How can injection molds support the high-precision requirements of automotive electronic devices?

1. Material Characteristics' Constraints and Breakthroughs Regarding Mold Accuracy
plastic material shrinkage rate control
While PPS (polyphenylene sulfide) has a shrinkage rate of 0.8% -1.2%, the often utilized materials for in car electronic systems, such LCP (liquid crystal polymer, have a shrinkage rate of about 0.1% -0.3%. Design of mold calls for the development of a material process shrinkage mapping model like:
using a dynamic cooling system to regulate PPS material shrinkage, therefore lowering the dimensional deviation from ± 0.15mm to ± 0.05mm
Use CAE simulation to maximize the gate position of LCP material thereby lowering 0.02mm warpage deformation.
Materials fluidity and mold matching
High CTI value materials (like PCTG) call for a thin-walled long channel design with a channel width regulated between 1.2–1.5mm and a channel length to wall thickness ratio of < 150:1. As in:
With a 3mm wall thickness and ideal channel length of 180mm, the Tesla Model 3 central control screen bracket achieves a steady filling pace of 0.8mm/s.
Resistance of materials against temperature and mold cooling
The mold cooling system must reach -40 ℃~125 ℃, the working temperature range of onboard electronic devices.
Dynamic control of temperature precision ± 1 ℃
5% variation in cooling water flow
3 ℃ mold cavity surface temperature homogeneity
2, Innovation of die structure design
Precision cavity machining technology in high degree
The cavity's surface roughness Ra of five axis linkage machining center is ≤ 0.2 μ m.
Process microstructures using electrical discharge machining (EDM) technology, minimum machining diameter 0.1mm
Through laser etching, realize 0.01mm level texture duplication.
System for precision sliders and ejections
Ball screw transmission guarantees sliding block stroke control precision ± 0.005mm.
The top output distribution's homogeneity is ≤ 5%, so finite element analysis helps to maximize the top pin's arrangement.
Using a pneumatic ejection system helps to lessen ejection markings.
Balanced design with many cavities
The multi cavity mold used in car electronic equipment has to satisfy the following criteria:
0.05s for filling time differential
Rate of pressure loss: 8%.
Every cavity has a size variation smaller than 0.02mm.
For dimensional consistency of > 99.5%, the BMW iX central control module, for instance, has an 8-cavity mold design and monitors the pressure of every cavity in real time via pressure sensors.
3, Precise control of molding process parameters
System of temperature regulation
7-zone heating controls the material cylinder's temperature, which fluctuates ± 2 ℃.
Independent temperature control equipment enables ± 0.5 ℃ mold temperature control accuracy
5 ℃/100mm hot runner system temperature gradient
Stress management technique
Three phases of control govern injection pressure:
Filling range: 800 to 1200 bar
Pressures holding stage: 600–800 bar
Stage of shrinkage: 400–600 bar
Back pressure control precision ± one bar to stop material breakdown
Technologies for speed control
Using a servo driven injection molding machine, the injection speed control precision ranges ± 0.1mm/s.
Five steps of control over switching mode speed help to prevent collision and vibration.
PID controls the ejection speed to lower product deformation.
Optimisation of the time parameter
A thermal imaging tool tracks the cooling time and tunes it to the least effective duration.
The material viscosity curve drives dynamic adjustment in the holding time.
Reduce cycle variations by timing the mold opening time with the mechanical arm picking time.
4, Typical defect control techniques
Dealing with warping deformation
Analyzing deformation trends and improving reinforcement layout with CAE simulation
Raise the cooling water channels' density in the mold and make sure the mold cavity's surface temperature difference is less than five degrees Celsius.
Conformal cooling technique has raised the cooling efficiency by thirty percent.
Fusion line maximization
Change the gate position to prevent the functional region from fusing.
Control the melt front with sequential valve hot runner.
Add a 0.2mm depth groove structure right at the fusion line place.
Management of surface defects
Maximize the mold polishing technique using Ra≤0.1μm.
Using nitrogen aided molding techniques to lower gas residue
Reducing surface roughness with vacuum coating method instead of electroplating
5, Advanced Technology Application Cases
The central control screen bracket of Tesla Model Y
Material science: LCP plus twenty percent Gf
Sixteen cavity molds under hot runner and sequential valve control
Dimensional variation ± 0.03mm; flatness 0.02mm
28s/mold cycle with 98.7% yield rate
Mercedes iDrive knob
Source: PCTG+ASA double color injection molding
Mold: dual color switching time 1.5s, rotating core shaft construction
Accuracy: 0.01mm centering, 95GU surface glossiness
Cycle: 35s/mold with 99.2% yield rate
Huawei Bracket for a Car Camera
PPS + 30% is material science. GG
Wall thickness 1.2mm and gas assisted molding technology
Verticality 0.01mm, parallelism 0.015mm
Cycle: 42s/unit, 15% weight loss
6, Mold maintenance and quality control
intelligent tracking system
Install pressure sensors to check every chamber's pressure.
Using thermal imaging equipment to identify molds' temperature distribution
tracking product parameters with a visual inspection system
Preventive care:
Build a mold wear database to forecast cavity life.
Test surface hardness on the mold cavity often using HV ≥ 500.
Calculate monthly slider clearance (<0.01mm).
MEMED
Standard mold frame interface allows mold change time of two hours.
RFID technology applied to attain automatic calling of mold parameters
Create a digital twin model of the mold and run a mold replacement simulation.