Disposable bulk plastic cups, an indispensable daily necessity in modern life, have their production process directly impacting product quality, cost control, and environmental performance. In the field of bulk plastic cup manufacturing, injection molding and thermoforming are the two main technological routes, differing significantly in production process, product characteristics, economic benefits, and environmental impact. This article provides a comprehensive comparison of the two processes across four core dimensions, offering decision-making references for companies choosing their manufacturing process.
I. Comparison of Production Process Differences
1.1 Fundamental Differences in Process Flow
The processes of injection molding and thermoforming have fundamental differences, directly determining their technical characteristics and application scenarios.
Injection molding: This is a "one-step molding" technology. The process involves: adding plastic granules to the injection molding machine barrel, melting them at a high temperature of 180-240°C; injecting the molten material into a closed mold cavity using a screw at a high pressure of 80-140 MPa (180 MPa for thin-walled parts); rapid cooling and solidification using cooling water or air; and then post-processing such as trimming and polishing after demolding. A typical injection molding cycle is 15-30 seconds, with cooling time accounting for approximately 60%. The equipment configuration is precise, requiring an injection molding machine, mold system, and auxiliary equipment.
Thermoforming: This is a "two-step molding" technology. The process involves: first, producing plastic sheets from raw materials using sheet extrusion equipment; heating the sheets to a softened state (not melted); using vacuum suction or pressure to make the softened sheets conform to the mold surface; and then cutting the finished product after cooling and shaping. The process mainly consists of five steps: stamping, feeding, heating, forming, and cooling. The equipment is relatively simple, including a thermoforming machine and a heating furnace, but requires pre-made sheets, adding an extra step.
1.2 Comparison of Production Efficiency and Capacity
The efficiency advantages of the two processes depend on the equipment, molds, and product specifications. Both can meet market demand during large-scale production.
Injection molding: High-speed thin-wall technology drives efficiency improvements. Taking a 700ml milk tea cup as an example, a Demag Systec 450/820-2300 SP injection molding machine with an eight-cavity mold has a molding cycle of only 5.3 seconds and an injection speed of 420 mm/s, resulting in a daily production capacity of over 120,000 units; Wanrong Packaging uses an "8+8" stacked mold in-mold labeling system, producing 16 cups in 3.8 seconds, with a daily output exceeding 3 million units; a conventional eight-cavity injection molding machine has a production cycle of 5.5-5.8 seconds, resulting in higher quality and precision for individual products.
Thermoforming process: Modern thermoforming machines can achieve a production capacity of 60 molds per minute, with a 50-cavity machine producing approximately 20 molds per minute, resulting in 60,000 cups per hour. Taking a 95mm diameter PP disposable cup as an example, a 28-cavity machine opens 14 molds per minute, resulting in a 24-hour production capacity of 560,000 units; the American BROWN molding machine can produce up to 3 million thermoformed cups per day, with a molding depth of 228mm, and typically higher output per mold (e.g., 50 cavities).
1.3 Equipment Investment and Technological Development
Equipment investment is a crucial consideration in a company's process selection, and the two processes differ significantly in cost and technological development direction.
Equipment investment: Injection molding equipment is expensive, with small machines costing 10,000-100,000 RMB, medium-sized 90-ton machines costing 30,000-32,000 USD (approximately 210,000-230,000 RMB), large 260-ton machines costing 35,000-40,000 USD (approximately 250,000-290,000 RMB), and all-electric models reaching 43,500 USD (approximately 310,000 RMB). A Taiwanese Liansu 650-ton machine with a robotic arm has a total investment of approximately 800,000 RMB; thermoforming equipment is less expensive, with economical automatic PS/PET cup lid thermoforming machines costing 28,000-30,000 USD (approximately 200,000-220,000 RMB), fully automatic PET cup forming machines costing 191,000 USD (approximately 1,380,000 RMB), and domestically produced Yongxu thermoforming machines costing only 150,000 RMB.
Technological Development: By 2026, injection molding technology will develop towards intelligence and precision. Temperature control accuracy will improve from ±5℃ to ±2℃, pressure control accuracy from ±5% to ±2%, and injection speed control accuracy to ±1%. The molding cycle will be shortened from 20-30 seconds to 15-25 seconds, product dimensional accuracy will improve from ±0.1mm to ±0.05mm, and the defect rate will decrease from 3-5% to 1-2%. Combined with the Industrial Internet and MES/ERP systems, the on-time delivery rate will increase by 12 percentage points. Thermoforming technology will focus on automation and material innovation, with automation reducing labor costs and resulting in near-zero defect rates. PS substrate thickness control will be 0.3-3.0mm, flocking fiber length 0.3-1.2mm, and density adjustable from 50-500 fibers/cm², improving product consistency.
