DE3737945A1 - Vacuum laminator - Google Patents

Abstract

A vacuum laminator is described for applying a thin film-like solder resist mask onto the conductor tracks of one or both sides of a board, the solder resist mask initially being applied cold onto the boards by means of rollers, like a film, and becomes the board covered with the film, where the film is coated on the board under pressure and heat. Known devices use rubber pads which are heated for coating the solder resist mask onto the board and are pressed onto the board, under pressure, in the vacuum chamber. However, in this case, it is possible for air enclosures to arise in a disadvantageous manner. Furthermore, the solder resist mask is disadvantageously not cut until after passing through the vacuum chamber, which results in considerable film losses. In order to avoid the disadvantages it is proposed that a cutting device be provided upstream of the vacuum chamber and that rotating, heated coating rollers are arranged in a stationary manner and opposite one another in the vacuum chamber, with a passage gap for the board 1 and with a transportation device connected upstream and downstream of the coating rollers. In a kinematic reversal, the coating rollers can also be arranged in the vacuum chamber such that they can be moved in the longitudinal direction of the board. This results in the solder resist mask being rolled onto the board in the manner of pinching rollers, as a result of which air enclosures are reliably prevented.

Description

The invention relates to a vacuum laminator for one or both sides Application of a thin foil-like solder mask on conductor tracks a circuit board according to the preamble of claim 1.

When manufacturing printed circuit boards or circuit boards is first on a copper-clad circuit board a positively coated film material laminated like a cut under heat and pressure. The The circuit board is then coated and etched so as to close the conductor track receive.

The solder mask is therefore at the end of the PCB manufacturing process applied, so in the last Production phase, with the solder mask on the finished etched PCB is laminated and there permanently for different Functions remains. The film can be applied by hand or with an upstream cut-sheet laminator or other laminator.

The electrical results as a function for the solder mask Insulation, protection against corrosion etc. and the cover and Protection when soldering yourself.

The solder mask can also be called a solder mask and was previously used primarily in screen printing, but now more and more in Photo printing process using dry photo films.

The application, i.e. the lamination of this solder mask is carried out by Pressure and heat through laminators, especially in a vacuum, thereby Air pockets between the film or the solder mask and the circuit board  to avoid.

This is already required for a DuPont device Vacuum laminator known, the foil-like solder mask according to Art of a film is rolled onto a circuit board and then the circuit board is opened a treadmill is fed to a vacuum chamber. In the vacuum chamber heated rubber plates are arranged in the known device, which under pressure and heat on one or both sides of the board are pressed on, in order to move the solder mask to the circuit board conceal. The disadvantage here is that in the area of Air trapped in solder mask, especially in the area of the flanks of the conductor tracks by pressing the rubber plates not completely can escape, so that air pockets remain in the lamination, which later impair the function of the solder stop mask when soldering can.

In the known device, the solder mask is still only on Output of the vacuum chamber trimmed, so that disadvantageous because of the Circuit board existing film material a significant film loss arises.

In the known device, it has also proven to be disadvantageous that the film is already in the area in front of the vacuum chamber on the board is rolled on relatively firmly, so from the start There are air pockets.

The object of the present invention is therefore to provide a vacuum Develop laminator of the type mentioned so that at constructive simple and reliable arrangement a good combination of Solder mask is created with the board without air pockets and that film losses are avoided.

To solve the problem are the characteristic features of the Claim 1 provided.  

The essence of the invention is that the board including the Soldering mask for lamination by rotating driven laminating rollers is passed through, due to a crushing effect Air pockets continuously between the solder mask and the circuit board to be ousted.

In a further embodiment of the invention it is provided that the Laminating rollers in the vacuum chamber in the longitudinal direction of the board are arranged movable. To that extent, here is a kinematically reversed the board with the film cut and the movable laminating rollers run like squeeze rollers across the board, which also makes it reliable here Air pockets are expelled.

The transport device within the vacuum chamber with fixed Laminating rollers are advantageously designed as a treadmill.

In a preferred embodiment, the passage gap of the laminating rollers is inside the vacuum chamber by means of a pressing device from the outside arranged so that the film can be cut under increased pressure rolled onto the board.

Are advantageous in front of the vacuum chamber for film application on the PCB unheated laminating rollers arranged with adjustable gap, a cutting device above or below the laminating rollers is intended for the film.

In a preferred embodiment, the cutting device runs in each case with the film in a partial area, the film being put on on the board and feeding into the laminating roller during its Movement in the direction of transport is cut off.

It is preferred that the cutting device cuts the film shorter than the board length in order to avoid such film loss or protruding edges - which could crumble away.

In a preferred embodiment it is provided that before Vacuum chamber for placing the solder mask on the circuit board Cut-sheet laminator with unheated laminating rollers with one opposite the board is provided with an enlarged gap, with a Feeder for the board with sensor scanning, the Film feed is provided on the board via suction tube rollers, and the cutting device for the film in the area of the suction tube rollers is pivotally arranged on a lever, and in the direction of Film transport along with cutting the film.

