How to Make Hollow Plastic Molds and Molding Types

Plastics can be described as synthetically produced compounds that can be easily molded into a wide range of forms and naturally hardened for various commercial uses. Today, you can see plastic molded virtually everywhere. Good examples could be jars, protective caps, plastic tubes, grips, baby toys, plastic bottles, plastic cases, plastic accessories, plastic kitchen utensils and so on. Plastic molds are a controversial topic these days in industrial and product fabrication all over the world due to their environmental impacts.

However, there are different types of plastic molding process. Technically speaking, you can find plastic molding services that offer the following types of services. You can decide on the type of service you need for suiting to your unique needs.

When it comes to Injection Molding, the melted plastic will be forced into special mold cavities. When they cool down, the mold is removed. Such plastic mold process is usually utilized in mass-production lines or for product prototyping. Many factories out there are making toys, plastic kitchen utensils, plastic bottle caps, or even cell phone stands. In plastic injection molding, heated plastic and is fed into the mold, which forms into the part as it cools. This often produces "flash lines" of extra plastic around the seams where the plastic mold would close. The molds themselves are created by industrial moldmakers.

Blow Molding

This process is pretty much comparable with injection molding but the only difference is that, in this case, heated liquid plastic vertically pours out of barrel-like pot into molten tubes. This way, the mold simply closes on it, while forcing it outward. This is to make sure that it conforms to the inner shape of that mold. As it cools down, the vacuum part is created. Most bottles, tubes or containers are formed with this type of molding. Blow molding is mostly used for creating hollow parts, unlike regular injection molding. Hot plastic resin is combined with a pressurized gas to fill and press the mold cavity, forming a hollow part.

Compression Molding

This process also deals with plastic mold processes, but it involves pressing of solid plastic slugs between highly hot mold halves. So, this sort of compression molding involves vertical presses rather than horizontal presses for injection or blow molding. Thus the parts created air-cooled afterwards.This molding process can also result in "flash lines" of extra plastic, like with regular injection molding.

Film Insert Molding

This molding technique literally imbeds images underneath the exterior of molded parts. At this point, materials akin to film or fabric will be slotted into the mold. Then plastic will be injected.

Plastic Mold Types

It may surprise you to know there are even more types of plastic mold designs! Here's some information about them. Plastic molds are used all over the world for industrial fabrication, commodity product building, and product design.

Gas Assisted Molding

This one is alternatively known as gas injection molding and is used for making various types of plastic parts that have hollow interiors. Then it’s time to introduce some partial plastic shot followed by hi-pressure gas, which fills up the cavity of the mold with plastic.

Rotational Molding

Here, hollow molds will be packed with special powdered plastic (all secured spokes which look like pipe and extends from a core hub). These molds rotate onto separate axes simultaneously. This hub will swing the entire mold towards an enclosed furnace room, which causes this powder to easily melt down as well as stick to the inner sides of these tools. As these molds keep turning gradually, these tools move inside a separate cooling room. At this point, water is sprayed and this will make the plastic to sufficiently harden – creating a useful hollow part.

Structural Foam Molding

This process is used especially for the parts that need rather thicker walls compared to typical injection molding. Actually, it’s all about inserting a little bit of nitrogen and/or chemical blow agents inside that plastic material, which in tern creates thicker walls. In addition to this, foaming takes place when the liquefied plastic material makes way into that mold cavity. A lean plastic skin will forms and solidify within the mold wall. Such molding process is used with thermoplastics which are suitable for injection molding.

Thermoforming

Here, pre-extruded hard plastic sheets will be heated horizontally, to be eventually sucked down inside empty single-piece tools. As the heated plastic solidifies, its shape will naturally adopt with that of the mold.

Besides this, there are micro-molding services, two-shot injection molding services, machining services and hot stamping services. However, special characteristics of these services differentiate them of one another. The plastic mold industry is pretty sophisticated today!