Dispensing

Dispensing cells lay down a bead or dot of adhesive, sealant, RTV, grease, or another liquid along a programmed path. The robot moves the applicator at a set speed while a metering pump or valve controls flow, and the goal is a bead of consistent width and height from start to end.

Selection turns on repeatability at the tool center point and how tightly path speed can be held. Corners and radius changes are where beads get thick or thin, so the cell needs enough acceleration margin to stay on program speed through curves rather than dropping and recovering.

The applicator drives most of the process. Auger valves suit medium-viscosity adhesives, jet valves shoot dots without dragging the tip, and static-mix nozzles handle two-part epoxies with a scheduled purge between shots. Applicator tip changeover matters when the cell runs multiple materials in a shift.

Path speed and flow rate have to move together. Speed up the tool without adjusting flow and the bead thins; slow down and it puddles or strings at the endpoint. Getting that ratio right on curves is the most common tuning problem, and a fixed flow calibration that worked at 250 mm/s won't behave the same at 100 mm/s through a tight radius.

Common failure modes: material cure in the nozzle after a line stop, air pockets in the pump that break the bead midway, and a tip that clips the part on approach and offsets by a millimeter for the rest of the run. A short purge and weigh station catches flow drift before it lands on a real part.

Compatibility limits: high-viscosity or particle-filled materials wear tips and valves fast and may need heated lines. Very small dots at high frequency start to argue for a dedicated jetting head over a general-purpose robot. Any two-part material without a scheduled purge routine will set inside the mixer.

On the floor: the FANUC M-20iD/25 handles mid-payload dispense heads on auto and appliance parts, Universal Robots UR5e shows up on smaller electronic and lighting assemblies, and the EPSON SCARA T6 covers flat-part dispensing on a table. Related: sealing, gluing, assembly.