In the manufacture of printed circuit cards for assembling electronic components, the space available for desired pattern, i. e. drawing circuits, is limited due to the small dimensions of the electronic components. In today's advanced electronics, therefore, these conductive patterns are to a great extent produced on varying numbers of internal layers. These patterned internal layers are glued together to a finished multi-ply or multi-layer card and connection between the patterns of the various layers is effected by drilling through the contact points of the patterns and subsequent copper-plating the inside of the holes. Two essential requirements must be fulfilled if good adhesion between the internal layers is to be achieved when they are glued together under high pressure. First of all the internal layers must have a surface which will adhere to glue or insulating layers, and this is obtained in a microscopically visible barb-like surface structure by brown or black-finishing the internal layers. Secondly, the internal layers must be optimally dry, which is

achieved by drying in 90°C kiln heat for a period of normally 1 hour.

With current technology the internal layers are brown or black-finished in spray machines-conveyor plants-or in dipping machines, after which the internal layers are transferred separately by hand to some form of transport trolley that can be inserted into the above-mentioned kiln. After drying, the gluing process must take place in press equipment before the internal layers have reabsorbed moisture from the surroundings. Besides this being a complicated procedure, all manual handling constitutes a risk of damage occurring in the oxide layer which is extremely sensitive to scratching. The technology described also requires a considerable amount of space since the surface-treating machine must still include a section in which liquid can drip off the goods, the separate drying kiln must be relatively large, and considerable floor space is required for these treating units.

Two alternative process principles are currently available for performing brown or black-finishing of internal layers for printed circuit cards. In the first process, surface treatment is conveyorised, chemicals and rinsing water being sprayed onto the goods, after which the goods are drip-dried in a simple drying equipment.

The problems involved in conveyorised brown and black-finishing are well known in the art since the extremely sensitive oxide layer is easily damaged.

According to the second process principle the goods are surface-treated in baskets which are transported from one tank to another by an overhead crane or with the aid of individual lowering and raising devices at each tank, as proposed in US-5,014, 726 (corresp. to EP-0 391 912). Such surface treatment gives the best brown or black-finish quality thanks to a combination of it being gentler and

control over the chemicals being better. When brown or black-finishing is complete the goods are dried for about 1 hour in a drying kiln, with controlled drying parameters, in order to drive the moisture out of the treated goods to enable them to be combined with the other internal layers, thereby producing a final product known as a multilayer card. However, such a drying procedure is a practical impossibility in a conveyer machine for the first-mentioned process principle since it would then be unreasonably long. In a conventional machine for basket surface-treating a drying tunnel can be installed as the last station. This entails a doubling of the length of the machine to about 9 meters. The supply and discharge sides are then at opposite ends of the machine, which entails problems for the operator.

The object of the present invention is to provide an improved machine of the type described in the introduction, which integrates various treating and handling units and measures that can be run completely automatically, which increases capacity, which treats scratch-sensitive goods gently, and which needs less space for installation and operation.

The machine according to the invention is characterized in that it comprises a) a second treating department for treating the goods with heat in an environment of air, which is integrated with the first treating department of the machine, said second treating department comprising transport means to convey the goods carriers from an inlet end to an outlet end of the second treating department; b) transport means for moving the goods carriers from the outlet end of the first treating department to the inlet end of the second treating department;

c) a loading and unloading station for loading goods into an empty goods carrier and unloading a goods carrier containing ready-treated goods; d) a device for moving the goods carriers from the loading and unloading station to the inlet end of the first treating department and from the-outlet end of the second treating department to the loading and unloading station; and e) in that said transport line for the goods carriers forms a closed loop.

The invention is described further in the following with reference to the drawings.

Figure 1 is a schematic top view of parts of a machine in accordance with the invention for treating sheets of printed circuit cards.

Figure 2 is an end view of the machine along the line II-II in Figure 1, turned 90°.

Figure 3 is a schematic view in perspective of the machine in accordance with Figure 1, certain sections and parts having been removed.

Figure 4 is a schematic view in perspective of the machine similar to Figure 3, but also showing a vertical conveyor.

Figure 5 shows parts of a goods carrier and its suspension.

Figure 6 is a view in perspective of a goods carrier used in the machine.

Figure 7 shows the goods carrier according to Figure 6 filled with sheets of printed circuit cards.

Figures 8 and 9 are side and end views of the goods carrier according to Figure 6.

Figure 10 is an enlargement of certain details in the machine according to Figure 4.

