US3795561A

US3795561A - Vertical etchers for minute parts

Info

Publication number: US3795561A
Application number: US00274346A
Authority: US
Inventors: H Bond; M Rucinski
Original assignee: Buckbee Mears Co
Current assignee: Buckbee Mears Co
Priority date: 1972-07-24
Filing date: 1972-07-24
Publication date: 1974-03-05
Anticipated expiration: 1991-03-05
Also published as: IT991144B; BE802735A; JPS5548111B2; FR2194136A5; GB1409484A; CA986394A; DE2333443A1; JPS4944944A; NL7309812A

Abstract

A vertical etcher is provided having means for controlling the angular velocity as well as the linear velocity of a part as it passes through a multiple nozzle spray etching chamber. Further means are included for spacing and adjusting the enchant spray nozzles to produce a uniform spray of etchant over the part to be etched as well as etchant wipers located at the entrance and exit to the etchant chambers to stop the etching action as quickly as possible.

Description

March 5, 1974 H. M. BOND ErAL VERTICAL ETCHERS FOR MINUTE PARTS Filed July 24, 1972 LO lf) 3 Sheets-Sheet l March 5, i974 H. M. BOND ErAL 3,795,561

VERTICAL ETCHEHS FOR MINUTE PARTS 5 Sheets-Sheet 2 Filed July 24, 1972 March 5, 1974 H, M BOND ETAL VERTICAL ETCHERS FOR MINUTE PARTS 3 Sheets-Sheet 5 Filed July 24, 1972 o U i m\.\U

.n l mm N U E. Hlm

United States Patent O 3,795,561 VERTICAL ETCHERS FOR MINUTE PARTS Herbert M. Bond and Michael E. Rucinski, St. Paul, Minn., assignors to Buckbee-Mears Company, St. Paul,

inn.

Filed July 24, 1972, Ser. No. 274,346 Int. Cl. C23f 1/02 U.S. Cl. 156-345 12 Claims ABSTRACT OF THE DISCLOSURE A vertical etcher is provided having means for controlling the angular velocity as well as the linear velocity of a part as it passes through la multiple nozzle spray etching chamber. Further means are included for spacing and adjusting the etchant spray nozzles to produce a uniform spray of etchant over the part to be etched as well as etchant wipers located at the entrance and exit to the etchant chambers to stop the etching action as quickly as possible.

BACKGROUND OF THE INVENTION Field of the invention This invention relates generally to etching machines and more specifically, to vertical spray etching machines for uniformly etching small and minute parts.

Description of the prior art Vertical etchers and vertical etching machines are known in the prior art and have been used for some time in the etching of moving webs. Typical etchers of this type are shown in Mears Pat. 2,762,149 which shows a vertical etcher for etching elongated webbing in which the nozzles are spaced along the header. The nozzles are stationary and the web moves horizontally through the vertical etching machine so that the etchant impinges on the web at right angles.

Another embodiment of a vertical etching machine for Webs is shown in the Mears Pat. 2,822,635 which shows another vertical etcher for spray etching a web that moves horizontally at a continuous rate through an etching chamber. The nozzles in this latter vertical etcher oscillate about a central axis during operation to alternately direct the etchant upward and downward. In addition, 'an upward and downward velocity is imparted to the nozzles so that the nozzle spray scans the web during the etching process. One of the problems of spray etching a web is that areas or pockets of localized passivity occur which affects the iinal dimension of the etched article. This problem is virtually eliminated in the aforementioned Mears patents, which are assigned to the same assignee as the present invention, by directing a high velocity spray alternately upward, downward and vertically across the web surface. In addition, nozzle motion prevents the lodging of minute gas bubbles which form during the etching reaction in the web aperture. The local passivity and lodging of gas bubbles are one of the principal causes of nonuniform etching where the concentration, the temperature of the etchant and distribution of the etchant orver the area to be etched are under proper control. Thus, by adjusting the angle of oscillation of the several nozzles, one can obtain reliable and uniform results with the apparatus shown in the Mears patents. However, one uncompensated drawback exists in the use of vertical etchers such as Mears is the influence of the gravitational field on the etchant liuid. That is, the etching uid after impinging on the part begins to run to the bottom of the part. While for ,some operations such as etching metal webs, the overetching produced by rundown is so minimal, it can be compensated for or tolerated, it is not always possible to tolerate or compensate for overice etching produced in etching operations on precision etched items requiring tolerances of less than .0005 inch. Therefore, it is necessary to have some means of controlling the etchant spray to obtain a uniform spray over the entire surface of the article to be etched as well as controlling the etchant runoff. This is particularly true with articles which are to be etched from both sides and which vary considerably in areas to be etched. The present invention is an outgrowth of the problem of providing a vertical etcher for etching small or large parts which eliminates irregularities in etching due to nozzle spacing, gravitational fields, over-exposure and nozzle spray patterns.

