TWI635032B - Transport device for flat substrates - Google Patents

Abstract

The present invention relates to the delivery of flat substrate substrates such as printed circuit boards and similar electronic substrates or electrical engineering substrates. The conveying device comprises one or preferably a plurality of conveying rollers (1) continuously arranged in the conveying direction, and/or at least one of which is disposed in a stacked manner with each other, and which is perpendicular to the conveying direction, and forms a substrate conveying gap therebetween (5). Each of the conveyor rollers includes a shaft (2) and a substrate contact zone (4') rotatably secured to the shaft. The conveyor further comprises a feed carrier (6) having a journal bearing (9), wherein each conveyor roller is mounted on one side, or preferably on both sides, with the respective terminal pin (10) Rotatable movement.

Description

Flat substrate conveying device

The present invention relates to a flat substrate transport device, and more particularly to printed circuit boards and similar electronic substrates or electrical engineering substrates such as structured and unstructured semiconductor wafers for electronic and electrical engineering and Delivery of film components). The conveying device comprises one or preferably a plurality of conveying rollers continuously arranged in the conveying direction, and/or a pair of at least two of which are disposed one on another, and which is perpendicular to the conveying direction and forms a substrate conveying gap therebetween. Each of the conveyor rollers includes a shaft and a substrate contact zone rotatably secured to the shaft. The conveyor further includes a feed carrier having a journal bearing, wherein each conveyor roller is mounted on one side, or preferably on both sides, that rotatably moves with the respective terminal pin.

These delivery devices are conventional in various embodiments. A conveyor device of this type is disclosed, for example, in the patent publication DE 101 28 386 A1, in which the journal bearings for the conveyor rollers are exclusively formed by inserts which are replaceably inserted into corresponding recesses of the feed carrier. The shaft of the conveyor roller is usually made of titanium, stainless steel or polytetrafluoroethylene (PTFE). Feed carriers with journal bearings are typically constructed of a plastic material such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC) or polyvinylidene fluoride (PVDF).

For printed circuit boards and similar substrates, it is often necessary or required to protect them from electrostatic charges. In situations where the substrate undergoes a process that uses liquid treatment, this situation typically prevents such undesirable electrostatic charges. This protection mechanism is not provided on a transport path without liquid handling. These "dry" transport paths are, for example, typical entry into the module substrate processing system. Modules, control modules, drying modules and exit modules.

It is known to counteract electrostatic charges in such dry transport paths by using ion spray bars above and/or below the substrate transport plane. However, under many environmental conditions, such as for use in, for example, printed circuit board processing, such plasma spray bars cannot be used continuously, such as in ambient air of hybrid chemicals and at elevated temperatures (such as in dry modules). Predominant in the environment.

Although it is also possible to protect the substrate from electrostatic charges by causing the metal transfer roller to contact the substrate not only in its shaft but also in its substrate contact area, this situation is likely to result in a surface of the substrate. Damage, which may result in functional failure under conditions of the printed circuit board, for example, by damage to its fine conductive track structure. In addition, metal materials commonly used for conveyor rolls, such as stainless steel or titanium, are only limitedly compatible with use in printed circuit board manufacturing plants due to their limited chemical stability.

The present invention is based on the technical problem of providing a conveying device of the type mentioned in the introduction, in which a flat substrate such as a printed circuit board can be protected from electrostatic charges during transport in an improved manner.

The present invention achieves this object by providing a conveying device having the features of claim 1. In this conveying device, the contact area of the conveying roller substrate and the journal bearing area of the feeding carrier are composed of a conductive plastic material. Further providing a discharge path, the conveyor roller substrate contact zone and/or the feed carrier journal bearing zone are electrically connected to the discharge path.

The conveying device according to the invention thus ensures that the charge is sufficiently dissipated from the flat substrate conveyed by the discharge path or from the conveying roller and the feed carrier, so that an unwanted electrostatic charge which would cause damage to the substrate is not formed. The charge in the journal bearing zone of the feed carrier can be dissipated directly without reaching the substrate. The charge formed in the contact area of the conveying roller with the substrate can be dissipated via the conveying roller and the feed carrier. The substrate contact area of the transport roller (which consists of a conductive plastic material) contacts the substrate such that contact of the transported substrate with the metal transfer roll zone is avoided.

