A method and apparatus for making pouches is disclosed. It includes using one or more of the following features: using two servo motors to drive a platen, providing a calibration routine is run at start-up and/or after the machine has been operating; controlling in response to feed back from the servo motor(s) such as feedback indicative of the distance the platen travels; the feedback is not of force exerted by the platen; and/or the platen is controlled to prevent unacceptable fracturing of the film laminate.

A thermal welder is configured to weld a back seam of a bag formed of thermoplastic sheet material. The welder may include a weld heater and a compression mechanism downstream of the weld heater to compress the sheet material to form the back seam. The welder may also include a weld breaker downstream of the compression mechanism to break apart incidental welds which are formed adjacent the back seam.

A method and apparatus for making pouches is disclosed. It includes using one or more of the following features: using two servo motors to drive a platen, providing a calibration routine is run at start-up and/or after the machine has been operating; controlling in response to feed back from the servo motor(s) such as feedback indicative of the distance the platen travels; the feedback is not of force exerted by the platen; and/or the platen is controlled to prevent unacceptable fracturing of the film laminate.

A thermal welder is configured to weld a back seam of a bag formed of thermoplastic sheet material. The welder may include a weld heater and a compression mechanism downstream of the weld heater to compress the sheet material to form the back seam. The welder may also include a weld breaker downstream of the compression mechanism to break apart incidental welds which are formed adjacent the back seam.

A thermal welder is configured to weld a back seam of a bag formed of thermoplastic sheet material. The welder may include a weld heater and a compression mechanism downstream of the weld heater to compress the sheet material to form the back seam. The welder may also include a weld breaker downstream of the compression mechanism to break apart incidental welds which are formed adjacent the back seam.

A gusset bag is formed of a pair of flat surface parts facing each other, and side gusset parts folded to the inside of the bag. The gusset bag has side heat-sealing portions at which the sides of the flat surface part and sides of the side gusset parts are joined at the inner surfaces thereof, side heat-sealing portions at which the sides of the flat surface part and the other sides of the side gusset parts are joined at the inner surfaces thereof, and closing sealing portions at which the side heat-sealing portions and the side heat-sealing portions are joined at the outer surfaces of the side gusset parts by ultrasonic sealing. With this configuration, in the gusset bag, it is possible to easily close the gusset parts, while preventing film pieces or dust from entering the bag in a step of closing the gusset parts.