Figure-s 1-4 show schematically a machine for treating goods 1 in the form of sheets containing one or more printed circuit cards. The machine has a synchronised transport system and a computer-controlled control and monitoring system connected to the transport system. The machine comprises a first treating department 2 for treating the printed circuit card sheets 1 with different liquids and a second treating department 3 for treating the printed circuit card sheets 1 with heat in an environment of air. The first treating department 2 has an inlet end 4 and an outlet end 5. The second treating department 3 is situated above the first treating department 2 and its inlet end 6 is located vertically above the outlet end 5 of the first treating department 2, whereas its outlet end 7 is located vertically above the inlet end 4 of the first treating department 2.

The machine comprises a plurality of identical goods carriers 8 which are manipulated by said transport system in a predetermined manner with the aid of the computerised control and monitoring system. Each goods carrier 8 carries a plurality of printed circuit card sheets 1.

The first treating department 2 is a bath department comprising a plurality of similar vessels 9 placed close together in a straight row from the inlet end 4 to the outlet end 5. The vessels 9 are open at the top and their dimensions are such that a goods carrier 8 can be lowered down through the opening to a lowest end level in which

the printed circuit card sheets 1 are fully submerged in the liquid contained in the vessel. Each vessel 9 has a lowering and raising device 10 comprising a pair of brackets 11 which are slidably journalled in a vertical stand 12 in the inner vertical wall of the bath department 2, and an actuator (not shown) for moving the pair of brackets down and up. On the free ends of the brackets 11 is a rail section 13 which is situated above the vessel 9. The rail section 13 supported by the pair of brackets 11 is moved by means of the actuator between an upper end position and a lower end position. The rail section 13 may also have movable intermediate positions and be moved in shorter or longer upward and downward movements within desired distances between said end positions. In its upper end position the rail section 13 is situated in a horizontal part of a transport path or line 14, this part of the transport path extending from the inlet end 4 to the outlet end 5 of the bath department 2. When all the rail sections 13 are in their upper end positions, which may occur when the machine is started up, but not during operation, they form a continuous rail coinciding with or forming said horizontal part of the transport path 14. Close to this part of the transport path 14 is a horizontal beam 15, arranged in a roof stand of the bath department 2 (see Figure 5), which beam 15 is provided with a driver 16 for each rail section 13. Each driver 16 is movable from its starting position at its rail section 13 to a forward position situated within the next downstream rail section 13a in a reciprocating movement.

The second treating department 3 is a drying department comprising a closable tunnel 17 extending continuously from the inlet end 6 to the outlet end 7 and means (not shown) for supplying heat to the tunnel, preferably hot air for controlled drying of the printed circuit card sheets 1. A rail 18 is also arranged in the roof stand of

the drying department 3 and extends continuously between the inlet end 6 and the outlet end 7. A feeding arrangement (not shown) is provided in the vicinity of the rail 18, comprising a plurality of drivers and an actuator for reciprocating movement of the drivers. The inlet and outlet ends 6, 7 of the drying department are provided with openable hatches 20 to close the tunnel 17.

A preferred embodiment of a goods carrier 8, shown in Figures 6-9, comprises a carriage 41 and a basket-like part 36. The basket part 36 is constructed from sturdy wires with circular cross section, and has a feed-in end 21 at one long side 22, a feed-out end 23 at its other, opposite long side 24, a bottom side 25, a top side 26 and two opposing, parallel, flat larger sides 27, 28. The wires are arranged in a plurality of parallel wire planes 29 located a predetermined distance from each other so that open goods compartments 30 are formed between the wire planes 29. These goods compartments are open from the feed-in end 21 to the feed-out end 23, as can be seen in Figures 5 and 6, so that a printed circuit card sheet 1 can be fed in through the feed-in end 21 of the goods compartment 30 and fed out through the feed-out end 23.

The goods compartment 30 is sufficiently wide for a printed circuit card sheet 1 to be easily inserted into and withdrawn from the goods compartment 30 without friction or clamping. In other words, a clearance shall exist between the printed circuit card sheet 1 and the opposite wire planes 29 forming the goods compartment.

The wires 31 forming the feed-in end 21 of the goods carrier 8 are bend outwards, similar to a plough, the point 32 being situated a predetermined distance from the wires 33 of the bottom side 25 which is about half the vertical dimension of the printed circuit card sheet 1 as seen when the printed circuit card sheet 1 is in the goods compartment 30. These plough tips 32 facilitate feeding in the printed circuit card sheets 1 since they

function as guides between which the printed circuit card sheets 1 are first inserted. The wire parts forming the plough tip suitably encompass an angle of approximately 155°. At the feed-out end 23 the wires 34 are bent inwards in corresponding manner. During transport in vertical position the printed circuit card sheets 1 rest on wires 35 running transversely in the bottom side 25.