In an optimisation of the invention, the electrically conductive plastic material used to convey the roll substrate contact zone or the feed carrier journal bearing zone is a conductive PP material or a PE material or a PVDF material or a polyetherketone (PEEK) material. These materials have proven to be highly suitable for this application.

In an optimisation of the invention, in order to provide the desired conductivity, the electrically conductive plastic material contains a filler which is preferably introduced in the form of particles, the filler being composed of a carbon black material or a graphite material or a palladium material.

In an optimization of the invention, the discharge path is configured for discharge resistance in the range from 0.1 MΩ to 2 MΩ. The discharge path thus constitutes a defined high value resistor, such as a controlled dissipation that is particularly suitable for the undesirable electrostatic charge that may occur.

In an optimisation of the invention, the shaft of each conveyor roller is formed from a metallic material, in particular, the metallic material may be a stainless steel material.

In an optimisation of the invention, the feed carrier comprises a metal substrate and a journal bearing insert attached thereto, the journal bearing insert comprising a journal bearing region of the feed carrier, and correspondingly the latter It is made of conductive plastic material.

In an optimisation of the invention, the feed carrier comprises a metal rail electrically connected to the journal bearing region of each conveyor roller and the discharge line is electrically connected to the metal rail. The metal rails can thus be used as collector rails for the discharge path, in which the electrostatic charge of the conveyor rollers or their journal bearings can be dissipated together by the collector rails in the case of a plurality of conveyor rollers Discharge line. The metal rails further satisfy the mechanical stabilization function for the feed carrier.

1 to 3 show a transport device in which a printed circuit board or similar flat substrate, such as specifically used in the electronics and electrical engineering industries, can be transported along a transport direction T, for example, on a horizontal transport path. For this purpose, the conveying device comprises a plurality of conveying rollers 1, which can be arranged identically or differently from each other, as required. In the illustrated example, it is a condition that is configured differently from each other. In the partial views of Figs. 1 to 3, one of the roller type pair of the conveying roller 1a and one of the roller type to the conveying roller 1b can be seen, and the two roller pairs are continuously arranged in the conveying direction T, and two of each pair are conveyed. The rollers are arranged to be stacked one on another in a direction perpendicular to the conveying direction T. All of the conveying rollers 1a, 1b are arranged with mutually parallel longitudinal axes.

The roller-type conveying roller 1a contains a shaft 2 on which a large number of rollers 3 are held rotatably fixed at axial distances from each other. In the state of the roller-type conveying roller 1b, the roller drum 3' is rotatably fixed to the shaft, and the lateral surface 4 of the drum forms a substrate contact area, and the conveying roller 1b is contacted by the substrate. The substrate is contacted and the substrates are transported by rotational movement of the rolls. In the case of the roll type conveying roller 1a, the substrate contact area is formed by the circumferential surface 4' of the roll 3. As can be seen from FIG. 2 and FIG. 3, the conveying rollers 1a, 1b which are arranged in pairs in a roll type and a drum type, respectively, are formed with a substrate conveying gap 5 therebetween, and the substrate is conveyed in the conveying direction T. The material conveying gap transports the substrate, at its end, each pair of the conveying rollers 1 rotates in the opposite sense, and the conveying rollers 1 continuously arranged at the same height in the conveying direction T rotate in the same sense.

In order to support and drive the transport roller 1, the transport device has a feed carrier which, in the example shown, contains two lateral feed carrier units 6a, 6b on the side of the transport roller 1. Each feed carrier unit 6a, 6b comprises a longitudinal extension below the transport roller 1 parallel to the transport direction T The base body 7 and the journal bearing region 8 projecting upward from the longitudinal direction of the conveying roller and the longitudinal axis of the conveying roller. Each journal bearing region 8 contains a journal bearing 9 in which the shaft 2 of the conveyor roller 1 is kept rotatably movable with the respective shaft end or shaft pin 10.

On one side, here on the right hand side of Figures 1 to 3 (on which the feed carrier unit 6a is located), the feed carrier 6 comprises a conventionally designed roller drive with a continuous drive shaft in the conveying direction 11. The individual conveyor rollers 1 are coupled to the roller drive by means of bevel gears.

