We could use 3D printing to create a variety of different things, not all of which have to be finished products. Instead, we could construct a variety of tools, templates, and containers, as well as casting molds. This particular course of action is the focus of the article that we are currently working on. We are going to show you how to cast materials like wax or soap in your own home using tools that are readily available to you.
Our objective is to demonstrate that casting from silicone molds is considerably less difficult than it may appear to be at first glance. Before I figured out the proper procedures, I had to go through a period of trial and error with my own attempts. As a result, it is my sincere hope that this post will enable others to save some resources, as well as some time and effort.
In order to create the mold, we will be utilizing a silicone rubber that cures via condensation and consists of two parts. In our particular instance, we use a product called Lukopren N Super that is manufactured locally in the Czech Republic; however, there are probably many other products just like it that are sold all over the world, such as Smooth-on, ACC Silicones, RTV, and many others.
Lukopren is made up of two parts, A (the silicone itself) and B (a hardener/activator), and it takes approximately twenty-four hours to cure when left at room temperature. The amount of hardener used and the temperature of the surrounding environment both have an impact on the curing time.
The mold that is produced as a result is chemically and thermally resistant, and it maintains its original shape
1. It is possible to cast a wide variety of materials with it, such as polyurethane, epoxide, polyester, plaster, concrete, cement, wax, low melting alloys, and soap
2. This type of mold material can be used to create both small, detailed casts as well as large objects (such as statues)
3. Because of its superior flowability and low viscosity, a vacuum pump is not required to be used
4. Silicone rubber can be brushed on or poured (with a thickener being added to the mix in either case), although there are better options for brushing, such as the Smooth-on product that was mentioned earlier in this paragraph
In an upcoming article that will focus on jewelry making and dental applications, we will provide a comprehensive description of the metal casting process.
The prototype
In order to make a good mold, we need a good master model in the first place. Only then can we make a good cast.
Particularly if we are unfamiliar with 3D modeling apps, the process of designing such a model may be laborious and call for a great deal of patience as well as close attention to detail. You could completely skip over this step by simply downloading a pre-made model from a website database .
Be wary of what are known as overhangs, which are model outlines that meet the mold parting plane at an angle that is more acute than a right angle (90 degrees). To put it another way, if you look into a mold directly from above, you ought to be able to see the entire inner surface, and there shouldn't be anything hidden "behind a corner."Because of these overhangs, the master model or final cast might become stuck in the mold after some time has passed. It is fortunate that one of the primary benefits of silicone rubber is its elasticity, as this property allows it to yield slightly when bent and twisted in order to remove the finished cast from the material. This indicates that we would be able to afford a particular level of overhangs. After only a light amount of pressure has been applied to the mold, the properly casted model should almost immediately pop out.
If we use a technique known as lost-wax resin casting, we won't have to worry about overhangs at all, of course, because we won't be taking the model out of the mold and it will be destroyed there. This eliminates the need for us to take any measurements.
Any material that does not have pores can be used as a master model for the production of silicone rubber molds. This indicates that you could use 3D prints made from filament or resin depending on your needs. Print layers are not difficult to remove from the mold; however, you will be able to see them on the final cast. This is inevitable. That indicates that printing from resin is the better option; the Original Prusa SL1 printer was the one I used.
There are specialized aluminum die casting parts resins that can be used for lost-wax casting. These zinc alloy die casting factory resins can be completely melted or burned out of the mold, depending on which method is used. The subsequent article will also include a more in-depth discussion of this approach with additional details.
The master that was printed using a 3D printer is much more disposable than the one that was made by hand. Even if it is damaged in some way while we are making our first attempt at the mold, we always have the option of printing it again from scratch.
Before you use the surface of the master model to make molds, you should give it a careful inspection. Take care of any imperfections, such as scuffs, support stubs, or even fingerprints, if you can. In that case, each and every one of these surface flaws will be transferred into the final cast!
We need to lay out the dividing plane of the two-part mold before we can actually make the mold itself. Later on, before the actual die casting mould takes place, we are going to cut the pouring channel and air vents into the mold.
In the following manner, the dividing plane will be created:firmly press the master model into the modeling clay until it reaches the desired level of the dividing plane.
These could be simple holes made using the handle of a brush, grooves carved into the surface, or anything else to disrupt the smooth surface, which could cause the mold halves to slide apart.