In the following, the invention is illustrated on the basis of several design options illustrative drawings explained in more detail. Here go from the drawing gene and its description further features essential to the invention and Advantages of the invention.

The subject matter of the present invention results not only from the subject matter of the individual patent claims, but also from the combination of the individual patent claims with one another. All information and features disclosed in the documents - including the summary - , in particular the spatial design shown in the drawings, are claimed to be essential to the invention, insofar as they are new to the prior art, individually or in combination. It shows

Fig. 1 a vacuum laminator according to the invention in a schematic representation in side view with an upstream cut-sheet laminator,

Fig. 2 shows a vacuum laminator shown in FIG. 1, but with movable laminating rollers in the vacuum chamber

Fig. 3 is a vacuum laminator upstream cutting device for cutting the soldering spot mask and an upstream laminator 2 for placing the film 18 or the solder mask on the board. 1

The laminator 2 consists of a feed device 19 for the circuit board 1 , which is then captured by the non-heated laminating rollers 3, including the film 18 placed thereon. In the laminating rollers 3 , the film 18 is only placed loosely on the board 1 in the manner of a blank because of the increased gap width.

The film 18 and the solder mask is in this case drawn off from a supply roll 17 and over Saugrohrwalzen 20 of the continuously running board 1 defined at the top 23 of the gap region is laminating rollers 3 is supplied, in conjunction with a sensor scanning in accordance with Fig. 3, consisting of sensors 21, 22 , which scan the circuit board 1 and, starting therefrom, start feeding the suction tube roller 20 , which then feed the film 18 to the circuit board 1 in the initial region 23 of the laminating rollers 3 .

The feeding of the solder mask or the film takes place in connection with the sensor scanning so that either the cut is as long as the board length is done, or that the cut is shorter than the board is cut to prevent film loss or any protruding edges of the To avoid film.

In the following, only one side of the film feeder is placed on the Circuit board or the cutting device described. With a double-sided The board to be loaded is the film feed or the cutting device structurally identical from the other side.

Between the Saugrohrwalzen 20, according to FIGS. 1 and arranged to Fig. 2 in front of the laminating rollers 3 a cutting means 16 which is shown in more detail in Fig. 3, and in particular, the film 18 is cut, during its movement, so that the plate 1 is continuously runs into the vacuum chamber 14 between the laminating rollers 3 . According to FIG. 3, the cutting device 16 from rotating knives 24 which are driven by a motor 25 or by a pneumatic drive. The cutting device 16 is pivotably arranged on a lever 26 and, starting from a pivot point 27 in the direction of the arrow 28 , also pivots with the running film 18 in order to cut it off during its movement.

The pivoting movement of the lever 26 is brought about via a pinion 29 which engages in a toothed rack 30 on the cutting device 16 .

To cut the film 18, the cutting knives 24 including the motor 25 move on a slide mounted on the lever 26 perpendicular to the lever 26 , ie in the transverse direction to the film 18 , and synchronously with respect to the sensor scanning via the sensors 21, 22 with respect to the length the circuit board 1 . In one embodiment , a preselection is provided in connection with the scanning pulses of the sensors 21, 22 in order to correspondingly pivot the cutting device 16 accordingly, in order thereby to cut the film 18 correspondingly shorter.

The cut end of the film 18 then runs over the lower suction tube roller 20 onto the circuit board 1 , ie the film blank including the circuit board 1 is drawn into the gap of the laminating rollers 3 and there, in particular according to a large gap between the laminating rollers 3, only loosely onto the circuit board 1 hung up.

In the case of blanks 1 to be coated on both sides, an equivalent film feed and cutting device is provided from the bottom according to FIGS . 1 to 3.

The FIGS. 1 and 2 covered with the film blank board 1 then runs into a vacuum chamber 14 where a vacuum device is put into service. 13

According to Fig. 1, fixed heated laminating rollers 7 are arranged in the vacuum chamber 14 , which are driven in rotation by a motor and are pressurized by a pressing device 8 in order to thus capture the circuit board 1 - and laminate the film blank onto the circuit board 1 - in a vacuum .

The circuit board 1 - in the exemplary embodiment according to FIG. 1 is fed to the laminating rollers 7 lying on a conveyor belt 6 in the direction of the arrow 5 . In connection to the laminating rollers 7 , a conveyor belt 9 according to FIG. 1 is also provided and further also at the outlet end 10 where the circuit board 1 '' is discharged via an outlet conveyor belt 11 in the direction of the arrow 12 . This passage of the board 1 , 1 - and 1 '' through the vacuum chamber, starting from the upstream laminator 2 , is particularly advantageous because fully automatic operation can be formed here.

