CN101937744B - The nead frame termination case of chip potentiometer and method for production thereof - Google Patents

Abstract

The present invention relates to a kind of nead frame termination case and method for production thereof of chip potentiometer.By several traditional single weld tabs, make continuous print weld tabs framework, weld tabs framework has extraction weld tabs, and for realizing the framework of location hole, cut-off rule and carrying extraction weld tabs needed for the technical processs such as continuous termination, continuously plastic compression, continuously assembling; Location hole plays the role of positioning in continued operation; Cut-off rule is beneficial to potentiometer and framework apart after completing assembling; Framework makes numerous extraction weld tabs form a continuous print entirety; Distance between adjacent weld tabs framework is 8 ~ 10mm.Present invention achieves the effect of continuous termination, continuously plastic compression, continuous chip pin of potentiometer framework termination of assembling, improve production efficiency, meet the demand of scale, automated production.

Description

The nead frame termination case of chip potentiometer and method for production thereof

Technical field

The present invention relates to a kind of method for production of electronic component, specifically, is the method for chip pin of potentiometer framework termination.

Background technology

Chip components and parts are the Miniature components of new generation without lead-in wire or short leg, it is the specific components adopting surface mounting technology (SMT) to carry out Electronic Assemblies, have that size is little, lightweight, simple firmly without lead-in wire or short leg, structure, easily automatic assembling and packaging density high, become the main flow of current electronic devices and components development, the chip rate of developed countries electronic equipment reaches more than 80%, the output of world's chip component has exceeded the output of lead elements and production method thereof, and increases in the annual growth with more than 20%.

Traditional contact pin type potentiometer, all with fairlead on its substrate, inserts fairlead by single lead-in wire during termination, then forms through welding or riveted joint.And traditional bIade glass glaze potentiometer (hereinafter referred to as chip potentiometer), as shown in Figure 1, form primarily of shell 4, rotating shaft 3, elastic tape 1, contact spring 2 and pedestal 5, pedestal then becomes conducting element by band conductor rail porcelain basal body (being called for short conductive substrate 6) with weld tabs 7 termination, then forms through plastic compression.Its substrate does not have fairlead, pin is weld tabs, is directly communicated with on-chip electrode, and the technique of traditional chip pin of potentiometer termination is: pin is made single weld tabs, together with being terminated at the mode of conductive substrate soldering by three single weld tabs again, see Fig. 2.But because chip potentiometer volume is very little, substrate and weld tabs are all very little, operate more difficult, inefficiency.

Summary of the invention

In order to enhance productivity, meet the demand of scale, automated production, the object of the present invention is to provide a kind of new method that can realize continuous termination, continuously plastic compression, continuous chip pin of potentiometer framework termination of assembling.

The present invention is achieved in that a weld tabs framework be made up of continuously multiple extraction weld tabs, weld tabs framework has and draws weld tabs and the framework for realizing location hole, cut-off rule and carrying extraction weld tabs needed for continuous termination, continuously plastic compression, continuous assembling technology procedure.

Location hole plays the role of positioning in continued operation, and cut-off rule is beneficial to potentiometer and framework apart after completing assembling.Framework makes numerous extraction weld tabs form a continuous print entirety, to realize with above-mentioned continuous process.There are nickel electrodeposited coating and tin electrodeposited coating in weld tabs framework surface.Distance between adjacent weld tabs frame strip is 8 ~ 10mm.

Terminating method and the step of the chip pin of potentiometer framework of the present invention are:

1. make weld tabs framework;

2. first nickel plating, zinc-plated again: nickel plating thickness is 0.8 ~ 1.2 μm, tin coating thickness 4 ~ 6 μm;

3. welding operation step during termination is:

(1) at the reflow welding cream of substrate assigned position printing 0.2 ~ 0.3mg;

(2) drying makes soldering paste solidify, and drying condition is 140 ~ 150 DEG C, 10 ~ 15min;

(3) weld---after substrate and weld tabs framework are positioned, then to soldering paste heating, make it fusing, substrate and weld tabs are welded together.

Present invention achieves the effect of continuous termination, continuously plastic compression, continuous chip pin of potentiometer framework termination of assembling, improve production efficiency, meet the demand of scale, automated production.

Accompanying drawing explanation

1. accompanying drawing 1 is the structural representation of the bIade glass glaze potentiometer of tradition;

2. accompanying drawing 2 is schematic diagrames of the conducting element of the bIade glass glaze potentiometer of tradition;

3. accompanying drawing 3 is schematic diagrames of the weld tabs framework of the present invention;

4. Fig. 4 is the conductive substrate with reflow welding cream;

5. Fig. 5-1, Fig. 5-2 are front view and the left view of chip potentiometer termination case respectively.

Embodiment

Describe an embodiment below in conjunction with accompanying drawing, the present invention will be further described.

