Author(s):
1. Sara Srebrenkoska, Faculty of Mechanical Engineering, Goce Delcev University, Krste Misirkov, No. 10-A Stip, Republic o, Macedonia
2. Vineta Srebrenkoska, University “Goce Delčev”, Štip, Faculty of Technology, Macedonia
3. Svetlana Risteska, University of St.Kliment Ohridski Bitola, Faculty of Economics - Prilep, Macedonia

Abstract:
Thermoplastic composites are ideal materials for aerospace, automotive and other industries where the use of high-performance advanced materials directly enhances their capability. Automated manufacturing is widely used to manufacture advanced composite laminates from unidirectional prepregs. Unidirectional (UD) continuous fiber reinforced tapes with high fiber content are used as semi-finished material. These tapes are usually fully impregnated and consolidated. Within the thermoplastic tape placement process, tapes are melted by a heat source like, laser beam, infrared light, hot gas torch, and bonded to laminates by compaction force induced by a consolidation roller. During consolidation step, the tapes are cooled down to tool temperature. In this study, we have produced unidirectional laminates from carbon UD thermoplastic tapes with different matrices: PEEK, PPS, PEKK and by using of laser assisted automate tape laying process (LATL). Automated Fiber Placement (AFP) and Automated Tape Laying (ATL) are the two main technologies that are used to make composite parts. Both processes use robotic system to lay one or several layers of uunidirectional prepreg tape onto a tool to manufacture a part. Each layer can be laid with different orientation, which benefits a structure capable to carry load in their required direction. Each tape is pressed to the mould by a roller for proper compaction. LATL consists of three main steps: impregnation, consolidation and crystallinity. Impregnation is a parameter that cannot be controlled by automatic fiber/tape laying while consolidation and crystallinity can be controlled. Consolidation consists of two sub-processes: intimate contact and autohesion. To achieve better final characteristics of the thermoplastic composite it is necessary to achieve a good degree of intimate contact and good self-connection. This paper examines the impact of compaction roller on several types of thermoplastic matrices that have different flows after melting. The aim is to reduce the percentage of pores in the lamina that is present in the material itself, because process parameters cannot reduce the voids in the tape that has the raw material itself. The results show that the compaction roller in the LATP process for given materials reduces the percentage of pores present in the laminate of the raw material. This is another reason that the impregnation of the prepreg used in this technology is a key part of the final product. After a good selection of technological processes, the composite laminates were manufactured using LATL (in-situ laser assisted tape laying). The carbon fiber volume fraction was 60% in the CF/PPS laminate/ CF/PEEK laminate and CF/PEKK laminate. Then the composite laminates were cut into a specimen by a water-cooled diamond saw, for mechanical characterisation. In this study, flexural strength tests were used to determine the bonding strength of tape with laser. For all three types of laminate plates, it has been found that the processing temperature and the compact pressure of the roller significantly influence on the flexural strength of the laminate plates. This research will present and discuss some of laser control system variables and final properties of flat panel specimens, manufactured with conventional LATL process. Following the experiments, the damage and fracture morphologies of composite specimens after failure were examined by scanning electron microscope (SEM).

Key words:
thermoplastic prepreg,automated tape laying,automated fiber placement,interlaminated bonding,flexural strength,scanning microscopy.

Thematic field:
SYMPOSIUM A - Science of matter, condensed matter and physics of solid states

Date of abstract submission:
28.06.2024.

Conference:
Contemporary Materials 2024 - Savremeni Materijali

Applied paper from author