BRIEF SUMMARY OF THE INVENTION Briefiy, the present invention comprises a vertical etcher in which one controls the angular velocity of the part to be etched, the linear velocity of the part to be etched, the Ivertical velocity of the nozzles, the vertical nozzle spacing and the horizontal spacing of the nozzles -from the part to be etched. In addition to nozzle spray pattern control, llow meters and valves are provided to increase or decrease the amount of etchant impinging on the article as well as the momentum of the etchant impinging on the article. Furthermore, a pair of similar etching chambers and etching nozzles are provided in order to provide iiner control and adjustment of the spray etchant. Other features of the invention will be described in the description of the preferred embodiment of the machine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a front elevation view of my vertical etching machine;

FIG. 2 is a side elevation view of the vertical etching machine;

FIG. 3 is a cross-sectional view of the oscillating and adjusting mechanism for the nozzle supply;

FIG. 4 is a side elevation view of the holder for holding the article to be etched as it passes through the vertical etching chambers; and

FIG. 5 is an end view partially in schematic showing the vertical etcher part support ring as it fits into a track and guides which propel the article to be etched through the various etching and rinsing chambers.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. l and 2, reference numeral 10 generally designates a vertical etching machine. Vertical etcher 10 comprises a first etching chamber 11, a second etching chamber 12 and a rinse chamber 13. As etching chamber 11 and etching chamber 12 are identical, only one of the chambers will be described Kwith respect to the vertical etching machine 10. Etching chamber 12 contains a supply header 14 which is mounted horizontally in chamber 12. Supply header 14 is connected to a source of etchant fluid under pressure while one end of header 14 is rotatably mounted in a housing 15 and the other end of header 14 is rotatably mounted in a similar housing (not shown). Housing 15 is mounted on a first threaded rod 16 and a second threaded rod (not shown) and is fastened in a horizontal position on the threaded rods by double nutting flange 15a to the two threaded rods. Similarly,

supply headers

17, 18, 19 and 20 are mounted and fastened to a rst threaded rod 16 and a second threaded rod (not shown) by identical housings and fianges and therefore will not be described. The mounting of

supply headers

14, 17, 18, 19 and 20 on threaded rods allows for vertical adjustment of the spacing between headers to thereby control the spray pattern and the amount of etchant sprayed on an article to be etched.

Referring to FIG. 3,

supply headers

14, 17, 18, 19 and 20 are shown in cross-sectional View with sets of

nozzles

14a, 17a, 18a, 19a and 20a located thereon. 'Each set of nozzles is connected to headers and sprays etchant toward an article to be etched which would be located vertically between the two banks of supply headers. Located on the opposite side of

headers

14, 17, 18, 19 and 20 are a similar bank of

headers

21, 22, 23, 24 and 25 which respectively have sets of nozzles 21a, 22a, 23a, 24a and 25a. It should be noted that some of the

nozzles

21, 22, 23, 24 and 25 are illustrated positioned downward and some nozzles are positioned upward rather than perpendicular to an article to be etched. The various positions of the nozzles on the headers is for illustrating static positioning of nozzles by rotating a header. For example, an operator can adjust the orientation of the spray nozzle set 21a to spray upward by rotating header 21 clockwise. This feature provides static control of nozzle orientation as opposed to dynamic oscillation positioning in prior art devices. This static adjustability allows one to eliminate irregular spray patterns on the article to be etched through adjusting the nozzles before etching. For example, suppose an article is to be etched more on the periphery than in the center. The operator then directs the nozzles upward so the main thrust of etchant impinges on the periphery of the part to be etched.

Located on the bottom of threaded rod 16 and threaded rod 29 is another adjustment rod 30 having a plurality of fastening members thereon for holding threaded rod 16 and threaded rod 29. Similarly, located on the top of threaded rod 16 and threaded rod 29 is another threaded adjustment rod 34. By loosening

nuts

31 and 32, one can position the bottom of threaded rod 16 inward or outward by securing

nuts

31 and 32 to the L-shaped member 44. Similarly, nuts (not shown) are located on threaded adjustment rod 34 to provide adjustment of the top of threaded rod 16. With this conguration the supply headers can be moved in or out by adjustment of the position of nuts on threaded adjustment rod and threaded adjustment rod 34. Similarly, the opposite supply headers have means for adjusting and positioning inward also.

