CUSTOM ROTOMOLDING
(ROTATIONAL MOLDING)
WHAT IS ROTOMOLDING?
Rotational molding, also called rotomolding, is a method of creating hollow plastic products of any size. It is especially cost-effective for producing large plastic parts. The rotational molding process includes the following steps:
- Polyethylene resin pellets are put into particle-size reduction machines to grind them to a fine mesh powder
- The powder is blended with pigments and additives
- The mixture is put into molds made from heat-conductive materials
- Mechanical arms position the molds in an oven where they are rotated vertically and horizontally so they revolve in a 360-degree circle
- The mixture melts and coats the inside of the heated molds
- The plastic in the mold is cooled to room temperature to retain the desired shape
Rotational molding is an ideal plastics manufacturing process if you desire:
- Large, one-piece hollow parts
- Double-walled open containers
- Hollow components
Rotational molding can be used to create a variety of products such as:
- Bins and containers
- Automotive parts
- Road cones and barriers
- Toys
- Flower pots and planters
- Kayaks
- Sports equipment
- Storage tanks
OUR CUSTOM ROTOMOLDING CAPABILITIES
At Cooper Plastics, we produce rotomolded products with uniform thickness and stress-free parts for longevity and consistency. Our expertise in roto dynamics ensures that we deliver customized solutions tailored to your specific needs, taking into account factors such as mold design, complexity, and material costs. Below is an overview of Cooper Plastics rotational molding capabilities.
OUR MATERIALS
Plastic rotational molding companies like Cooper Plastics utilize a variety of high-quality polymers to create functional, durable products that meet customers’ specific needs. Below is a list of the common materials we use to fabricate rotationally molded products.
- Our primary material is LLDPE
- Other acceptable materials: HDPE, MDPE, XL-HDPE, LDPE, Nylon
Polyethylene is the most commonly used material in custom roto molding. It is flexible, chemical-resistant, and able to withstand extreme temperatures. Polyethylene is available in different grades including linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE). Each has unique characteristics such as level of hardness and flexibility.
The material utilized in your plastic product should be carefully selected based on its intended use. If you need assistance choosing, our knowledgeable experts can provide recommendations to ensure the final product aligns perfectly with your specifications and meets or exceeds industry standards.
OUR ROTOMOLDING MACHINES
Manufacturing consistent, durable rotomolded products and components requires specialized machines. Carousel machines are the most common in the industry. They feature multiple arms that rotate the molds in a circular motion for efficient, continuous production. Shuttle machines move molds between heating and cooling stations along a linear path, while more compact clamshell machines allow for easy mold changes and maintenance.
Roto molding machines feature advanced controls that allow the operator to manage heating, cooling, and rotational speeds. Carefully controlling these operations ensures uniform thickness and consistent quality across the production run. The temperature-control systems and rotation mechanisms are crucial to achieving intricate designs and custom specifications.
Learn about the rotomolding machines we use at Cooper Plastics below.
- McNeil 1500 2x-Machines
– 3x fixed arms
– Maximum part size = 72”
- Ferry 2600
– 4x independent arms
– Maximum part size = 85”
- Ferry 3300 2x-Machines
– 4x independent arms– Maximum part size = 120”
VALUE ADDED SERVICES FOR YOUR PROJECT
At Cooper Plastics, we offer numerous other value-added services, or secondary operations, in addition to our custom rotational molding service. These services, some of which are listed below, relate to things like product development, surface finish, assembly, and more.
- Scrape & clean
- Water test
- Flaming
- Spin welding
- Plastic welding & repair
- Drilling
- Full assembly of component parts & mechanicals to functioning product
HOW DOES CUSTOM ROTOMOLDING WORK?
Custom rotomolding is a plastic manufacturing process that transforms raw plastic materials into durable, hollow products. The process begins with a pre-measured amount of plastic resin, usually in powder form, being loaded into a mold cavity. The mold is then sealed and mounted onto a rotomolding machine that rotates it along two perpendicular axes.
As the mold rotates, it is simultaneously heated in an oven so that the resin melts and evenly coats the interior of the mold. After the plastic has fully melted and achieved the desired wall thickness, the mold is moved to a cooling station where it continues to be rotated. The cooling process solidifies the plastic and ensures it retains its shape and structural integrity. Finally, the mold is opened after the cooling process is complete and the finished product is removed.
Rotational molding is a good option if you need to create complex designs, as it allows for the production of large, intricate components without the need for welding or assembly. Rotomolded products are strong and consistent in quality.
HOW TO IDENTIFY QUALITY CUSTOM ROTOMOLDING COMPANIES
How do you separate the best custom rotomolding companies from the average ones? You need to evaluate factors that include industry knowledge and experience, dependability, and a track record of meeting and exceeding customer expectations.
You may be surprised what a difference professionals with extensive experience can make compared to those who are new to the industry. A company that employs engineers, designers, machinists, and other support staff with many years, if not decades, of experience will have refined its processes and developed a proven yet flexible approach. They should have innovative, custom solutions and the ability to act quickly to meet your standards and deadlines.
Look for a portfolio that showcases a range of successful projects across various industries. This will demonstrate the company’s versatility and capability to handle diverse, complex designs. A quality rotomolding company should have state-of-the-art equipment, which is critical for producing high-precision, durable products.
Since the mold is at the heart of plastic fabrication, seek a certified mold builder that can provide fabricated molds that meet your exact specifications. In addition to in-house mold building, mold repair capabilities are also critical to keep production running efficiently.
Last but not least, one component you don’t want to overlook is customer service. The rotomolding company you’re considering should be responsive and work closely with clients to offer custom design consultations, material recommendations, and flexible production capabilities. They should also have a rigorous quality control process in place to ensure every product meets specifications before it leaves the facility.
Cooper Plastics is a trusted partner of companies that want the best in custom rotomolding. Learn more about our company and what makes us stand out.
HOW MUCH DOES CUSTOM ROTOMOLDING COST?
The cost of custom rotomolding is impacted by a variety of factors. How complex is the design? How big is the product? What materials will be used? How large is the order? These are some of the questions that must be answered before an accurate cost can be calculated. Additional considerations include finishing services and product testing, which add to the price as well.
One advantage of rotational molding is that it is a cost-effective process for producing large, hollow, seamless products in medium to large quantities. When considering a particular company, make sure they can provide a detailed quote for your project. Cost transparency is important so that you have all the information you need to decide if you should partner with that company for the project.
Want to partner with us for your rotational molding needs? Request a free quote or contact us for more information.