A Design Method for a Multilayer Positioning Constant Acceleration Batch Screening Die

Abstract

The present invention belongs to the field of the design of constant acceleration screening molds, and discloses a design method for a multi-layer positioning constant acceleration batch screening mold. By using the centrifugal force generated during the operation of a centrifuge and the structure of a carrier basket, according to the size of the device to be screened and the requirements of the screening direction, the size of the positioning groove and the lead wire avoidance groove are determined, so as to realize the efficient screening of devices with various sizes and shapes. The mold designed by using this method can effectively protect the appearance of the device during the screening process, reduce the operation steps, realize screening of multiple quantities at one time, improve the efficiency and reduce the production cost.

Description

Technical Field

[0001] The present invention belongs to the field of design of constant acceleration screening molds, and specifically relates to the design of a batch constant acceleration screening mold for deep cavity devices of parallel seam welding type. Background Art

[0002] The constant acceleration screening project is used to determine the impact of constant acceleration on microelectronic devices according to the relevant requirements of Method 2001.1 in GJB548B-2005. The purpose of designing this acceleration test is to reveal structural and mechanical type defects that may not be detected during shock and vibration tests, and to eliminate products whose mechanical strength of structural components is lower than the nominal value.

[0003] A low-speed centrifuge is a conventional instrument used for centrifugation tests in the laboratory. It uses a DC brushless motor and can preselect the rotation speed, time, and centrifugal force. The device has a simple structure, and is powered by a single or multiple rotors. The rotating shaft connected to the rotor is connected to 4 sample baskets, and the angle between the sample baskets is 90°, and the arm lengths are the same. When in use, equal-weight single devices to be screened are respectively placed at the center of the bottom of the four sample baskets. The device accelerates step by step according to a preset program. During this process, the sample baskets gradually change from the vertical direction to the horizontal direction as the rotation speed increases; when reaching the predetermined rotation speed, the acceleration stops, and this rotation speed is maintained for 1 minute; after the constant speed process ends, it gradually decelerates to a stop, and during this process, the sample baskets return from the horizontal direction to the vertical direction.

[0004] The direction in which the device tends to break out of the base is defined as the Y1 direction, and then the top cover plate of the device contacts the sample basket. To avoid damage to the appearance or flying out of the device due to collision and extrusion during the equipment speed change process, only one device is placed in each sample basket, and a flat flexible material is padded on the bottom surface of the sample basket. Summary of the Invention

[0005] The purpose of the present invention is to provide a design method for a multi-layer positioning constant acceleration batch screening mold. By using the centrifugal force generated during the operation of the centrifuge and the structure of the sample basket, according to the size of the device to be screened and the requirements of the screening direction, the size of the positioning groove and the lead wire avoidance groove are determined, so as to realize the efficient screening of devices of various sizes and shapes. The mold designed by this method can effectively protect the appearance of the device during the screening process, reduce the operation steps, realize screening of multiple quantities at one time, improve the efficiency, and reduce the production cost.

[0006] The technical solution of the present invention is as follows: A design method for a multi-layer positioning constant acceleration batch screening mold, characterized in that the total height of the mold is not greater than 3 cm, and the length and width dimensions of the mold are each 1 mm smaller than the length and width dimensions of the carrier basket; to ensure the stable positioning of the device to be screened during the acceleration process of the equipment, the depth of the positioning groove shall not be less than 3 mm, the shape of the positioning groove is the same as the top plane of the device to be screened, the side length dimension of the positioning groove is 0.2 mm larger than the side length of the top plane of the device to be screened, and the side extension lead of the device to be screened must have a gap of more than 3 mm from the mold in the Y1 direction, where the direction in which the internal components of the device to be screened tend to break out of its base is defined as the Y1 direction; the mold includes a single-layer mold and a multi-layer mold.

