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Metal 3D printing frees us from using a mold

6 October 2021

Metal Injection Molding (MIM) is already a very innovative process combining two technologies. It's a fusion of traditional plastic injection molding with powdered metallurgy. For the MIM process Rompa Group uses a standard injection molding machine that melts the powder and injects it into the mold. But what if it can be done without having to make a mold? That's right! Goodbye mold, hello 3D metal printing!

Types of metal 3D printing

The very first patent for metal 3d printing was registered in 1990 by a german company. In this patent the method of DMLS was explained. From then on engineers all over the globe started to work with this method and also came up with other ways of metal 3d printing.

Let's start at the beginning: DMLS stands for Direct Metal Laser Sintering and is currently categorized under Metal Powder Bed Fusion. Other methods that fall under this category are: SLM (Selective Laser Melting) and EBM (Electron Beam Melting). For melting, high temperatures are used for the parts to get joined. Sintering means combining high temperature and pressure to join the parts.

Then there is the category of Direct Energy Deposition. The printing systems that fall in this category are known as LENS (Laser Engineered Net Shaping) and DMD (Direct Metal Deposition). This method is similar to welding, metal wire or powder is used to melt the part into shape. This is also used to repair existing metal parts.

Metal Binder Jetting is a great type of 3D printing as it can handle not only metal materials but also sand and ceramics. These machines operate at room temperature and are used for smaller quantities of production.

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How does metal 3D printing work?

While there are different types of metal 3D printing machines, methods and processes, the overall production process is very similar. Below we give you an easy explanation of how metal 3d printing works.

As always, it starts with an innovative design. Our engineers make sure the 3D model design is optimized taking all possible considerations into account. 

When the design is finished we start with filling the production chamber of the printer with an inert gas, argon for example. This will make sure oxidation of a particular metal powder is prevented. The chamber will then be heated to the optimal temperature.

Then the scanning process starts. The high power laser scanner of the 3D metal printer spreads a thin layer of metal powder over the build platform. The model is constantly scanned throughout the process, the metal particles are melted together until it's ready for the next layer. This makes the object fully solid. The process is repeated layer by layer until the object is completed.

When the final layers are fusioned, the chamber starts to cool down to room temperature. Excess metal powder will now be removed and in most cases a heat treatment follows while the part is still located on the build platform. The final stage is detaching the object from the build platform and now the piece is ready for any post-processing, if necessary.

Freedom of design

3D metal printing gives our engineers more freedom in making the design for a particular part. During the MIM process a mold is made and during the production process there is not much optimization to be done once the mold is done. With 3D printing the design can be changed or updated. Also, during this design process our engineers have more freedom and can design more complex shapes, so they often turn to 3D printing when we get a request to manufacture specialized parts. For example, some specialized parts can be for medical professionals who use metal 3D printed parts for implants.

When do we choose metal 3D Printing?

There are several considerations when it comes to deciding which technology is best suited for producing a particular part. Below we list some of the considerations when it comes to metal 3D printing.

  • Metal 3D printing is for complex designs. As mentioned above, we have a lot of freedom in the design but it also allows our engineers to create a complex design for a part.
  • Making prototypes is also ideal for metal AM. Say there are only a few pieces required for prototyping, metal 3D printing makes it ideal as the prototype design can easily be changed throughout the process, without having to produce a mold.
  • In most cases when producing parts for the aerospace or medical industry, light weight components are necessary. These industries often require strong but light weight components. Using the metal laser sintering technology this is no problem.
  • Metal 3D printing is very efficient, it reduces waste during the process. If we want to minimize wastage of material then metal 3D printing is our choice.
  • A consideration is also the size of the piece. The build chamber has a maximum part size, larger pieces are not suitable for our 3D printers.
  • The surface of the 3D printed metal piece does not have a smooth surface but a more grainy one. Due to the additive process the surface most likely will have texture. Even though there are post processes available to finish the surface as requested, it’s still a consideration to take into account.

Would you like to know if the metal 3D printer is ideal for producing your part? Make sure to contact Rompa Group for more information, our experts can find you the best production process. Whether this is MIM or 3D printing, there is always an optimal solution for everything. Would you like to learn more about our MIM process that uses a mold? Make sure to read it here, give our experts a call or drop them an email! You can find our contact details here.