Method and apparatus for dispensing material in a printer

• US 6,453,810 B1
• Filed: 11/08/1999
• Issued: 09/24/2002
• Est. Priority Date: 11/07/1997
• Status: Expired due to Term

• Current Assignee: KPS Special Situations Fund II, L.P.
• Original Assignee: Speedline Technologies Incorporated (Illinois Tool Works Inc.)
• Inventors: Balog, Robert, Rossmeisl, Mark, Freeman, Gary T.
• Primary Examiner(s): COLILLA, DANIEL JAMES
• Application Number:
  US09/435,727
• Time in Patent Office: 1,051 Days
• Field of Search: 101/123, 101/129, 101/114
• US Class Current: 101/123
• CPC Class Codes: B23K 2101/36 Electric or electronic devices
• CPC Class Codes: B23K 3/0607 Solder feeding devices
• CPC Class Codes: B23K 3/0692 with intermediary means for bringing solder on workpiece, e.g. rollers
• CPC Class Codes: H05K 2203/0126 Dispenser, e.g. for solder paste, for supplying conductive paste for screen printing or for filling holes
• CPC Class Codes: H05K 2203/0783 Using solvent, e.g. for cleaning; Regulating solvent content of pastes or coatings for adjusting the viscosity
• CPC Class Codes: H05K 2203/1105 Heating or thermal processing not related to soldering, firing, curing or laminating, e.g. for shaping the substrate or during finish plating
• CPC Class Codes: H05K 3/1233 Methods or means for supplying the conductive material and for forcing it through the screen or stencil
• CPC Class Codes: H05K 3/3485 Applying solder paste, slurry or powder thick film methods for applying conductive paste or ink patterns H05K3/12

Abstract

A printer for printing a viscous material at predetermined positions forming a pattern on a substrate. The printer includes a frame, a device, mounted to the frame, having a number of perforations arranged to form the pattern, a support apparatus, coupled to the frame, that supports the substrate in a printing position beneath the device, and a material dispenser. The material dispenser has a chamber to contain the viscous material to be printed on the substrate. The chamber has an opening through which the viscous material is dispensed. The material dispenser is coupled to the frame, positioned over the device, and constructed and arranged to dispense the viscous material through the perforations in the device and onto the substrate. The material dispenser has a retraction device that prevents leakage of the viscous material from the opening after dispensing is complete. The material dispenser includes a temperature control system.

Claims

1. A printer for printing a viscous material at predetermined positions forming a pattern on a substrate, the printer comprising:

a frame;

a device, mounted to the frame, having a number of perforations arranged to form the pattern;

a support apparatus, coupled to the frame, that supports the substrate in printing position beneath the device;

a material dispenser having a chamber to contain the viscous material to be printed on the substrate, the chamber having an opening through which the viscous material is dispensed, the material dispenser being coupled to the frame, positioned over the device, and constructed and arranged to dispense the viscous material through the perforations in the device and onto the substrate, the material dispenser having a retraction device that prevents leakage of the viscous material from the opening after dispensing is complete, the material dispenser further having at least one port and a removable cartridge coupled to the port, the removable cartridge containing material to be dispensed and having an inlet to receive pressurized air to force material from the cartridge through the port and out of the opening of the chamber; and

a temperature control system to control the temperature of the viscous material contained in the chamber.

2. The printer of claim 1, wherein the temperature control system comprises:

a temperature sensor disposed on the material dispenser to measure temperature of the viscous material contained in the chamber, and a controller coupled to the temperature sensor to control a temperature of a heating and cooling element disposed in the chamber to maintain the temperature of the viscous material at a desired value.

3. The printer of claim 2, wherein the heating and cooling element is an elongated conduction rod disposed in the chamber having a first terminal end and a second terminal end and of a length sufficient to control temperature of the viscous material contained within the chamber.

4. The printer of claim 3, further comprising a first thermoelectric device coupled to the controller and disposed at a first terminal end of the conduction rod to control the temperature of the conduction rod.

5. The printer of claim 4, further comprising a first thermal block coupled between the first thermoelectric device and the conduction rod to transfer heat to the conduction rod from the first thermoelectric device.

6. The printer of claim 5, further comprising a second thermoelectric device coupled to the controller and disposed at a second terminal end of the conduction rod to control the temperature of the conduction rod.

7. The printer of claim 6, further comprising a second thermal block coupled between the second thermoelectric device and the conduction rod to transfer heat to the conduction rod from the second thermoelectric device.