The conveyor further includes a discharge path to which the conveyor roller substrate contact zones 4, 4' and the feed carrier journal bearing zone 8 are electrically connected. As an alternative, for example only the journal bearing region 8 can be electrically coupled to this discharge path. The discharge paths respectively contain discharge lines 12a, 12b starting from each of the feed carrier units 6a, 6b and being electrically contactably attached to the feed carrier units 6a, 6b by means of associated threaded connections. In the illustrated example, the continuous conductive and preferably metal rails 13a, 13b are respectively attached in the lower region of the feed carrier unit 6a, 6b with the same threaded connection, in electrical contact with the latter and with the discharge lines 12a, 12b. . The two rails 13a, 13b have a mechanical stabilization function for the respective feed carrier units 6a, 6b and are used to dissipate charge from the journal bearing region 8 to the associated discharge lines 12a, 12b. A collector rail is assigned to the various conveyor rollers 1.

The circumferential surface 4' of the roll cylinder 3 serving as the substrate contact area is composed of a conductive plastic material (preferably, a PP material, a PVDF material or a PEEK material) by a particle filler of a carbon black material, a graphite material or a palladium material. The conductive plastic material can be made conductive to a desired degree. Depending on the requirements and application, the remainder of the roller 3 can also be made from this electrically conductive plastic material. The lateral surface 4 of the cylindrical conveying roller 1b serving as the substrate contact region is likewise composed of electrically conductive and preferably thermoplastic plastic material, and there are also the following conditions, depending on the requirements and applications, the roller portion of the conveying roller 1b. This is likewise composed of a conductive plastic material or alternatively a different material. The shaft 2 of the conveying roller 1 is preferably made of stainless steel or another metal material. As an alternative, in the event that this situation seems to be advantageous, it will be understood that the shaft 2 may be constructed from one of the aforementioned electrically conductive plastic materials.

The journal bearing region 8 of the feed carrier 6 is also made of a conductive plastic material (specifically, one of the materials mentioned above in this regard). Conductive PE materials or PEEK materials are preferably used herein. The use of PEEK material is preferably limited to the journal bearing zone 8, while the remainder of the feed carrier 6 (i.e., its base 7) is then preferably made of a metallic material such as titanium or stainless steel. As an alternative, the feed carrier base 7 can also be constructed of a conductive plastic material for the journal bearing zone 8, in which case a single piece production of the individual feed carrier units 6a, 6b is also possible. The use of PEEK materials is advantageous especially for applications where relatively high ambient temperatures occur, such as in a dry module where ambient temperature is prevalent, for example, up to 90 °C.

In each of the embodiment variants mentioned, it is ensured that there is a continuous electrical connection from the transport roller substrate contact regions 4, 4' to the discharge lines 12a, 12b (for any dissipation of electrostatic charge) of). In this case, the discharge path in question is preferably configured for discharge resistance in the range from 0.1 MΩ to 2 MΩ, in particular, by the conductivity of the conductive plastic material or material used. Adjust to achieve this situation. In this way, in the conveying device, when the electric charges are formed by the rotation operation of the conveying roller 1 in the contact area with the substrate 1 and in the journal bearing region 8 of the feeding carrier units 6a, 6b The substrate or printed circuit board thus transported is reliably prevented from being exposed to excessive electrostatic charges. According to the invention, these electrostatic charges are reliably dissipated in the transport device via the discharge path and its discharge lines 12a, 12b.

Figures 4 and 5 illustrate variants of the delivery device of Figures 1 to 3, for the sake of easier understanding, the same and functionally equivalent elements use the same reference, and in this regard, reference may be made to the delivery device of Figures 1 to 3 Described above.

The conveyors of Figures 4 and 5 differ from those of Figures 1 to 3 above in that the journal bearing regions 8 of the two feed carrier units 6a, 6b are formed as separate components from the respective substrates 7. And as a journal bearing insert mates with a corresponding recess of the feed carrier units 6a, 6b. This situation on the one hand allows a simple material decoupling of the journal bearing region 8, and on the other hand allows The simple material of the base body 7 is decoupled and, if necessary, allows for a simple alternative of the journal bearing regions 8, which are more sensitive to wear when the base body 7 is held. The base body 7 can in this case be made, for example, of a stainless steel material, while the journal bearing insert can be made of a conductive PEEK material if necessary.