II. Comparison and Analysis of Physical Properties
2.1 Cup Strength and Durability
Cup strength directly affects the user experience, and the two processes show significant differences in product performance.
Injection molded cups: Higher strength and durability. High-pressure injection molding results in a stable product structure and uniform wall thickness. PP injection molded cups have high hardness and heat resistance, and do not become hot to the touch or deform when holding hot beverages. In tests, the 90mm diameter thickened frosted injection molded cup showed excellent compressive strength, with no cracks or damage after compression, and good toughness and drop resistance, remaining intact after accidental drops. PP material has a density of 0.89-0.91 g/cm³, and its strength, rigidity, and heat resistance are superior to those of low-density polyethylene. It can be used at around 100℃, with a tensile strength of over 30 MPa, and can be bent 10⁶ times at room temperature without damage.
Thermoformed cups: Relatively lower strength. Although they have good flexibility and impact resistance, their overall durability is inferior to injection molded cups. While PP thermoformed cups are heat-resistant, uneven wall thickness affects their strength, and deep cups larger than 750ml are prone to "collapsing"; the PET material commonly used in thermoforming has high transparency but high hardness and brittleness, making it easily breakable.
2.2 Transparency and Appearance Quality
Transparency is related to visual appeal, and appearance quality affects product competitiveness.
Thermoformed Cups: Outstanding transparency advantage. PET thermoformed cups have high transparency and gloss, and do not discolor, making them suitable for cold drinks; PP thermoformed cups have good transparency and high production efficiency, occupying approximately 70% of the market share. However, the appearance quality is relatively rough, with problems such as uneven wall thickness (thick at the rim and bottom, thin in the middle of the cup body), stretching marks or bubbles on the surface, and poor batch consistency, which restricts their development in high-end applications.
Injection Molded Cups: Transparency has improved significantly in recent years. Using high-transparency food-grade PP material, they can withstand high temperatures of 120℃ while maintaining transparency, and some high-end products approach the transparency of thermoformed cups. They have an exquisite appearance, smooth surface, high dimensional accuracy, and uniform wall thickness, enabling the production of complex cup shapes and fine textures. Wall thickness uniformity control reaches ±0.1mm, far exceeding the thermoforming process.
2.3 Thickness Uniformity and Dimensional Accuracy
Thickness uniformity affects performance and cost, while dimensional accuracy determines product consistency.
Injection Molded Cups: Significant advantages in thickness uniformity and dimensional accuracy. Through precision molds and parameter control, wall thickness uniformity reaches ±0.1mm. Molten plastic is uniformly injected into the mold cavity under high pressure, resulting in consistent wall thickness after cooling, which improves strength stability and reduces material consumption. Product dimensional accuracy is improved from ±0.1mm to ±0.05mm, with precise control of key dimensions such as cup rim diameter and height, resulting in a yield rate exceeding 90%.
Thermoformed Cups: Thickness uniformity is a technical bottleneck. Sheet stretching and forming easily result in unevenness, especially for deep cups above 750ml, where wall thickness differences are significant; although modern technology has improved, it is still difficult to reach the level of injection molding. Dimensional accuracy is poor, affected by sheet thickness deviations, difficulty in controlling stretching deformation, and cutting errors, resulting in low consistency and a yield rate of approximately 85%, putting them at a disadvantage in high-precision applications.
2.4 User Experience and Functionality
User experience influences consumer choice, and functionality determines the suitability for application scenarios.
Core Physical Performance Metrics :
- Injection Molded Cups: "Hard" feel, with a sturdy and solid cup body, enhancing the sense of quality and user confidence. High design freedom allows for the production of various cup shapes, including double-compartment cups. The injection-molded cups offer excellent sealing performance; a 500ml cup sealed at 175℃ will not leak even when shaken or tilted, making them ideal for takeout. They can withstand high temperatures of 100-120℃, suitable for hot drinks. The cups have high strength, are easy to stack and transport, and can integrate functional features such as anti-slip textures and measurement markings.
- Thermoformed Cups: They have a "soft" feel, are tough and not easily damaged, and resist cracking when squeezed while holding beverages like milk tea. However, being too soft might lead consumers to question the quality. They offer good sealing performance and, with a tight-fitting lid, prevent leaks; they are lightweight, portable, and cost-effective for large-scale use, offering good flexibility and high safety.