FIG. 3 also shows a rectangular or support frame 35 for the banks of etching headers which are connected to rod 30 and rod 34. Member 35 includes a cam follower 36 which is rotatably mounted in a housing 37. Cam follower 36 operates in conjunction with a cam 38 (FIGS. 1

Vand 2). Rotation of a cam shaft 39, which is driven by a motor 40 and a suitable gear reducing mechanism y41, causes cam 38 to rotate thus forcing cam follower 36 and frame to follow the surface of cam 38. The particular cam shown is a constant velocity cam and provides a uniform upward and downward velocity of the member 35 with a constant rate of rotation of shaft 39. Thus, the vertical motion transferred to member 35 causes the nozzles and the spray to sweep up and down at a constant velocity within etching chambers 11 and etching chamber 12. This feature of the oscillation of the supply headers and the nozzles at a uniform velocity provides a uniform sweeping spray of the etchant onto the article or part to be etched.

Referring to FIG. l, the article to be etched is designated by reference numeral 50 and is attached to a circular holding member 51 which has an opening S2 therein. The article to be etched generally is of a type that requires uniform etching from both sides. In order to etch from both sides, one fastens article 50 over opening 52 in circular member 51. Circular holding member 51 has a set of teeth 51a thereon which form mating engagement with a continuous lower drive belt 54 and an upper continuous drive belt 55. Upper belt 55 continuously contacts the topmost portion of ring 51 as it passes through the etching chambers within a track 56 which passes through etching chamber 11, etching chamber 12 and rinse chamber 13. Upper drive belt 55 passes around a wheel 62 and around a power driven wheel 57 which is connected to motor 58 by a suitable variable speed drive mechanism (not shown). Similarly, lower drive belt 54 passes around a wheel 63 through etching chamber 11, etching chamber 12 and rinse chamber 13 in a track guide 60. Belt 54 then continues around a power driven wheel 61. Wheel 61 is driven by a motor 59 and a variable speed drive mechanism similar to the mechanism driving upper belt 55 (not shown).

In order to illustrate the operation and function of holding member 51, reference should be made to FIG. 4 and FIG. 5 which shows a portion of the section for guiding and holding wheel 51 in an upright position. Upper drive belt 55 and lower drive belt 54 are shown engaging the upper portion and lower portion of wheel 51. To keep wheel 51 `from falling over, there is provided a pair of lower guide member 70 and 71 which substantially encase track 54 and a similar pair of

upper guide members

72 and 73 which substantially encase track 55. These guide members maintain circular article holder 51 in a vertical orientation as it passes through etching chamber 11, etching chamber 12 and rinse chamber 13.

The two

drive belts

54 and 55 are controlled by separate variable speed drive mechanisms so that the linear velocity of the two tracks as Well as the direction of rotation of the two drive belts can be independently controlled. Thus, because article holder 51 will be driven by belt 54 and belt 55, one can control the angular velocity as well as the linear velocity article holder 51 takes in its journey through etching chamber 11, etching chamber 12 and rinse chamber 13. For example, if belt 55 and belt 54 are rotated at the same velocity and in opposite directions, article 50 on circular member 51 will pass through the etching chamber in the same orientation as it enters without any angular velocity. However, by maintaining a slight differential linear velocity or slowing down, stopping, or even reversing the direction of one drive belt will rotate article holder 51 as it passes through the various chambers. In fact, with the rates of rotation of the drive belts constant but in the same direction, the article holder 51 will have only angular velocity. That 1s, one can cause article holder 51 `to rotate in one position much in the same manner as if it was attached to a rotating shaft.

While the various components of the etching apparatus have been described, the operation of the etching appa ratus in conjunction with an article holder will now be described. Briey, in operation of vertical etcher 10, one rst powers drive

belts

54 and 55 at predetermined speed and direction so that article 50 enters etching chamber 11 through a door 80 and a door 81 which have a wiper ap 82 and a wiper ap 83 respectively connected thereto.

Wiper aps

82 and 83 are preferably made from a rubber-like or pliable material to produce a squeegee type wiping on the surface of the article as it enters chamber 11. In addition to wiper flaps 82 and 83 at the entrance of the chamber, there is a pair of wiper flaps (not shown) located between etching chamber 11 and etching chamber 12, a pair of wiper flaps l(not shown) between rinse chamber 12 and etching chamber 13 and a air of wiper tlaps (not shown) at the exit of rinse cham- When article 50 and article holder S1 enter etching chamber 11, a spray of etchant from spray nozzles located on the headers sweeps across the article thus etching the article. As article 50 leaves chamber 11, the Wiper aps (not shown) located between chamber 11 and chamber 12, wipe off any excess etchant. After leaving etching chamber 11 article 50 enters a second etching chamber 12 where it is similarly subjected to a spray of etchant from a second set of sweeping spray nozzles.

