US 2018/0043388 A1 · PNEUMATICALLY-DRIVEN JETTING VALVES WITH VARIABLE DRIVE PIN VELOCITY, IMPROVED JETTING SYSTEMS AND IMPROVED JETTING METHODS

Abstract

An improved pneumatic jetting valve includes a housing with first and second chambers. A pneumatic piston is enclosed between the chambers. First and second solenoid valves are configured to respectively supply air pressure to the chambers and to exhaust the chambers. A controller is operable to regulate the pressurization and venting of the chambers. The controller controls the timing of control signals for the first and second solenoid valves to control the overlap time during which both the first and second chambers are pressurized. By controlling this overlap time, the controller controls the speed of the drive pin of the jetting valve and thereby the speed at which the valve closes to jet a droplet of material. This allows a valve speed to be selected that is most appropriate for the viscosity of the material being jetted. Numerous new methods for utilizing the improved jetting valve and system are disclosed.

Claims20

Dependent claims

A method for jetting droplets of material onto a substrate using a system having a jetting device and a controller, the jetting device having a pneumatically driven piston that causes movement of a valve element into contact with a valve seat to jet a droplet of material, wherein the jetting device has upper and lower piston chambers on opposite sides of the piston that are controlled by independent solenoid valves, the method comprising:

providing a user interface that the user can use to vary the speed of the valve element;
accepting an input from the user at the user interface;
and
using that input to control the speed of the valve element by controlling the solenoids to provide a desired overlap time period during which compressed air is supplied to both the upper and lower piston chambers at the same time.

1 more element

A method for jetting droplets from a pneumatically actuated jetting device by controlling the speed of a drive pin of a jetting device through a controller, wherein the drive pin is fixed to a piston that is reciprocated by compressed air that is supplied to first and second air chambers that are located above and below the piston, and wherein movement of the drive pin in a first direction moves the drive pin towards a valve seat of a fluid chamber at a drive pin velocity to cause a valve element within the fluid chamber to strike the valve seat and jet a droplet of material through a nozzle orifice that is in fluid communication with the fluid chamber, and wherein movement of the piston and drive pin in a second direction opposite to the first direction allows the valve element to retract away from the valve seat, the method comprising:

maintaining the valve in a closed position with the valve element forced against the valve seat;
after maintaining the valve in the closed position, connecting the first air chamber on one side of the piston to a supply of compressed air at a time T1 to move the piston, drive pin and valve element in the second direction to allow the valve element to retract away from the valve seat and allow fluid material to flow into the valve seat;
at a time T2 that is after T1, connecting the second chamber on the opposite side of the piston to a supply of compressed air, to move the piston, drive pin and valve element in the first direction towards the valve seat;
at a time T3 that is after T2, disconnecting the first air chamber from the supply of compressed and allowing pressure in the first air chamber to be vented;
and
at a time T4 that is after T3, disconnecting the second chamber from the supply of compressed air and allowing pressure in the second chamber to be vented, wherein the time period between T2 and T3 comprises an overlap period during which both the first chamber and the second chamber are connected to a supply of compressed air, and wherein the duration of the overlap period is utilized to control the drive pin velocity of the drive pin while it moves in the first direction towards the valve seat.

3 more elements

Dependencies are inferred from the claim text.

Pneumatically-driven jetting valves with variable drive pin velocity, improved jetting systems and improved jetting methods

Life of this patent

Pneumatically-driven jetting valves with variable drive pin velocity, improved jetting systems and improved jetting methods

Life of this patent

Abstract

Claims20