- PP Material Advantage: Density 0.89-0.91 g/cm³, can be bent 10⁶ times at room temperature without damage
III. Cost Comparison Analysis
3.1 Equipment and Mold Investment Costs
Initial equipment and mold investment affect a company's financial pressure and payback period.
Injection molding process: High initial investment. For equipment, an eight-cavity high-speed injection molding machine with a robotic arm costs approximately 800,000 RMB; mold costs are even higher, requiring precision steel manufacturing, with a development cycle of 2 months and a single set costing 200,000-300,000 RMB, which is 10-20 times more expensive than thermoforming molds. However, injection molds have a long lifespan, making them suitable for large-scale, long-term production, resulting in significant cost advantages over the long term.
Thermoforming process: Low initial investment. Equipment costs are affordable, with domestic thermoforming machines costing 150,000 RMB and economical thermoforming machines costing 200,000-220,000 RMB; molds are made of ordinary aluminum, with a development cycle of 20 days and a single set costing 10,000-20,000 RMB. 3D printed rapid prototyping molds have a cycle of 3 days and a minimum cost of 500 RMB, and can also use low-cost materials such as gypsum and resin. However, the molds have a short lifespan and require regular replacement, increasing long-term operating costs, making them suitable for small and medium-sized enterprises and startups.
3.2 Raw Material Costs and Utilization Rate
Raw material costs dominate production costs, and the utilization rate affects the degree of material waste.
Injection molding process: Significant advantages in raw material costs and utilization rate. Using plastic granules as raw materials, the utilization rate exceeds 95%, with only a small amount of gate waste, which can be directly recycled and reused; it can use some recycled materials without affecting quality, and the material performance is stable with small batch differences. In 2026, the price of PP plastic granules is 6.94-27.74 RMB/kg, and the price of recycled granules is even lower (white transparent grade 1: 4900-5100 RMB/ton, grade 2: 4600-4800 RMB/ton), resulting in stable unit material costs during large-scale production.
Thermoforming process: High raw material costs and low utilization rate. Using sheet materials as raw materials, the price is higher than plastic granules; cutting generates 20-30% of scrap, resulting in a utilization rate of only 70-80%; the product weight needs to be 10-20% higher than injection molded cups to achieve the same strength, leading to significantly higher raw material costs and consumption compared to injection molded products. Furthermore, scrap recycling is difficult, and repeated heating reduces material performance, affecting product quality.
3.3 Energy Consumption and Labor Costs
Energy consumption and labor costs are high operating costs, and differences in manufacturing processes lead to different cost structures.
Energy consumption costs: Thermoforming consumes approximately 8% of material costs in energy. The process requires heating the plastic sheets until softened, and thicker sheets or larger products require even more energy. Injection molding energy consumption is concentrated in granule heating and equipment operation. High-pressure injection molding machines have electricity costs accounting for 15-20% of total costs, but technological advancements are driving improved energy efficiency. For example, Changhong Aichuang's intelligent low-carbon factory reduced energy costs per ton of material processed from 763 yuan in 2019 to 513.6 yuan in 2024, a decrease of 32.7%.
Labor costs: Thermoforming relies on machines for production, requiring less labor, with costs accounting for approximately 10% of material costs. However, manual cutting and trimming are still required, resulting in a relatively high dependence on manual labor. Injection molding requires manual involvement in loading, operation, and quality inspection, resulting in relatively higher costs. Based on a 15-second cycle and a rate of 30 yuan/hour, the labor cost per piece is approximately 0.125 yuan. However, automation technologies such as "dark factories" are significantly reducing labor requirements.
3.4 Cost Advantages of Large-Scale Production
IV. Environmental Performance Comparison
4.1 Material Recyclability Analysis
With increasing global environmental awareness, material recyclability has become a key consideration.
PET materials: Good recyclability, with a recycling rate of 90%, and mature technology. For example, CARBIOS's enzymatic recycling technology can process colored bottle flakes, waste textiles, and other PET waste. The depolymerized monomers meet EU food contact standards and can be directly polymerized into new PET, reducing carbon emissions by 90%, with a recycling cycle of 10-20 times.
