JP4411284B2 - Drop test device - Google Patents

Description

  The present invention relates to a drop test apparatus used in a drop test performed for evaluating the reliability of a built-in electronic device with respect to a drop shock, and in particular, a drop test used in a drop test of an impact acceleration method. Relates to the device.

  For example, in portable devices such as mobile phones and mobile portable terminals, reliability against drop impacts that can occur while being carried is strongly required. For this reason, mobile device manufacturers, boards built into mobile devices (printed boards on which electronic components such as semiconductor devices are mounted), electronic component manufacturers, etc. should perform drop tests for reliability evaluation against drop impacts. Yes. There are two drop tests, a free fall method and an impact acceleration method. In the free fall method, the test object is collided with the landing surface in a free fall state to perform the test. On the other hand, in the impact acceleration method, the test object is dropped while being supported by some support means, and the test is performed by applying a predetermined impact acceleration to the test object through a drop collision of the support means. This impact acceleration type drop test is a standard specified by JEDEC (Joint Electronic Device Committee): JESD22- as a drop test for electronic components at the board level, that is, a drop test for electronic components mounted on a board. There is B11 (a method of dropping a substrate used as a component of an electronic device) (Non-Patent Document 1), and the impact resistance evaluation of an electronic component in a state of being mounted on the substrate is tested in accordance with this standard. This is one of the desirable test forms.

  The JESD22-B11 standard defines the basic structure of the test apparatus. According to this, the test apparatus includes a drop table guided by a vertically standing guide rod so as to fall, and a collision cradle that receives a drop collision of the drop table. Then, a predetermined impact acceleration is applied to the test object by dropping and colliding a drop table, on which the test object (the board on which the electronic component to be tested) is fixed, with a predetermined fixing structure, onto the collision cradle. . In addition, the JESD22-B11 standard prescribes a basic condition of 1500 G, 0.5 millisecond sine half wave for impact acceleration applied to a test object. In such a JESD22-B11 standard drop test, an event that occurs in a test object by applying an impact acceleration of 1500 G, 0.5 millisecond sine half wave, for example, a change in electrical resistance that occurs in an electronic component mounted on a board Impact resistance is evaluated by using events such as strain and strain as indicators.

JEDEC STANDARD `` Board Level Drop Test Method of Components for Handheld Electronic Products '', JESD22-B111

  In the impact acceleration drop test, when the impact acceleration load is repeated up to 30 times for one test target substrate, the impact acceleration load is repeated many times as specified in the JESD22-B11 standard. The impact resistance of the test object is evaluated by analysis through impact acceleration load. In such an impact acceleration drop test, the reproducibility of the impact acceleration applied to the test object for each drop test is particularly important. More specifically, when the impact acceleration condition of 1500 G, 0.5 millisecond sine half wave specified by the JESD22-B11 standard is used, the waveform becomes a sine half wave of 0.5 millisecond width. However, it is important that the waveform is always constant in the repeated drop test. That is, the impact acceleration type drop test apparatus is strongly required to have high reproducibility of impact acceleration as a performance characteristic.

  In addition, impact acceleration type drop test equipment is strongly demanded to be downsized due to its use environment where it is used in the production site of high-precision electronic equipment, and low noise due to noise problems associated with drop tests. There is also a strong demand for conversion.

  From the above viewpoint, the conventional impact acceleration type drop test apparatus is insufficient for any requirement. In other words, the conventional drop test apparatus has a structure in which the basic apparatus structure defined in the JESD22-B11 standard is applied as it is. In such a drop test apparatus, the G value of impact acceleration is measured for each drop test. In addition, the width of the sine half wave is not constant, the reproducibility is not sufficient, and in order to obtain an acceleration of 1500 G, the drop height is required to be 1500 mm or more. It will be big.

  The present invention has been made in the background as described above, and a first object is to provide a drop test apparatus that enables high reproducibility of impact acceleration, and a second object is to provide impact acceleration. To provide a drop tester that can be miniaturized and reduced noise with high reproducibility.

