The influence of mold temperature on thermoset in-mold forming

2020 ◽  
Vol 40 (3) ◽  
pp. 256-266
Author(s):  
Tim Deringer ◽  
Dietmar Drummer
Keyword(s):  
Injection Molding ◽  
Bond Strength ◽  
Mechanical Performance ◽  
Mold Temperature ◽  
Short Fiber ◽  
Epoxy Compound ◽  
Fiber Reinforced ◽  
Continuous Fiber ◽  
New Process ◽  
One Step

AbstractA new process, called thermoset in-mold forming, for combining thermoset master forming and thermoset forming in one mold is in development. A pre-impregnated continuous-fiber reinforced sheet based on epoxy (prepreg) is formed in the injection molding machine, followed by instantaneous overmolding of a short-fiber reinforced epoxy compound in one step. Compared with conventional processes in which thermoset injection molding, prepreg compression molding, and hence curing of the materials are separated, the new process allows for the combination in one step and simultaneous curing of both components. The result is a hybrid component, which features a continuous-fiber reinforced part for higher mechanical performance and a short-fiber reinforced part with high design freedom for integration of additional functions. For a successful combination of both materials in one process, it is essential to investigate the bond strength between them in relation to the processing parameters and their influence on the degree of cure. This paper analyzes the influence of the mold temperature in this process on curing degree, bond strength, and the processing viscosity.

Effect of Processing Conditions on the Shrinkage and Warpage of Glass Fiber Reinforced PP Using Microcellular Injection Molding

2012 ◽  
Vol 501 ◽  
pp. 294-299 ◽  
Author(s):  
Zhi Bian ◽  
Peng Cheng Xie ◽  
Yu Mei Ding ◽  
Wei Min Yang
Keyword(s):  
Injection Molding ◽  
Glass Fiber ◽  
Injection Pressure ◽  
Mold Temperature ◽  
Process Conditions ◽  
Fiber Reinforced ◽  
Injection Speed ◽  
Glass Fiber Reinforced ◽  
Microcellular Injection Molding ◽  
Molded Parts

This study was aimed at understanding how the process conditions affected the dimensional stability of glass fiber reinforced PP by microcellular injection molding. A design of experiments (DOE) was performed and plane test specimens were produced for the shrinkage and warpage analysis. Injection molding trials were performed by systematically adjusting six process parameters (i.e., Injection speed, Injection pressure, Shot temperature, SCF level, Mold temperature, and Cooling time). By analyzing the statistically significant main and two-factor interaction effects, the results showed that the supercritical fluid (SCF) level and the injection speed affected the shrinkage and warpage of microcellular injection molded parts the most.

STABILIZATION OF TUFF MATERIAL BY ELECTROSPINNING OF LOW AREAL WEIGHT TPU VEIL MATERIAL

2021 ◽  
Author(s):  
JOSEPH DEITZEL ◽  
DIRK HEIDER ◽  
ROGER CRANE ◽  
TEKIN OZDEMIR
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Complex Geometry ◽  
Fiber Material ◽  
Short Fiber ◽  
Continuous Fiber ◽  
Forming Process ◽  
Fiber Volume ◽  
Carbon Fiber Material

The Tailored Universal Feedstock for Forming (TuFF) material is an aligned, discontinuous carbon fiber material with high fiber volume fraction up to 63% and mechanical performance equivalent to continuous fiber, unidirectional composites. The short fiber material allows at least 40% in-plane extension during processing enabling metal-like forming approaches simplifying composites manufacturing significantly. Traditionally, TuFF preforms are produced at areal weight (AW) of ~8 grams per square meter (gsm), stacked and impregnated with thermoset or thermoplastic polymer to create prepreg followed by curing/consolidation in an autoclave or stamp forming process resulting in high-performance structural parts. Here, the impregnated TuFF prepreg can be handled the same way as traditional continuous fiber prepreg. In contrast, to enable liquid composite molding (LCM) processes with TuFF material, the unimpregnated (dry) short fiber TuFF preforms must be stabilized for handling and preforming purposes. This paper details an electrospun veil approach as shown in Figure 1 to stabilize the individual TuFF sheets while maintaining the in-plane extensibility for complex geometry parts. Electrospun TPU fibers are applied onto the TuFF surface and then consolidated via a combination of heating and pressure, formingtrials were carried out using the stabilized preforms and composites werefabricated using LCM. Tensile tests show ~90-95% property retention versus theunstabilized baseline. The approach allows fabrication of stabilized TuFF fabricsfor the first time enabling the use of LCM processes for complex geometry parts.

Bond strength of fiber posts and short fiber-reinforced composite to root canal dentin following cyclic loading

2016 ◽  
Vol 31 (13) ◽  
pp. 1397-1407 ◽  
Author(s):  
Emre Nagas ◽  
Isil Cekic-Nagas ◽  
Ferhan Egilmez ◽  
Gulfem Ergun ◽  
Pekka K. Vallittu ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Bond Strength ◽  
Root Canal ◽  
Short Fiber ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Fiber Posts ◽  
Reinforced Composite ◽  
Root Canal Dentin

scholarly journals Mechanical Performance of Additively Manufactured Fiber-Reinforced Functionally Graded Lattices

JOM ◽  
2019 ◽  
Vol 72 (3) ◽  
pp. 1292-1298 ◽  
Author(s):  
János Plocher ◽  
Ajit Panesar
Keyword(s):  
Energy Absorption ◽  
Mechanical Performance ◽  
Weight Ratio ◽  
Short Fiber ◽  
Functionally Graded ◽  
Fused Deposition Modelling ◽  
Valuable Insight ◽  
Fiber Reinforced ◽  
Fused Deposition ◽  
Unit Cells

AbstractLatticing has become a common design practice in additive manufacturing (AM) and represents a key lightweighting strategy to date. Functional graded lattices (FGLs) have recently gained immense traction in the AM community, offering a unique way of tailoring the structural performance. This paper constitutes the first ever investigation on the combination of graded strut- and surface-based lattices with fiber-reinforced AM to further increase the performance-to-weight ratio. The energy absorption behavior of cubic lattice specimens composed of body-centered cubic and Schwarz-P unit cells with different severities of grading but the same mass, considered for uniaxial compression testing and printed by fused deposition modelling of short fiber-reinforced nylon, were investigated. The results elucidate that grading affects the energy absorption capability and deformation behavior of these lattice types differently. These findings can provide engineers with valuable insight into the properties of FGLs, aiding targeted rather than expertise-driven utilization of lattices in design for AM.

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