PP materials: Recyclable but with a low recycling rate, facing challenges such as difficult separation, performance degradation after multiple recycling cycles, and limited market demand. However, physical recycling technology (cleaning, crushing, and granulation) can convert waste injection-molded cups into recycled materials. In 2023, the industry's use of recycled plastics reached 15.8%, a significant increase from 6.2% in 2019.
Process differences: Injection-molded cups have a stable structure, uniform wall thickness, and a single component, making them easy to classify and recycle. They can incorporate 10-30% recycled material without affecting quality; thermoformed cups may use composite materials such as PP+PET, making separation difficult. Edge scraps degrade in performance after multiple heating cycles, resulting in low recycling value, and uneven wall thickness also affects the quality of recycled products.
Policy-driven: Environmental policies will become stricter from 2026 onwards. The EU PPWR regulation was implemented in August, controlling the entire packaging chain; China is promoting the application of single polymer materials (such as single PP or PET) to achieve closed-loop recycling, forcing companies to improve material recyclability.
4.2 Biodegradability Comparison
Traditional materials: Both PP and PET are not biodegradable. PET has a stable structure, and the natural world lacks enzymes to decompose it; although the bacterium Ideonella sakaiensis was discovered in 2016 to decompose PET, the technology is still in the laboratory stage and far from large-scale application. Biodegradable Materials: The mainstream solutions involve blending and modification of materials such as PCL, PLA, and PBAT. Among these, PLA (polylactic acid) is the most promising, using lactic acid fermented from biomass such as corn and cassava as raw materials. It is 100% bio-based, completely degrades within 6 months under composting conditions, and produces no toxic substances when burned. It can be processed by injection molding and thermoforming. However, PLA faces bottlenecks such as the need for over 99.5% purity of lactide, a heat resistance of only below 60℃, and a price 30-50% higher than traditional plastics.
Application Trends: The proportion of biodegradable materials used in injection-molded cups increased from 8.7% in 2019 to 32.4% in 2023; it is projected that by 2030, the market share of biodegradable bulk plastic cups will increase from 12% in 2025 to over 25%, and the penetration rate in segmented fields will increase from 15% to over 35%.
Degradation Certification: Internationally, the EU EN13432 and US ASTM D6400 standards are commonly used, requiring over 90% degradation within 180 days; China's "Technical Requirements for Biodegradable Plastic Food Contact Materials" stipulates that heavy metal migration should be less than 0.01 mg/kg, and the oxygen permeability index should be ≤5 cm³/(m²・24h・0.1MPa).
4.3 Environmental Friendliness Assessment of Production Process
The environmental friendliness of the production process is related to carbon footprint and corporate social responsibility.
Energy Consumption: Thermoforming processes have high energy consumption for heat processing, accounting for 8% of material costs. Energy consumption increases with sheet thickness, heating temperature, and time; injection molding process energy consumption is concentrated in heating and equipment operation. Although injection molding machines have high power, the short molding cycle and high efficiency mean that the energy consumption per unit product is not necessarily high.
Furthermore, significant energy-saving improvements have been made in injection molding technology, such as the use of magnetic levitation water pumps + closed-loop water cooling towers + phase change cold storage materials in the mold cooling system. This saves an average of 147 kWh of electricity per day per mold. By 2025, 23,000 new environmentally friendly cup molds will be added nationwide, resulting in annual electricity savings equivalent to a reduction of 186,000 tons of carbon emissions. Waste Generation: Injection molding produces almost no waste, with only a small amount of gate and runner waste that can be directly recycled; thermoforming generates 20-30% edge trim waste during cutting, which is difficult to recycle and reuse due to potential performance degradation.
Carbon Emissions: A traditional PP space cup generates approximately 48 grams of CO₂ in carbon emissions per unit, with even higher emissions over its entire lifecycle. Companies are reducing carbon emissions through clean energy, process optimization, and bio-based materials. For example, Berry Global Group's PET cup production line uses microwave heating, reducing energy consumption by 37%, resulting in a reduction of 23,000 tons of carbon emissions annually for a factory with a capacity of 5 billion units.
Clean Production: Injection molding is a closed production process, reducing VOC emissions, and high automation reduces the risk of human contact with chemicals, resulting in more stable products and fewer defects; thermoforming involves heating plastic sheets, which easily generates exhaust gases and requires corresponding exhaust gas treatment equipment.
4.4 Environmental Policy Impact Analysis
Environmental policies are driving the green transformation of the industry and have a profound impact on process development.
