Material Degradation
Gradual loss of the piezoelectric properties in lead zirconate titanate ceramics occurs after billions of electrical cycles. This pzt crystal fatigue reduces the ability of the actuator to flex and generate the pressure needed for ink ejection. Over time, the drops produced by a tired crystal become smaller or slower, leading to a loss of print density.
Mechanical Breakdown
Microscopic changes in the crystalline structure are permanent and cannot be reversed by cleaning. As pzt crystal fatigue progresses, the electrical voltage required to achieve the mechanical movement must be increased. Eventually, the material reaches a point where it can no longer function within the specifications of the printhead.
Performance Impact
Subtle shifts in color saturation are often the first sign that a machine is reaching this stage. Because pzt crystal fatigue does not happen to all nozzles at the same rate, it can create a mottled or uneven appearance on the fabric. High volume mills track the total number of firings to predict when this wear will begin to affect the commercial quality of their output.
Lifespan Factors
Operational choices such as the use of high viscosity inks or extreme jetting frequencies accelerate the aging process. Managing the load on the printhead is the only way to slow down the onset of pzt crystal fatigue. Once the crystals are spent, the entire printhead must be replaced to restore the original performance of the machine.
Monitoring pulse counts is the most effective method for predicting when this fatigue will occur.
