The most important part of ultrasonic welding is the
design of the two mating surfaces. The four main types of joints are
step, butt, shear, and tongue and groove. The diagrams below illustrate the
four main types of joints. Should you require further information or details
on other types of joints please contact Ultrasonic Engineering.
BUTT
JOINT
The butt joint is the most common type of joint design
as it is easy to mould into the plastic part. The main feature of this type of
joint is the triangle shaped ridge which has been moulded into one of mating
Surfaces. The purpose behind the triangle is to focus the ultrasonic sound
waves to a very small area. During the weld time the ultrasonic waves cause
the plastic to melt and to flow through the joint area.
Good for amorphous materials such as Stryrene, ABS, Polycarbonate
STEP
JOINT
The step joint provides a well-aligned, strong bond
between the two mating surfaces. This type of joint is recommended if a good
appearance is required. Good with amorphous materials.
SHEAR
JOINT
The shear joint is recommended for high-strength
hermetic seals on parts with square corners or rectangular designs, as the
seal is on the Note that a certain amount of flash may be visible on the
surface after welding. This type of joint is ideal for crystalline materials
such as Nylon, PPS, PSO and can also used for large parts made of amorphous
materials.
TONGUE
AND GROOVE JOINT
The tongue and groove joint is another type of design as
it is a good prevention of flash both internally and externally, and provides a
good bond between all mating surfaces. This type of joint is good for thick
walled amorphous materials such as Styrene, ABS, Polycarbonate.
