Publicação
Behaviour of core and cavity inserts in injection moulding of high-performance polymers
| Resumo: | This dissertation project comes to conclude the Master in Polymer Engineering at University of Minho. Performed at Celoplás the work was based on the study of the behaviour of core and cavity inserts in injection moulding of high-performance polymers, specifically polyetherimide and polybutylene terephthalate, an amorphous and a semicrystalline polymer respectively. The primary objectives of this work focused on designing two prototype parts and the respective productive tool (mould), followed by the production of those parts, through injection moulding. The ultimate purpose was to assess wear in different types of steel chosen for the mould components. Variations were incorporated into the feeding system, part geometry, raw material, and processing conditions. Each factor was investigated at two levels: feeding system with both fan and tunnel designs (with different tunnel gate diameters), prototype part geometry, raw materials: PEI (ULTEM 1010 1000 NAT) and PBT (ULTRADUR B4406 G6 BLACK) and injection velocities (100 mm/s and 170 mm/s). The injection mould was designed to evaluate the deformation resistance properties of different steels. Therefore, the mould inserts were made from 1.2311, 1.2343, and 1.2083 steels to assess their performance simultaneously. Textured and polished finish surfaces were added to the cavity inserts in order to study their behaviour when submitted to the processing conditions of the mentioned raw materials. To analyse the effects of these factors on mould component wear, an experimental design (DOE) was employed, leading to the planning of eight injection trials. Through Moldex 3D, simulations were conducted to draw insights regarding filling behaviour, temperature distribution, and shear rates. The evaluation of wear on the mould components included visual inspection, optical analysis, and the measurement of surface roughness. Thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and capillary rheometry tests were performed on the raw materials. The capillary rheometry tests were also extended to the injected parts to evaluate the degradation of the processed material during the injection moulding tests. The results indicate that the type of steel significantly influenced wear, with 1.2311 steel exhibiting more wear compared to 1.2343. Injection velocity also played an important role, with higher velocities resulting in increased wear. Gate configuration affected wear, with the 0.85 mm and fan gates showing higher wear. PEI caused accentuated wear than PBT-GF30, on both core and cavity inserts. |
|---|---|
| Autores principais: | Costa, Cristiana Patrícia Marques da |
| Assunto: | High-performance polymers Injection moulding Steels Wear Aços Desgaste Moldação por injeção Polímeros de elevado desempenho |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso embargado |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | This dissertation project comes to conclude the Master in Polymer Engineering at University of Minho. Performed at Celoplás the work was based on the study of the behaviour of core and cavity inserts in injection moulding of high-performance polymers, specifically polyetherimide and polybutylene terephthalate, an amorphous and a semicrystalline polymer respectively. The primary objectives of this work focused on designing two prototype parts and the respective productive tool (mould), followed by the production of those parts, through injection moulding. The ultimate purpose was to assess wear in different types of steel chosen for the mould components. Variations were incorporated into the feeding system, part geometry, raw material, and processing conditions. Each factor was investigated at two levels: feeding system with both fan and tunnel designs (with different tunnel gate diameters), prototype part geometry, raw materials: PEI (ULTEM 1010 1000 NAT) and PBT (ULTRADUR B4406 G6 BLACK) and injection velocities (100 mm/s and 170 mm/s). The injection mould was designed to evaluate the deformation resistance properties of different steels. Therefore, the mould inserts were made from 1.2311, 1.2343, and 1.2083 steels to assess their performance simultaneously. Textured and polished finish surfaces were added to the cavity inserts in order to study their behaviour when submitted to the processing conditions of the mentioned raw materials. To analyse the effects of these factors on mould component wear, an experimental design (DOE) was employed, leading to the planning of eight injection trials. Through Moldex 3D, simulations were conducted to draw insights regarding filling behaviour, temperature distribution, and shear rates. The evaluation of wear on the mould components included visual inspection, optical analysis, and the measurement of surface roughness. Thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and capillary rheometry tests were performed on the raw materials. The capillary rheometry tests were also extended to the injected parts to evaluate the degradation of the processed material during the injection moulding tests. The results indicate that the type of steel significantly influenced wear, with 1.2311 steel exhibiting more wear compared to 1.2343. Injection velocity also played an important role, with higher velocities resulting in increased wear. Gate configuration affected wear, with the 0.85 mm and fan gates showing higher wear. PEI caused accentuated wear than PBT-GF30, on both core and cavity inserts. |
|---|