JPH10329303A - Cream solder printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the print quality by eliminating defective printing, e.g. a print miss or a shift of printing position, even in the case of fine printing or high speed printing and performing printing stably on a surface to be printed. SOLUTION: A relation L1 >L2 is set between the dimension L1 in the printing direction of a print mask provided with a pattern opening and the dimension L1 in the printing direction of the print mask on the inside of a frame. Cream solder is printed on the mask and the frame on the side vertical to the printing direction using a mask connected through a resilient member, e.g. a mesh material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cream solder printing apparatus for printing and applying cream solder on a printing surface.

[0002]

2. Description of the Related Art In the manufacture of electronic circuit boards, cream solder is mainly used when soldering electronic components such as chip components onto a printed circuit board, and when printing and applying cream solder onto a printed circuit board. A printing mask in which an opening of a desired pattern is formed is used. As a material of a mask used for cream solder printing, a metal such as stainless steel or a nickel alloy is generally used, and is usually called a metal mask. In recent years, a resin material mask has appeared. Here, a metal mask generally used as a mask used for cream solder printing will be described.

As shown in FIGS. 4A and 4B, a metal mask 1 is attached to a frame 2 for holding the metal mask 1 through a highly elastic mesh material 3. Usually, this fixing method is called a combination. That is, the mesh material 3 adhered and fixed to the frame 2 and the metal mask 1 are adhered and fixed (hereinafter, referred to as a combination) at the joint 4.
A metal mask 1 is held on a frame 2.

A cream solder printing method using the metal mask 1 will be described with reference to FIGS. 5A and 5B and FIGS. 6A to 6C. 5 and 6, reference numeral 5 denotes a printing squeegee that moves linearly on the metal mask 1 along the printing direction, 6 denotes cream solder, and 7 denotes a printed circuit board. FIG. 5B shows a squeegee 5 for rightward printing that moves from left to right. Although not shown, a squeegee 1 for leftward printing is usually arranged at a position facing the squeegee 1 for rightward printing, and the squeegee 1 for leftward printing moves leftward from right to left. Used during printing. In FIG. 6, reference numeral 1a denotes an opening of the metal mask 1, 8 denotes a land on which the cream solder 6 is printed, and 9 denotes a solder resist.

In the cream solder printing, first, after the printed circuit board 7 is positioned on the metal mask 1 and overlapped, the squeegee 5 is lowered and the tip of the squeegee 5 is moved to the surface 1b of the metal mask 1 (FIG. 6A). (See FIG. 2) at an appropriate printing pressure, and linearly move along the printing direction to separate the printed circuit board 7 in which the cream solder 6 has been filled into the opening 1a of the metal mask 1 from the metal mask 1 (hereinafter referred to as separation of the plate). Is described). In this manner, the cream solder 6 is continuously printed and applied on the lands 8 of the printed circuit board 7 via the metal mask 1 by alternately repeating these operations in the right and left directions.

By the way, cream solder printing is performed by the above-described apparatus and method. Originally, cream solder printing is an application of a technique of mesh screen printing for printing a paste material or the like. Therefore, the mask configuration and method, etc.
In many cases, the main parts are taken over as they are. Here, regarding the mesh screen printing, FIG.
This will be briefly described with reference to FIG. 8B and FIGS. 8A and 8B. In the mesh screen printing method, as shown in FIG. 7A, first, the substrate 21 is arranged on the back side of the mesh screen mask 22. At this time, a gap G of several millimeters is provided between the substrate 21 and the mesh screen mask 22. As shown in FIG. 7B, in this state, the squeegee 23 is lowered and linearly moved in the printing direction, so that the paste 24 is printed and applied onto the substrate 21 via the mesh screen mask 22.

Here, as can be seen from FIG. 7A, since a gap G is provided between the substrate 21 and the mesh screen mask 22, the squeegee 23 is used to remove the mesh screen mask 22 during printing. It is deformed and brought into contact with the substrate 21. Therefore, the plate separating operation is performed at any time by the expansion and contraction of the mesh screen mask 22 accompanying the movement of the squeegee 23.