8. The printer of claim 7, further comprising a heat exchanger coupled to each of the first and second thermoelectric devices and having a fan mounted thereon for cooling.

9. The printer of claim 1, wherein the material dispenser includes at least one port to receive pressurized air to provide pressure to the chamber to force the viscous material through the opening of the chamber.

10. The printer of claim 1, wherein the material dispenser includes a pressure control system to control on a real-time basis the pressurized air delivered to the cartridge to maintain the pressure with which the viscous material is forced from the cartridge and to maintain the pressure in the chamber at a desired value during dispensing.

11. The printer of claim 10, wherein the pressure control system comprises:

a pressure sensor to measure the pressure in the chamber at at least one time interval as the material dispenser moves along a first axis across the device during dispensing; and

a programmable regulator coupled to the pressure sensor to receive real-time pressure values, wherein the programmable regulator maintains or adjusts after the at least one time interval an amount of pressurized air delivered to the cartridge to maintain the pressure at which the viscous material is forced from the cartridge and to maintain the pressure in the chamber at the desired value.

12. The printer of claim 11, wherein the at least one time interval at which the pressure in the chamber is measured by the pressure sensor is approximately at least 25 milliseconds.

13. The printer of claim 11, further comprising a bracket mounted to the frame of the printer having at least a first connector constructed and arranged to receive at least a second connector attached to the material dispenser which receives pressurized air from the programmable regulator of the printer, wherein removal of the second connector from the first connector permits the pressure control system to be disconnected from the material dispenser.

14. The printer of claim 1, wherein the removable cartridge is connected to the material dispenser by a removable fitting which includes a smooth insert having a spring-biased plunger, the insert configured and arranged for insertion into a port with smooth side wall surfaces disposed in a portion of the material dispenser above the chamber, and the plunger configured and arranged to couple to a pad disposed above the port to achieve a secure connection to the material dispenser.

15. A printer for printing a viscous material at predetermined positions forming a pattern on a substrate, the printer comprising:

a frame;

a device, mounted to the frame, having a number of perforations arranged to form the pattern;

a support apparatus, coupled to the frame, that supports the substrate in printing

position beneath the device;

a material dispenser having a chamber to contain the viscous material to be printed on the substrate, the chamber having an opening through which the viscous material is dispensed, the material dispenser being coupled to the frame, positioned over the device, and constructed and arranged to dispense the viscous material through the perforations in the device and onto the substrate, the material dispenser further having at least one port and a removable cartridge coupled to the port, the removable cartridge containing material to be dispensed and having an inlet to receive pressurized air to force material from the cartridge through the port and out of the opening of the chamber; and

a device to prevent leakage of the viscous material from the chamber after the material dispenser is lifted from the substrate.

16. The printer of claim 15, wherein the device to prevent leakage of the viscous material from the chamber is a blocking assembly disposed in the chamber which includes a mounting bracket to couple the blocking assembly to the chamber and at least one plug mounted thereon to conform to an upper portion of the chamber.

17. The printer of claim 15, wherein the device to prevent leakage of the viscous material from the chamber is a material holding plate disposed in the chamber which includes an elongate, planar member having an upper surface and a lower surface with a plurality of through-holes.

18. The printer of claim 15, wherein the material dispenser further includes a pressure control system to control on a real-time basis the pressurized air delivered to the cartridge to maintain the pressure with which the viscous material is forced from the cartridge and to maintain the pressure in the chamber at a desired value during dispensing.

19. The printer of claim 18, wherein the pressure control system comprises:

a pressure sensor to measure the pressure in the chamber at at least one predetermined time interval as the material dispenser moves along a first axis across the device during dispensing; and

a programmable regulator coupled to the pressure sensor to receive real-time pressure values, wherein the programmable regulator controller maintains or adjusts after the predetermined time interval an amount of pressurized air delivered to the cartridge to maintain the pressure at which the viscous material is forced from the cartridge and to maintain the pressure in the chamber at the desired value.

20. The printer of claim 19, wherein the at least one time interval at which the pressure in the chamber is measured by the pressure sensor is approximately at least 25 milliseconds.