Domestic policies: The 2024 "Action Plan for Reducing and Replacing Single-Use Plastic Products" requires that non-degradable bulk plastic cups be banned in food delivery services in cities at or above the prefecture level before 2026, and compliant enterprises will enjoy a 5% value-added tax refund. The national carbon market has expanded to the light industry sector, with an average carbon price of 68 yuan/ton CO₂ in 2025. Local policies are even stricter; Hainan issued the first local plastic ban regulation in 2020, and Zhejiang has implemented bans and restrictions on plastic products in various sectors.
International policies: The UAE will completely ban plastic beverage cups from January 2026; the EU's "Single-Use Plastics Directive" requires that single-use plastic packaging contain 30% biodegradable materials before 2025; and countries such as the US, Canada, and Australia also have plastic ban policies.
Process impact: Injection molding processes are more likely to meet policy requirements due to the good recyclability of products and the ease of incorporating recycled and biodegradable materials, thus gaining opportunities in the high-end market; thermoforming processes face greater pressure and need to develop biodegradable sheets, improve material utilization, improve processes to reduce waste, and strengthen recycling cooperation to cope with the challenges.
Industry trends: In the next five years, the disposable cup industry will increase the proportion of biodegradable materials used, optimize product design to enhance recyclability and biodegradability, promote process development towards low energy consumption and low emissions, and build a circular economy model of "production-use-recycling-reproduction".
V. Comprehensive Comparison and Selection Recommendations
5.1 Comprehensive Advantages and Limitations
| Comparison Dimension | Injection Molding Advantages | Injection Molding Limitations | Thermoforming Advantages | Thermoforming Limitations |
|---|---|---|---|---|
| Production Process | One-step molding, cycle 5.3-5.8s, high automation | Complex equipment, parameter pre-debugging required | Flexible two-step process, simple operation | Extra sheet process, low single-mold precision |
| Physical Properties | High strength, ±0.1mm wall uniformity, ±0.05mm accuracy | Slightly lower transparency vs thermoforming | High PET transparency, good toughness | Uneven thickness, 85% yield rate, easy deformation |
| Cost Control | 95%+ material utilization, low unit cost in mass production | High initial equipment & mold investment | Low initial investment, cheap aluminum molds | 70-80% material utilization, hard scrap recycling |
| Environmental Performance | Easy recycling, 10-30% recycled material usable, low waste | High initial high-pressure equipment energy consumption | Adaptable to biodegradable sheets | Composite material separation is hard, and heating exhaust gas |
5.2 Scenario-Based Selection Recommendations
✅ Choose Injection Molding If:
- High-end product positioning (branded milk tea/coffee hot cups, 100-120°C heat resistance)
- Large-scale stable production (≥10 million units/year, chain restaurant centralized procurement)
- Complex functional requirements (double-compartment cups, frosted anti-slip texture)
- Strict environmental compliance (EU PPWR, domestic plastic ban policies)
✅ Choose Thermoforming If:
- Mid-to-low-end mass market (affordable cold drink cups, cost sensitive ≤0.5 RMB/unit)
- Small-batch, multi-variety production (≤5 million units/year, seasonal promotional cups)
- Lightweight & portable needs (outdoor event disposable water cups)
- Start-up companies (equipment budget ≤500,000 RMB, low investment risk)
5.3 Industry Transformation Strategy Suggestions
Technological Upgrading Directions: Injection molding companies can introduce magnetic levitation water cooling systems (saving 147 kWh of electricity per mold per day) and industrial internet control (improving on-time order delivery rate by 12%); thermoforming companies can upgrade automated cutting equipment (reducing labor costs by 30%) and optimize heating temperature curves (reducing energy consumption by 15%). Material Innovation Strategy: Both types of companies need to proactively reserve biodegradable material technologies. For example, injection molding companies can test PLA/PP blends (balancing heat resistance and biodegradability), while thermoforming companies can develop single-layer PET biodegradable sheets (avoiding the separation problems of composite materials).
Flexible Production Configuration: Medium-sized enterprises can adopt a "injection molding + thermoforming" dual-process combination, using injection molding lines for high-end orders and thermoforming lines for mass-market orders; or choose compatible molds (such as thermoforming machines with switchable cavities) to improve equipment utilization.
Regional Industrial Collaboration: Leveraging the advantages of the plastics industry chain in South China (such as Guangdong and Zhejiang), injection molding companies can procure precision molds locally (such as suppliers of Liansu and Demag), and thermoforming companies can reduce sheet material procurement costs (sheet manufacturers within the region have a delivery radius of ≤100 kilometers).
