Influence of the thermomechanical properties on the joining of adhesion incompatible polymers by form-fit using the vibration welding process

Abstract

In the product manufacturing cycle, the joining of polymers often takes a central position. Vibration welding is characterized by short cycle times, high process flexibility and stability as well as by the achievement of high bond strengths without using additives. However, the vibration welding process is clearly restricted by a necessary adhesion compatibility of the joining partners. By means of structuring one joining partner and subsequent filling of the structures by a second joining partner, the joining by form-fit using vibration welding enables the combination of adhesion incompatible polymers. Within these investigations, bonds between adhesion incompatible semi-crystalline thermoplastics were generated based on mechanical adhesion. Also semi-crystalline and amorphous polymers could be connected for the first time without any connecting elements, although they conventionally do not show mechanical resilience. The analysis of the thermomechanical material properties and the resulting multimaterial link enabled the determination of first influences on the resulting formfit connection caused by the occurring joining zone temperature.

Separation of Multi-Material Polymer Combinations Produced by Joining Using Pin-like Structures

“…To avoid a deformation of the existing pin structures during the joining step, the bonding-partner should be flowable in a temperature range in which the structure-partner does not melt. In the case of PA66 as a structured-partner, this could be achieved in previous investigations using, for example, PE, PP, or PMMA as a bonding-partner [13,16]. A detailed description of the form-fit joining process using pin-like structures is shown in earlier investigations [16].…”

“…In the case of PA66 as a structured-partner, this could be achieved in previous investigations using, for example, PE, PP, or PMMA as a bonding-partner [13,16]. A detailed description of the form-fit joining process using pin-like structures is shown in earlier investigations [16].…”

“…In addition to the functionality and the high potential for joining incompatible semicrystalline thermoplastics [13,16] as well as for joining incompatible semi-crystalline and amorphous thermoplastics [16], first process correlations have been developed. The investigation of the thermomechanical properties shows a stability of the pin-like structures in the PA66 during the joining process for the material combination investigated in this study [16].…”

“…In addition to the functionality and the high potential for joining incompatible semicrystalline thermoplastics [13,16] as well as for joining incompatible semi-crystalline and amorphous thermoplastics [16], first process correlations have been developed. The investigation of the thermomechanical properties shows a stability of the pin-like structures in the PA66 during the joining process for the material combination investigated in this study [16]. Further investigations address the influence of the used structuring-tool geometry on the generation of the pin-like structures, their filling behavior during the joining process, as well as the resulting bond properties [14], and they allow first design criteria for the geometry of the pin-like structure in dependence on the used material combination [15].…”

Bonding strength calculation in multicomponent plastic processing technologies

“…Bonding between coupled thermoplastic parts in the case of all processing technologies is governed by fusion. It is the result of heat and pressure applied to the interface for a certain amount of time [11][12][13][14][15] . Therefore, the bonding strength (σ) between thermoplastic parts is generally a function of processing temperature (T), holding pressure (p), and processing time (t): σ = 𝑓 (𝑇, 𝑝, 𝑡).…”