Process for use in rapidly producing printed circuit boards using a computer controlled plotter

• US 4,720,798 A
• Filed: 04/16/1985
• Issued: 01/19/1988
• Est. Priority Date: 04/16/1985
• Status: Expired due to Fees

• Current Assignee: HC TANG & Associates
• Original Assignee: Protocad Incorporated
• Inventors: Rasper, John T., Reed, Ronald G.
• Primary Examiner(s): Krass, Errol A.
• Assistant Examiner(s): Black, Thomas G.
• Application Number:
  US06/725,817
• Time in Patent Office: 1,008 Days
• Field of Search: 364/488-491, 364/475, 364/559, 356/399-401, 156/901, 156/625, 156/659.1, 318/567, 346/140 R, 118/401, 118/410
• US Class Current: 29/847
• CPC Class Codes: H05K 2201/0355 Metal foils
• CPC Class Codes: H05K 2201/0959 Plated through-holes or plated blind vias filled with insulating material
• CPC Class Codes: H05K 2201/09981 Metallised walls
• 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 2203/013 Inkjet printing, e.g. for printing insulating material or resist
• CPC Class Codes: H05K 2203/0191 Using tape or non-metallic foil in a process, e.g. during filling of a hole with conductive paste
• CPC Class Codes: H05K 2203/0554 Metal used as mask for etching vias, e.g. by laser ablation
• CPC Class Codes: H05K 2203/0763 Treating individual holes or single row of holes, e.g. by nozzle
• CPC Class Codes: H05K 2203/082 Suction, e.g. for holding solder balls or components
• CPC Class Codes: H05K 3/0008 for aligning or positioning of tools relative to the circuit board H05K3/4638, H05K3/4679 take precedence; for manufacturing assemblages of components H05K13/0015
• CPC Class Codes: H05K 3/0047 Drilling of holes
• CPC Class Codes: H05K 3/061 Etching masks
• CPC Class Codes: H05K 3/424 by direct electroplating
• CPC Class Codes: H05K 3/427 initial plating of through-holes in metal-clad substrates
• CPC Class Codes: Y10T 29/49156 with selective destruction of conductive paths

Abstract

A conductor clad board from which the printed circuit board is produced is operatively retained for manipulation in a plotter controlled by a computer. Etchant-resist material is laid down in a printed circuit conductor pattern on at least one conductive sheet of the board by a marking instrument operatively manipulated by the plotter. The computer controls the application of the resist material in accordance with printed circuit board computer aided design information in the computer memory. Both conductive sheets of the board can be marked with resist after establishing the orientation of the board so the printed circuit patterns on opposite sides of the board occupy a predetermined aligned relationship. After etching, the board is again retained in the plotter and holes are drilled through the board by using drill apparatus operatively adapted for use and manipulation by the plotter.

Claims

1. A process for use in the production of a printed circuit board utilizing a computer and a computer controlled plotter, comprising:

retaining a conductive sheet-clad board in the plotter while performing the following activities on the conductive sheet,

applying resist by capillary effect directly to the conductive sheet from a marking device manipulated by the plotter, and

creating a predetermined printed circuit pattern of resist on the conductive sheet by controlling the plotter to move the marking device relative to a stationary reference and relative to the board.

2. A process as defined in claim 1 wherein the plotter is controlled by the computer, and the computer has a memory containing information defining the predetermined printed circuit pattern, and the computer controls the plotter to create the predetermined printed circuit pattern of resist on the conductive sheet.

3. A process as defined in claim 2 wherein the printed circuit pattern of applied resist includes a plurality of lines of resist, and at least two of the lines of resist have different widths.

4. A process as defined in claim 3 wherein the marking device has a marking point which applies resist to the conductive sheet in a line of predetermined width, and wherein at least one conductor of the circuit pattern is greater in width than the width of the line applied by the marking device, and further comprising:

applying resist on the conductive sheet to define the conductor by applying a series of generally parallel, transversely offset and adjoining lines of resist from the marking device, under the control of the computer.

5. A process as defined in claim 4 further comprising:

overlapping each of the series of generally parallel lines of resist by a predetermined amount related to the width of the line of resist applied from the marking device and related to the width of the conductor, under control of the computer.

6. A process as defined in claim 2 wherein the resist material is applied in at least one connector pad ring, and a center of the ring is devoid of applied resist.

7. A process as defined in claim 6 wherein the ring of resist is defined by a plurality of concentric and radially offset circular lines of resist which radially adjoin one another.