Fig. 1, Fig. 2 respectively illustrate traditional structure of bIade glass glaze potentiometer and the structure of single conducting element.As can be seen from Figure 1, bIade glass glaze potentiometer is formed primarily of elastic tape 1, contact spring 2, rotating shaft 3, shell 4 and pedestal 5, and pedestal 5 is then that the conducting element (Fig. 2 display) formed together with conductive substrate 6 is connected on three weld tabs 8,9,10 end is embedded in plastics and forms.Its assembly relation is: be provided with elastic tape 1 and rotating shaft 3 in pedestal 5, be provided with again contact spring 2 in rotating shaft 3, and contact spring 2 and conductive substrate 6 reliable contacts, be finally fixed together all parts by shell 4 outside pedestal 5 and rotating shaft 3.As can be seen from Figure 2, chip potentiometer conducting element is made up of one end weld tabs 8, three end weld tabs 9, conductive substrate 6 and two end weld tabs 10, gets up between each weld tabs and conductive substrate 6 by the mode termination of soldering; Its technical process is: three of potentiometer pins are made three single weld tabs, i.e. 1 end weld tabs, 2 end weld tabs and 3 end weld tabs, then together with these three single weld tabs are terminated at the mode of conductive substrate soldering.Chip potentiometer volume is very little, and substrate and weld tabs are also all very little, therefore it is more difficult to operate, inefficiency.

Fig. 3 shows bIade glass glaze potentiometer weld tabs frame structure involved in the present invention.As can be seen from Figure 3, Middle Eocene device weld tabs framework is provided with one end weld tabs 8, two end weld tabs 10, three end weld tabs 9, location hole 11, cut-off rule 13 and framework 12 (note: framework 12 is parts of weld tabs framework 14), each own respective function.

Single weld tabs being made continuous print weld tabs frame form, weld tabs framework being set one end in need weld tabs 8, two end weld tabs 10, three end weld tabs 9 and the framework 12 as realizing location hole 11, cut-off rule 13 and carrying extraction weld tabs needed for the technical processs such as continuous termination, continuously plastic compression, continuously assembling.With location hole 11 on the framework 12 of weld tabs framework, location hole 11 plays the role of positioning in continued operation, the size of location hole 11 and spacing must ensure that higher dimensional accuracy---dimensional accuracy ensures within the scope of 0.02mm, so that the resetting of follow-up termination and plastic compression.In weld tabs framework, three extraction weld tabs 8,9,10 roots have cut-off rule 13 (impression), and cut-off rule 13 is convenient to potentiometer and is separated with framework 12 after completing assembling.Framework 12 makes multiple extraction weld tabs 8,9,10 form a continuous print entirety, to realize above-mentioned continuous process.For saving material, reducing costs, the distance between every assembly welding sheet framework is designed to 8 ~ 10mm, the distance of only enough termination, plastic compression and assembling.

Need repeatedly to bend in assembling process owing to drawing weld tabs, require that material is softer, therefore its material thickness is the copper belt of 0.2mm.Chip potentiometer adopts surface mounting technology (SMT) to install, product will pass through reflow welding, require that weld tabs should have good solderability, therefore after the machine-shaping of weld tabs framework, electroplate: i.e. first nickel plating (nickel bottoming) is zinc-plated again, nickel plating thickness is 0.8 ~ 1.2 μm, and tin coating thickness 4 ~ 6 μm, can ensure weld tabs surface quality and solderability like this.Nickel coating is unsuitable blocked up, otherwise easily causes weld tabs really up to the mark, ruptures when bending.

Fig. 4 is the conductive substrate with reflow welding cream.Three extraction electrodes of conductive substrate 6 print the reflow welding cream 16 of 0.2 ~ 0.3mg, see Fig. 4, drying makes soldering paste solidify, by after positioning with the conductive substrate of reflow welding cream and weld tabs framework during welding, with electric iron, reflow welding cream 16 is heated again, make it fusing, conductive substrate 6 and weld tabs 8,9,10 are welded together, reaches the reliable object of termination.

Fig. 5-1, Fig. 5-2 are front view and the left view of chip potentiometer termination case respectively.

The conducting element that termination is good is shown in Fig. 5.Due to when printing reflow welding cream 16, carried out fixing quantity to soldering paste consumption, therefore solder joint 15 size can control according to technological requirement.In termination process, conductive substrate 6 is very important with the location of weld tabs framework 14, locates the position that bad meeting directly has influence on conductor rail in pedestal, thus affects the overlap joint of Product Assembly center brush and conductor rail.Take the terminating method of reflow welding not only easy and simple to handle, solder joint 15 size can control, and also easily realizes automation, but solder joint can or can not to be heated disengagement in the plastic compression process in later stage, also needs pedestal plastic compression process to verify.

Pedestal plastic compression process is the process of the continuous plastic pressure forming that is carrier with the weld tabs framework 14 of conductive substrate in termination 6, conducting element will be embedded in PPA plastics by this process intactly, and ensure substrate working face and draw on weld tabs to have plastics, solder joint 15 has not also allowed open circuit, determine comparatively suitable positioning gap, plastic compression qualification rate can be made to reach more than 97%.

Test proves, single weld tabs is made into weld tabs framework, then carries out the termination of pin and substrate by the mode of reflow welding, meet the requirement of the scale of chip potentiometer, automated production, production efficiency is high, and quality is good.

Claims (1)

1. a manufacture method for the nead frame termination case of chip potentiometer, its feature comprises the following steps:

1) weld tabs framework (14) is made;

2) first nickel plating, zinc-plated again: nickel plating thickness is 0.8 ~ 1.2 μm, tin coating thickness 4 ~ 6 μm;

3) welding operation step during termination is:

(1) at the reflow welding cream of substrate assigned position printing 0.2 ~ 0.3mg;

(2) drying makes soldering paste solidify, and drying condition is 140 ~ 150 DEG C, 10 ~ 15min;

(3) weld---after substrate and weld tabs framework are positioned, then heat, make it fusing, substrate and weld tabs are welded together.