It is further possible to ensure that all device components have the required chemical stability and the thermal stability required for such various device components by the above explained selection of suitable materials for the various mentioned components of the delivery device. , depending on the application.

It should be understood that in alternative embodiments, the delivery device according to the present invention may contain different numbers and configurations and different configurations of delivery rollers depending on the type of substrate to be delivered and the location or environmental conditions. However, in each case, a discharge path is provided by which the electrostatic charge in the conveyor roll substrate contact zone and/or the feed carrier journal bearing zone can be reliably dissipated and thereby avoided. On the other hand, in the absence of such a situation, the problem of a decrease in the chemical or thermal stability of the device is caused.

1‧‧‧Conveying roller

1a‧‧‧Roll type conveyor roller

1b‧‧‧Roller type conveyor roller

2‧‧‧ shaft

3‧‧‧ Roll

3'‧‧‧ Roller

4‧‧‧Feed roller substrate contact area/lateral surface

4'‧‧‧Conveyor roll substrate contact area/circumferential surface

5‧‧‧Substrate transport gap

6‧‧‧Feeding carrier

6a‧‧‧Feeder unit

6b‧‧‧Feeder unit

7‧‧‧ base

8‧‧‧ journal bearing area / journal bearing insert

9‧‧‧ journal bearings

10‧‧‧ terminal pin

11‧‧‧Roller drive

12a‧‧‧Discharge line

12b‧‧‧Discharge line

13a‧‧‧Metal rail

13b‧‧‧Metal rail

Advantageous embodiments of the invention are shown in the drawings and will be described below. In the drawings: Figure 1 shows a partial plan view of a printed circuit board transport device comprising a plurality of transports arranged in pairs in a transport direction and arranged in pairs in a direction transverse to the transport direction. Roller, Figure 2 shows a cross-sectional view taken along line II-II of Figure 1, Figure 3 shows a cross-sectional view along line III-III of Figure 1, and Figure 4 shows a corresponding view of a variant for the transport device of Figures 1 to 3. 1 is a plan view, and FIG. 5 shows a cross-sectional view taken along line VV of FIG.

Claims (7)

A conveying device for a flat substrate, comprising: one or more conveying rollers (1) continuously arranged in a conveying direction and/or stacked in a direction transverse to the conveying direction and forming a substrate therebetween At least one pair of conveying rollers (1) conveying a gap, wherein each conveying roller comprises a shaft (2) and a substrate contact region (4, 4') rotatably fixed to the shaft, and has a journal bearing ( 9) a feed carrier (6), wherein each conveyor roller is mounted for rotatably moving with a terminal pin (10), wherein the conveyor roller substrate contact zone (4, 4') and the feed The journal bearing region (8) of the carrier (6) is formed of a conductive plastic material to provide a discharge path, and the conveyor roller substrate contact region and/or the feed carrier journal bearing region are electrically connected to the discharge path, And the feed carrier comprises continuous metal rails (13a, 13b) electrically connected to the journal bearing zone (8) of each conveyor roller, and the discharge lines (12a, 12b) are electrically connected to the metal rails Where the metal rails (13a, 13b) and the discharge lines (12a, 12b) are attached to the lower region of the feed carrier (6) with the same threaded connection The metal rail (13a, 13b) is formed for dissipating a charge from the journal bearing region (8) to the discharge line (12a, 12b) of the current collector rail. The delivery device of claim 1, wherein the electrically conductive plastic material is a conductive PP material or a PE material or a PVDF material or a PEEK material. The delivery device of claim 1 or 2, wherein the electrically conductive plastic material comprises a conductive filler composed of a carbon black material or a graphite material or a palladium material. The delivery device of claim 1 or 2, wherein the discharge path is configured for a discharge resistance in a range from 0.1 MΩ to 2 MΩ. The conveying device of claim 1 or 2, wherein the shaft of each of the conveying rollers is formed of a metallic material, in particular stainless steel. The conveying device of claim 1 or 2, wherein the feeding carrier comprises a base body (7) composed of a metallic material, in particular stainless steel, and a journal bearing insert (8) composed of the electrically conductive plastic material, the shaft A neck bearing insert is attached to the base and contains the journal bearing region. A delivery device according to claim 1 or 2, wherein the delivery device is configured to convey a printed circuit board as the flat substrate.