8. A process as defined in claim 2 wherein the information in the memory of the computer also includes information defining the speed at which the marking device can move relative to the conductive sheet in order to obtain a predetermined degree of capillary effect fluid flow of the resist onto the conductive sheet, and further comprising:

controlling the speed of movement of the marking device relative to the conductor sheet to obtain the predetermined desired capillary effect fluid flow of the resist on the conductive sheet.

9. A process for use in the production of a printed circuit board utilizing a computer and a plotter controlled by the computer, the computer having a memory containing information defining a predetermined printed circuit pattern, the computer controlling the plotter to create the predetermined printed circuit pattern, and the plotter including a carrier mechanism which retains a pen, comprising:

retaining a conductive sheet-clad board in the plotter while performing the following activities on the board,

applying resist directly on the conductive sheet from at least two marking devices manipulated by the plotter, each marking device comprising a pen having a marking point which applies resist to the conductive sheet in a line of predetermined width, the width of the resist line applied by one pen being different than the width of the resist line applied by the other pen,

holding the pen in the carrier mechanism,

moving the carrier mechanism to apply resist from the pen onto the conductive sheet,

applying resist in a line of one width with one pen held in the carrier mechanism,

transferring the one pen from the carrier mechanism and thereafter transferring the other pen to the carrier mechanism,

accomplishing both transferring steps automatically under the control of the computer, and

applying resist in a line of another width with the other pen held in the carrier mechanism.

10. A process for use in the production of a printed circuit board utilizing a computer and a plotter controlled by the computer, the computer having a memory containing information defining a predetermined printed circuit pattern, the computer controlling the plotter to create the predetermined circuit pattern, the plotter including a carrier mechanism which selectively holds an instrument useful in the process, one such instrument being a marking device and another such instrument being a hole drilling instrument, the process comprising:

retaining a conductive sheet-clad board in the plotter while performing the following activities on the board,

applying etchant resist directly to the conductive sheet from the marking device manipulated by the carrier mechanism of the plotter,

creating the predetermined circuit pattern of resist on the conductive sheet by controlling the plotter to move the marking device and the board relative to one another, and

drilling a hole through the board by use of the hole drilling instrument held in the carrier mechanism under the control of the computer.

11. A process as defined in claim 10 further comprising:

transferring the marking device from the carrier mechanism after applying the resist, and thereafter

transferring the hole drilling instrument to the carrier mechanism prior to drilling the hole, and

automatically accomplishing both transfers under the control of the computer.

12. A process as defined in claim 11 further comprising:

drilling each of a plurality of holes in the board by use of a hole drilling instrument held by the carrier mechanism, at least two of the holes having a different diameter or cross sectional size,

using one hole drilling instrument to drill a hole of one size in the board, and

using another hole drilling instrument to drill a hole of a different size in the board.

13. A process as defined in claim 12 wherein each hole drilling instrument comprises a drill motor having a drill bit attached thereto.

14. A process as defined in claim 12 further comprising:

controlling the selection of the one and the another hole drilling instruments under the control of the computer.

15. A process as defined in claim 11 further comprising:

carrying drill particles created by drilling the board away from the plotter in a stream of air.

16. A process as defined in claim 15 wherein the stream of air is created by a low pressure vacuum source.

17. A process as defined in claim 16 further comprising:

selectively creating the stream of air under the control of the computer prior to drilling a hole into the board.

18. A process as defined in claim 15 wherein the stream of air is created by a vacuum device having a low pressure inlet and a high pressure outlet, the high and low pressures being relative to ambient pressure, and further comprising:

attaching an air supply plenum and a vacuum plenum to the plotter,

connecting the air supply plenum to the outlet of the vacuum device,

connecting the vacuum supply plenum to the inlet of the vacuum device, and

arranging the plenums to create a stream of air across the conductive sheet when drilling the hole.

19. A process as defined in claim 11 further comprising establishing the orientation of the board as retained in the plotter by steps comprising:

holding an optical sight instrument in the carrier mechanism, and

aligning a reference location on the board with an optical axis through the optical sight instrument by controlling the plotter to create relative movement between the optical sight instrument held in the carrier mechanism and the board until optical alignment occurs.

20. A process as defined in claim 19 further comprising:

removing the board from the plotter for etching after the printed circuit pattern of resist has been applied and before drilling the hole through the board at a location in the printed circuit pattern,

again retaining the board in the plotter after etching,

establishing the orientation of the board in the manner aforesaid by using the optical sight instrument, and thereafter

drilling a hole through the board by using the hole drilling instrument held in the carrier mechanism.

