Lower-concentration cleaning agents are one response to “green” demands.

Writing this column is a tremendous opportunity to comment on the rapidly changing world of precision cleaning within electronics. In short, cleaning is becoming more difficult and more demanding. It is our job to meet these new challenges head on and translate them into opportunities. So, what is changing, you might ask?
For one, the increasing local and global (i.e., RoHS, UNEP, GHS, etc.) initiatives to become “greener” have customers requesting more environmentally sound process solutions. At the same time, the need to clean better under low-standoff components has arisen. And, if that is not enough, customers expect more engineering support to identify additional improvements to their cleaning process, leading to a lower cost per cleaned part.

While we all understand and embrace efforts to provide our children with a safer and healthier world, we cannot easily ignore the effects of the global recession. At first glance, it seems that this calls for some tough choices. How can we continue to produce high-reliability products on a tighter budget, while implementing new and green technologies? Often, innovations as well as cost savings require upfront investment. It is here where we have to educate our customers about the solutions they might not be even aware of.

Let’s take a few prime examples to illustrate the possibilities of making a cleaning process greener:

• Lower, yet stable, operating concentrations to minimize chemistry consumption.
• Elimination or reduction of volatile organic compounds (VOC).
• Cleaning agents with lower pH levels to reduce effluent operating costs.

Operating chemistry concentrations is one topic I have addressed in various previous columns.  Greener cleaning processes can be achieved through lower and more stable concentrations that in turn help minimize chemistry consumption. One obvious fact: The higher the concentration, the higher the user cost. Factors such as the bath life of the cleaning agent also have to be taken into account. Assuming the same bath life, a lower concentration leads to direct savings, which is exactly what the latest cleaning agent technologies provide, as they can be used at 10% or less. It is also important to point out, however, that actual and perceived concentration can be two entirely different values. Once the operator begins to use the cleaning agent, the dissolved contamination affects the concentration measurement. Thus, overconcentration through ineffective measuring techniques can cost you handsomely. New bath analyzing technologies have emerged to help users accurately maintain concentrations. So, please, check your process, as this could lead to significant savings.

Second, VOCs are integral parts of many cleaning agents and serve a very important purpose. They support the cleaning agent’s job by solubilizing organic contamination. Reducing VOCs generated by cleaning processes, however, is a worthwhile thought because it would minimize their environmental effects. However, if one were to simply eliminate VOCs from the cleaning agent, it would have detrimental effects on the cleaning results, and product reliability would be everyone’s buzzword.  On the other hand, numerous avenues do exist to control the environmental impact of cleaning agents containing VOCs. Most notable are vapor recovery techniques with efficiency rates between 15% and 85%. 

This type of investment in process improvements also can help minimize cost. Appropriate vapor recovery techniques such as “condensation” (through active cooling) not only help maximize the collection of chemistry, but also recover DI water. Both are subsequently returned to the wash tank and recycled in the process, leading to substantial cost savings and a minimal impact on the environment.

Third, pH-neutral products for defluxing and stencil cleaning have emerged and are undergoing test and implementation. Similar to vapor recovery, the use of pH-neutral products enables users to benefit from more environmentally sound process solutions at an overall lower price. Users can now directly dispose effluent water from the chemical isolation section (sometimes 5 gal./min.) without extensive wastewater treatment. Given an acceptable cleaning performance, these new innovations combine environmental benefits with process savings: a win-win situation for vendor and customer.

We should set goals for ourselves to work toward. Accepting the status quo or waiting for someone else to innovate does not exemplify leadership, nor does it show responsibility for tomorrow’s world. So, how low can you go?

Ed.: Those concerned about environmental regulations should read Kal Kawar each week at circuitsassembly.com/blog.

Harald Wack, Ph.D., is president of Zestron (zestron.com); h.wack@zestronusa.com.

• Prev
• Next