Automobile Mold

Lamp
Automobile lamps are mainly used for lighting, which can be said to be eyes of car. Lamp is a general term for all automobile lighting systems. Appearance of automobile lamps is required to be high. Several important parts are transparent parts, electroplated parts, etc. It can be said that part with the highest appearance requirements of car is lamp, so requirements for mold design and manufacturing are extremely high. Main lighting parts of a general car are front and rear headlights. Different car series have different configurations of lamps, same car series has different configurations according to high and low configurations. Main parts that make up front and rear lamps of a car are: left and right lenses, left and right decorative frames, left and right lamp shells, left and right reflectors, etc.

Analysis of car light mold problems 1
Cracks at junction of black and white sheets during chemical testing and painting

 

Since movable mold of mold is a concave mold, a slider was designed to fix product to prevent product from shifting when turntable rotates during initial design.
Following problems were found during production:
1. Cylinder body expands after heating (90°), and oil seal leaks, resulting in poor bonding of black and white sheets
2. Slider is not strong enough, seal position is easily deformed to produce flash, and bright lines after painting
3. Slider is difficult to match mold. If it is too loose, peak will run and there will be bright lines when painting. If it is too tight, slider will easily burn, tear edge of white sheet, and cause a slight change in position of product. Stress increases during second injection molding and cracks occur during painting.

 

Slider is removed from rear mold, and corresponding position of front mold is added with an insert to adjust gap.
1. Try not to place cylinder directly on high-temperature insert
2. Slider with a large contact area of glue position must be equipped with a water channel

 

Problem: Exhaust insert is pulled.
Cause: Exhaust insert of front mold has no cooling water channel, which causes front mold to expand higher than insert surface during production, resulting in strain.
Correction: Since front mold has been quenched, it is not convenient to add water channels. Gap can only be straightened on machine after a period of mold trial.
Suggestion: Consider adding water channels in subsequent mold design stage. Exhaust insert parting line is offset by 0.1mm.

 

Cause: Product sucks mold and ejection is unbalanced.
Correction: Add glue at joint, increase draft angle, as shown in figure below, and add an ejector.
Suggestion: The highest point of product arc needs to be designed for ejection.

 

Analysis of headlight mold problems 2
Problem: Parting surface gap.
Cause: After parting surface is re-matched, boundaries of front and rear mold cavities cannot be aligned.
Correction: Since lowering of front mold surface will bring many derivative problems, glue can only be added in direction of pink line shown in mold diagram.
Suggestion: When designing parting surface, try to extend a distance in direction of product tangent as sealing surface to facilitate later adjustment.

 

Problem: Red sheet is miniature near gate.
Reason: Red sheet needs to cover top of white sheet, glue thickness is too thin (1.1mm) and far away from gate.
Correction: Reduce glue near gate of white sheet.

 

 

Drop of lifter is large. Angle between guide strips shown in figure below is used to assist positioning of lifter.
Prevent position of lifter from moving during injection process.

 

Glue area on lifter is large, and product is supported by straight top to prevent sticking to lifter. At the same time, lifter is designed to tilt downward to facilitate air entry, prevent sticking to lifter A>B and prevent strain.

 

Some ribs of headlight lens product are designed on slider to increase strength. If slider is designed in full, there is a risk of sticking to slider.

 

Problem point: Seam line is bright, reason is that there are fine burrs at the seam line, and water ripples at the end of product.
Reason: To prevent burns from internal draw and lifter, a gap of about 0.05mm will be left at the front end during assembly. And during trial production, mold temperature of ordinary lens mold is 80 degrees for rear mold, 65 degrees for lifter and internal draw. However, 75% of glue position of this product is on lifter and internal draw, resulting in too low rear mold temperature.
Solution: Change moving mold temperature setting; internal draw lifter = 80 degrees; mold core = 65 degrees.