As shown in FIG. 8, a mesh screen mask 22 used for such mesh screen printing is formed by joining a high elastic mesh material 26 adhered and fixed to a frame 25 to a mesh screen mask 22.
It is a combination of the part. Incidentally, the mesh screen mask 22 is expensive because a fine mesh material is used.
By combining No. 6, the cost and life of the entire mask are reduced.

A comparison between the mesh screen mask 22 used for the above-described mesh screen printing and the metal mask 1 used for the cream solder printing shows that, except for the difference in the material of the mesh screen mask 22 and the metal mask 1 itself, the structure is as follows. It is clear that the metal mask 1 is made by applying the configuration of the mesh screen mask 22.

[0010]

By the way, in recent years, the pitch of the openings of the metal mask 1 has become 0.3
mm is required, but cream solder printing using the metal mask 1 having the above-mentioned conventional configuration requires the printing shown in FIG.
As shown in the figure, even if the printed circuit board 7 is accurately positioned and superposed on the metal mask 1, more precisely, even if the land 8 of the printed circuit board 7 is accurately positioned on the opening 1 a of the metal mask 1, When the tip of the squeegee 5 moves while being in contact with the surface 1 b of the metal mask 1, the metal mask 1 moves with the squeegee 5 and shifts to a position between the opening 1 a of the metal mask 1 and the land 8 of the printed circuit board 7. There has been a problem that a displacement X (see FIG. 6B) occurs and a printing failure such as a print omission failure Y or a printing position displacement failure Z (see FIG. 6C) occurs.

Here, the displacement of the metal mask 1 at the time of printing is caused by the following phenomenon. Squeegee 5 when printing
The printing pressure acts on the squeegee 5 and the metal mask 1
Since the surface 1b of the squeegee 5 is in contact with the pressed state, a frictional force is generated between the squeegee 5 and the
The metal mask 1 is pulled in the same direction as the printing direction.

As shown in FIG. 4, in the conventional configuration, a dimension A _{1 in the} same direction as the printing direction on the metal mask 1 and a dimension A _{1 in the} same direction as the printing direction inside the frame 2.
₂ and A ₁ <A ₂ . As can be seen from this relationship, since the metal mask 1 is held in the frame 2 by being combined via the elastic portion of the highly elastic mesh material 3, the portion of the mesh material 3 which expands and contracts in the same direction as the printing direction. Exists. For this reason,
The portion of the mesh material 3 expands and contracts due to the frictional force acting on the metal mask 1, causing the metal mask 1 to shift. In particular, when the printing speed is increased, when the printing pressure is increased, and the like, the frictional force is increased, so that the deviation is also increased.

An object of the present invention is to solve the above-mentioned problems, and to perform stable printing on a printing surface without occurrence of printing defects or printing position deviations even in fine printing or high-speed printing. It is an object of the present invention to provide a cream solder printing apparatus capable of improving printing quality.

[0014]

In order to solve the above-mentioned problems, a cream solder printing apparatus according to the present invention comprises a printing mask in which an opening of a desired pattern is formed, and a frame having a frame shape for holding the mask. And a squeegee for applying cream solder, and a cream solder printing apparatus for printing and applying cream solder on a surface to be printed via a mask by moving the squeegee on the mask, wherein a printing direction in the mask is provided. and the same dimension L _1, a dimension L ₂ of the same direction as the printing direction in the frame inside, L ₂ <L
It is configured to be ₁ .

With this configuration, even in fine printing, high-speed printing, etc., there is no occurrence of a printing defect or a printing position shift, and stable printing can be performed on the printing surface, thereby improving printing quality. can do.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cream solder printing apparatus according to claim 1 of the present invention comprises a printing mask having a desired pattern of openings, a frame holding the mask, and a cream solder. A cream solder printing apparatus that includes a coating squeegee, and moves and moves the squeegee on the mask to print and apply cream solder on the printing surface via the mask. The dimension L ₁ and the dimension L _{2 in the} same direction as the printing direction on the inner side of the frame are configured such that L ₂ <L ₁ . Because it is in a fixed state, even in fine printing or high-speed printing, there is no occurrence of printing failure such as printing omission failure or printing position deviation failure, and stable printing is performed on the printing surface, Printing quality can be improved.