[0007] Further, when designing the single-layer mold, according to the dimensions of the device to be screened and the carrier basket, arranging the positioning grooves is divided into the following two situations:

[0008] When only a single device to be screened can be arranged in the carrier basket, determine the balance point according to the internal mass distribution of the device to be screened, design the position of the positioning groove so that the balance point of the device to be screened coincides with the center point of the mold, and determine the size and direction of the lead groove according to the size and side extension lead direction of the device to be screened; during the screening operation, the placement direction of the device to be screened must be consistent with the design direction;

[0009] When multiple devices to be screened are arranged in the carrier basket, the number of positioning grooves is an even number. Determine the size of the positioning grooves according to the size of the device to be screened. Design the positions of the positioning grooves on both sides of the center line of the mold, showing left-right symmetry; determine the grooving direction and size of the lead groove according to the side extension lead direction and position; for symmetric positioning, there is no need to consider the balance point of the device to be screened. If the same amount of devices to be screened is loaded on both sides of the mold, the mold is balanced as a whole left and right; during the screening operation, there is no need to consider the placement direction of the device to be screened, which is efficient and convenient.

[0010] Further, the multi-layer mold is composed of a positioning layer and a support layer. The positioning layer is designed with alignment holes, and alignment pins are used at the corresponding positions of the support layer. Except for the positioning layer at the bottom layer, the support layer and the positioning layer are tightened with countersunk head screws in pairs, which is convenient for overall picking and placing, and a weight reduction window is designed on the side of the support layer.

[0011] Further, the positioning layer and the support layer must be designed with alignment holes and alignment pins in pairs to facilitate the alignment operation.

[0012] Further, the thickness of the support layer is not less than 5 mm.

[0013] Further, the flatness of the contact surface between the mold and the device to be screened is not greater than 0.05, and the roughness is not greater than 3.2.

[0014] Further, the hardness of the mold material must be greater than the hardness of the device to be screened.

[0015] The present invention has the following beneficial effects:

[0016] 1. The special mold of the present invention can effectively limit the position of the device in the carrier basket and avoid appearance damage.

[0017] 2. The mold design of the present invention takes into account the size of the carrier basket and the size of the device to be screened, and determines the direction and depth of the lead groove according to the direction and length of the lead of the device to be screened.

[0018] 3. The present invention arranges the positioning grooves reasonably and adds a multi-layer structure, so that a single screening procedure can screen devices in multiples, and the operation is simple and convenient, which effectively improves the screening efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the connection between the loading basket and the rotating arm (stationary state).

[0020] Figure 2 It is a schematic diagram of the connection between the loading basket and the rotating arm (reaching the predetermined rotation speed).

[0021] Figure 3 It is a schematic diagram of the Y1 direction.

[0022] Figure 4 It is a schematic diagram of a single-layer single-device mold.

[0023] Figure 5 It is a schematic diagram of a single-layer dual-device mold.

[0024] Figure 6 yes Figure 5 Top view of the .

[0025] Figure 7 It is a schematic diagram of the positioning layer structure.

[0026] Figure 8 yes Figure 7 Top view of the .

[0027] Figure 9 It is a schematic diagram of the support layer structure.

[0028] Figure 10 yes Figure 9 Top view of the .

[0029] Figure 11 It is a schematic diagram of a double-layer four-device mold. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The load basket of the low-speed centrifugal equipment is a deep cavity rectangular groove, without positioning devices and cushioning materials inside. After laying flexible materials at the bottom of each load basket, only 4 devices can be screened at a time. During the acceleration process of the equipment, the load basket rotates 90° from the vertical direction to the horizontal direction. During this process, there are potential risks of appearance wear such as displacement, collision, and flying of the devices, as Figure 1 、 Figure 2 shown.

