When selecting plastic materials for manufacturing—whether for rapid prototyping, small-batch customization, or large-scale production—understanding the gaps between 3D printing plastic materials and ordinary plastic materials is essential. This article breaks down their core differences in molding processes, structural traits, material properties, and application scenarios, helping you pick the right material for your project.
1. At-a-Glance Comparison: 3D Printing vs. Ordinary Plastic Materials
To quickly grasp the biggest contrasts, start with this comprehensive table. It highlights 6 key dimensions that directly impact material performance and usability.
| Comparison Dimension | 3D Printing Plastic Materials | Ordinary Plastic Materials |
| Molding Process | Additive manufacturing: Layer-by-layer stacking (e.g., FDM, SLA) | Subtractive/forming manufacturing: Injection molding, extrusion molding |
| Structural Characteristics | Layered bonds; weaker strength in vertical (layer-thickness) direction; potential interlayer gaps | Uniform internal structure (injection molding); good lengthwise continuity (extrusion); minimal interlayer issues |
| Mechanical Properties | Lower tensile/flexural/impact strength (e.g., PLA: ~50MPa tensile strength); improved via annealing | Higher strength (e.g., ABS: ~40MPa tensile strength, PC: ~65MPa); optimized via formula/process |
| Thermal Stability | Poor for some types; prone to deformation/discoloration (due to repeated heating/cooling) | Variable (PC/nylon: good stability; PE film: poor stability) |
| Dimensional Accuracy | ±0.1–0.5mm (industrial-grade); improved with high-end equipment | CT4–CT5 levels (injection molding); lower for extrusion (good lengthwise stability) |
| Surface Quality | Rough (layered texture); improved via sanding/polishing | Smooth (injection molding, via mold finish); minimal post-processing needed |
2. Deep Dive Into Core Differences
Below is an in-depth analysis of the most critical differences, using a “process + trait + example” structure to connect technical details to real-world use cases.
2.1 Molding Process & Structural Characteristics: Layered Stacking vs. Uniform Forming
The way materials are shaped directly defines their internal structure:
- 3D Printing Plastic Materials: They rely on layer-by-layer accumulation. For example, in FDM (Fused Deposition Modeling), PLA filament is heated to ~190–220°C, extruded through a 0.4mm nozzle, and deposited on the platform one 0.1mm-thick layer at a time. This creates a structure where layers bond externally but may have tiny gaps internally. As a result, the material is weaker in the vertical direction—e.g., a 3D-printed plastic bracket may break when pulled vertically but hold up better when pulled horizontally.
- Ordinary Plastic Materials: They use high-pressure forming or extrusion. In injection molding, ABS particles are heated to ~220–260°C, injected into a mold cavity at high pressure (~50–150MPa), and cooled. This forces the material to fill every mold detail, creating a uniform internal structure with regular molecular arrangement. For example, an injection-molded plastic toy has consistent strength in all directions—no weak vertical layers. In extrusion molding, PE is melted and pushed through a pipe-shaped die, resulting in good continuity along the pipe’s length (ideal for water pipes).
Why It Matters: 3D printing’s layered structure limits its use in load-bearing parts, while ordinary plastics’ uniform structure makes them suitable for structural components.
2.2 Material Properties: Strength, Thermal Stability & Precision
How well do these materials perform under real-world conditions?
2.2.1 Mechanical Strength: Lower Baseline vs. Optimized Performance
- 3D Printing Plastics: Their strength is inherently lower. For instance, 3D-printed PLA has a tensile strength of ~50MPa—enough for a decorative prototype but not for a phone case that needs to withstand drops. However, post-processing like annealing (heating to ~60–80°C for 1–2 hours) can improve interlayer bonding, boosting tensile strength by ~10–15%.
- Ordinary Plastics: Their strength is optimized for function. Engineering plastics like PC (polycarbonate) have a tensile strength of ~65MPa—strong enough for laptop casings. ABS, used in Lego bricks, has high impact resistance—able to withstand repeated drops without breaking—thanks to its formula and injection molding process.
