According to the report, there is a saying that the first test flight of the new aircraft list is the most important thing, because it might fall off, so people have to burn paper to pray for the help of heaven. In the same way, the first trial of the injection mold list is also very important, because the mold will be ruined if it is not possible. It’s no wonder that mold factories in the industry have stricter requirements on trial mold technology and discipline than in mass production. This is the reason.
There are many checkpoints for the first test of the new mold. Here is an important parameter in the process—the amount of glue injected for the first injection.
The amount of glue for the first shot is how much material should be shot for the first time on the list, and there is a lot of attention.
If you shoot too much, the mold will explode and the mold will be greatly damaged.
With less shots, products with certain structures may not be able to be ejected.
Especially when the barrel structure product has no ejector pin or the top plate is pushed out, there is less glue that cannot be ejected, so the first shot is very critical.
In the final analysis, it is the question of how much material should be shot? What is the problem of the travel interval of the machine screw?
Generally speaking, when designing the mold, the weight of the product will be calculated by the software, even if there is an error, it will not be very large. So how can it be converted into the screw movement interval of the machine?
Formula: Screw movement interval = product accounting component / screw cross-sectional area / plastic density plastic / compensation coefficient
Case: The theoretical value of the product weight is 200g, using a 280-ton machine with a diameter of 50mm, the density of the PS material is 1.05, and the compensation coefficient is 0.85
Then the screw movement interval = 200 / (2.5*2.5*3.14) / 1.05 /0.85 = 11.4 cm
This is the final total screw movement interval. According to the actual situation, if the mold structure agrees, the list can shoot 50% full and move 5cm for the first time. If the mold structure needs to be filled at once, then it must shoot more than 10cm. Look like. Reply to “Injection”, check more
A few small questions
Post time: May-31-2021