Nowadays there is a wide range of possibilities for the production of parts made of steel and other materials at industrial level. This range extends from machining to MIM (Metal Injection Moulding) through more classical techniques such as investment casting. In this article we will explain the different techniques for manufacturing metal parts.
Different technologies for the manufacture of metal parts
Broadly speaking, metal parts manufacturing technologies can be classified into the following technological areas:
- PM (Powder Metallurgy) or Powder Metallurgy.
- Forming: Forging, stamping, extrusion, rolling, etc.
- Casting, in its different aspects: Investment casting, sand casting, mold casting, vacuum casting, etc.
- Metal Injection Moulding (M.I.M.)
- 3D Printing (Additive Manufacturing)
All these technologies bring to the market different solutions and approaches to the challenge of mass production of parts.
The following is a brief description of each of them:
It is the process of compacting fine powders of the chosen material to give the required geometry. This compaction is done through hydraulic or pneumatic presses. This is followed by a sintering process in a muffle in a controlled atmosphere to avoid oxidation. The main disadvantages of this technology are its improvable precision and the fact that high densities are not achieved and, therefore, the mechanical properties obtained are very limited.
Depending on the forming system and whether the process is hot or cold, there are different variants. The main ones are:
It consists of the deformation of red-hot metal through impact and pressure.
In this case the deformation is done through pressure between 2 dies or molds.
It can be done hot or cold and consists of pushing the material through a die that has the desired shape.
In this case the objective is to reduce the thickness by using pairs of rollers.
It consists of the set of operations that, by cutting and chip removal, are used to obtain the dimensions and specifications of the parts, through different operations and abrasion and cutting tools. In the case of obtaining the part with 100% machining, there is an obvious waste of material and tools, in addition to the time required. However, it is a complementary technology (and in many cases necessary) to obtain the required finishes of a part.
It is a technology used since ancient times that consists of melting the metal at high temperatures to pour it into a mold and let it cool. The main variants of this process are the:
As its name suggests, the casting is poured into a mold made of refractory sand. It is used in large pieces since the mold is destroyed.
Investment casting or lost wax casting
It consists of the injection molding of the wax part. From this wax part, the ceramic molds are created where the chosen steel or other metal (for example, aluminum) will be cast. It is one of the main manufacturing processes in Ecrimesa Group.
Valid for low melting point metals such as aluminum, where the liquid aluminum is injected into a mold and a high clamping force is applied to the two semi-molds. It is a process suitable for the production of large series.
Metal Injection Moulding
This is another of Ecrimesa Group’s main processes. It is the injection molding of a mixture of steel powder and plastic material. In a subsequent process, the polymer is eliminated to obtain the steel part. Ideal for small parts of complex geometry that require high accuracy and surface quality.
3D Printing (Additive Manufacturing)
It is the newest process of parts manufacturing that continues with the advance of 3D printing technology so present nowadays. In Ecrimesa Group we have implemented this technology both in the manufacture of prototypes prior to the manufacture of the mold and to accelerate the MIM process through the study of prototypes of the final parts. Also, short series of parts with complex geometry are produced with Additive Manufacturing.
Investment Casting and MIM at Ecrimesa Group: advantages over other processes
Ecrimesa was the first company in the world to install a continuous furnace for the MIM process and we have more than 50 years of experience in investment casting. Today, the combination of these two technologies provides a number of advantages over manufacturing by a single technique.
- Flexibility in the range of part sizes and quantities. It is possible to make both long series of small parts (with MIM technology <1 g) and smaller quantities of larger parts (e.g. >20Kg) and high added value.
- High precision in complex three-dimensional shapes, tight dimensional tolerances and high surface quality.
- Large catalog of steels, especially in investment casting, arriving, in some cases practically à la carte and/or customized for specific customers. All this is complemented with the performance of heat treatments “in house”, which allows to widen the offer of metallurgical properties of the parts.
- In the case of the new Additive Manufacturing technologies, they are not currently in competition with the MIM process. In fact, they are complementary since there are still very few materials available on the market, with a high price.
The importance of machining
All the advantages of Investment Casting and MIM are completed with machining operations within the same manufacturing process.
Because of the versatility and material flexibility of investment casting, machining can be the ideal solution for delivering parts directly to the assembly line. These machining operations are usually quite straightforward, as the precision of the investment casting part is already quite high.
In the case of the MIM process, these machining operations are more unusual given the intrinsic precision and surface quality of the process. Even so, in very specific cases, machining operations, usually simple, are performed.
What is the best technology for manufacturing metal parts?
All technologies have advantages and disadvantages; there is no one better than another, the most important thing is to choose the one that best suits the needs required by the project, both in metallurgical and dimensional terms and even aesthetics. In some cases, the combination of several is the best option.
In Ecrimesa, we advise and accompany our customers in every step of the production, from the design of the part and the selection of the most appropriate technology for manufacturing, to machining and final heat treatments.
Ecrimesa Group has the latest machinery and qualified personnel to develop manufacturing projects of steel and aluminum parts by investment casting, MIM, machining and additive manufacturing.