Key Points and Advantages of Custom Plastic Products

According to the 2024 industry report of the China Plastics Processing Industry Association, the proportion of customized 

plastic products in the overall plastic output value has increased from 18% in 2019 to 29%, with a compound annual growth 

rate of 10.3%. This growth is mainly due to the rigid demand for functional and differentiated products in industries such 

as automotive, medical, and electronics, and customized plastic products have become a core link in the optimization of the 

manufacturing supply chain.

1. Core Points of Custom Plastic Products

1.1 Definition of Requirements and Parameter Quantification

Core performance indicators need to be locked according to industry characteristics: customized medical implant parts must 

comply with GB/T 16886 "Biological Evaluation of Medical Devices", and the cytotoxicity grade is ≤ 1; parts around automobile 

engines need to meet the deformation ≤ 0.3% under the temperature cycle of -40℃ ~ 120℃. In terms of assembly compatibility, 

according to GB/T 1800.1-2020, precision transmission parts adopt IT5 - IT7 tolerance, and ordinary structural parts adopt 

IT8 - IT10 tolerance.

Different production batches need to match the corresponding mold types to balance cost and efficiency:

Small batch (100 - 500 pieces): resin 3D printing mold is selected, the mold cost is 0.5 - 20,000 yuan, and the production cycle is 

3 - 5 days / 10,000 pieces.

Medium batch (500 - 5,000 pieces): aluminum alloy mold is used, the mold cost is 20,000 - 80,000 yuan, and the production cycle 

is 1 - 2 days / 10,000 pieces.

Large batch (more than 5,000 pieces): P20 steel mold is used, the mold cost is 80,000 - 500,000 yuan, and the production cycle is 

0.3 - 0.8 days / 10,000 pieces.

1.2 Technical Specifications for Material Selection

Material Density (g/cm3) Tensile Strength (MPa) Heat Deflection Temperature (℃) Typical Applications

HDPE 0.94 - 0.96 28 - 35 70 - 80 Chemical storage tanks, bottle caps

PP 0.90 - 0.91 30 - 40 100 - 120 Automobile bumpers, home appliance casings

ABS 1.02 - 1.05 40 - 50 90 - 110 Laptop casings

PC 1.20 - 1.22 60 - 70 130 - 140 Optical lenses, baby bottles

PEEK 1.30 - 1.32 90 - 100 340 - 350 Aviation engine components

Food - contact products must comply with GB 4806.7 - 2016, and the total migration of heavy metals is ≤ 10mg/kg; electronic and 

electrical products must meet the RoHS 2.0 directive, restricting the use of 6 harmful substances such as lead and mercury.

1.3 Key Technologies for Mold Development

1.3.1 Structural Optimization Design

Cooling System: The conformal waterway design is adopted to control the temperature fluctuation of the mold cavity within ±2℃, 

which shortens the molding cycle by more than 30% compared with the traditional straight waterway.

Exhaust System: The depth of the exhaust groove is 0.01 - 0.03mm and the width is 5 - 10mm, ensuring that the gas discharge rate in 

the cavity is ≥ 99% and avoiding bubble defects.

1.3.2 Processing Precision Control

Five - axis linkage machining centers (positioning accuracy ≤ 0.005mm) are used to process the mold cavity, and the surface 

roughness of EDM is Ra ≤ 0.4μm to ensure the product size and surface quality.

1.4 Control of Molding Process Parameters

Taking injection molding as an example, the control standards of core process parameters are as follows:

Process Parameter PP Material PC Material Control Precision

Barrel Temperature (℃) 180 - 220 260 - 300 ±5℃

Injection Pressure (MPa) 60 - 90 80 - 120 ±2MPa

Holding Pressure (MPa) 40 - 60 50 - 80 ±1MPa

Cooling Time (s) 15 - 30 25 - 45 ±1s

1.5 Quality Inspection and Traceability

1.5.1 Whole - process Inspection System

Raw Material Inspection: Test the melt flow index according to GB/T 3682.1 - 2018 and control the ash content ≤ 0.5%.

Process Inspection: Sample and inspect the size with a coordinate measuring machine (accuracy ≤ 0.001mm) every 2 hours.

Finished Product Inspection: Test the mechanical properties according to GB/T 1040.1 - 2018 and GB/T 1043.1 - 2008, and the color 

difference ΔE ≤ 3 after 500h of UV aging.

1.5.2 Whole - chain Traceability Management

Record the raw material batch number, mold number, process parameters and inspection data through the MES system to realize 

the whole - process traceability from order to delivery.

2. Technical Advantages of Custom Plastic Products

2.1 Function Integration, Cost Reduction and Efficiency Increase

Through integrated molding design, multi - part assembly can be replaced. An automobile parts enterprise replaced 3 metal parts 

with customized ABS integrated parts, realizing a 40% reduction in weight, a 60% reduction in assembly processes, and a 25% 

reduction in unit cost.

2.2 Quick Response to Market Demand

With the help of 3D printing rapid prototyping technology, the development cycle of new products is shortened from 45 - 60 days 

of traditional molds to 7 - 10 days, and the small - batch trial production cycle is compressed by more than 80% to meet the demand 

for rapid iteration.

2.3 Optimize Cost Structure

The on - demand production mode greatly improves the inventory turnover rate (≥ 50%). Through customized production, an 

electronic parts manufacturer reduced the inventory capital occupation from 8 million yuan to 3 million yuan, saving about 400,000 

yuan in financial costs annually.

2.4 Improve Environmental Performance

Customized products using biodegradable materials such as PBAT/PLA can be completely degraded in the natural environment within 

6 - 12 months, reducing more than 90% of plastic pollution compared with traditional PE materials.

3. Conclusion

Custom plastic products need to focus on five core links: demand quantification, material matching, mold development, process 

control and quality inspection, and achieve the optimal balance between function and cost by accurately controlling technical 

parameters. With the popularization of CAD/CAE digital design and Industry 4.0 intelligent equipment, customized production will 

develop in the direction of higher precision (dimensional tolerance ≤ 0.005mm) and shorter cycle (24 - hour fast delivery), providing 

key support for high - end manufacturing.