Three Injection Molding Temperatures

Today we talk about the three main injection molding temperatures and their settings.
1. Barrel temperature in the injection molding temperature
Each material has its own melting temperature range. If the temperature is low, the material will not melt well, and if the temperature is high, it will decompose. Therefore, the appropriate temperature must be selected. However, our injection molding machine temperature control system also has certain differences, so we must learn to watch the rubber head and analyze whether the temperature is appropriate.
There are abnormal noises in the glue, and there are obvious granular particles of incompletely melted materials on the printed materials. When the fluidity is not too good, it means that the temperature is too low and the temperature needs to be increased.
Gluing is very smooth, and the injected material has very good fluidity like water, indicating that the temperature is too high and the temperature needs to be lowered.
The material temperature is very important. If it is too high, it will decompose slightly, which will seriously affect the strength and quality of the product. Therefore, changing the material temperature is generally not considered during production.
2. Mold temperature in the injection molding temperature
The mold temperature directly affects the product size. Generally, it is set according to the material category at the trial stage, and slightly adjusted according to the product quality. It is better not to consider the change in mass production.
When the mold temperature is high, the melt fluidity is better, which is conducive to molding, but the shrinkage of the product increases, and the size will be correspondingly smaller.
When the mold temperature is low, the melt fluidity is poor, which is not conducive to molding, but the shrinkage of the product is reduced, and the size is correspondingly larger.
The mold temperature not only affects the product size but also determines the degree of crystallinity. When the mold temperature is high, the crystallinity is greater, and when the mold temperature is low, the crystallinity is small.
The mold temperature also has a certain influence on the strength of the product. When the mold temperature is low, the product strength is also low. When the mold temperature is low, the fluidity of the product becomes poor, then the position fusion of the bonding line will be affected, and the bonding line will obviously reduce the strength. , When the mold temperature is low, its crystallinity is low, and its strength is correspondingly low.
3. Drying temperature in the injection molding temperature
Some materials have trace amounts of water molecules, which will promote the accelerated decomposition of polymers, such as PC, PBT, etc., so they must be fully dried before molding.
If the drying is not in place, not only will the decomposition of the material be accelerated, and a large number of bubbles will be generated, and the fluidity will also become very good and easy to produce defects such as drape. Therefore, it must be dried well before molding.
See the table below for specific settings for reference;
Commonly used plastic injection processing information
Material name | Density | Mold temperature | Material temperature | Decomposition temperature | Drying temperature | Shrinkage rate |
GPPS | 1.04-1.09 | 30-70 | 170-260 | 280 | 80 | 0.2-0.8 |
HIPS | 1.08-1.10 | 40-60 | 190-290 | 310 | 80 | 0.2-0.8 |
ABS | 1.05 | 40-90 | 200-240 | 280 | 75-80 | 0.4-0.7 |
LDPE | 0.91-0.94 | 30-60 | 150-230 | 300 | 70-85 | 1.5-4.0 |
HDPE | 0.94-0.97 | 30-80 | 160-280 | 300 | 70-85 | 1.5-3.6 |
PP | 0.9-0.91 | 30-90 | 190-290 | 320 | 70-90 | 1.0-2.5 |
Soft PVC | 1.16-1.35 | 20-40 | 140-190 | 200 | 70 | 1.0-2.5 |
Hard PVC | 1.35-1.45 | 30-60 | 140-190 | 200 | 80 | 0.1-0.6 |
PA-6 | 1.15 | 20-90 | 210-300 | 320 | 80-100 | 0.8-1.5 |
PA-66 | 1.15 | 20-90 | 230-310 | 360 | 85-120 | 1.2-1.8 |
PMMA | 1.18 | 40-100 | 220-250 | 260 | 80-100 | 0.1-0.8 |
PC | 1.20 | 80-110 | 250-320 | 360 | 110-130 | 0.4-0.8 |
POM | 1.41-1.43 | 60-100 | 160-210 | 230 | 60-80 | 1.8-3.5 |
PET | 1.2-1.38 | 50-120 | 250-310 | 360 | 140-180 | 0.2-2.0 |
PBT | 1.31 | 50-80 | 220-270 | 280 | 120-140 | 0.9-1.8 |
PBT Fiber | 1.52 | 60-90 | 230-280 | 290 | 120-150 | 0.4 |
PPO | 1.06-1.07 | 80-150 | 280-340 | 360 | 110-140 | 0.1-0.7 |
PPS | 1.36 | 120-180 | 280-340 | 390 | 130-150 | 0.5-0.7 |
LCP | 1.4-1.7 | 30-150 | 300-400 | 420 | 120-150 | 0.1-0.6 |
You may also be interested in the below articles.
What Is A Mold Clamp?
What Are Mold Clamps?
What Is A Mold Clamp Used For?
How To Make Mold Clamps?
How To Install Mold Clamps?
How To Install Easy Mold Clamps?
How To Install Injection Mold Clamps?
How To Use Step Block And Clamp?
Mechanical design and Taboos of mechanical design
What is the standard injection mold development process?
18 FAQ Of Injection Molding Machine Mold Clamping