In the direction perpendicular to the printing direction, the dimension L _{4 of} the mask and the dimension L ₅ inside the frame are set.
Are connected such that L ₄ <L ₅ , and the outer portion of the metal mask and the inner side of the frame are connected by an elastic member made of a stretchable mesh material or the like. Acting on the mask, the metal mask is held on the frame without wrinkles or sagging.

Hereinafter, a cream solder printing apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIGS. 1A and 1B are a plan view and a front sectional view taken along the line II, respectively, showing a metal mask and its vicinity in the cream solder printing apparatus according to this embodiment. The same components are denoted by the same reference numerals and description thereof will be omitted.

The metal mask 1 has a frame 2 having a frame shape.
In addition, a dimension L _{1 in the} same direction as the printing direction on the metal mask ₁ and a printing direction inside the frame 2 are adhered and fixed to the frame 2 via a highly elastic mesh material 3 as an elastic member. Dimension L in the same direction as
₂ is such that L ₁ > L ₂ . The outer diameter L ₄ and the frame 2 of the metal mask 1 with respect to a direction perpendicular to the printing direction in the metal mask 1
Inside of the dimension L ₅ of, and configured to be L ₄ <L _5.

That is, since L ₁ > L _{2 in} the same direction as the printing direction, the metal mask 1 is held almost directly on the frame 2 by being adhered and fixed to the frame 2. Here, strictly speaking, a mesh material 3 is interposed between the metal mask 1 and the frame 2. However, since the mesh material 3 in this portion is bonded and fixed to both the metal mask 1 and the frame 2, it does not substantially expand and contract, and the metal mask 1 is directly bonded and fixed to the frame 2. It is securely fixed as well. On the other hand, since L ₄ <L _{5 in} the direction perpendicular to the printing direction, only the mesh material 3 is provided between the outside of the metal mask 1 and the inside of the frame 2. This part of 3 is freely expandable and contractable.

As an example of a procedure for fixing the metal mask 1 to the frame 2, first, a mesh material 3 is bonded and fixed to the entire surface of the frame 2. At this time, the attachment is performed in a state where tension is applied so that wrinkles and sagging do not enter the mesh material 3. Next, the mesh material 3 and the metal mask 1 are bonded and fixed at the joint 4. After that, unnecessary portions of the mesh material 3 are removed to fix and hold the metal mask 1 on the frame 2. Therefore, the metal mask 1 is held in the frame 2 via the mesh material 3 by being combined with the mesh material 3 in the direction perpendicular to the printing direction, and the tension by the mesh material 3 acts on the metal mask 1. The metal mask 1 is held by the frame 2 without wrinkles or sagging.

Using the metal mask 1 configured as described above, cream solder printing is performed by the method described below. This will be described with reference to FIGS. The same components as those in the related art are denoted by the same reference numerals, and description thereof is omitted.

First, a predetermined amount of cream solder 6 is supplied onto the surface 1b of the metal mask 1. Next, after the printed circuit board 7 is positioned and superposed on the metal mask 1, the squeegee 5 is lowered, and the leading end of the squeegee 5 is brought into contact with the surface 1 b of the metal mask 1 at an appropriate printing pressure in the printing direction. Then, the cream solder 6 is filled in the opening 1a of the metal mask 1 by linear movement. Thereafter, cream solder printing is performed by separating the printed board 7 from the metal mask 1. In this way, by repeating these operations alternately in the right and left directions, the cream solder 6 is continuously printed and applied on the lands 8 of the printed circuit board 7 via the metal mask 1.

At this time, even if the metal mask 1 is pulled in the same direction as the printing direction by the frictional force generated by the movement of the squeegee 5, the dimensional relationship between the metal mask 1 and the frame 2 in the same direction as the printing direction. Are set to L ₁ > L _2, and the metal mask 1 is securely fixed to the frame 2 in the same manner as when the metal mask 1 is directly bonded and fixed.
The metal mask 1 is not displaced because there is almost no expansion and contraction due to the above. Therefore, even when the printing speed is increased or the printing pressure is increased, the displacement of the metal mask 1 due to the frictional force does not occur. That is, the opening 1a of the metal mask 1
And the land 8 of the printed circuit board 7 are not misaligned, so that even when the printing pressure is increased by fine printing, high-speed printing, or the like, printing defects such as printing omission defects and printing position deviation defects may occur. , Stable printing can be performed, and print quality can be improved.

