Whether you are an Oil & Gas Operator, a Chemical Company, an Integrator/Distributor, or a Manufacturing Company requiring custom roto-molding services you need innovative partners who will help support your growth by providing creative solutions to your everyday problems.
we pride ourselves on our ability to consistently deliver fresh new approaches to our roto-tank product line resulting in:
- Better well performance
- Better chemical performance
- More accurate budgeting
- Better insight into critical metrics and KPI's
- Reduced headcount for operators/chemical companies
- Reduced emissions
- Quicker product performance calculations & recommendations
- Reduced road exposure
- Reduction of exposure in field of non-operator employees
Rotomolding Manufacturing Process
The manufacturing process begins with a rotomoulding machine with arms called spindles. These spindles support the molds in which the plastic material is contained. The molding machine transports the molds from the loading area to a heating chamber and then to a cooling chamber. From start to finish, the rotational molding process consists of four different stages. They are completed in anywhere from 15 to 90 minutes.
Charging Phase
In the first stage, which is referred to as the charging phase, the metal mold is loaded with a measured quantity of raw plastic material and is sealed shut. Different types of machines have distinct loading mechanisms.
Heating Stage
In the second stage, the mold is heated in a heating station, usually an oven, as it slowly rotates on the vertical and horizontal axes of the spindles. The axes rotate the mold at varying speeds so that the plastic material does not accumulate. Rotation continues until the plastic powder is molten and evenly coated on the interior walls of the mold. This ensures uniform wall thickness.
In this step, the critical part is the time for which the mold remains in the heating station. If the mold stays for too long, the plastic material can degrade, which will decrease the finished product's ability to withstand impact. Conversely, if the mold remains for an inadequate time, the plastic pallets would not melt and stick on the mold wall. Insufficient melting can lead to large bubbles in the finished product, rendering it useless.
The reason that manufacturers start this process with fine powder resin is because
rotomolders use low pressure and would struggle to get the plastic to coat the mold cavity evenly. The plastic material can feature additives that contribute to corrosion resistance and static resistance, and the finished molded product assumes these properties when it emerges from the molding process.
Cooling Stage
The third phase of rotational molding is a cooling stage that cures the plastic within the mold, using cold air and water. This cold air often comes from a fan, which stays pointed at the mold until the plastic hardens.
The mold usually sets in about ten minutes. As the material cools down and hardens, it starts to shrink, which facilitates the removal of the product from the mold. The cooling process is also critical, and the rate of cooling must be regulated carefully. If a product is cooled down rapidly, it can result in disfigurement of the finished product. There was a time when an operator would determine the length of the time for cooling down the mold; however, modern machines have sensors that monitor the temperature of the molds.
Removal Phase
The last phase is the removal of the product from the mold by an operator. After the plastic has fully dried, the mold is reopened and the solid plastic part is manually removed. Because shrinking often occurs, removal can prove to be difficult. For applications that require additional strength, reinforcing ribs can be fabricated into the part.