When troubleshooting dimensional is

When troubleshooting dimensional issues it is important to verify that the correct pressure is being supplied to the cavity. One often-overlooked problem area is the nozzle tip. If the wrong tip is being used the pressure drop from the machine will be higher. Care must be taken to ensure that the correct orifice is used as well as the correct style (i.e., nylon versus general purpose). Nozzle tip orifice and style must be documented and matched every time with the mold. Figure 26.4 shows a cavity pressure comparison between the same process running with a general-purpose 3/16-in tip and a general-purpose 5/32-in tip. On this process a one-size change in tip orifice had a huge impact on the plastic conditions. Tip orifice cannot be taken for granted, ever!