21. A process as defined in claim 20 wherein the board has two parallel conductive sheets attached on opposite sides of a flat substrate, and the process further comprises:

removing the board after applying the resist in the printed circuit pattern on a first conductive sheet of the board,

retaining the board in the plotter in a second instance with the other conductive sheet in position for applying resist thereto,

establishing the orientation of the board in the plotter in the second instance by using the optical site instrument in the manner aforesaid,

applying resist in a second predetermined printed circuit pattern on the other conductive sheet by controlling the plotter and the carrier mechanism holding the marking device in the manner aforesaid, and

locating portions of the second printed circuit pattern in side to side alignment on the board to orient opposite portions which are to be drilled through an substantial orthogonal alignment with respect to the planes of the conductive sheets.

22. A process as defined in claim 21 wherein at least two of the portions to be drilled through are conductor pad rings substantially coaxially positioned on opposite sides of the board about an axis orthogonal to the planes of the conductor sheets.

23. A process as defined in claim 22 wherein the center of each conductor pad ring of resist is devoid of resist.

24. A process as defined in claim 23 further comprising:

etching the board after applying the resist, and

drilling a hole through the centers of the conductor ring pads of conductive sheet material which are in orthogonal alignment on opposite sides of the board.

25. A process as defined in claim 21 wherein at least two of the portions to be drilled through are conductor ring pads of resist having a center portion devoid of resist and located on opposite sides of the board, each center portion being substantially coaxially positioned about an axis orthogonal to the planes of the conductor sheets.

26. A process as defined in claim 21 wherein the plotter includes a carousel for holding instruments and for transfering the instruments to the carrier mechanism, the carousel holding at least one marking device instrument and at least one hole drilling instrument, and the process further comprising:

transfering one type of instrument from the carrier mechanism to the carousel, and thereafter

transfering another type of instrument from the carousel to the carrier mechanism during the aforesaid process, and

automatically accomplishing all transfers under the control of the computer.

27. A process as defined in claim 26 wherein the carousel further holds at least one optical sight instrument.

28. A process as defined in claim 21 wherein the step of locating portions of the second printed circuit pattern further comprises:

drilling at least one locating hole in the circuit board prior to applying the resist in the second printed circuit pattern to the second side of the circuit board.

29. A process as defined in claim 10 wherein the step of retaining the conductive sheet clad board in the plotter further comprises:

attaching the board to a carrier sheet, and

retaining the carrier sheet in the plotter for movement by the plotter.

30. A process for use in the production of printed circuit boards utilizing a computer and a computer controlled plotter, comprising:

retaining a printed circuit board having an undrilled predetermined printed circuit pattern of conductors formed thereon in the plotter for movement by the plotter,

establishing the orientation of the predetermined printed circuit pattern of conductors in relation to the retention of the board by the plotter under the control of the computer, by holding a locating device in the plotter, by moving the locating device relative to at least three predetermined locating points on the board to position the locating device at a predetermined location with respect to each locating point, and by utilizing information defining each predetermined location of the three locating points established by positioning the locating device,

holding a hole drilling device in the plotter,

moving the hole drilling device relative to the printed circuit pattern while held by the plotter to position the hole drilling device to drill holes at predetermined hole locations, and

drilling holes through the printed circuit pattern and the board at predetermined hole locations by using the hole drilling device held in the plotter under the control of the computer.

31. A process as defined in claim 30 further comprising:

locating the predetermined locations for the holes by moving the hole drilling device relative to the printed circuit pattern under the control of the computer after the orientation of the printed circuit pattern has been established.

32. A process as defined in claim 31 further comprising:

carrying drill particles created by drilling the board away from the plotter in a stream of air moving across the board.

33. A process as defined in claim 30 further comprising:

automatically transferring the locating device from the plotter and the hole drilling device to the plotter after the orientation of the printed circuit pattern has been established.

34. A process for use in the production of printed circuit boards utilizing a computer and a computer controlled plotter, the plotter including a carrier mechanism which retains an instrument useful in the process, one such instrument being a hole drilling device, comprising:

retaining a printed circuit board having an undrilled predetermined printed circuit pattern of conductors formed thereon in the plotter for movement by the plotter,

establishing the orientation of the predetermined printed circuit pattern of conductors in relation to the retention of the board by the plotter,

holding the hole drilling device in the carrier mechanism,

moving the hole drilling device held in the carrier mechanism under the control of the computer to position the hole drilling device to drill holes in the undrilled printed circuit pattern at predetermined hole locations, the predetermined location of each hole to be drilled being established by manipulating the carrier mechanism and the printed circuit board relative to one another under the control of the computer, the computer having a memory which includes information defining the predetermined printed circuit pattern and the location of each hole to be drilled relative to the printed circuit pattern, and

drilling holes through the printed circuit pattern and the board at predetermined hole locations by using the hole drilling device held in the carrier mechanism under the control of the computer.

