Plastic injection molding relies heavily on temperature, and two types of temperature are particularly critical: melt temperature and mold temperature. When it comes to how long your finished injection molded products will survive and how they will look, feel, and function, these two measurements are crucial.
This is the temperature at which your injection molding material "melts" into a liquid before entering the mold after leaving the nozzle, and this is what we're talking about when we talk about melt temperature. Injection molded plastics product design and development is heavily reliant on knowing exactly what kind of molten plastic state you need to get the desired appearance, feel, and functioning in a finished product.
It's for this reason that melt temperatures are meticulously monitored and regulated during the injection molding process. There are typical melt temperatures for each of our equipment, but these might vary amongst different types of plastics, even if they are created from the same fundamental formula. Among the plastics that are frequently found in everyday home objects is ABS, whose melting point is 220 degrees Celsius (428 degrees Fahrenheit). While ABS has a melting point of 240 degrees Celsius according to Plastics Technology, this might vary from manufacturer to manufacturer (464 degrees Fahrenheit).
When possible, it's crucial to keep in mind that different batches of plastic within the same formula may have somewhat varied melting points. Environmental factors, such as temperature and pressure, can also have a role. This means that there is no way to predict the melting point of your polymer based on the recipe or its previous use; you'll need to experiment with different batches before deciding.
Impact of Melting Temperature on Moulded Goods.
Varied resin types have different melt temperatures, which can have an effect on the finished product in a variety of ways. This list includes:
For a given melt temperature, the viscosity of a resin will be reduced. An too high temperature might cause resin to be too thin, making it impossible for it to properly fit into a mould and therefore creating an unfinished product.
Dimensions of molded part's molecular weight The melting point decreases with increasing temperature. More resin is drawn into your final product when you choose a heavier weight resin, making it stronger and longer lasting.
Slight reduction: When it comes to injection molding materials, "shrink" actually refers to expansion; drawing in too much material could result in a thick and flimsy product, while drawing in too little could leave your part hollow. Preventing damage or even an explosion in the mold cavity is possible by using lower melt temperatures when over-molding an existing object with a second resin to reinforce it.
As a result, when it comes to melting temperature, injection molding experts take into account a variety of parameters, including the resin used, the residence time, the screw and barrel design, and the final property needs of the product.
Tolerable Temperatures for Mold
A mold's surface temperature, in contrast, is what is meant by the term "mold temperature". This is critical to the injection molding process because it determines how your product heats up and cools down, which in turn affects its final appearance, feel, and quality.
Even for plastic components with highly specific property requirements, mold temperature must be closely monitored throughout the injection molding process.
If you're considering the mold temperature for injection molded parts, Plastics Design & Fabrication magazine recommends looking at it during the cooling down period known as "quenching," the annealing process at the end of the injection molding known as "painting," and finally any post-processing steps like painting.
It is far more likely that flaws, warping, and jetting will be present in the final molded product if the mold temperature is not set correctly.
How temperature affects molded products in the molder
What effect does the temperature of the mold have on the final qualities of the molded product? Several ways, to be precise:
The cooling process of an injection molded item can "set" any inherent stress in the polymer, even if it doesn't seem like a big deal. Shock-cooling at particular times during production (due to wrong mold temperature) could cause issues with the product's endurance or robustness.
A product's ability to withstand long-term stresses and environmental variables will be reduced if it is cooled down at key moments throughout the injection molding process. This means that if it's being utilized as a vehicle exterior component, for example, its resistance to wear may be reduced after just a few months of driving.
The molecular weight The molecular weight of the material is one of the most significant factors to take into account while determining mold temperature. This will influence not just how much tension may be imposed but also how long it takes for that stress to take effect.
For a material's ability to withstand wear and tear, elements such as mold temperature and molecular weight will play a significant role.
It is possible for a product to become exceedingly brittle and even break under pressure from an impact or force when it is cooled too quickly.