In-depth Demand Report | Disassembling Injection Mold Solutions

     In the development of plastic products, choosing between 3D printing and injection molding requires comprehensive consideration of factors such as cost, precision, batch size, and design complexity. The following is an analysis of the two processes from the two core dimensions of cost optimization and high-precision requirements, combined with the characteristics of the two processes, and provides a basis for decision-making.

 1) Production batches determine the core cost structure

3D printing: suitable for small batches (usually <1000 pieces) or single-piece production. It does not require mold costs, has low material loss (only the support structure may waste a small amount of material), and is flexible in iteration. For example, when using FDM technology to print a prototype, the cost per piece may be only 1/10 of that of injection molding.

Injection molding: more cost-effective in large-scale (>1000 pieces) production. Although the mold development cost is high (thousands to tens of thousands of yuan), the cost per piece decreases significantly as the batch increases. For example, in one case, the injection mold cost $10,000, but the cost per piece was only $0.1 when producing 100,000 pieces.

 2)Design and iteration cost comparison

3D printing: CAD models can be directly printed after modification, without additional costs, suitable for the prototype stage where the design is frequently adjusted. For example, a company shortened the R&D cycle from 4 weeks to 48 hours by using 3D printing molds.

Injection molding: Mold modification costs are high (especially metal molds), suitable for mass production after the design is finalized. If the mold structure needs to be adjusted, it may be necessary to re-open the mold, which will increase the cost by tens of thousands of yuan.

 3)Material And Post-Processing Costs

3D printing: limited material types (such as PLA, nylon, resin, etc.), some high-performance materials (such as PEEK) are expensive; post-processing usually only requires grinding or sandblasting.

Injection molding: wide selection of materials (such as ABS, PP, PC, etc.), lower prices; but post-processing such as mold polishing and electroplating may increase costs.

Decision suggestions:

Small batch/prototype: choose 3D printing (FDM, SLA or SLS);

Large batch/finalized product: choose injection molding.

 1) Process accuracy comparison

3D printing:

SLA/DLP: accuracy of ±0.01 mm, smooth surface, suitable for precision medical or electronic parts.

SLS/MJF: accuracy of ±0.1 mm, suitable for complex structures but slightly rough surface.

FDM: lower accuracy (±0.2 mm), obvious layer pattern, need post-processing.

Injection molding:

accuracy is usually ±0.05 mm, high surface finish (Ra 0.8~1.6 μm), no additional processing required.

 2)Material strength and stability

3D printing: weak interlayer bonding, which may affect mechanical properties; easy to deform at high temperatures (such as PLA softening point is 55°C).

Injection molding: The material is dense, high in strength and isotropic, and has better temperature resistance (such as ABS can withstand 80~100°C).

 3) Complex structure adaptability

3D printing: It can manufacture complex structures that are difficult to achieve with traditional processes, such as hollowing and conformal water channels. For example, the curved cooling channel in the mold can improve the injection efficiency.

Injection molding: Due to the mold demolding requirements, the design must avoid internal right angles or too deep cavities, otherwise it will increase the difficulty of processing.

Decision suggestions:

High precision + complex design: choose SLA or metal 3D printing (such as SLM), but you need to accept higher costs;

High precision + large batch: injection molding combined with CNC precision mold to ensure dimensional stability.

Clear requirements: batch, budget, design complexity, precision level, material performance.

Cost accounting: compare mold costs, single-piece material costs and post-processing costs.

Technology matching:

If fast iteration or small batches are required, 3D printing is preferred;

If high strength or surface finish is required, injection molding is preferred.

Hybrid solution: For example, use 3D printing to make prototypes or conformal water channel molds, and then mass produce them through injection molding.

1) Pepsi bottle mold: By combining 3D printed inserts with traditional metal molds, the cost is reduced by 96%, and the production cycle is shortened from 4 weeks to 48 hours.

2) Medical implants: Use SLA to print high-precision prototypes, and then switch to injection molding for mass production after verification.

3) Shoe mold manufacturing: 3D printing can achieve complex patterns, replacing traditional CNC, and increasing efficiency by 50%.

Between low cost and high precision, a balance needs to be made according to specific scenarios:

3D printing: the first choice for small batches, complex designs, and rapid iterations;

Injection molding: an economical solution for large batches, high precision, and high-strength scenarios.

