JP3044905B2 - Design method of opening of metal mask - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the application of cream solder when mounting electronic components on a printed circuit board in the manufacture of electronic equipment and the like, and the opening of a metal mask used for applying the cream solder. On the design method of the department

[0002]

2. Description of the Related Art Heretofore, a method of designing an opening of a metal mask of this type has been determined to have a shape substantially equal in size to a land portion on a printed circuit board.

The above-mentioned land portion indicates a portion connected to a lead portion of an electronic component by solder.

[0004]

However, recent developments in high-density mounting technology have made the lead pitch of electronic components much narrower and increased the variety of lead shapes of electronic components.
Advances in production technology have also led to the development of various automated equipment. The types of cream solder used for soldering electronic component mounting machines used here are increasing, and the materials and components can be changed, including the ratio of alloy to flux, as well as the size and shape of the alloy particles. Things existed.

[0005] Therefore, in the above situation, if the shape of the opening of the metal mask is simply determined from the land shape of the printed circuit board as in the above-described conventional example, the soldering of the connection portion at the time of soldering. There has been a problem in that the supply amount becomes excessive or insufficient, resulting in a solder bridge or a lack of solder (disconnection).

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and provides an excellent method for designing an opening of a metal mask so that optimal soldering can be performed regardless of the lead shape of any electronic component. .

[0007]

Means for Solving the Problems The present invention is a virtual a Ruha Sunda shape to connect the electronic component leads and PCB land when soldering the electronic components on a printed board in order to achieve the above object Simulate the stain
Calculate the volume of the solder part obtained by the calculation,
Apply to the printed circuit board from the volume of the solder part
Calculate the amount of cream solder and measure the size of the opening of the metal mask.
It calculates the law .

[0008]

Therefore, according to the present invention, the amount of cream solder to be applied can be calculated by simulating the optimum soldering condition from the lead shape of the electronic component and the land shape of the printed circuit board, and the opening of the metal mask can be calculated therefrom. Since the shape of the hole can be calculated, the application amount of the cream solder does not become excessive or insufficient, so that even when soldering, there is no solder bridge or no solder.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a flow chart showing a procedure of a method for designing an opening of a metal mask according to the present invention, and FIG.
FIG. 4 is a schematic diagram in which the flow is replaced by a virtual object.

In FIG. 1, in step 1, lead shape information of an electronic component, land shape information of a printed circuit board, and material information of cream solder are input. In this input, the size, material, and the like of the lead shape are input, and the material, size, thickness, and the like of the conductive portion of the printed circuit board are input. In the case of cream solder, the size of the alloy particles, the ratio of the alloy to the flux, the melting point, and the like are input.

In step 2, the optimum soldering state when soldering the leads of the electronic component and the land of the printed circuit board using the cream solder input from the information in step 1 is simulated, and the shape thereof is changed. Virtual calculation. For example, as shown in FIG. 2A, this simulates a state in which the leads 10 which are the leads of the IC and the printed circuit board 11 are optimally connected to the solder, and determines the shape of the solder 12 virtually.

In step 3, the volume of the solder portion is calculated from the solder shape obtained in step 2.

In step 4, the application amount of the cream solder is calculated from the volume of the solder portion obtained in step 3, and the volume including the alloy and the flux is calculated. For example, FIG.
As shown in FIG. 2B, the volume of the cream solder 13 including the alloy and the flux is calculated as a rectangular solid from the volume of only the alloy in the solder 12 portion of FIG. 2A.

In step 5, the shape of the opening of the metal mask is calculated from the volume of the cream solder obtained in step 4, and for example, the opening 15 is formed in the metal mask 14 as shown in FIG. Is calculated to form

Next, the respective relationships will be described from the flow of the method for designing the opening. Let the volume of the solder part in step 3 be A
When the volume of the cream solder in step 4 is a, the volume of the alloy portion of the cream solder is a1, and the volume of the flux portion of the cream solder is a2, A <a∵A = a1, a = a1 + a2 In the metal mask dimension calculation in step 5, if the area of the opening portion of the metal mask is b and the thickness of the metal mask is c, a ≒ b × c.

As described above, according to the above embodiment, the optimum soldering state is simulated from the lead shape of the electronic component and the land shape of the printed circuit board, the volume of the solder is calculated, and the volume of the solder is calculated from the volume of the solder. The amount of cream solder to be applied to the substrate is calculated and the shape of the opening of the metal mask is set.Therefore, the amount of cream solder applied is not excessive or insufficient, and even if soldering is performed, This has the effect of not causing bridging or unsoldering.

[0018]

As is apparent from the above embodiment, the present invention uses virtual solder shape calculating means for virtually simulating an optimum solder shape for connecting a lead and a land when an electronic component is soldered to a printed circuit board. The optimum solder shape is reproduced. Then, the volume of the solder portion having the virtual solder shape can be calculated by the solder portion volume calculating means, and further converted from the volume of the solder portion to the volume of the cream solder by the metal mask opening portion shape calculating means, based on this volume. The shape of the opening of the metal mask is calculated. Therefore, the amount of the cream solder applied is not excessive or short from the above, and since there is no solder bridging or no soldering even when soldering, excellent productivity and cost reduction are achieved. It has the effect of being able to.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a procedure of a method for designing an opening of a metal mask according to an embodiment of the present invention.

FIG. 2 is a schematic diagram in which the flow in FIG. 1 is replaced with a virtual object;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Lead 11 Printed circuit board 12 Solder 13 Cream solder 14 Metal mask 15 Opening part 16 Copper foil

Claims (3)

(57) [Claims] 1. A to the virtual simulation of Ruha Sunda shape connecting the lead and the printed circuit board lands of electronic components when soldering the electronic components on a printed board, wherein
Calculate the volume of the solder part obtained by simulation
And apply it to the printed circuit board from the volume of the solder part.
Calculate the amount of cream solder to be applied
A method for designing an opening of a metal mask, wherein the dimension of the metal mask is calculated . 2. A virtual simulation of the solder shape.
The lead shape information of the electronic component and the print
Using land shape information of the substrate
Item 3. The method for designing an opening of a metal mask according to Item 1. 3. When calculating the amount of the cream solder,
From the volume of the solder part, the alloy and flux
Determine the ream solder volume and then the amount of cream solder
2. The metal mass according to claim 1, wherein
How to design the opening of the hole.