2.2.2 Thermal Stability: Repeated Heating Risks vs. Material-Specific Durability
- 3D Printing Plastics: Many struggle with high temperatures. PLA, for example, softens at ~60°C—leaving a 3D-printed PLA cup deformed if filled with hot coffee. This is because the material undergoes multiple heating/cooling cycles during printing, weakening its thermal resistance.
- Ordinary Plastics: Stability varies by type. PC can withstand temperatures up to ~130°C—safe for microwave-safe food containers. Nylon (used in 3D printing too, but more commonly in ordinary plastics) has a melting point of ~220°C, making it suitable for engine bay components in cars. However, ordinary PE film melts at ~110°C—unsuitable for hot applications.
2.2.3 Dimensional Accuracy & Surface Quality: Rough vs. Refined
- 3D Printing Plastics: Accuracy depends on equipment. A consumer-grade FDM printer has ±0.3mm accuracy—fine for a prototype but not for a part that needs to fit with other components. The surface is rough (Ra ~5–10μm) due to layered stacking; sanding with 400-grit paper can smooth it to Ra ~1–2μm, but this adds time.
- Ordinary Plastics: Injection molding delivers precision. It reaches CT4–CT5 tolerance levels (±0.05–0.1mm)—perfect for smartphone components that need exact fits. The surface is smooth (Ra ~0.8–1.6μm) right out of the mold, thanks to the mold’s polished finish—no post-processing needed for most applications.
2.3 Application Scenarios: Prototyping vs. Mass Production
Each material excels in specific use cases, based on their traits:
| Material Type | Key Application Scenarios |
| 3D Printing Plastic Materials | – Rapid prototyping: Convert digital models to physical samples in hours (e.g., auto interior prototypes for ergonomic tests).- Small-batch customization: Make personalized parts (e.g., medical implants tailored to a patient’s anatomy).- Complex structures: Print parts with internal cavities/lattices (e.g., lightweight drone frames with wiring channels). |
| Ordinary Plastic Materials | – Large-scale production: Mass-produce standardized goods (e.g., injection-molded plastic containers, extrusion-molded water pipes).- Structural components: Make durable parts (e.g., PC laptop casings, ABS toy parts).- Everyday items: Manufacture low-cost products (e.g., PE plastic bags, PP food containers). |
3. Yigu Technology’s View on 3D Printing vs. Ordinary Plastic Materials
At Yigu Technology, we see 3D printing and ordinary plastic materials as complementary, not competing. For rapid design iterations (e.g., testing 3 versions of a product prototype), 3D printing saves time and reduces waste. For mass production (e.g., 10,000+ plastic toys), ordinary plastics via injection molding are more cost-effective and durable. We often guide clients to combine both: use 3D printing to validate designs, then switch to ordinary plastics for production. We’re also exploring modified 3D printing plastics (e.g., reinforced PLA with glass fibers) to bridge the strength gap, making them more viable for functional parts.
4. FAQ: Common Questions About 3D Printing vs. Ordinary Plastic Materials
Q1: Can 3D printing plastic materials replace ordinary plastics for mass production?
No. 3D printing is too slow (a single part takes hours) and has higher per-unit costs for large batches. Ordinary plastics via injection molding can produce 1,000+ parts per hour at lower cost—making them better for mass production.
Q2: Is 3D printing plastic always weaker than ordinary plastic?
Not always. High-performance 3D printing plastics like carbon-fiber-reinforced nylon have tensile strength (~80MPa) that matches or exceeds some ordinary plastics (e.g., ABS: ~40MPa). However, these 3D printing materials are more expensive and require specialized printers.
Q3: Can ordinary plastic materials be used for complex structures (e.g., internal cavities)?
It’s possible but costly. Ordinary plastics need custom molds for complex structures—mold costs can reach $10,000+ for intricate designs. 3D printing can make these structures without molds, saving money for small batches or prototypes.