TY  - JOUR
A1  - Kessler, Julia
A1  - Balc, Nicolae
A1  - Gebhardt, Andreas
A1  - Abbas, Karim
T1  - Basic Research on Lattice Structures Focused on the Tensile Strength
JF  - Applied Mechanics and Materials
Y1  - 2015
U6  - http://dx.doi.org/10.4028/www.scientific.net/AMM.808.193
SN  - 1662-7482
N1  - MTeM ; October 14-16, 2015, Cluj-Napoca, Romania
VL  - Vol. 808
SP  - 193
EP  - 198
PB  - Trans Tech Publications
CY  - Bäch
ER  - 
TY  - CHAP
A1  - Kessler, Julia
A1  - Balc, Nicolae
A1  - Gebhardt, Andreas
A1  - Abbas, Karim
T1  - Basic research on lattice structures focused on the reliance of the cross sectional area and additional coatings
T2  - The 4th International Conference on Computing and Solutions in Manufacturing Engineering 2016 – CoSME’16
Y1  - 2017
U6  - http://dx.doi.org/10.1051/matecconf/20179403008
N1  - MATEC Web Conf. Vol 94, 2017, 03008
MATEC Web of Conferences 94, 03008 (2017)
ET  - Vol. 94
ER  - 
TY  - JOUR
A1  - Abbas, Karim
A1  - Balc, Nicolae
A1  - Bremen, Sebastian
A1  - Skupin, Marco
T1  - Crystallization and aging behavior of polyetheretherketone PEEK within rapid tooling and rubber molding
JF  - Journal of Manufacturing and Materials Processing
N2  - In times of short product life cycles, additive manufacturing and rapid tooling are important methods to make tool development and manufacturing more efficient. High-performance polymers are the key to mold production for prototypes and small series. However, the high temperatures during vulcanization injection molding cause thermal aging and can impair service life. The extent to which the thermal stress over the entire process chain stresses the material and whether it leads to irreversible material aging is evaluated. To this end, a mold made of PEEK is fabricated using fused filament fabrication and examined for its potential application. The mold is heated to 200 ◦C, filled with rubber, and cured. A differential scanning calorimetry analysis of each process step illustrates the crystallization behavior and first indicates the material resistance. It shows distinct cold crystallization regions at a build chamber temperature of 90 ◦C. At an ambient temperature above Tg, crystallization of 30% is achieved, and cold crystallization no longer occurs. Additional tensile tests show a decrease in tensile strength after ten days of thermal aging. The steady decrease in recrystallization temperature indicates degradation of the additives. However, the tensile tests reveal steady embrittlement of the material due to increasing crosslinking.
KW  - additive manufacturing
KW  - fused filament fabrication
KW  - crystallization
KW  - polyetheretherketone
KW  - rapid tooling
Y1  - 2022
U6  - http://dx.doi.org/10.3390/jmmp6050093
SN  - 2504-4494
N1  - The article belongs to the Special Issue Advances in Injection Molding: Process, Materials and Applications
VL  - 6
IS  - 5
SP  - 1
EP  - 12
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Abbas, Karim
A1  - Hedwig, Lukas
A1  - Balc, Nicolae
A1  - Bremen, Sebastian
T1  - Advanced FFF of PEEK: Infill strategies and material characteristics for rapid tooling
JF  - Polymers
N2  - Traditional vulcanization mold manufacturing is complex, costly, and under pressure due to shorter product lifecycles and diverse variations. Additive manufacturing using Fused Filament Fabrication and high-performance polymers like PEEK offer a promising future in this industry. This study assesses the compressive strength of various infill structures (honeycomb, grid, triangle, cubic, and gyroid) when considering two distinct build directions (Z, XY) to enhance PEEK’s economic and resource efficiency in rapid tooling. A comparison with PETG samples shows the behavior of the infill strategies. Additionally, a proof of concept illustrates the application of a PEEK mold in vulcanization. A peak compressive strength of 135.6 MPa was attained in specimens that were 100% solid and subjected to thermal post-treatment. This corresponds to a 20% strength improvement in the Z direction. In terms of time and mechanical properties, the anisotropic grid and isotropic cubic infill have emerged for use in rapid tooling. Furthermore, the study highlights that reducing the layer thickness from 0.15 mm to 0.1 mm can result in a 15% strength increase. The study unveils the successful utilization of a room-temperature FFF-printed PEEK mold in vulcanization injection molding. The parameters and infill strategies identified in this research enable the resource-efficient FFF printing of PEEK without compromising its strength properties. Using PEEK in rapid tooling allows a cost reduction of up to 70% in tool production.
KW  - polyetheretherketone (PEEK)
KW  - rapid tooling
KW  - infill strategy
KW  - compression behavior
KW  - additive manufacturing
KW  - fused filament fabrication
Y1  - 2023
U6  - http://dx.doi.org/10.3390/polym15214293
N1  - This article belongs to the Special Issue "Polymer Materials and Design Processes for Additively Manufactured Products"
VL  - 2023
IS  - 15
PB  - MDPI
CY  - Basel
ER  -