The optimum melt quality for injection molding applications is to have at each location inside the polymer melt volume, just prior to injection, a well mixed/uniform concentration of colorant and additives and the same melt temperature. The mixing performance of static mixers have been investigated in laboratories, compared to each other and compared in many thousands of field applications. In these tests, comparisons were made of the degree of mixing at the inlet of the static mixer and at the outlet of the static mixer. Based on these measurements, a Homogeneity Improvement Factor per mixing element can be calculated. The Homogeneity Improvement Factor is defined as follows and is visualized in Figure #3. Figure # 3: Mixing of Blue and White resin (~1:1 volumetric ratio) is demonstrated through a standard eight (8) mixing element assembly used in the PolymMIXER Mixing Nozzle. As shown, the mix quality increases dramatically after mixing element where each adjacent mixing elements are oriented 90 o . Table #1: Homogeneity Improvement Factor (Mixing Efficiency) of PolymMIXER SMN Mixing Elements. As shown in Table #1, Column , we will assume a melt stream entering the static mixer shows a 10%. Relative Standard Deviation of colorant/additive concentration from the mean value. After passing through a standard PolymMIXER 8-mixing element assembly, the concentration difference will decrease to ~1.7% at the mixer outlet (a 6-fold decrease per Column with calculation 10%/6=~1.7%). With 10-mixing elements, a ~1% deviation will result (a 10-fold decrease) and with 12-mixing elements, a ~0.6% deviation will result (a 16-fold decrease). In most applications, the standard 8-mixing element assembly is satisfactory. An example of a part made without and with a static mixer is shown in the image below. Distribution of a 2% Master Batch with and without a static mixer in an injection molded red cap approximately 6 inches in diameter. Machine settings are identical.