In the future, hybrid manufacturing (such as 3D printing molds + injection molding mass production) may become the mainstream direction for balancing cost and performance.

3D Printing vs. Injection Molding: Coexistence in the Age of Digital Manufacturing

Why Neither Technology Will "Win"—And Why That’s Good for Industry

Injection Molding remains the backbone of mass production:

Scale & Speed: Produces 10,000–1M+ identical parts at <30-second cycles (e.g., automotive trim, consumer packaging) .

Material Edge: Supports 30,000+ engineered polymers (e.g., PEEK, COC/COP) with ISO-certified mechanical properties crucial for medical/auto sectors.

Cost Structure: High initial tooling ($50k–$500k for steel molds) but pennies per part at scale.

3D Printing (Additive Manufacturing) excels in digital agility:

Zero Tooling: Direct digital-to-part production enables overnight prototyping and design iterations.

Complexity for Free: Generates hollow structures, organic lattices, and integrated assemblies impossible for molds (e.g., GE’s fuel nozzles with 20 parts consolidated into one) .

Localized Production: "Print farms" like China’s Jinqi (4,000 printers) deliver 50k+ custom toys/day to global markets, bypassing shipping/logistics .

Criterion

Injection Molding

3D Printing

Optimal Batch Size

10k–1M+ units

1–10k units

Lead Time

8–16 weeks (tooling)

Hours to days

Material Range

30k+ polymers

300–500 certified materials

Part Cost at Scale

<$0.50 (e.g., bottle caps)

<$0.50 (e.g., bottle caps)

Design Constraints

Draft angles, parting lines

None

     Injection molding is an important process for manufacturing a variety of plastic parts. Its flexibility enables it to produce a variety of products from thin to thick walls. However, there are certain limitations to the thickness of injection molding, and overly thick plastic parts may face a series of technical challenges during the production process. This article will explore the thickness range of injection molding, factors that affect thickness, possible technical challenges, and how to optimize the molding process.

     Plastic parts molded by injection molding can generally range in thickness from a few millimeters to several centimeters. For most plastic parts, a common thickness range is 1-10 mm. For thick-walled products, the injection molding process can mold greater thicknesses, even up to 30 mm or more, but this usually depends on the type of material used, the mold design, and the capabilities of the injection molding machine.

    In injection molding, the thickness of a part is affected by several factors. First, the fluidity of the plastic material is inversely proportional to its thickness. Thicker parts require the material to have better fluidity so that they can evenly fill the mold. Second, mold design is also crucial. The mold's cooling system, exhaust system, and runner design must all take into account the molding needs of thicker parts. Finally, the injection pressure and injection speed of the injection molding machine also need to be adjusted accordingly to ensure that thick-walled products can be molded smoothly.

     When the thickness of injection molded parts is too large, there are many technical challenges. First, thicker plastic parts require longer injection cycles because the plastic takes longer to fill the mold and cool to solidify. Second, thicker parts are prone to uneven shrinkage during the cooling process, which can cause warping, cracking, or dimensional instability of the parts. In order to ensure the quality of thick-walled injection molded products, the cooling system and mold design need to be optimized to ensure uniform cooling and solidification of the plastic.

     In order to solve the challenges faced by thick-wall injection molding, a series of optimization measures can be taken. First, choose plastic materials with higher fluidity so that they can flow more evenly in thicker wall thicknesses. Secondly, when designing the mold, the cooling system of the mold should be enhanced, and an effective flow channel and exhaust system should be designed to avoid the problem of uneven cooling of thick-walled products. In addition, by increasing the injection pressure and speed of the injection molding machine, combined with a reasonable temperature control system, the injection molding efficiency can be effectively improved and the molding quality of thick-walled parts can be guaranteed.

     Injection molding can handle a variety of plastic parts thicknesses, ranging from thin-walled to thick-walled products. Although thick-wall injection molding faces some technical challenges, these problems can be overcome through optimized material selection, precise mold design, and reasonable injection molding process control. As technology continues to develop, the application range of injection molding will become wider and wider, and manufacturers can produce high-quality plastic parts of various thicknesses to meet the needs of different industries.