How to tune an ultrasonic welding horn

There are several methods available for tuning an ultrasonic welding horn.  Ultrasonic horn manufactures rely upon frequency analyzers to measure the frequency of the ultrasonic horns during the manufacturing process.

CAUTION: Because multiple modes of vibration are present in all tooling, it is very important that the ultrasonic horn is tuned to operate on the correct axial frequency.  Tuning an ultrasonic horn to an incorrect non-axial frequency can result in catastrophic failure of the ultrasonic horn and/or damage to another component of the ultrasonic system (booster, converter/transducer, power supply, etc).

The most common method for tuning an ultrasonic horn is to build a "blank" horn with a tuned length that is .250"-.500" longer than the expected final tuned length (this results in a frequency which is lower than your target frequency).  Material is then removed from the working face of the horn, thus raising the frequency of the ultrasonic horn until the proper frequency is achieved.  The anticipated tuned length of an ultrasonic horn can usually be accurately achieved with proper use of FEA software.

Another common method for tuning an ultrasonic horn is to adjust the location of the radius "step" that is present on many ultrasonic horns, both circular and rectangular.  This method is commonly used when building multiple ultrasonic horns which require the same final tuned length.

Although not as common, the frequency can also be raised by removing material from the surface of the horn on which the stud is located.

On slotted horns, adjusting the slots will also affect the frequency of the horn but this is typically reserved for optimizing the performance of the ultrasonic horn rather than trying to simply adjust the frequency.

One of Industrial Ultrasonics, Inc cost saving services includes re-facing and re-tuning our customers' existing ultrasonic horns once the working surface has become worn or damaged.  If you are a customer with in-house machining capabilities, we can further increase your savings by advising you as to how much material can be removed from the face of the ultrasonic horn before it would need to be returned to Industrial Ultrasonics, Inc for re-tuning.

Disclaimer: Keith Anderson of Industrial Ultrasonics, Inc designs and manufactures ultrasonic welding horns for use on all brands of ultrasonic welders including, but not limited to, Branson, Dukane, Forward Technologies, Herrmann, Rinco, Sonobond, and Stapla.

Information required for quoting and designing an ultrasonic welding horn

If you are in need of a quote for an ultrasonic welding horn for a new application, here are a few key pieces of information that will be required by an ultrasonic horn manufacturer in order to provide you with an accurate quotation for the ultrasonic tooling:

• Part Material - What is the material composition of the part that is to be assembled (ABS, PC, etc)?
• Material Color - What is the color of the material (black, white, clear, light vs dark, etc)?
• Quantity - How many parts do you anticipate producing (monthly, annually, life time, etc)?
• Part print / file - Do you have a print and/or 2D/3D CAD file of your part?
• Frequency - What is the operating frequency of the ultrasonic welder that the ultrasonic horn will be used on (15 kHz, 20 kHz, 35 kHz, 40 kHz, etc)?
• Welder Information - What is the make and model of the welder that the ultrasonic horn will be used with (Herrmann, Branson, Dukane, etc)?
• Stud Size - What stud size is required to connect the ultrasonic horn to your booster (3/8-24, 1/2-20, M8x1.25, M10x1.5, M12x1.25, etc)?

Depending upon the complexity of the application, more information may be required by the ultrasonic horn manufacturer but supplying the above information is a great place to start.

Keith Anderson, President

Industrial Ultrasonics, Inc

www.industrialultrasonics.com