21. A method of controlling temperature of a viscous material to be printed by a material dispenser of a printer at predetermined positions on a substrate forming a pattern, the material dispenser being constructed and arranged to print the viscous material on the substrate and having a chamber in which the viscous material is contained with an inlet to receive the viscous material and an opening through which the viscous material is dispensed to the substrate, the method comprising the steps of:

measuring a temperature of the viscous material contained in the chamber of the material dispenser;

detecting a differential between a value of the measured temperature and a value of a desired temperature; and

adjusting the temperature of the viscous material by applying a sufficient amount of heat to a conduction rod disposed within the chamber to maintain the desired temperature; and

reducing the temperature of the viscous material to maintain the desired temperature by removing a sufficient amount of heat from the conduction rod by forced convection.

22. The method of claim 21, wherein temperature of the viscous material contained in the chamber is controlled to +/−

0.2°

C. of a desired value.

23. A printer for printing a viscous material at predetermined positions forming a pattern on a substrate, the printer comprising:

a frame;

a device, mounted to the frame, having a number of perforations arranged to form the pattern;

a support apparatus, coupled to the frame, that supports the substrate in printing

position beneath the device;

a material dispenser having a chamber to contain the viscous material to be printed on the substrate, the chamber having an opening through which the viscous material is dispensed, the material dispenser being coupled to the frame, positioned over the device, and constructed and arranged to dispense the viscous material through the perforations in the device and onto the substrate, the material dispenser having a retraction device that prevents leakage of the viscous material from the opening after dispensing is complete; and

a temperature control system to control the temperature of the viscous material contained in the chamber, the temperature control system including a temperature sensor disposed on the material dispenser to measure temperature of the viscous material contained in the chamber, and a controller coupled to the temperature sensor to control a temperature of a heating and cooling element disposed in the chamber to maintain the temperature of the viscous material at a desired value, wherein the heating and cooling element includes a conduction rod disposed in the chamber having a first terminal end and a second terminal end and of a length sufficient to control temperature of the viscous material contained within the chamber.

24. The printer of claim 23, further comprising a first thermoelectric device coupled to the controller and disposed at a first terminal end of the conduction rod to control the temperature of the conduction rod, and a first thermal block coupled between the first thermoelectric device and the conduction rod to transfer heat to the conduction rod from the first thermoelectric device.

25. The printer of claim 24, further comprising a second thermoelectric device coupled to the controller and disposed at a second terminal end of the conduction rod to control the temperature of the conduction rod, and a second thermal block coupled between the second thermoelectric device and the conduction rod to transfer heat to the conduction rod from the second thermoelectric device.

26. The printer of claim 25, further comprising a heat exchanger coupled to each of the first and second thermoelectric devices and having a fan mounted thereon for cooling.

27. A printer for printing a viscous material at predetermined positions forming a pattern on a substrate, the printer comprising:

a frame;

a device, mounted to the frame, having a number of perforations arranged to form the pattern;

a support apparatus, coupled to the frame, that supports the substrate in printing

position beneath the device;

a material dispenser having a chamber to contain the viscous material to be printed on the substrate, the chamber having an opening through which the viscous material is dispensed, the material dispenser being coupled to the frame, positioned over the device, and constructed and arranged to dispense the viscous material through the perforations in the device and onto the substrate, the material dispenser having a retraction device that prevents leakage of the viscous material from the opening after dispensing is complete, the material dispenser further having at least one port and a removable cartridge coupled to the port, the removable cartridge containing material to be dispensed and having an inlet to receive pressurized air to force material from the cartridge through the port and out of the opening of the chamber; and

a pressure control system to control on a real-time basis the pressurized air delivered to the cartridge to maintain the pressure with which the viscous material is forced from the cartridge and to maintain the pressure in the chamber at a desired value during dispensing.

28. The printer of claim 27 wherein the pressure control system comprises a pressure sensor to measure the pressure in the chamber at at least one time interval as the material dispenser moves along a first axis across the device during dispensing, and a programmable regulator coupled to the pressure sensor to receive real-time pressure values wherein the programmable regulator maintains or adjusts after the at least one time interval an amount of pressurized air delivered to the cartridge to maintain the pressure at which the viscous material is forced from the cartridge and to maintain the pressure in the chamber at the desired value.

29. The printer of claim 28, wherein the at least one time interval at which the pressure in the chamber is measured by the pressure sensor is approximately at least 25 milliseconds.

30. The printer of claim 27 further comprising a bracket mounted to the frame of the printer having at least a first connector constructed and arranged to receive at least a second connector attached to the material dispenser wherein removal of the second connector from the first connector permits the pressure control system to be disconnected from the material dispenser.