Free coating consultancy on Productronica

In combination with the Dima know-how about automating the coating process each thinkable subject can be discussed in detail. Compared to different steps within the electronics production process, Selective Conformal Coating comprehends more than only a coating material a machine and a curing device. Selective Conformal Coating is a process on its own with many parameters, which all contribute to a successful end product from day one up until the last day of production. Learning about and understanding these process parameters will contribute to a successful introduction of the Selective Conformal Coating process into any production environment, whether it is at a small manufacturer of delicate electronics, or the manufacturer is into mass production, each can run into specific issues when starting to coat boards.

In most cases the initial contact will be made through a coating material supplier in order to find the best suited product for the application. Depending on the specific product related requirements there are several materials to choose from and each material has its specific advantages and disadvantages. Coating is being applied to protect electronics against moisture, chemicals, high temperatures, mechanical shocks, tin whisker growth and even unauthorised copying. Related to the reason of protection you can choose from various materials. If for the application more materials are suited, than a specific material specification will determine the final choice. Materials can be easy rework able, cure very fast, are VOC free or have a combination of these factors. Also important but very often forgotten is the purity of the boards that need to be coated. Like when bonding two parts with an adhesive the surface of the parts first need to be clean and dry. Equal to adhesive bonding the coating surfaces need to be clean and dry before applying the coating material. This involves the previous production steps and also the handling of the electronics before they enter into the coating process.

Within the Selective Conformal Coating process you can determine machine related parameters, but also some environmental parameters that can influence the end result. Some of the coating materials need to be mixed with a thinner. The mix ratio is determining the viscosity of the material in this case. If this viscosity is subject to changes, than this will have its repercussion on the output of the machine. The viscosity can also be influenced by changes of temperature. Some materials become lower in viscosity (more liquid) when the temperature in going up, or the opposite become higher in viscosity (thicker) when the temperature drops. Like with the mix ratio this will have its repercussion on the output of the machine. Other materials cure by means of humidity and therefore are more sensitive to changes of the humidity within the production environment. Some coating materials cure by means of (UV) light and precautions have to be taken to avoid this from happening while applying the material on the boards. Controlling all these parameters will secure the production process.

Within the automated process many functionalities are being actuated by air pressure. Monitoring of these air pressures and automatic operator notification is important to secure the production process and provide high yields. Applying the coating material there where it is needed is obvious. This involves product recognition before starting the coating process. Using automatic fiducial recognition and alignment software will secure the production process and will avoid material being applied in wrong positions or even on the wrong products.

Coating electronics is a relative young technique. From a design point of view not too often coating is being considered when an new board is being developed. Sometimes restricted areas are designed so close next to an area that needs to be coated that the capillary flow of the coating material will cause the restricted areas to easily be polluted. Different viscosities within one type of material can be used to overcome these issues. A small dam of material can prevent the lower viscosity material to reach the restricted area. The same can be used in case fine pitch connectors are being used on a board. When applying a low viscosity material on the leads of a fine pitch connector, the capillary flow will cause the connector to soak the material inside. To prevent this from happening a higher viscosity version of the same type of material can be applied in such case.

Curing a coated board is another specific subject that is very much depending on the type of material being used. Most materials cure in open air, but this involves long curing times and bad smell caused by fumes evaporating from the coating material. Heat is one of the most common curing mechanism that is being used. However when using a UV-material it is obvious that the correct wave length of UV-light should be used for fast curing. When the coating material that is being applied requires a heat cure system, the best heat source to be used is Infra Red. Often an old reflow oven is being used, but hot air can cause many problems in the end result. Furthermore in case the used coating material is solvent based, precaution measurement should be taken to prevent the flammable solvents from creating dangerous situations. Solvent based materials should also outgas as much as possible in a flash off conveyor before entering into the curing oven for the best end result.

Selective Conformal Coating involves many interesting details. Those that are being well informed will have a head start when starting up this process, but those that underestimate this process can run into many problems that could have been prevented. Finding the right partners that will guide you through this process will help you to get a flying start. Visiting the Dima application laboratory in the Netherlands will be standard procedure to answer all questions. This november there is the unique chance to visit the Dima booth at Productronica.

Dima Group B.V. is an international operating group of divisions specialized in developing and producing machines and tools for the Surface Mount and Dispense Technology. Since 1986 Dima is the brand customers count on the most for the best product performance and expert care and advice in this industry. With its own Research and Development centre and Software Department Dima continues to develop innovative products and solutions. Next to the existing application laboratory for SMT it also has a test laboratory & chemical kitchen for Dispense Technology. Dima believes that a strong commitment to the needs of your customer will evaluate into success. Therefore it shares its knowledge and specialism at the in-house knowledge centre & showroom where customers are individually trained on various machines. The Service Department offers support on technical questions, in-house or on site. All products are designed and manufactured to the strictest quality standards in the industry, resulting in a worldwide reputation for reliability.

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Während der Productronica lädt Dima die Besucher ein, am Stand im Dialog mit den Materialherstellern/-lieferanten Henkel, Humiseal, Lackwerke Peters und Dow Corning mehr über Selective Conformal Coating zu erfahren. Das Angebot gilt über alle vier Messetage.

A l’occasion du salon Productronica, Dima invite les visiteurs à en apprendre plus sur les revêtements enrobants sélectifs en dialoguant sur son stand avec les producteurs/fournisseurs Henkel, Humiseal, Lackwerke Peters et Dow Corning. Cette offre est valable pendant les quatre jours.