JPH10145038A - Pallet for transfer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the flatness of a pallet body even when it is transferred through a reflow furnace by forming the pallet with a flat type pallet body providing many holes and an external frame for placing the pallet body and then providing a guide section to the external frame for guiding the pallet body in the flat surface and then placing the pallet body to the guide section for expansion and contraction purpose. SOLUTION: When a pallet 11 for transfer passes through a reflow furnace, positional relationship between a mesh plate 12 and external frame 13 is changed due to difference of heat capacity of mesh plate 12 and external frame 13. In this case, since the mesh plate 12 is fixed at the point P, it is guided by the guide section 15 and can be expanded and contacted without limitation in the diagonal direction of the point P. Therefore, the mesh plate 12 can be expanded and contracted keeping the flatness without generating warp in the vertical direction. Thereby, even when the pallet is transferred through the reflow furnace, flatness of the pallet body can be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer pallet used for transferring a wiring board on which electronic components are mounted in a reflow furnace by a conveyor in order to solder the electronic components to the wiring board.

[0002]

2. Description of the Related Art When a wiring board on which electronic components are mounted is passed through a reflow furnace by a conveyer and the electronic components are soldered to the wiring board, a pallet for selectively supporting a part without parts on the lower surface of the wiring board is used. Then, a wiring board is placed on this pallet and transported in a reflow furnace by a conveyor. The pallet 1 used for this purpose is, for example, as shown in FIGS. 2A and 2B, such that heat supplied from the lower surface of the pallet 1 efficiently heats the wiring board placed on the pallet 1. Pallet body 3 provided with a plurality of through holes 2
And an outer frame 4 on which the pallet body 3 is placed and fixed. The pallet body 3 has four sides fixed to the outer frame 4.
As shown in FIG. 3, a support pin 5 is set up in the hole 2 of the pallet body 3, and an upper end of the support pin 5 selectively supports a portion of the lower surface of the wiring board 6 where there is no component 7. Since the purpose of the pallet 1 is to prevent the wiring board 6 from warping due to heating, it is important that the pallet body 3 maintain flatness even after passing through the reflow furnace.

[0003]

However, when the pallet 1 is passed through a reflow furnace, the pallet body 3 is distorted up and down due to thermal expansion and contraction. In the conventional pallet, since the pallet body 3 is fixed to the outer frame 4, there is no escape of the thermal distortion of the pallet body 3. Must be passed through. Therefore, it is important that the pallet main body 3 is not deformed in the reflow furnace, and that the pallet main body 3 keeps its flatness.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and comprises a flat pallet body provided with a large number of holes and an outer frame on which the pallet body is placed. The outer frame has a guide portion for guiding the pallet body in a planar shape, and the pallet body is mounted on the guide portion so as to be extendable and contractible.

According to the present invention, since the pallet body is mounted on the guide portion of the outer frame so as to be extendable and contractible, even if the pallet body passes through the reflow furnace and undergoes thermal expansion or contraction, the pallet body remains in the pallet body. No thermal stress is generated, and the pallet body is guided by the guide portion and expands and contracts in a plane, so that the flatness of the pallet body is maintained.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1A is a plan view of one embodiment of a transport pallet according to the present invention, and FIG. 1B is a cross-sectional view taken along line XX of FIG. The transport pallet 11 of the present embodiment includes a mesh plate 1 serving as a pallet body.
2 and an outer frame 13. The mesh plate 12 has a thickness of 0.8 to 2.0 mm, is made of a rectangular flat stainless plate, and has a large number of through holes 14 for holding pins for supporting the substrate. The outer frame 13 has a thickness of 5 to 5.
It is 10 mm, square, and has structural strength. A groove having a U-shaped cross section is provided along the inside of the outer frame 13, and the groove serves as the guide portion 15 of the mesh plate 12. The mesh plate 12 is placed in the guide portion 15 of the outer frame 13 and is fixed at a square corner point P. The mesh plate 12 is in contact with the inner wall of the guide portion 15 on the two sides A and B on both sides of the point P, and between the mesh plate 12 and the inner wall forming the guide portion 15 on the other two sides C and D. Has an extra space 15a. This point P serves as a reference point for positioning the mesh plate 12.

When the transport pallet 11 passes through the reflow furnace, the positional relationship between the mesh plate 12 and the outer frame 13 changes due to the difference in heat capacity between the mesh plate 12 and the outer frame 13. At this time, the mesh plate 12
Because it is fixed by the guide part 15
It thermally expands and contracts without being restricted in the diagonal direction of the point P. Accordingly, the mesh plate 12 expands and contracts while maintaining flatness without warping in the vertical direction. In this embodiment, since the mesh plate 12 is fixed at the point P, the arrangement of the holes 14 is constant, and when a large number of transport pallets 11 are used, the transport pallets 11
Variations in the position of each hole 14 can be prevented. Note that the above embodiment is an example in which the present invention is embodied, and does not limit the technical scope of the present invention.

[0008]

According to the present invention, there is an excellent effect that the flatness of the pallet body can be maintained even when the pallet is passed through a reflow furnace.

[Brief description of the drawings]

FIG. 1A is a plan view of an embodiment of a transport pallet according to the present invention, and FIG. 1B is a sectional view taken along line XX of FIG.

FIGS. 2A and 2B are a plan view and a side view of an embodiment of a conventional transport pallet, respectively.

FIG. 3 is a side view showing a state where a wiring board is placed on a transport pallet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Pallet for conveyance 12 Mesh plate 13 Outer frame 14 Hole 15 Guide part 15a Extra space

Claims (1)

[Claims] 1. A flat pallet body provided with a large number of holes, and an outer frame on which the pallet body is placed, the outer frame having a guide portion for guiding the pallet body in a plane. The pallet body is mounted on the guide portion so as to be extendable and contractible.