Embedded Components from Concept-To-Manufacturing
Copper Foil Elements Affecting Transmission Loss with High Speed Circuits
pH neutral Cleaning Agents - Market Expectation & Field Performance
Reducing Dust Deposition on Electronic Equipment
New Requirements for Sir Measurement
Effects of Mixing Solder Sphere Alloys with Bismuth-Based Pastes
The Development of a 0.3 mm Pitch CSP Assembly Process
Generalizations About Component Flatness at Elevated Temperature
Latest Industry News
iPhone 12 Production Could Be Delayed
Acer sees PC component shortages
Bio-Ink for 3-D Printing Inside the Body
Covid Seen Driving the Security Sector
U.S. Eases Restrictions on Private Remote-Sensing Satellites
EMS Manufacturing quote complexity drives OEMs to look behind EMS curtain
U.S. Manufacturing Rebounds to 14-Month High
IBM's New AI Tool Parses A Tidal Wave of Coronavirus Research

Ultrasonics as an Option for Electronics Assembly Cleaning

Ultrasonics as an Option for Electronics Assembly Cleaning
Ultrasonic cleaning parameters including frequency, power, time, temperature and chemistries results demonstrate developments in technology.
Production Floor


Authored By:

Ed Kanegsberg, Ph.D.
BFK Solutions LLC
Pacific Palisades, CA, USA

Barbara Kanegsberg
BFK Solutions LLC
Pacific Palisades, CA, USA


We report results from on-going studies with ultrasonic cleaning systems that support using ultrasonic technology for cleaning electronic assemblies. Ultrasonics is an important option especially when assemblies contain hard to reach regions between or under components. Electronic assembly performance criteria have become more demanding and assembly parameters have become more challenging. Residues can limit product performance and lifetime. Cleaning to acceptable levels is difficult. Currently accepted cleaning techniques, whether in-line or batch processing, may not adequately clean flux and other residues from between or under components. Cleaning is frequently the limiting time and cost bottleneck.

Traditionally there has been a reluctance to use ultrasonics, in part because of a concern with the potential for substrate and component damage. However, as assemblies have become more densely-populated, current techniques must also be evaluated in terms of efficacy of cleaning and the potential for product damage. Many predominant cleaning methods are limited because they require line-of-sight technology. This means that assemblies must be optimally oriented to avoid shadowing of the cleaning force. In contrast, ultrasonics is, in general, not a line-of-sight technique. It therefore can overcome limitations of spray cleaning, including meticulous maintenance and orientation of spray nozzles, slow throughput, or the potential damaging high pressures needed to get cleaning and rinsing fluids to their destination.

We are studying ultrasonic cleaning parameters including frequency, power, time, temperature and chemistries. Results demonstrate that developments in technology require rethinking of our older assumptions. With appropriate process controls, ultrasonics can significantly reduce both the potential for damage and also allow the appropriate cleaning energy and chemistry to reach the area to be cleaned. Our findings indicate that cleaning times might be reduced from large fractions of an hour for conventional techniques to a few seconds. Cleaning resources including capital investment, floorspace, water and energy use may also be favorably reduced.


Ultrasonics should be considered as an option for cleaning of electronic assemblies, especially when there are hard to reach regions such as under low stand-off components. The availability of high frequency ultrasonics, as well as optimization of other parameters such as temperature and cleaning chemistry, minimizes the potential for erosive damage to leads, boards and components. Our tests also show that ultrasonic cleaning can be both quick and effective when the flux residue or other soils are in regions with small gaps.

Ultrasonic cleaning shows the potential for increased throughput through significantly shorter clean times, reduced equipment footprint, and lower energy and water resource consumption. Our tests are continuing and will continue to study the effects of different cleaning agents, temperature, and other parameters to achieve a balance that optimizes cleaning while minimizing potential damage.

Initially Published in the SMTA Proceedings


No comments have been submitted to date.

Submit A Comment

Comments are reviewed prior to posting. You must include your full name to have your comments posted. We will not post your email address.

Your Name

Your Company
Your E-mail

Your Country
Your Comments

Board Talk
Solder Paste Beyond The Shelf Life?
Issues With Fillets on Via Holes?
Can Tape Residue Contaminate a Clean Tank?
Suggested Stencil Wipe Frequency?
Reflow Oven Zone Separation Challenges
When To Use Adhesive To Bond SMT Components
How To Clean a Vintage Circuit Board Assembly?
PCBA Inspection Concerns
Ask the Experts
Lifted Lead on SOT Component
Allowable Bow and Twist on Round PC Fab
Mixed MSL Baking
Step Stencil Squeegee Angle
Solder Balling Splash After Reflow
Application Using No-Clean and Water Soluble Fluxes
IPC SOIC Defect Question
Mixed Process Solder Joint Appearance, Smooth or Grainy?