Plastic products have become an integral part of our daily lives, from car and motor parts in transportation to washing machines in home appliances, tables and chairs in furniture, crates in logistics, and baskets in our living rooms...
The common thread among all these items is that they are produced using plastic mould through the process of injection molding.
Today, let’s take a closer look at the fascinating world of plastic mould!
A "plastic mould" (or mold) is a tool or die used in the process of ”injection molding” to shape and form plastic materials into specific shapes or parts.
The plastic mould is typically made of metal, such as steel or aluminum, P20,718 are common mould raw material , and consists of two main halves: the "core" and the "cavity".
When these halves are closed together, they create a hollow space that reflects the desired shape of the final plastic product.
In the "injection molding process", molten plastic is injected into the mold under high pressure. The plastic fills the hollow space and, once cooled, solidifies into the shape of the mold.
After cooling, the mold opens, and the finished plastic part is ejected.
Plastic molds can be simple, producing a single part at a time (single-cavity molds), or complex, creating multiple parts in a single cycle (multi-cavity molds).
The design and construction of a plastic mould depend on the complexity, size, and material requirements of the final part being produced.
Custom mould plastics , plastic injection mould manufacturer ,injection molding
Usually , A plastic mould can last from 10000 cycles to 1,000,000 cycles or even longer, there are a lot of factors affect a plastic mould lifetime.
Here are some personal views regarding the mold lifetime:
At Guangchao Mould ,we have 4 class of plastic mould according to deferrent mold lifespan : Class A ,B ,C and D .
CLASS 'A' MOLD = 1,000,000 CYCLES, CLASS 'B' MOLD = 500,000 CYCLES, CLASS 'C' MOLD = 300,000 CYCLES, CLASS 'D' (TEMPORARY MOLDS )= 10,000 CYCLES MIN.
To be honest, the plastic mould lifespan depends heavily on the type of material being injected, as some materials have a high wear factor.
Another key consideration is production volume—some molds are designed for low-volume production, while others are built to run continuously, 24/7.
The most vulnerable areas of a plastic mould tend to be sharp edges, such as ejector holes, the split line, sliding cores, and up-and-away risers.
Rotating and copper alloy cores are also prone to wear.
Copper alloy cores, in particular, serve specific functions.
Some are used for thermal contraction, helping to facilitate easier ejection of the part, while others are designed for molding transparent parts with highly polished surfaces.
Due to the combination of high injection pressure and certain materials used, these polished surfaces tend to wear out more quickly.
TOTAL 6 types of plastic mould ,they are Injection Molding , Blow Molding, Extrusion Molding, Compression Molding, Thermoforming Molding and Rotational Molding (Rotomolding) .
Process of Injection molding : Molten plastic is injected into a mold cavity under high pressure, where it cools and solidifies into the desired shape.
Process of blow molding : A heated plastic preform or parison is placed in a mold, air is blown into it, expanding the plastic to fit the mold's shape.
Process of Extrusion Molding : Molten plastic is pushed through a shaped die, and as it exits, it takes the form of a continuous profile.
Process of Compression Molding: A pre-heated plastic material is placed into an open, heated mold cavity. The mold is closed, and pressure is applied to form the shape.
Process of Thermoforming Molding: A plastic sheet is heated until it becomes pliable, then formed over a mold by applying vacuum or pressure.
Process of Rotational Molding (Rotomolding) : A hollow mold is filled with powdered plastic, then heated and rotated slowly so that the material coats the interior of the mold.
l Stage 1: Load powder polyethylene resin into the mold.
l Stage 2: Mold moves into the heating chamber of the oven while rotating on two axes at a low speed.
l Stage 3: Mold moves into the cooling chamber and is cooled by air or water spray or a combination of both, while still rotating.
l Stage 4: Mold is unloaded revealing the molded part.
If you want to know more about the difference among these plastic mould types , please check my another article named “TOP 5 DECK BOX MANUFACTURER IN THE WORLD” which explained the differ among injection moulding ,blowing moulding and extrusion moulding .
Or are you interested in the topic of “PLASTIC INJECTION MOLD VS BLOWING MOLD “ ? The another my article may help you to better understand them .
These two molding techniques differ significantly in their principles, application domains, and final product characteristics. This article delves into the definitions, process workflows, and distinct applications of plastic injection moulds and blowing molds.
The birth of a plastic mould needs to go through the following steps :
Evaluation
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Mold design
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Materials Ordering
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Materials Inspection
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Mold Roughing
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Heat Treatment
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Electrode Processing
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Right-angles
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Cutting
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Core Finishing
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EDM
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Polishing
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Tryout
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Trail Production
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Shipping
Several critical factors must be considered when designing a mold for injection molding.
The most important of these include the cavity shape, the gate location, and the parting line, as they all significantly impact the quality and functionality of the final product.
At Guangchao Mould, they specialize in custom plastic injection mould tool manufacturing. They create custom-designed tools for the injection molding process, where molten plastic is injected into a mold cavity under high pressure.
This technique allows for the production of a vast range of products, from small components like screws and rivets to larger items such as automotive parts and home appliances, ensuring versatility and precision in manufacturing.
Plastic molding itself is not inherently toxic, but certain aspects of the process and materials used can pose potential health and environmental risks.
Let’s dive in and learn more about the situation about plastic molding toxic problem:
polypropylene (PP) and polyethylene (PE) are generally considered safe and non-toxic during both injection molding and regular use. These plastics are widely used in food packaging and Commodity items.
However , for example, polyvinyl chloride (PVC) can release harmful gases, such as hydrogen chloride and dioxins, when heated to high temperatures or burned, making it potentially toxic.
phenolic resins or epoxy may release toxic volatile compounds, such as formaldehyde, during the curing process, requiring special precautions.
Many plastics contain plasticizers, flame retardants, stabilizers, and other chemical additives that enhance performance.
These additives can break down or off-gas during the molding process, releasing harmful chemicals. For instance, plastics containing phthalates or Bisphenol A (BPA) may emit toxic substances when heated.
Improper temperature control during molding can cause certain plastics to decompose, releasing toxic gases or harmful byproducts. For example, nylon (polyamides) can release toxic ammonia-like fumes if overheated.
ABS plastics (Acrylonitrile Butadiene Styrene), often used in everyday items, can release harmful substances like acrylonitrile when exposed to excessively high temperatures.
The cost of a plastic injection mould can vary widely, ranging from $200 to over $100,000, depending on the complexity and design of the custom mold.
For example, a small, simple single-cavity mold, like one used to make a plastic crate box , typically costs between $2,000 and $10,000.
On the other hand, larger or more complex molds can run as high as $50,000, $80,000, or even $100,000+.
For example ,the big headlamp base & headlamp lampshade of the car lamp,the outdoor chairs with full rattan grain in the surface, The price will be higher because of the complex structure of these plastic moulds.
Actually , It's difficult to label a plastic mould as "expensive" or "cheap" because the price depends heavily on its scope, design and intricacy.
It’s similar to asking, "How much does clothing cost?" The answer depends—are you looking for a T-shirt or a coat?
Likewise, is your plastic mould going to be simple or complex?
And remember, the cost of the plastic mould is just the start.
When calculating the total expense for a plastic injection molding project, you also need to factor in the costs of raw materials, operation, and future maintenance or repairs.
For any problems about plastic industry ,welcome to contact Guangchao Mould .
