How are the plastic products we see with multiple colors produced? For as far as multiple colors are concerned both bi-color injection molding and over molding can produce such products, so what is the difference between Bi-color injection molds and over molding?
Bi-color injection / two-components injection / two-material injection/ 2K injection
Bi-color injection molding refers to the molding method of injecting two different colors of plastic into the same mold. It can make the plastic parts appear two different colors. And can make the plastic parts show regular patterns or irregular cloud-like patterns. In order to improve the practicality and aesthetics of the plastic parts.
Over molding molds
The two plastic materials are not necessarily in the same injection molding machine, divided into two molding. After the product is removed from a set of molds. It is put into another set of molds for a second injection molding.
Therefore, generally this molding process is usually completed by two sets of molds, without the need for a special two-color injection molding machine.
The structure of its molds and single-color injection molds are the same, mainly by adjusting the injection parameters of the flow rate to control the bonding point of the material.
So what are the disadvantages of the two injection molding methods?
About Bi-color injection
Advantages:
- Enhanced Aesthetics: making your products more visually captivating.
- Improved Functionality: Bi-color injection can combine 2 different material in one part, especially the application of soft material. It not only improve the touch feeling, also can realize the functional of sealing, anti-slip and so on.
- Increased Efficiency: Bi-color injection can save process steps and reduce scrap rate compare to traditional way.
Disadvantages:
- Bi-color molds require special Bi-color injection molding machines. But the cost of Bi-color injection molding machines is much more expensive than ordinary injection molding machines.
About over moldings
Advantages
- Can use ordinary injection molding machine processing, equipment investment is relatively small;
Disadvantages
- Not suitable for injection molding precision double material and multi-material injection molding products.
- The molding process cycle is relatively long, and the production efficiency is lower than that of the two-color mold
- It is difficult to place the position accurately manually, so a large amount of scrap.
To sum up, the obvious advantage of two-color injection molding is to simplify the mold. And it can increase the yield exponentially than the previously used “over moldings”. And fundamentally avoid the bad product caused by the shrinkage and deformation of the “hard glue” back into the cavity.
Leave A Comment