In recent years, silicone has been a definitive choice for manufacturers who want to produce affordable, detailed, and fast products. However, there are plenty of challenges in manufacturing molds. The best solution for this problem is 3D printing.
Read this to learn more about how 3D printing simplifies silicone molding.
Why is Silicone Ideal for Mold Making?
Silicon rubber or Poly siloxane belongs to the elastomer family and possesses similar elasticity and low-hardness properties to the one for which this family is known. That makes it stand out among rubber materials. However, before moving on, let us briefly overview these properties.
Depending on the formulation, silicones’ elasticity range is between 30% and 1200%. Therefore, when the cast is finished, it can be removed easily and without damaging the result or the mold by splitting or deforming it. This characteristic also makes the final shape neat.
Comparatively speaking, silicone rubbers are more stable than other rubbers. This elastomer won’t distort or break in extremely cold or hot settings while keeping its characteristics constant from -100°C up to 300°C. It can stretch with enormous force and won’t break easily, in addition to being one of the most trustworthy insulation materials. This is perfect for hot castings, baking food, or freezing fluids to generate ice for producing molds.
Although not the best among other rubbers, it has adequate tensile strength, tear-resistance, and fatigue cycles for manufacturing reusable and high-quality molds (At higher temperatures, silicone is much more durable). Aside from its mechanical qualities, silicone excels in applications involving food safety, medicine, and the outdoors due to its exceptional resistance to microbial growth, chemical reactivity, UV light, oxygen, and ozone.
It works well as a sealer and helps to prevent leaks and seam problems while flawlessly retaining liquid casting materials. Contrarily, silicone is gas-permeable, which, together with its low toxicity, contributes to its widespread use in food and medicine.
Comparatively speaking to other rubbers, silicone rubber is overly expensive. The formula and the seller determine the actual cost. But always keep that in mind before choosing to purchase this stuff.
Types of Silicone
The following are the types of silicone that are used in for a variety of applications.
- High consistency rubber (HCR) is a putty-like substance used mostly in compression molding.
- Liquid Silicone Rubber (LSR) is used primarily in liquid injection molding.
- Fluor silicone Rubber (FSR) – is used in engine seals and gaskets
- Room Temperature Vulcanize (RTV) – with the help of a catalyst, it can cure at room temperature.
- Tin Catalyzed – it possesses long-term stability and tends to shrink. However, it is affordable.
- Platinum Catalyzed – it has shorter stability and has low shrinkage after curing. But it comes at a higher cost.
3D Printing and Silicone Molding
You can use 3D printing to create tooling for silicone molding. Since you need the mold to be as detailed and accurate as possible, the type of technology used for this process is resin-based SLA 3D printing.
Compared to FDM prints, SLA-printed molds are more robust, dimensionally close to the original, and adhere to finer details. However, SLA printers are more expensive.
In printing a 3D mold, you must create a 3D model of the component you want to duplicate before you can 3D print a mold. After that, you must make a “negative” replica of this model.
Making a box more prominent than your model and “subtracting” it from the box is the simplest method. The cavity that results from this should serve as your mold. The place where you divide this box will serve as the mold’s separation line.
Remember that the model must not be upright in the mold box. Additionally, it’s not necessary to split the box precisely in half. There are several diverse ways to 3D print mold, so it will take some trial and error to get it exactly right for your design.
This technique presents specific difficulties because not all 3D printing materials can be used for silicone molding. For mold removal, you’ll need a substance that can endure elevated temperatures while also having good elasticity. These are pricey.
Using 3D printing to create tooling for silicone molding is a notable example of combining both old and recent technologies that complement each other to create a viable alternative to manufacturing goods. While 3D printing will not replace other manufacturing techniques, it provides a cheaper and simpler alternative.
Just a reminder, all the rules in mold designs apply with this technique. The good news is you will have plenty of room for error with this technique, as creating mold with 3D printing is much cheaper than its alternative.