[0032] Based on these conditional limitations, this embodiment provides a design method for a multi-layer positioning constant acceleration batch screening mold. The total height of the mold is not greater than the depth of the load basket, and the length and width dimensions of the mold are 1 mm smaller than the length and width dimensions of the load basket respectively. To ensure the stable positioning of the devices during the equipment speed-up process, the depth of the positioning groove shall not be less than 3 mm, the shape of the positioning groove is the same as the top plane of the device, and the side length dimension of the positioning groove is 0.2 mm larger than the side length of the top plane of the device. The flatness of the contact surface between the mold and the device is not greater than 0.05, and the roughness is not greater than 3.2. When designing the mold, it is necessary to avoid the lead direction and length of the device. Since the copper core lead is relatively soft, it is easy to deform in the Y1 direction during high-speed centrifugation, as Figure 3 shown, and it is required that the side-extended lead shall maintain a gap of more than 3 mm from the mold in the Y1 direction.

[0033] When the centrifuge is working, the rotor rotates at a high speed, and it is required that the four force arms are balanced, that is, the mass difference of the 4 load baskets shall not be too large; the load basket is connected to the rotating arm by a shaft, and the connecting shaft coincides with the center line of the load basket. To ensure the stable rotation of the load basket at high speed, it is required that the mass difference between the left and right sides of the mold after loading the devices shall not be too large.

[0034] When designing a single-layer mold, according to the device and load basket dimensions, arranging the positioning grooves is divided into the following two situations:

[0035] When only a single device can be arranged in the load basket, determine the balance point according to the internal mass distribution of the device, make this point coincide with the center point of the mold, and determine the positioning groove dimensions, lead avoidance groove dimensions, and direction according to the device dimensions and lead direction. When performing the screening operation, the device placement direction must be consistent with the design direction.

[0036] When multiple devices can be arranged in the load basket, the number of positioning grooves shall be an even number. Determine the positioning groove dimensions according to the device dimensions, and position them on both sides of the mold center line, showing left-right symmetry. Determine the grooving direction and dimensions of the lead groove according to the lead direction and position. Symmetrical positioning does not need to consider the balance point of the device. If the same amount of devices are loaded on both sides of the mold, the overall left-right balance of the mold can be achieved. When performing the screening operation, there is no need to consider the device placement direction, which is efficient and convenient.

[0037] Based on the single-layer design, for the multi-layer mold design, it is necessary to note that the overall size of the multi-layer structure must be smaller than the depth of the loading basket, and the overall weight after adding components must not be greater than the nominal load of the equipment. The multi-layer mold consists of a positioning layer and a support layer: the positioning layer functions to position the components, and the support layer functions to provide support. Except for the positioning layer at the bottom, the support layer and the positioning layer are connected using countersunk screws in pairs for convenient overall handling; the positioning layer and the support layer must be designed with alignment holes and pins in pairs for convenient alignment operation. Weight-reducing windows can be designed on the side of the support layer, and the thickness of the support layer is not less than 5 mm. Chamfers must be designed when necessary to increase strength.

[0038] The hardness of the mold material must be greater than that of the components to be screened to avoid deformation of the mold during the screening process, resulting in positioning failure, or uneven contact surfaces due to surface bumps, scratching the appearance of the components.

[0039] Figure 4 This is an example of a single-layer single-component mold. The position of the positioning groove should be designed so that the balance point of the component coincides with the center point of the mold, and the placement direction of the component is marked. When in use, place the component into the positioning groove according to the marked direction, then place the mold with the component into the loading basket, and execute the screening program. After the program ends, take out the mold as a whole, and then take out the component to complete the screening.

[0040] Figure 5 、 Figure 6 This is an example of a single-layer two-component mold. The positions of the positioning grooves are on both sides of the center line of the mold, showing left-right symmetry. Since the components have side-extended leads, there is a 3-mm gap between the leads and the mold. When in use, place the components into the positioning grooves, then place the mold with the components into the loading basket, and execute the screening program. After the program ends, take out the mold as a whole, and then take out the components to complete the screening.

