Simplified: Rotational Molding vs. Other Plastic Processes

 

1. Differences in Core Competitiveness (Core Basis for Process Selection)​

 

Rotational Molding (Rotomolding): Takes "rotomolding-specific low mold cost + large-part rotomolding capability" as its core advantages. Leveraging the uniqueness of the rotomolding process, it precisely addresses the pain points of injection molding ("unable to handle large parts") and blow molding ("unable to produce thick-walled parts"). It is particularly suitable for customized, medium-batch rotomolding projects involving large, complex structural components—such as rotomolding-produced military shelters, rotomolding-based large-scale environmental protection equipment, and rotomolding-manufactured industrial containers. These products, due to their size or structural complexity, are difficult to produce via other processes, making rotomolding an irreplaceable solution in this field.

 

Injection Molding: Excels in "high efficiency + precision molding" and is ideal for high-batch production of small-to-medium-sized precision parts (e.g., mobile phone charger casings). However, for extra-large parts, the cost of molds and equipment increases exponentially. Moreover, it cannot match the cost-effectiveness and feasibility of rotomolding when manufacturing large, thick-walled components—a key strength of the rotomolding process.

 

Blow Molding: Focuses on "high-batch production of small-to-medium-sized hollow parts" (e.g., bottled water packaging). It cannot replace rotomolding for large hollow parts (e.g., rotomolding-manufactured 1000L storage tanks) nor produce non-hollow structures like injection molding. In the field of large, thick-walled hollow parts that rotomolding specializes in, blow molding has no competitive edge.

 

Thermoforming (Vacuum Thermoforming): Features "ultra-low cost + mass production of ultra-thin parts" and is suitable for disposable packaging or simple casings (e.g., fast food boxes). Its molding structure is limited, and it cannot compete with rotomolding or the other three processes in the complex part market—especially lacking rotomolding’s ability to form complex curved surfaces and thick-walled structures, which are hallmarks of advanced rotomolding applications.

 

2. "Trade-off Relationship" Between Materials and Costs

Rotational Molding (Rotomolding): Although rotomolding molds offer rotomolding’s core cost advantage (lower upfront mold investment), the rotomolding process characteristics lead to a rotomolding raw material utilization rate of only 85%-90% (primarily due to rotomolding powder residues in the mold cavity). Additionally, longer rotomolding production cycles (compared to injection or blow molding) result in higher unit labor costs for rotomolding. This creates a typical trade-off: "low rotomolding mold costs vs. higher raw material/labor costs."

 

Injection Molding: Boasts a raw material utilization rate of over 95%, far exceeding rotomolding’s raw material efficiency. However, its mold costs are extremely high—requiring an annual output of ≥100,000 units to amortize expenses. For small-batch production, its cost-effectiveness is significantly lower than that of rotomolding, especially for rotomolding-focused small-batch custom parts (e.g., personalized industrial rotomolding components).

 

Blow Molding & Thermoforming: Both have relatively high raw material utilization rates (90%-98%), close to rotomolding’s efficiency. However, they are limited by their molding capabilities—only specific materials can be used (e.g., PE for blow molding, PVC for thermoforming). Their material options are far narrower than rotomolding-compatible materials (rotomolding works with HDPE, LLDPE, PVC, PA, and other polymers), making them unable to meet the multi-material, complex structural needs of rotomolding applications.

This revision embeds "rotomolding" into key links (molds, process, materials, applications) while clarifying its competitive advantages. If you need to add more rotomolding-related terms (e.g., rotomolding quality control, rotomolding post-processing) or expand on specific rotomolding use cases (e.g., rotomolding medical equipment housings), feel free to let me know.