The reliability of joints in plastic assemblies depends strongly on the interaction between material behavior,

joining technique, and loading conditions. In this study, Engineering components made from PMMA and PC-

ABS were joined using two different methods: laser welding and adhesive joining. The objective is not a full

comparative evaluation, but rather to understand the joint formation mechanisms and assess their mechanical

response under typical service-level loading. This study primarily focuses on numerical simulation. However,

Polymethyl methacrylate and Polycarbonate-Acrylonitrile Butadiene Styrene are widely adopted in the

automotive industry, particularly for interior and exterior trim components, due to their balanced combination of

mechanical strength, dimensional stability, and surface quality. PMMA offers excellent optical clarity and scratch

resistance, making it suitable for decorative trims, light guides, and transparent covers. PC-ABS, on the other

hand, provides high impact resistance and good thermal stability, which are essential for parts exposed to varying

environmental conditions within the vehicle. Because these materials often appear together in automotive

assemblies, understanding how to effectively join PMMA and PC-ABS is crucial for achieving reliable structural

and aesthetic performance.

This study focuses on joining PMMA and PC-ABS components using laser welding and adhesive Plexus

For the knowledge of various plastic joining methods, I have studied different research papers. The behaviour of

the plastics and their properties are studied and analyzed. There are various joining methods available, such as

Mechanical joining, Adhesive joining, and Welding processes.

Grewell, D., Benatar, A. (2007), et al [1] provide information on the welding processes which are widely used

in the current automotive market, such as Friction welding, Hot plate welding, ultrasonic welding, Laser welding,

RF welding, and Hot gas welding.

Ries, M. (2024), et al [9] author discussed regarding the adhesive joint and modeling of complex behaviour of

the polymeric adhesive. Molecular dynamics and continuum approach are employed to understand the complex

behaviour of the polymer adhesive.

a pathway to lightweight automotive structures.Also, emphasized methods to evaluate and regulate joint quality,

focusing on interface bonding and mechanical reliability.

An explicit analysis was performed to investigate the adhesive bond strength between two thermoplastic

materials, Polymethyl methacrylate (PMMA) and PolycarbonateAcrylonitrile Butadiene Styrene (PC-ABS). The

study was carried out using the CAE solver LS-DYNA R12, with HyperMesh 2022.2 as the pre-processor for

geometry

Fig. 1. Dimensions of the plastic component

capture debonding and progressive failure under applied loading conditions. The results obtained from the

simulation are presented, highlighting Force-Displacement responses and failure characteristics. In addition,

graphs were plotted and shown to illustrate the comparative bond strength between PC-ABS and PMMA,

providing clear insight into adhesive performance under the chosen loading scenario.

Both components are modelled as hollow cuboidal structures, as shown in Fig. 1. The Dimensions of each cuboid

are 45 mm × 15 mm × 2.5 mm, with the PMMA block positioned at the bottom and the PC-ABS block placed

directly above. In the simulation environment, the PMMA cuboid is constrained to the base to represent its

attachment to the vehicle structure, whereas the PC-ABS cuboid is fixed to the top boundary.

interface is modelled according to the expected fusion characteristics of PMMA and PC-ABS under laser energy.

This configuration is again simulated in LS-DYNA to evaluate its mechanical response.

For both joining methods, only tensile (pull) strength and shear strength are considered. Loads are applied to the

PC-ABS component while the PMMA base remains fixed, enabling the study of joint performance under

controlled boundary conditions.

Fig. 4. Tensile load simulation results of Adhesive-bonded PMMA and PCABS Plastics

The material properties of both Polymethyl methacrylate and Polycarbonate-Acrylonitrile Butadiene Styrene are

listed in Tables 3 and 4, while the properties of adhesive Plexus MA3940LH are referred to.[8]

TABLE III Properties Of Polymethyl Methacrylate

Tensile load simulation test results of adhesive joint areshown below in Fig. 4 and graphical values in Fig. 5.

Also, the Tensile load simulation results of the welded joint are shown in Fig. 6 and graphical values in Fig. 7.

The tensile test results show a major difference in joint performance, with the adhesive bond reaching 1516.8 N.

(Fig. 5) while the weld joint withstands 4073.1 N (Fig. 7).

This indicates that the Laser-welded interface creates a much

Fig. 5. Tensile Force(N) vs Displacement (mm)

Fig. 6.Tensile load simulation results of Laser-welded joined PMMA and

Fig. 9. shear Force(N) along X-direction vs Displacement (mm)

stronger load-bearing connection compared to the adhesive layer.

3517.7 N (Fig. 11). The large gap between these values suggests that welding provides better resistance against

lateral sliding forces.

In summary, the simulation outcomes indicate that laser welding offers superior strength and reliability for

PMMA and PC-ABS joints under both tensile and shear conditions. These findings provide a useful

computational basis for selecting appropriate joining strategies in polymer component design, particularly in

engineering applications where structural integrity and load resistance are critical.