By: Zvi Glick - AIM Solder Technologist
Let's begin with what needs to be cleaned. Electronics manufacturing processes for PCBs and cable assemblies involve various materials, some of which are acidic. At the end of the manufacturing process, residues left on the assemblies can cause damage or poor electrical performance, as acidic residues are both corrosive and conductive. These contaminants cannot remain on the assemblies and must be removed completely, preferably as quickly as possible.
In commercial applications, there are materials classified as No-Clean, meaning that cleaning is not required. However, even these materials are generally better removed rather than left on the assembly.
The basic principle of all cleaning processes is to separate the contamination from the surface of the assembly and then remove it through rinsing.
When it comes to Cleaning Systems for the Electronics Industry, there are two primary methods commonly used: equipment for aqueous/semi-aqueous cleaning processes and equipment (degreasers) designed for cleaning with volatile solvent-based materials.
Aqueous and Semi-Aqueous Cleaning Processes
In brief, this cleaning method is generally based on chemical agents that break down contaminants and separate them from the assembly surface, while water rinses away the dissolved contamination.
There are many parameters that must be considered when selecting both the cleaning process and the equipment.
The first step is selecting the appropriate cleaning agents, ensuring they are compatible with and capable of removing all contaminants generated during the manufacturing process. The next step is selecting suitable equipment to operate the cleaning process using the chosen cleaning agents. Here too, many factors must be considered, including equipment characteristics such as physical size, heating elements, kinetic energy, throughput capacity, cleaning uniformity, process cycle times, water treatment systems, material costs, environmental impact, ease of operation, maintenance requirements, and many other parameters.
It is important to emphasize that equipment cost is only one factor. Ongoing operating costs must also be considered, as over time they often exceed the initial equipment investment.
Solvent-Based Cleaning Systems - Degreasing Equipment
In brief, this method is based on the use of a cleaning agent (sometimes two agents) capable of removing contaminants from assemblies. Cleaning occurs both when the cleaning agent is in liquid form and when it is in the vapor phase. A degreaser typically contains a heated chamber where the cleaning agent is heated until it evaporates, creating a vapor layer above the chambers, as well as a clean "cold" chamber continuously replenished through condensation. Condensation occurs via a cold-water coil system located above the chambers.
As with aqueous cleaning, the cleaning agent must be carefully selected to ensure compatibility with all contaminants generated during manufacturing, while considering the same process and equipment parameters.
Both cleaning methods can be enhanced using additional technologies, such as ultrasonic agitation.
Selecting the right cleaning process and equipment is not a simple task and requires expertise and experience. At AIM Solder, we have been specializing in this field for many years and possess extensive knowledge and practical experience.
As a general recommendation, it is often best to purchase a complete process solution, meaning both the cleaning chemistry and the equipment from the same supplier.
We are available to assist you with consultation and guidance in selecting the most suitable cleaning process for your manufacturing requirements. Contact us, or leave your details using the contact form, and our team will get back to you.