Influence of injection moulding parameters on resistance for cracking on example of PP

Purpose: Purpose of this paper is analysis of injection moulding conditions influence on fracture mechanics on example of PP. Design/methodology/approach: For the cracking tests, polypropylene with the commercial name Reslen manufactured by Polimarky has been used. Samples for the tests have been made by injection method on injection machine Krauss-Maffei with symbol KM65 – 160. The machine was equipped with high class control system with symbol C4. Variability of the four following parameters of injection process was taken into consideration: injection temperature, temperature of mould, pressure of closing and injection speed. It also should be reminded about analysis of correlation multidimensional, analysis Pareto enabling evaluation of weight of following entrance values in model comparing (regression), what is the base of optimal actions. Crack resistance examination were carried out using a special device allowing measurements of basic parameters of crack mechanics, such as: coefficients of stress intensity, gap divergence and J integral. Findings: On value of the integrity J being measure of crack resistance the biggest influence have the mould temperature and injection temperature. Research limitations/implications: Analysis of influence the values of following injection parameters for changing the crack resistance during dynamic bending for PP has been done in the future. Practical implications: The results of experiments will allow to determine the recommendations referring to the optimization of processing conditions, and as a result of this polymer will have high fracture resistance Originality/value: The samples for the test have been prepared on base of elaborated schedule. It has been prepared with help of specialist modulus DoE Design of Experiment from packet STATISTICA 6.0 PL.