After etching article 56 in chambers 11 and 12, article 50 passes through wiper flaps (not shown) to remove any excess etchant. Next, article 50 enters a rinse chamber 13 which has spray nozzles 85 therein which spray water onto article S1 thus rinsing and diluting the etchant to prevent any further etching due to etchant on the article. The initial stopping of the etching action is provided by the squeegee action or wiping action of the iiaps located at the exit to etching chamber 12. However, to ensure a complete stopping of the etching action, one should immediately rinse the article with water to remove any excess etchant.

Thus, in operation of vertical etcher 10, an operator places the article to be etched on the circular member 51. Next,

motors

58 and 62 are activated to begin rotation of drive belt 54 and drive belt 55. By careful selection of the rotational velocities of

drive belts

55 and 54, the operator can preselect the angular velocity and the linear velocity of the article 50 as it passes through etch- 1 ing chamber 11 and etching chamber 12. This feature, in essence, allows one to control the time of etching without the aid of a timer as well as prevent etchant rundown. The article enters chamber 11 and rotates as it passes through the etching chamber which eliminates any rundown or accumulation of any etchant at the bottom of the part to be etched. However, to eliminate any spiral etched patterns on the article due to rotation of the article, we provide the aforementioned oscillating or vertical sweeping motion to the spray etchant by means of frame 3S, cam follower 36 and constant velocity cam 38. This control of the upward and downward sweeping motion of the etchant as well as the angular and linear velocity of the article to be etched provides a precision etching system for use in precision etching.

As a further modification, we can control the temperature of the etchant in the system by

heaters

90, 91, 92 and 93 which heat the etchant and maintain it at a constant temperature. Similarly, a set of valves and liow meters 101 through 105 are connected to supply

headers

14, 17, 18, 19 and 20 allow one to precisely control the amount of etchant ow as well as to ensure that etchant is continually owing into the supply chamber and supply nozzles.

We claim:

1. An etching apparatus for etching articles which are located substantially in a vertical plane comprising:

an etching chamber;

a plurality of etchant plenum chambers located in said etching chamber, a plurality of etchant spray nozzles attached to each of said plurality of plenum chambers, each of said spray nozzles operable for directing etchant in a preferred direction;

means for positioning said plurality of spray nozzles in a vertical direction, means for positioning said plurality of spray nozzles in a horizontal direction;

means for adjusting the nozzles to control the preferred direction of etchant ilowing from said nozzles;

means for oscillating said plurality of nozzles in a vertical direction; and

means for vertically mounting an article to be etched,

further means for propelling the means for vertically mounting an article to be etched through said etching chamber, said further means including means for rotating the article to be etched as it passes through said etching chamber so that the article to be etched is sprayed with etchant from said plurality of spray nozzles.

2. The invention of claim 1 lwherein said means for vertically mounting an article to be etched comprises a disc having a central opening therein.

3. The invention of claim 2 wherein said disc has a set of teeth thereon for engaging a drive belt.

4. The invention of claim 3 wherein said means for rotating the article includes a rst and second drive belt for forming mating engagement with said teeth on said disc.

5. The invention of claim 4 wherein said apparatus includes a rst and second variable speed drive mechanism or controlling the speed of said first and second drive elts.

6. The invention of claim S wherein said means for oscillating said plurality of nozzles in a vertical direction comprises a constant velocity mechanism.

7. The invention of claim 6 wherein said etching apparatus includes a iirst etching chamber, a second etching chamber and a rinse chamber.

8. The invention of claim 7 wherein said apparatus inclules means for wiping excess etchant from the article to be etched.

9. The invention of claim 8 wherein said means for wiping excess etchant from the article to be etched are positioned between said rst etching chamber and said second etching chamber.

10. The invention of claim 9 wherein said apparatus includes at least two banks of spray nozzles positioned to direct etchant spray toward an article to be etched which is centrally located between said bank of nozzles.

11. The invention of claim 10 including means for controlling the temperature of said etchant.

12. The invention of claim 11 wherein a ow meter connects to each of said plenum chambers.

References Cited UNITED STATES PATENTS 11/1972 Wessells et al. 156--345