Part One-How to learn the basics of molding according to the physical product ?
This article is for the guys who have just entered the business, so that they can also understand some basic knowledge of mold and molding.
When a product structure design is completed, it is necessary to carry out mold design and then injection molding. Then, after the product T0 comes out, there will be some problems like this, you need to find it, and then ask it to let the mold manufacturer solve it.
Therefore, you must be able to see those problems that are acceptable and those that are unacceptable, so as to better promote mass production.
Next, we will analyze the main points of mold and molding according to the physical product analysis.
According to the above picture, this is the middle frame of a mobile phone, all of which are non-faceted and material, so that you can better observe the problem.
Let's see where the gate is, what kind of gate is it and how many gates?
According to the above figure, the mark A is directly pointed into the gate at 4 points, and the mark B is the reserved gate point.
Q: Why do you want to design a reserved gate point?
A: In order to solve the problem of subsequent injection molding,which fill resin fully,reduce molding pressure, prevent shrinkage and other molding problems. It mainly plays a role in subsequent mitigation.
After T0, it is necessary to observe whether the feeding mode and the feeding point of the mold design are consistent with the manner of the previous structure discussion.
In addition, it is necessary to check whether the gate point is high or not, and whether it affects the structural assembly and other issues.
In addition to the pin point gate, what are other gate types there?
Expanding the feed along the outer circumference of the product. It benefit from symmetrical feeding point, the uniform filling, the easy-eliminated bonding line, good venting. The nozzle is usually removed by punching.
2, fan-shaped gate
gradually enlarged from the branching channel to the cavity direction, suitable for long or flat and thin products (PC lens type), can reduce flow and orientation stress. the fan angle is determined by the shape of the product. The cross-sectional area of the gate shall not be larger than the area of the runner.
3, Annular gate
expand along the entire outer circumference of the product to gate. it can make the plastic winding core uniform filling, good exhaust, reduce the bonding line. However, the gate is difficult to cut, it is suitable for thin-walled long tubular products.
4, Point gate
is a gate with a small cross-sectional area. Generally used for plastics with good flow. The gate length is generally not more than its diameter, so the gate is automatically cut off after demolding, no need to Corrected. The gate residue is not obvious. It is widely used in box covers, box casings and large-area products. It can add a parting surface to the mold to facilitate the demolding of the nozzle.
The disadvantage is that the pressure loss is caused by the small inlet gate, and some bad (flow marks, charred, black spots) are formed during the molding, and the shape thereof has a rhombus shape, a single point shape, a double point shape, a multi-point shape etc.
5, Side gate
generally put on the side of the mold, inside or outside of the parting surface. The cross section is mostly rectangular, suitable for a multi-cavity mold.
6, Direct gate
directly into the cavity by the main channel, suitable for single-hole deep cavity shell shape, box-shaped mold. Its runner is short, less pressure loss, is conducive to exhaust, but the gate is inconvenient to remove, will stay Obvious traces.
7, Sub-gate (banana gate)
The gate is inclined to lurk on the side of the parting surface, can automatically cut off the needle point gate when the part is released from the side or inside, suitable for automatic production.
Not finished! See more in next blog.
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