35. A process as defined in claim 34 wherein at least a plurality of holes are drilled in the printed circuit board and at least two of the holes drilled are of a different diameter of cross sectional sizes.

36. A process as defined in claim 35 using a plurality of hole drilling devices, each hole drilling device including a drill motor having a drill bit attached thereto, at least two of the drill motors having drill bits of different diameters or cross sectional sizes, and the process further comprises:

using one drill motor having a drill bit of one size to drill a hole of one size in the board, and

using another drill motor having a drill bit of another size to drill a different hole of a different size in the board.

37. A process as defined in claim 36 further comprising:

substituting one drill motor and attached drill bit on the carrier mechanism for the other drill motor and attached drill bit when the holes of different sizes are drilled.

38. A process as defined in claim 37 wherein the plotter includes means for transferring selected instruments to and from the carrier mechanism, and at least two of such selected instruments available for transfer to the carrier mechanism are the two drill motors which each have a different sized drill bit attached thereto, and the process further comprises:

transferring one drill motor with the attached drill bit to the carrier mechanism and thereafter drilling a hole of one size in the board, and thereafter

transferring the one drill motor from the carrier mechanism, and thereafter

transferring the other drill motor and the attached drill bit to the carrier mechanism, and thereafter

drilling the different hole of the different size in the board, and

accomplishing all the transfers under the control of the computer.

39. A process as defined in claim 38 further comprising:

coupling operative energy from the carrier mechanism to the drill motor for operating the drill motor.

40. A process as defined in claim 39 further comprising:

establishing a selective mechanical connection to the drill motor after it has been transferred to the carrier mechanism to supply the operative energy to the drill motor, and

selectively terminating the mechanical connection to the drill motor prior to transferring the drill motor from the carrier mechanism.

41. A process as defined in claim 40 further comprising:

orienting a drill bit of the hole drilling device orthogonal to the plane of the printed circuit board prior to drilling the hole.

42. A process as defined in claim 41 further comprising:

advancing the drill bit axially along an axis orthogonal to the printed circuit board after the orthogonal orientation has been established.

43. A process as defined in claim 42 further comprising:

accomplishing under the control of the computer the steps of orienting the drill bit orthogonal to the plane of the printed circuit board and advancing the drill bit.

44. A process as defined in claim 34 wherein the drill particles are removed by vacuuming the drill particles away from the plotter.

45. A process as defined in claim 34 wherein the drill particles are removed by steps comprising:

carrying the drill particles away from the plotter in a stream of air.

46. A process as defined in claim 45 wherein the stream of air is created by directing a high pressure source of air toward the hole from one direction and pulling air and the drill particles from the hole in the opposite direction by a vacuum source.

47. A process as defined in claim 45 further comprising:

creating the stream of air under the control of the computer.

48. A process for use in the production of a printed circuit board utilizing a computer and a computer controlled plotter, comprising:

establishing at least three locating points on a board from which the printed circuit board is to be produced,

retaining the board in the plotter for manipulation,

locating each of the three locating points by manipulating a locating device of the plotter and the board relative to one another until a reference axis of the locating device is located in a predetermined position with respect to each locating point, and

establishing the orientation of the board retained in the plotter from information obtained from locating all three locating points.

49. A process as defined in claim 48 further comprising:

establishing the side of the board upon which operative effects are to be achieved by the information obtained from locating of all three locating points.

50. A process as defined in claim 49 wherein the locating points are holes formed in the board.

51. A process as defined in claim 50 wherein the locating holes are formed in the board prior to retaining the board in the plotter.

52. A process as defined in claim 50 wherein the locating holes are formed in the board after the board is retained in the plotter.

53. A process as defined in claim 48 wherein the computer includes a memory containing information defining a predetermined pattern of printed circuit conductors to be formed on the board, and further comprising:

establishing a working area on the board within which the predetermined pattern of printed circuit conductors is to be formed, under the control of the computer and using information obtained by locating each of the three locating points.

54. A process as defined in claim 53 further comprising:

orienting the working area under the control of the computer by using the information contained in the memory defining the predetermined pattern of printed circuit conductors and by using the information obtained by locating each locating point.

55. A process as defined in claim 54 further comprising:

proportioning the size of the predetermined pattern of printed circuit conductors to fit within the working area established, automatically under the control of information contained in the memory of the computer.