[0041] Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 This is an example of a double-layer four-component mold. The positions of the positioning grooves are on both sides of the center line of the mold, showing left-right symmetry. The mold consists of three parts, with upper and lower double-positioning layers and a middle support layer. To reduce the overall weight of the mold and ensure the support strength, weight-reducing windows are opened on the support surface and a chamfer structure is designed. The positioning layer is designed with alignment holes, and alignment pins are used at the corresponding positions on the support layer. The two-layer positioning layer and the support layer are designed to be tightened with countersunk screws, and the overall size of the mold is smaller than the depth of the loading basket. When in use, place one layer of the positioning layer at the bottom of the loading basket, and place one layer of the components into the positioning grooves; assemble the two-layer positioning layer and the support layer through the alignment holes and alignment pins on the first layer, place the two-layer components into the corresponding positioning grooves, and execute the screening program. After the program ends, take out the two-layer components, the assembly of the two-layer positioning layer and the support layer, the one-layer components in sequence to complete the screening. The appearance of the screened components is bright and without damage, and no extra cleaning work is required, with simple operation and high efficiency.

[0042] As described above, this is only a specific implementation of the present invention. However, the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A design method for a multi-layer positioning constant acceleration batch screening die, characterized in that, The total height of the mold shall not be greater than 3 cm, and the length and width dimensions of the mold are 1 mm smaller than the length and width dimensions of the carrier basket respectively; the depth of the positioning groove shall not be less than 3 mm, the shape of the positioning groove is consistent with the top plane of the device to be screened, the side length dimension of the positioning groove is 0.2 mm larger than the side length of the top plane of the device to be screened, and there shall be a gap of more than 3 mm between the side extension leads of the device to be screened and the mold in the Y1 direction, where the direction in which the internal components of the device to be screened tend to break out of its base is defined as the Y1 direction; the mold includes a single-layer mold and a multi-layer mold; (1) When designing a single-layer mold, according to the dimensions of the device to be screened and the carrier basket, the positioning groove is designed in the following two cases: (1.1) When only a single device to be screened can be arranged in the carrier basket, the balance point is determined according to the internal mass distribution of the device to be screened, the position of the positioning groove is designed so that the balance point of the device to be screened coincides with the center point of the mold, and the dimensions and the dimensions and directions of the lead grooves are determined according to the dimensions of the device to be screened and the direction of the side extension leads; when screening, the placement direction of the device to be screened must be consistent with the design direction; (1.2) When multiple devices to be screened are arranged in the carrier basket, the number of positioning grooves is even, the dimensions of the positioning grooves are determined according to the dimensions of the device to be screened, the positions of the positioning grooves are designed on both sides of the center line of the mold and are symmetric left and right; the grooving directions and dimensions of the lead grooves are determined according to the directions and positions of the side extension leads; the balance point of the device to be screened does not need to be considered for symmetric positioning, and if the same amount of devices to be screened are loaded on both sides of the mold, the mold is balanced left and right as a whole; when screening, the placement direction of the device to be screened does not need to be considered; (2) When designing a multi-layer mold, the multi-layer mold is composed of a positioning layer and a support layer. The positioning layer is designed with alignment holes, and alignment pins are used at the corresponding positions of the support layer. Except for the positioning layer at the bottom layer, the support layer and the positioning layer are tightened with countersunk head screws in pairs, and weight-reducing windows are designed on the side of the support layer.

2. The design method of the multi-layer positioning constant acceleration batch screening die according to claim 1, characterized in that, The positioning layer and the support layer must be designed with alignment holes and alignment pins in pairs to facilitate alignment operations.

3. The design method of the multi-layer positioning constant acceleration batch screening die according to claim 1, characterized in that, The thickness of the support layer shall not be less than 5 mm.

4. The design method of the multi-layer positioning constant acceleration batch screening die according to claim 1, characterized in that, The flatness of the contact surface between the mold and the device to be screened shall not be greater than 0.05, and the roughness shall not be greater than 3.

2.

5. The design method of the multi-layer positioning constant acceleration batch screening die according to claim 1, characterized in that The hardness of the mold material must be greater than the hardness of the device to be screened.

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