Metal binder jetting has attracted the attention of mid-level manufacturers. It is envisioned to be an ideal technology for the production of low-cost, lightweight parts and small components with complex designs. Major players in the field claim that their version of binder jetting draws inspiration from metal injection moulding. With its patented single-pass jetting technology, Desktop Metal is a heavily funded company in this space. Other important players include Xjet and 3DEO. GE, a printing disruptor launched its binder jetting 3D printer last year. 3DEO claims that its intelligent layering technology (a version of binder jetting), performs CNC machining on green parts. The printers use a spray technology to jet binders on metal powders. The developed part is then machined to achieve the desired shapes. In the area of materials, Nanosteel produces steel powders that enable wear, impact and corrosion resistance for binder jetting additive manufacturing. Based on the use case and industry-focused applications, different versions of Binder jetting are getting adopted in the automotive, dental, healthcare, aerospace, jewellery and luxury fashion industries.
Traditional Binder Jetting uses a print head to jet binding agent on a heap of material. In the case of metal binder jetting, the material changes to metal powders. The processed parts are brittle and possess low mechanical properties and require post-processing. The unprocessed parts are often called “green parts”. The finishing operations strengthen these parts, thereby improving their mechanical properties.
Some advantages of metal binder jetting are:
The process does not require supports as the printing takes place on a platform on which the powders are kept.
The wastes are minimal. This is because after the printing process is completed, the leftover powder can be used for printing. This leads to cost savings. In the case of other technologies, the wastage of associated materials is significantly higher.
The process uses binding agents. As compared to SLM (using lasers or electron beams), the binder jetting process does not require the installation of expensive lasers. Moreover, these lasers consumer high power, making these processes inherently expensive.
The large volume of the build platform of metal binder jetting machines enables these printers to produce a large number of parts or large-sized parts.
The machines do not require any rest time, as in the case of laser-based machines, that need off times to cool down the printer/parts to ensure the safe removal of processed parts. This translates to speeds up to 10 times as fast as speeds provided by laser-based systems.
The process takes place at room temperature. This makes the final part free from heat distortions such as delamination that is common in SLM and DMLS technologies.
The developed parts are free from stresses as opposed to similar parts developed by competing technologies.
It can be seen that metal binder jetting is an ideal AM technology for producing complex metal parts with almost full density at a significantly lower cost than DMLS or SLM technologies. The business case proposed by this technology is strong and can lead to savings, without major compromises on the front of dimensional stability. The technology claims to transform mid volume, low-cost production.
Common challenges with additive manufacturing technologies include the inability to produce a large number of low-cost parts. With binder jetting, a number of parts can be produced at once. The post-processing methods like sintering can be conducted on a number of parts, enabling fast, reproducible parts.
However, binder jetting has certain drawbacks too. A major point of discussion among industry experts is the porosity of the developed parts. Porosity translates to fragile parts. Since the technology is new, there are not many materials at disposal for manufacturers. Though, it is expected that with time, companies in the field would develop new materials.
It would be interesting to see how manufacturers adopt this technology for transforming their mid volume rapid production.
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Image Courtesy : www.nanosteelco.com