Stripping or removal of unwanted conformal coating from a printed circuit board (PCB) can be a relatively simple process or a very messy difficult job. It does depend on several factors including the type of conformal coating you need to remove, where the coating is found and the type of components on the board.
Parylene Coating Blog by Diamond-MT
The Conformal Coating Standards that currently exist can be considered from two points of view. First, there are the standards that are used by the manufacturers of conformal coatings to qualify the products, whether that is done by self-certification or completed by independent testing. Second, the standards are a method for users to determine the quality of the conformal coatings they are considering to select.
Last time, we discussed the general requirements necessary to open a conformal coating facility. Now I will discuss the equipment that is required in order to have a properly operating facility.
Conformal Coatings are used regularly in an attempt to cover technology designs on printed circuit boards (PCBs). Normally, this is done by using a pigmented (coloured) conformal coating which obscures the components below the conformal coating material.
One thing to consider is the coating house’s experience level. Developing solid procedures and processes for conformal coating take time and experience. Many new vendors claim to be able to apply conformal coating as well as the experienced guys, but fall short whenever they run into issues they do not have the experience to troubleshoot. It will be tough to get referrals from your coating house, as a lot of times they are required to sign a non-disclosure agreement. A good way to evaluate their experience level would be to ask how many years they have been in business and their typical weekly, monthly, and yearly volumes processed. A visit to their facility, if warranted by the volume of the project, should give a good indication of the seriousness of their abilities.
Silicone conformal coating is becoming an increasingly popular choice for conformal coating applications. Because of its high temperature capabilities, moisture protection, and ease of application/rework, people are strongly considering silicone coatings for their projects.
Solvents can be used safely. However, the exposure of the operator to the solvent fumes must be REGULARLY measured and RECORDED. This ensures a safe operating environment and if an OSHA problem does arise in the future, evidence exists to rule out the conformal coating process as the culprit.
In applications that have an exposure to solvents, acrylic conformal coating is not the best choice. Acrylic conformal coating can be removed with a weaker solvent such as isopropyl alcohol or xylene. Whenever it faces even stronger solvents, it will not offer the protection that is needed, especially if your product is a mission critical device. Other coatings, such as urethane or parylene conformal coating have a far better resistance to solvents than acrylics.
Tags: acrylic conformal coating, parylene conformal coating, conformal coating, silicone conformal coating, conformal coatings, HumiSeal 1B31, urethane conformal coating, HumiSeal, epoxy conformal coating
Medical Conformal Coatings Used
While all conformal coating types can be used for different applications, for many medical devices, parylene is the way to go. Because parylene is biologically inert, FDA approval of parylene coated devices is well-documented. The coatings comply with USP Class VI plastics requirements and are MIL-I-46058C / IPC-CC-830B listed. Another benefit for medical devices such as stents and catheters is that parylene is entirely conformal, meaning that component configurations with sharp edges, points, flat surfaces, crevices or exposed internal surfaces are coated uniformly without voids or pinholes.
Tags: parylene conformal coating, parylene coating process, Diamond-MT, conformal coating, silicone conformal coating, conformal coatings, LED conformal coating, Automotive conformal coatings, Medical conformal coatings, conformal coating standards