possibility for
additional threading inserts. Other methods are cumbersome, while with
rotational molding can be processed at very low costs. Assembly techniques can be
changed in the rotational molding process easily. Other manufacturing methods do
not readily take inserts and this can make it more costly than rotational
molding.
Color Sectioning
Color sectioning is much easier with the rotomolding process. Color blending can be done in-house to a variety of
shades. Color matching is done easily on the process without extreme volumes. A number of colors can be
achieved at a lower cost.
Quality Surface Finishing
Rotational molding process offers
high quality surface finishing capabilities by taking the exact shape of the
particular mold as well as the texture. This allows very high gloss quality
finishes on the product surface. It can also produce smoothness and quality
artistic design, and can take on a high oriental texture finish on its surface.
Decorations
in Mold
The process takes any originally
designed decorations made in the mold and will feature it on the plastic in a
vibrant way. This amazing technique of in-mold graphics is used to decorate and design
graphics are a by-product of rotational molding. The unique designs will stick
permanently in the final plastic product. This method allows easy molding for items
such as serial numbers, bar codes, and colorful logos. The designs often appear
in better quality compared to the traditional ones.
Quick
Tooling
The molding process uses
low-pressure without any need of ejection or in-mold cooling, thus reducing the costs of a mold for rotomolding. Especially given the extreme heating and cooling cycles, aluminum manufactured molds tend to perform better. The process
is cheaper when aluminum is involved. Depending on the design and complexity
involved, a new tooling process can only take about four to twelve weeks.
Top
Quality Durability
Parts and cases that are roto-molded are stress-free and can withstand impact force, chemicals, and
environmental factors. This is the reason why the process is ideal for making
cases designed for both military and commercial use.
Quick
and Easy to Make and Customize
Rotomoulding can significantly
reduce lead times. Molds can be made in a matter of weeks when possible. The process
allows for tooling to be produced which would mold multiple cavities of a product to be integrated into one mold, thus reducing the part price. Rotomoulding also allows further customization since the molding process is capable of using a wide range of materials.
Cost-Effective
Rotomoulding is a very
inexpensive method to produce high quality products because of its speed and
unique integration process. Larger products are to be molded at a lower cost
than products made with other molding plastics processes. The cost of the
equipment needed for rotational molding is also less expensive compared to
other processes. With rotational molding, you get high quality products with superior durability at lower prices than plastics fabrication or even metal fabrications.
Consistent
Wall Thickness
Usually, metal components are
weakest at the corners. These are the exact areas where the parts endure the
most stress. With other processes of molding, it is difficult to achieve total
consistency in wall thickness. With rotational molding on the other hand, the
constant rotation allows the polyethylene to coat every surface evenly.
Rotomolding Summary
While not as widely utilized as injection molding or blow molding, the rotomoulding process has its place in each of our daily lives. The durability of a rotationally molded product in comparison to an injection molded or blow molded product is second to none. The low production requirements, inexpensive tooling costs and durability of the products help ensure that rotomolding is a polymer based manufacturing process that will be around for generations to come.