The StepDot valve enables high speed dispensing of solder paste and other high viscous materials, such as silver-filled epoxies and non-conductive bonding adhesives. The “macro” movement of the machine head with the “micro” movement of the StepDot valve creates an innovative hybrid drive. The z axis movement of the nozzle over the dispensing point is executed by the valve allowing continuous movement of the robot head during the dispensing process. This ”on the fly” capability is 15 times faster than traditional needle dispensing and achieves speeds of 100 dots per second at a dot pitch of 0.2 to 0.4 mm.
The small shifts in the x, y and z axes allow the valve to “step” in multiple directions (sideways, forwards, backwards) and to perform the critical dispensing movement at high frequencies. Both symmetrical and asymmetrical BGA patterns can be achieved as well as discrete dot patterns for passive devices. ”Dot on demand” parameters allow for dynamic adjustment of dot size for different sized components and optimization of PCB dispensing patterns where warping and planarity are an issue.
High-speed video of StepDot dispensing T6 solder paste on-the-fly at 90 dots/second
Dispensed T6 solder paste on-the-fly at 90 Hz
Dispensed T6 Solder Paste Dot Size Distribution