In the embodiment according to FIG. 1, the laminating rollers 7 are arranged in a fixed manner in the vacuum chamber 14 , as a result of which the circuit board 1 - and the film blank lying thereon are drawn into the roll gap of the laminating rollers 7 starting from the conveyor belt 6 .

In this case, from the beginning to the end of the circuit board 1 , the film blank or the solder mask is pressed on, as a result of which any air pockets are reliably squeezed out.

In the exemplary embodiment according to FIG. 2, the board 1 -, starting from the upstream cold laminating rollers, is supplied with a support 31 in the vacuum chamber 14 . . Subsequently, the movable arranged according to the embodiment of Figure 2 in direction of arrow 32 laminating rolls 15 press the solder mask continuously on the circuit board 1 - on, thus also any air inclusions can be reliably squeezed. In this respect, the embodiment according to FIG. 2 represents a kinematic reversal of the embodiment according to FIG. 1.

The movable laminating rollers 15 move according to FIG. 2 after being pressed back into the basic position and the board 1 '' is extended on an outlet table 33 from the vacuum chamber 14 .

To this extent, in the exemplary embodiments according to FIGS. 1 and 2, the air between the circuit board 1 and the film blank or the solder mask is completely displaced in the manner of a squeeze roller in continuous line contact, as a result of which very good air removal is achieved.

Due to the linear contact of the heated laminating rollers 7 , 15 on the film, there is a squeezing and also a temperature-related expansion or relative displacement of the film to the circuit board 1 '', which is slight, but sufficient, possibly still existing air pockets remove, and moreover, this results in an excellent heat welding process of the plastic mass of the film on the surface of the circuit board 1 ''.

The two versions according to FIGS. 1 and 2 have in common that after the lamination process in the vacuum chamber 14, the vacuum is released, so that in addition due to the sudden atmospheric pressure, a second lamination takes place in the manner of a sudden compression of the plastic material of the film the circuit board 1 - in connection with a further air removal.

In the vacuum laminator shown in FIG. 1 and FIG. 2, in particular with the combination of the upstream laminator to the film and board supply in connection with the cutting device 16 of FIG. 3, a fully automatic operation is enabled, wherein in connection with the in idaaler as during the lamination process, a particularly good bond between the solder mask on the circuit board is achieved and losses are avoided here.

Claims (8)

1. Vacuum laminator for one-sided or two-sided application of a thin, foil-like solder mask to the conductor tracks of a circuit board, the solder mask, in the manner of a film, first being placed cold on the circuit board by means of rollers, and the circuit board covered with the film is moved over a treadmill of a vacuum chamber where the film is laminated onto the board under pressure and heat, characterized in that a cutting device ( 16 ) is provided in front of the vacuum chamber ( 14 ) and in the vacuum chamber ( 14 ) stationary and oppositely rotating heated laminating rollers ( 7 ) are arranged with a passage gap for the circuit board 1 - and a transport device 6, 9 upstream and downstream of the laminating rollers ( 7 ) , FIG. 1. 2. Vacuum laminator according to claim 1, characterized in that the laminating rollers ( 15 ) in the vacuum chamber ( 15 ) in the longitudinal direction of the board 1 - are arranged movable ( Fig. 2). 3. Vacuum laminator according to claim 1, characterized in that the transport device 6, 9 is designed as a treadmill. 4. Vacuum laminator according to claim 1 and 2, characterized in that the passage gap of the laminating rollers 7, 9 is made adjustable by means of a pressing device. 5. Vacuum laminator according to claim 1, characterized in that in front of the vacuum chamber ( 14 ) for film application to the board 1 unheated laminating rollers ( 3 ) are arranged with an adjustable gap and that above or below the laminating rollers ( 3 ) a cutting device ( 16 ) is intended for the film. 6. Vacuum laminator according to claim 5, characterized in that the cutting device ( 16 ) runs in each case with the film ( 18 ) in a partial area and that the film ( 18 ) during placement on the board 1 and the feed into the laminating rollers ( 3 ) is cut off in the transport direction during its movement. 7. Vacuum laminator according to claim 5, characterized in that the cutting device ( 16 ) cuts the film ( 18 ) shorter than the board length. 8. Vacuum laminator according to claim 1, characterized in that in front of the vacuum chamber ( 14 ) for placing the solder mask on the board 1, a cut-sheed laminator ( 2 ) with unheated laminating rollers ( 3 ) with an enlarged gap compared to the board 1 is provided, with a feed device ( 19 ) for the circuit board 1 with sensor scanning, the film feed on circuit board 1 being provided via suction tube rollers ( 20 ) and the cutting device ( 16 ) for the film ( 18 ) pivotable in the region of the suction tube rollers ( 20 ) a lever ( 26 ) is arranged and moves in the direction of the film transport when cutting the film ( 18 ).