The wires 31, 34 in each wire plane 29 forming the feed-in and feed-out ends 21, 13 are joined together by wires 38 extending in the direction of movement of the printed circuit card sheets 1 into and out of the goods compartments 30. Some of these wires 38 are braced with a transverse wire 39. The goods carrier 8 thus has through-running, functional openings 40 defined by these wires as seen at right angles to the goods compartments 30. The bottom side 25 is somewhat longer than the dimension of the printed circuit card sheet 1 that extends in the feed-in and feed-out direction into and out of the goods compartment 30.

As can be seen in Figures 5-9 the carriage 41 is rigidly mounted on the top side 26 of the goods carrier 8 at a point somewhat off centre from the middle of the top side. The carriage 41 has a substantially U-shaped chassis 42 which is inverted. The carriage 41 is provided on one side with two bogie wheels 43, 44 and a rocker lever 45, the latter having two freely protruding pins 46, 47 running parallel to the axes of the bogie wheels 43, 44, one pin 47 of which functions as locking pin for the goods carrier 8 and the other, 46, as engagement pin for said driver 16. The rocker lever 45 endeavours to assume an inclined position so that the locking pin is brought into cooperation and engagement with a groove 48 in the upper side of the rail section 13 in order to fix a goods carrier 8 to the rail section 13. With the aid of the relevant driver 16 on the beam 15, the rocker lever 45 is caused by a forward movement of the driver 16 to

turn about its axis of rotation so that the locking pin 47 is lifted from its locking position in the groove 48 of the rail section 13 and so that the driver 16 hooks entirely into the engagement pin 46 in order to pull along the carriage 41 and its goods carrier 8 to the next rail section 13a. The driver 16 returns to its upstream starting position and the locking pin 47 falls freely down into the groove 48 in the new rail section 13a.

The machine also comprises a device for moving a goods carrier 8 from the outlet end of the drying department 3 to a loading and unloading station 49 for printed circuit card sheets 1, and thence to the inlet end 4 of the bath department 2. The device comprises a support frame 50 vertically journalled in vertical guide bars 51 of the machine stand and an actuator (not shown) for movement of the support frame 50 down and up between an upper collection point and a lower delivery point. The device also comprises a goods carrier holder 52, similar to a folding table, which is pivotably journalled on a horizontal shaft 56 to assume a vertical position, folded up, when it is inside the support frame 50 and a horizontal position, folded down, when it is in said loading and unloading station 49. The support frame is lifted by means of a cable 53 attached to the free end of the goods carrier holder 52, and a motor-driven drum 54 onto which the cable 53 is wound to fold up the goods carrier holder 52. The ends of the shaft 56 are journalled in the support frame 50 so that the whole goods carrier holder can be parallel-displaced in its folded-down position. The goods carrier holder 52 has a rail section 55, similar to the rail sections 13 in the bath department 2 described earlier, protruding at right angles from the goods carrier holder 52. When the goods carrier holder 52 is in its collect and delivery positions its rail section 55 is aligned with the rail 18 of the drying department and in an end-to-end

relationship and in line with the first rail section 13 of the bath department 2 which is then in its uppermost, collecting position, and is also in an end-to-end relationship. The goods carrier holder 52 is arranged in its horizontal, folded-down position to be moved in parallel by a motor, not shown, to effect lowering and raising in steps corresponding to the cc-distance between two adjacent goods compartments 30 in the goods carrier 8.

The loading and unloading station 49 comprises a central conveyor track 60, a first outer conveyor track 61 and a second outer conveyor track 62. The two outer conveyor tracks 61, 62 are situated one on each side of the central conveyor track 60. The three conveyor tracks 60, 61, 62 are situated in a common horizontal plane and move in directions perpendicular to a vertical central plane of the machine. The first outer conveyor track 61 is arranged to feed untreated printed circuit card sheets 1 from a stock, in the direction of the feed-in end 21 of the goods carrier 8 and in through the openings 63 of the empty goods compartments 30 (see Figure 8). Each goods compartment 30 is then directed to lie level with the feeding conveyor track 61. The second outer conveyor track 62 is arranged to feed treated printed circuit card sheets 1 away from the feed-out end 23 of the goods carrier 8 to a collection point 64 for the treated printed circuit card sheets 1. The middle conveyor track 60 is arranged to be driven in both directions, in the feed-in direction in the first case, i. e. the same direction as the first outer conveyor track 61, and in the feed-out direction in the second case, i. e. the same direction as the second outer conveyor track 62. The central conveyor track 60 comprises a plurality of parallel driving belts or transmission belts (not shown) of varying lengths, to run in the longer or shorter openings 40a, 40b, respectively, that extend transversely