In the above-described embodiment, the case where the mesh material 3 is interposed at all the locations where the metal mask 1 and the frame 2 face each other is described. However, the present invention is not limited to this. On the other hand, the side that is the end (the left and right sides in FIG.
(Where the metal mask 1 and the frame 2 face each other), the metal mask 1 may be directly bonded and fixed to the frame 2 without interposing the mesh material 3.

In the above embodiment, as shown in FIGS. 1A and 1B, the dimension L ₁ of the metal mask 2 and the outer dimension L _{3 of the} frame 2 in the same direction as the printing direction.
The dimensional relationship between, is a L ₁ = L _3, and L ₁ <L _3, L ₁
> Any L ₃ may, L ₁ to the print direction and the same direction> L
_It suffices that the relationship of ₂ is satisfied, and is not limited to this.

Further, in the above-described embodiment, in the direction perpendicular to the printing direction, the mesh material 3 adhered and fixed to the frame 2 and the metal mask 1 are combined at the joint 4. The frame is held in the frame 2 without any wrinkles. If the frame can be held in the frame 2 without wrinkling, as shown in FIG. Similarly to the above, the metal mask 1 may be directly bonded and fixed to the frame 2, and is limited to this as long as the relationship of L ₁ > L ₂ is satisfied with respect to the dimensional relationship in the same direction as the printing direction. Not something.

[0028]

As is evident from the foregoing description, according to the solder paste printing apparatus of the present invention, the dimensions L ₁ of the printing direction in the same direction in the mask, and the dimensions L ₂ in the same direction as the printing direction in the frame inside, By configuring so that L ₁ > L ₂ , printing defects such as printing missing defects and printing position deviation defects do not occur even in fine printing or high-speed printing, and are stable on the printing surface. Printing can be performed and print quality can be improved.

In the direction perpendicular to the printing direction, the dimension L _{4 of} the mask and the dimension L ₅ inside the frame are set.
Are configured such that L ₄ <L ₅ , and the metal mask is wrinkled or sagged by being connected between the outer portion of the metal mask and the inner side of the frame by an elastic member made of a stretchable mesh material or the like. And the like are held in the frame without entering, and the print quality is further improved.

[Brief description of the drawings]

FIGS. 1A and 1B are a plan view and a front sectional view taken along line II of a cream solder printing apparatus according to the present embodiment.

FIGS. 2A to 2C are enlarged cross-sectional views each showing a step of printing cream solder by the same cream solder printing apparatus.

FIGS. 3A and 3B are a plan view and a front sectional view taken along line III-III of the cream solder printing apparatus according to the present embodiment.

FIGS. 4A and 4B are a plan view and a front sectional view taken along line IV-IV of a conventional cream solder printing apparatus.

FIGS. 5A and 5B are cross-sectional views showing states of rightward printing in the conventional cream solder printing apparatus.

FIGS. 6A to 6C are enlarged cross-sectional views showing steps of printing cream solder by the conventional cream solder printing apparatus.

FIGS. 7 (a) and 7 (b) are cross-sectional views showing states of rightward printing by a conventional mesh screen printing method.

FIGS. 8A and 8B are a plan view and a sectional view showing a conventional mesh screen printing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal mask 2 Frame 3 Metal mask (elastic member) 4 Joining part 5 Squeegee 6 Cream solder 7 Printed circuit board

Claims (2)

[Claims] 1. A printing mask in which an opening of a desired pattern is formed, a frame having a frame shape for holding the mask, and a squeegee for applying cream solder, wherein the squeegee is moved on the mask. by printing a cream solder on the printed face through a mask, a solder paste printing apparatus for applying, printing the same direction in the mask and the dimensions L _1, of the same direction as the printing direction in the frame internal dimensions and L ₂ is, L _1> solder paste printing apparatus that is configured to be L _2. 2. In a direction perpendicular to the printing direction,
The dimension L of the mask _FourAnd the dimension L inside the frame_FiveWhen
Is L_Four<L_FiveIs configured to be outside the metal mask
Stretchable mesh material between the side parts and the inside of the frame
Claim 1 which is connected by an elastic member made of a material or the like.
Cream solder printing equipment.