Haft- und Entformungskräfte beim Spritzgießen in Abhängigkeit von Stahlwerkstoff, Oberflächenstruktur, Beschichtung und Kunststofftyp
Research output: Thesis › Master's Thesis
The adhesion and demolding forces in injection molding are influenced by the molded part design, the mold surface, the mold material, the processing conditions and the polymer. To evaluate these influences systematically, a measurement apparatus, designed as an injection mold with included friction test, was built. The development and the design of this mold was part of the multi-firm project 3.2 at the Polymer Competence Center Leoben (PCCL). Polymer specimens, made of various amorphous and semi-cristalline polymers (PP, ABS, ABS/PC, PC, POM, TPE), were injected using the measurement apparatus. During demolding the polymer specimen, a friction test was performed. The used cavity inserts were made of stainless steel Böhler M333 Isoplast plastic mold steel. The influences of mold surface structure, PVD-coating of mold surface, vertical force during the friction test and cooling temperature on the demolding behavior were evaluated. The static coefficient of friction was used to determine the influences mentioned above. The static coefficient of friction is calculated as quotient of the demolding force peak value measured and the set vertical force. The mold surface structure, the surface roughness and the cooling temperature show the greatest influence on the demolding behavior. The static coefficient of friction decreases with increasing cooling temperature, and decreases with increasing surface roughness in the examined range of Ra = 16 nm to Ra = 311 nm. The static coefficient of friction is slightly influenced by the contact pressure value, in most cases it remains constant. The influence of PVD-coatings (TiN, CrN, TiAlN) is dependent on the used polymer.
|Translated title of the contribution||Demolding forces in injection molding as a function of steel grade, surface structure, PVD-coating and polymer|
|Award date||19 Dec 2008|
|Publication status||Published - 2008|