through the goods carrier 8 between the flat large sides 27, 28. The longer driving belts thus extend between the feed-in end 21 and the feed-out end 23 but at a small distance from their wires 31, 34 so that the driving belts are completely free of any contact with the wires 31, 34. The shorter driving belts extend between the central bracing wires 39 and the feed-in end 21 on the one side and the feed-out end 23 on the other side. In a folded-down, horizontal position of the goods carrier holder 52 the driving belts will support the lowermost printed circuit card sheet 1 so that it does not touch the wires in the goods carrier 8, and when feed-out starts the driving belts carry printed circuit card sheet 1 with them, out through the feed-out end 23 and pass it to the second outer conveyor track. The goods carrier holder 52 is then lowered a step so that the driving belts will carry the next lowermost printed circuit card sheet 1. The procedure is repeated until the goods carrier 8 is empty. In this position loading of a new, untreated printed circuit card sheet 1 commences with the aid of the first outer conveyor track 61 and the central conveyor track 60, which is now driven in the other direction. The goods carrier holder 52 is moved stepwise upwards by means of parallel displacements and new printed circuit card sheets 1 are fed into the goods compartment 30 as they become substantially aligned with their central plane in a line with the first outer conveyor track 61. When the entire goods carrier 8 has been loaded, the goods carrier holder 52 is turned to vertical position with the aid of the cable 53, and in that position it is now situated at the inlet end 4 of the first treating department 2. This end is provided with an actuator (not shown) having a horizontal reciprocal rod with a driver which is brought into engagement with the forward pin 46 and pulls along the carriage 41 and its loaded goods carrier 8 to the aligned

rail section 13 of the first lowering and raising device 10.

At the outlet end 5 of the bath department 2 is a vertical conveyor 66. This is movable along a vertical stand 67 extending up to the inlet end 6 of the drying department 3 for transfer of a goods carrier 8 from the bath department 2 to the drying department 3. The vertical conveyor 66 is provided with a pair of brackets 68 and a rail section 69 supported thereby. In a collection position the rail section 69 is directed towards the last rail section 13 in the bath department 2. An actuator (not shown) has a rod protruding out over a goods carrier to the rail section 69 of the vertical conveyor. At the inlet end 6 of the drying department 3 is an actuator (not shown) with an arm having a driver which is brought into engagement with the carriage 41 of the raised goods carrier.

In an alternative embodiment of the machine, the loading and unloading station is mirror-inverted so that loading and unloading are performed in the opposite direction, i. e. from right to left in Figure 1. The goods carriers are also mirror-images. In an alternative embodiment of the goods carrier 8 the bogie wheels are situated on the other side of the carriage 41, i. e. on the side facing, or nearest to the feed-in end 21, with a corresponding change in the rocker-lever 45.

The machine described and illustrated above is thus intended for brown or black-finishing of printed circuit card sheets, which machine has a drying tunnel mounted above the department with process and rinsing steps, where the drying tunnel is integrated with the lower department and with the conveyor equipment for intermediate transport and return transport of goods carriers to and from a common feeding-in and feeding-out

station. The integration results in a machine requiring a minimum of space in this context and the space is exceptionally well utilised. The need for external drying unit and manipulation of the goods have been completely eliminated from untreated goods to treated goods. Extra space for the manipulating equipment has also been eliminated.

The mounting of a drying tunnel kiln above a dipping machine in accordance with the present invention, and simultaneous utilisation of the drying tunnel kiln for return transport of goods carriers to a common automatic feeding-in and feeding-out station for goods also results in the following advantages. A brown and black-finishing line on the market requiring by far the least amount of space, despite a drying tunnel kiln for an hour's drying having been integrated. The machine also has the capacity to deal with the requirements of the largest printed circuit card producers. Automatic and minimised movement of the scratch-sensitive goods is achieved. The machine is adapted to other automatic flows of material in the production. The capacity of the drying tunnel kiln is sufficient for all material surface-treated in the line and the kiln can therefore be used with great advantage as storage place and buffer station in the manufacturing process.

The machine is not limited to treating printed circuit cards or sheets containing printed circuit cards. It can be used for treating any objects that are or may become of interest for transportation in the manner described and for treating with various media and chemicals.

Examples of such other objects are stainless steel plates which are treated with various liquids and then dried.

Another machine for removing a layer of film from the goods, e. g. from the printed circuit card sheet, may be placed before and/or after the machine, which second machine is generally designated a"film stripper".