How to solve the problem of uneven pouring in vacuum casting equipment?

Technical solution of vacuum casting equipment to solve the problem of uneven casting

I. Analysis of the causes of uneven pouring

Unevenness occurring during the vacuum casting process is typically attributed to the following factors:

Material characteristic factors:

The resin viscosity is either too high or too low

The distribution of fillers is uneven

Insufficient material mixing

The material exhibits poor fluidity

Equipment factors:

The vacuum degree is unstable

The design of the pouring spout is unreasonable

Uneven distribution of mold temperature

Equipment vibration or uneven position

Process factors:

Improper control of pouring speed

Insufficient defoaming time

The curing temperature gradient is unreasonable

The operator is not skilled

II. Technical improvement plan for vacuum casting equipment

1. Optimization of material preprocessing system

Upgrade of vacuum defoaming system:

Adopt multi-level vacuum defoaming technology, and set gradient vacuum degrees (such as gradually decreasing from -0.08MPa to -0.095MPa)

Add a dynamic mixing device to maintain material uniformity in a vacuum environment

Install an online viscosity monitor to adjust defoaming parameters in real time

2. Improvement of pouring system design

Multi-pouring spout design:

Design 2-4 pouring ports according to the product shape to ensure that the material can enter the mold cavity from multiple locations simultaneously

Optimizing the position of the pouring gate through computer fluid dynamics (CFD) simulation

Set up a separate pouring system with adjustable flow rate

Intelligent flow control system:

Install high-precision metering pump (accuracy ±0.5%)

Driven by servo motor

Set up pressure sensors and flowmeters to form a closed-loop control system

Tilt pouring technology:

The equipment is equipped with a tilting mechanism (adjustable from 0-30°)

Design the tilt angle and speed curve based on the product structure

Gravity-assisted filling is adopted to reduce residual bubbles

3. Optimization of mold system

Mold temperature homogenization:

Use a mold temperature controller for temperature control (±1℃)

Design a reasonable layout of heating/cooling channels for molds

Employ temperature control technology by zones for large molds

Improvement of exhaust system:

Optimize the design of the exhaust slot (with a depth of 0.02-0.05mm)

Set up multi-level exhaust channels

Use special materials such as breathable steel to make local molds

Surface treatment technology:

The mold cavity undergoes mirror polishing (with a surface roughness of Ra≤0.2μm)

Apply non-stick coatings such as Teflon

Regularly perform mold maintenance

4. Vacuum system upgrade

Multi-stage vacuum system:

Pre-vacuum stage (-0.08MPa)

Main vacuum pumping stage (-0.095MPa)

Pressure maintaining stage (adjusted according to material properties)

Vacuum control:

Adopt digital vacuum controller

Set up multiple vacuum monitoring points

Establish a control algorithm correlating vacuum degree with pouring speed

Vacuum maintenance technology:

Adopting a large-capacity vacuum buffer tank

Equipped with a standby vacuum pump set

Set up a vacuum leak alarm system

III. Process parameter optimization scheme

Casting speed control:

Low-speed pouring in the initial stage (to prevent turbulence)

Increase the speed moderately in the medium term (while ensuring filling efficiency)

Reduce speed again in the final stage (reduce contraction)

Matching between vacuum degree and pouring speed:

Establish a vacuum degree-speed relationship curve

Develop parameter combinations tailored to different materials

Realize automatic parameter adjustment

Optimization of curing process:

Gradient temperature rise curing

Pressure-assisted curing

Post-curing treatment

IV. Quality monitoring system

Online monitoring system:

Camera monitoring during the pouring process

Infrared thermal imaging monitors temperature distribution

Ultrasonic detection of internal defects

Data collection and analysis:

Record all process parameters

Establish a product quality database

Develop intelligent diagnostic system

Automatic feedback control:

Adjust casting parameters in real-time

Automatic alarm for abnormal conditions

Automatic marking of defective products

The content of this article is sourced from the internet. If there are any issues, please contact me for removal!