What is precision mold?
Table of Contents
Introduction
Precision molds are special tools that have extremely high manufacturing accuracy, long service life, and can produce products with strict dimensional tolerances and demanding surface quality requirements. They are widely used in electronics, medical, automotive, optics and other fields that require extremely high part accuracy and consistency, such as mobile phone connectors, micro gears, precision sensors, etc.
Core features of precision molds
1、Ultra-high precision
- Dimensional tolerance: usually controlled within ±0.002mm (±0.05mm for ordinary molds).
- Surface finish: key areas need to reach the mirror level (Ra ≤ 0.01μm), reducing product burrs and demolding resistance.
- Repeatability: more than 100,000 times of continuous production, the product size fluctuation is less than 0.005mm.
2、Complex structure
- Complex features such as microscopic holes, ultra-thin walls (e.g. 0.1mm thick), and multi-stage steps can be molded.
- Case: Mobile phone SIM card slot molds need to meet the 0.4mm thin wall and ± 0.01mm tolerance.
3、Long life and high stability
- Adopting hard alloy, tungsten steel and other materials, the hardness reaches HRC 60-65 after heat treatment, and the service life can be more than one million times.
- Equipped with constant temperature control system to minimize the effect of thermal deformation on precision.
Key technologies of precision molds
Technology | Usage | Application Scenario Example |
Specular EDM (Mirror EDM) | Machining of complex surfaces with surface roughness Ra<0.1μm. | Optical lens molds, light guide plates. |
Slow-feed wire EDM (accuracy ±0.001mm) | Cutting high-precision shaped holes. | Connector terminal mold, microporous filter. |
Five-axis linkage CNC machining | Realize multi-angle precision milling. | Impeller mold, helical gear mold. |
Vacuum heat treatment + deep cold treatment | Enhance the wear resistance and deformation resistance of mold steel. | Automobile engine precision parts mold. |
Precision mold vs ordinary mold
Comparison item | Precision molds | Ordinary mold |
Accuracy | ±0.002mm or less | ±0.05mm-0.1mm |
Material | Tungsten carbide, powder metallurgy steel, ceramic coating. | Ordinary P20 steel, aluminum. |
Machining equipment | Nano CNC, mirror EDM, slow walking wire. | Conventional CNC, fast walking wire cutting. |
Cost | Hundreds of thousands to millions of dollars for a single set of molds. | Thousands to tens of thousands of dollars. |
Application Areas | Semiconductor package, micro motor, medical catheter. | Daily necessities, toys, general shell. |
Typical applications of precision molds
Electronics Industry
- Cell phone connector: 0.3mm pitch terminal, tolerance ± 0.005mm.
- Chip encapsulation mold: control plastic sealing thickness error ≤ 0.01mm.
Medical industry
- Insulin pump gears: backlash <0.003mm after in-mold assembly.
- Endoscope parts: mirror polishing to ensure no bacteria residue dead space.
Automotive industry
- Fuel nozzle: microporous diameter 0.1mm, flow rate error <1%.
- Transmission Valve Body: Multi-oil channel cross-hole positional accuracy ±0.003mm.
Cost and Return Analysis
Initial investment: a set of precision connector mold about ¥ 500,000, life of 2 million times.
Cost per piece: If mass production of 1 million pieces, the cost of mold sharing is about ¥0.5/piece (much lower than CNC processing ¥5/piece).
Premium ability: High-precision products can increase the selling price by 30%-50% (e.g. medical parts).
summarize
In summary, before designing a project, be sure to take the cost of precision molds and ordinary molds into consideration. If your project is a simple one, try to design the product within the technical boundaries of ordinary molds, which will greatly reduce the R&D cycle and project budget.
