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When the Germans coined the term Industry 4.0 back in 2011, it wasn’t clear to many what it actually stood for. Although the debate about all the nuances of the term’s meaning is still ongoing, one aspect of it is undisputed: The “computerization of manufacturing” is at the heart of it. Manufacturing techniques throughout many industries continue to become more and more digital. This is also true for PCB manufacturing. Several manufacturing steps offer incredible potential for digitalization. One prime example is the application of solder mask material using industrial inkjet technology.
Solder Mask Printing
The current manufacturing standard for solder mask application involves several process steps which have a significant cost impact:
- Pre-treatment of the PCB
- Full board coating (e.g., curtain coating)
- Artwork film production (photomask)
- UV exposure
- Post cure
Utilizing state of the art digital inkjet printing for the application of solder mask on PCB boards, the number of process steps can be reduced:
- Pre-treatment of the PCB
- Digital inkjet printing including in situ UV curing
- Post Cure
The benefits of this simplified manufacturing process are obvious. Besides the reduction in required capital equipment and associated labor, the digital process also significantly reduces the use of process chemicals and therefore also the related handling and disposal cost. Overall, the environmental benefits are enormous. Last but not least is the reduction in manufacturing turnaround time—an important asset in to-day’s fast moving electronics business.
Unique Characteristics of Inkjet
Inkjet technology is widely used in homes and offices all over the world for traditional printing applications. Although the fundamental concept of modern industrial inkjet applications is comparable to those printers, there are significant differences. Industrial use of inkjet technology is characterized to a large degree by the type of materials which are deposited. In-stead of traditional ink, materials such as resists, adhesives, conductive inks, polymers and their likes are deposited. Inkjet is a selective coating technology. This means that material is only deposited where it is needed. In the case of solder mask printing, this not only reduces material consumption, but also avoids solder mask material in via holes and other areas where it is difficult to remove or simply not desired. Flushing uncured solder mask material from high aspect ratio holes in the development step is a known challenge in the PCB industry and is completely avoided by inkjet printing.
To read the full version of this article which appeared in the February 2017 issue of The PCB Magazine, click here.