The technology relates to a heat sealing system (400). For instance, the heat sealing system may include a sealer assembly (800) including a pair of heat sealing bars (830, 840) configured to generate heat seals. The heat sealing system may also include a positioning (900) assembly including a platform (910) and a motor (952). The sealer assembly may be mounted to the positioning assembly, and the motor may be configured to move the sealer assembly towards and away from an edge of a table (1600).