Manufacturing objects, especially ones that require plastic molding, can be done easily using our special 3D printers. However, it’s not just as simple as putting a design into a computer and printing it out.
A few decisions are required before this can happen. For instance, a choice has to be made for the type of material you want to use for your product, like silicone or rubber.
Each material has its own pros and cons which is why it’s important to consider the intricacies of printing a mold and the process of how it’s done.
Liquid Silicone Injection Molding Design Guide
A liquid silicone injection molding design requires quite a few steps and decisions. These include choosing how large the mold needs to be and the type of surface coating to ensure that the mold stays durable.
The Process of Molding Liquid Silicone
The first step to molding liquid silicone (also known as LS) is to design an aluminum casting to pour the hot silicone mixture into. This casting is usually designed with a CNC machine to help prevent any irregularities in it so the mold is formed without deformations.
Once the casting has been designed, a surface coating has to be chosen. The surface coating will help to make removing the mold easy and add a shine or unique coating to the liquid silicone mold.
When it comes time to pour the silicone into a mold, a special pump will measure out the needed silicone before it’s poured into it. After the liquid has been measured out, the pump will move it into a large mixer where it will then be stirred up and packed into a specific mold. The mold will then be heated until the liquid silicone firms up and can be easily removed from it.
Shore Scale Hardness
An interesting aspect about liquid silicone is that you can mold it to a certain softness or hardness (known as the shore hardness). By using a Shore Scale durometer, at J-CAD Inc. we are able to keep track of how soft or hard a mold should be. The object can be as soft and tender as a gummy bear or hard and heavy-duty like a construction helmet.
There are 3 Shore Scales that are used to help determine this: Shore 00, Shore A, and Shore D. Shore 00 is used to measure soft rubbers and materials, Shore A is used mainly to test flexible rubbers, and Shore D is used to test hard and rigid plastics.
This scale is extremely important when it comes to custom plastic injection moldings because it determines whether or not the product will be properly created.
Silicone Injection Molding Temperature
The temperature for silicone injection molding is vital when it comes to forming objects. As mentioned above, the Shore Scale helps with finding the right temperature when trying to create a certain mold.
How this is determined isn’t necessarily that difficult because it only really depends on the type of silicone you’re using and how much of it. Typically, silicone injection molding temperatures can range anywhere from 340 – 400oF.
When the silicone is first poured into the mold, it starts out as liquid. These high temperatures then work to solidify it slowly. But even with the high temperatures the molding has to go through, it doesn’t burn or melt which shows just how durable and heavy-duty it is.
What is Silicone Overmolding?
A common technique that is often used with plastic molding is silicone overmolding. So, what exactly is this?
Silicone overmolding is when a silicone layer is poured over an object, like a wire, to help seal the materials inside and create a composite component. For instance, you’ve probably seen bundles of wires molded together for a computer or TV.
This is basically what silicone overmolding is. It keeps those materials together in one spot. This method is very cost-efficient and easy to create which makes it popular to use.
Rubber Injection Molding Troubleshooting
If you’re looking to have a certain mold created for you, we can help. At J-CAD Inc. we have some of the top-of-the-line machines that can create numerous types of molds for any type of product. Just ask us for a quote, and we’ll do whatever we can to help you create amazing things and make your business grow.