Category Archives

A student just e-mailed me this question… JH I am a little confused about the difference between Near Field and Far Field ultrasonic welding. Is this referring to the size of the part or the horn? My Response Actually, near and far field refers to the distance from the ultrasonic horn to the weld joint. Typically, […]

This is a question similar to others I often receive… MJ If I’m using a DII process, why should I turn off pack/hold time when I am filling 98% during first stage? My Response Turning off pack and hold is a great way to verify your fill is properly established, especially when you document the […]

I received this follow-up questions from a previous blog… Milan If I use a reverse profile, could I have problem with melted pellets or trapped air? My Response Basically, the purpose of a higher feed temperature in a reverse profile is to ensure the pellets soften enough to stick to the barrel so they convey […]

I received this question the other day… Rafael In a D1 (DECOUPLED MOLDING 1) process the first stage is filling and packing, yet a D2 process isolates filling in the first stage. Could you please explain the difference? My Response In a D1 process, the mold cavity is completely filled using velocity controlled first stage. […]

I got this question and felt it would make a good discussion on the blog… Larry Where and why is a reverse profile barrel temperature used? My Response A reverse profile is typically used when processing materials such as nylon and LCP. In fact it is quite common for many semi-crystalline polymers. Basically, such polymers have […]