  In the present invention, for the first object described above, a drop table guided by a vertically standing guide rod is provided and a collision cradle that receives a drop collision of the drop table is provided. In the drop test apparatus in which a predetermined impact acceleration is applied to the test object by causing the drop table on which an object is fixed to drop and collide with the collision cradle, the drop table is dropped by the guide rod. An impact receiving base that collides with the collision cradle is assembled to the attitude control plate that receives the guide, and the impact receiving base is applied to the attitude control plate with respect to the impact acceleration that is received by the collision with the collision cradle. It is characterized by being separated.

  In the present invention, for the second purpose, in the drop test apparatus as described above, the impact receiving base is formed of a plastic material.

  In the present invention, in the drop test apparatus as described above, the impact receiving base is formed in a cylindrical shape.

  According to the present invention, the drop test apparatus as described above is provided with a jumping-up receiver for suppressing the shock-receiving base from jumping up by the reaction when the shock-receiving base collides with the collision receiving base, and the shock-receiving base is In accordance with the timing of collision with the cradle, a drop receiver for receiving and stopping the posture control plate is provided.

  In the present invention, the drop table is configured such that the impact receiving base is assembled to the attitude control plate, and the impact receiving base is separated from the attitude control plate with respect to the impact acceleration received by the collision with the collision cradle. . Therefore, according to the present invention, the reproducibility of the impact acceleration applied to the test object in the repeated drop test becomes high, and it is possible to more effectively perform the impact resistance evaluation of electronic parts and the like by the drop test. It becomes.

  Further, in the present invention, the impact receiving base as described above is formed of plastics, whereby it is possible to improve the propagation property of the impact acceleration to the test object in the impact receiving base and the impact receiving base. Can be made lighter. For this reason, according to the present invention, the drop height required to obtain a predetermined G value in the impact acceleration can be reduced, which enables downsizing of the apparatus and reduces the impact energy of the impact receiver base. This can greatly reduce the noise of the device.

  Embodiments of the present invention will be described below. FIG. 1 shows the configuration of a drop test apparatus according to an embodiment. The drop test apparatus 1 of the present embodiment includes a guide rod 2, a drop table 3, a collision cradle 4 and a drop receiver 5 as main components. Among these components, the guide rod 2, the drop table 3, and the collision cradle 4 conform to the basic structure of the drop test apparatus defined by the JESD22-B11 standard. In addition to these main elements, the drop test apparatus 1 has a lifting mechanism for lifting the dropped drop table 3 to a predetermined drop height position, a test object fixed to the drop table 3, such as a substrate B (FIG. 2). ), And a control system for controlling the drop height position and start of the drop table 3 and the operation of the drop receiver 5, etc., are not shown.

  The guide rod 2 is an element that functions as a drop guide for the drop table 3, is formed in a rod structure using a metal material, and is provided vertically as a pair of left and right.

  As shown in FIGS. 2 to 4, the drop table 3 includes an attitude control plate 11, an impact receiving base 12, and a jump-up receiver 13, and is guided by the guide rod 2 so that it can freely fall. Yes.

  The posture control plate 11 is an element that adjusts the drop posture by receiving a drop guide by the guide rod 2, and is formed in a flat plate shape that is substantially rectangular using a metal material, specifically, an aluminum material. Guide receivers 14 are provided at both left and right ends in the longitudinal direction, and a drop guide by the guide rod 2 is received through the guide receivers 14.

  The impact receiving base 12 is an element that collides with the impact receiving base 4 when the falling table 3 is dropped, receives impact acceleration and transmits it to the substrate B, and is formed using a plastic material, and the overall shape is a circle. A flange portion 15 is provided at an intermediate position near the upper side. Further, the upper surface of the impact receiving base 12 is a fixing surface 16 for fixing the substrate B. As shown in FIG. 2, the substrate B can be fixed with a predetermined height away from the fixing surface 16. A plurality of screws 17 are provided in a predetermined arrangement. As shown in FIG. 4, the impact receiving base 12 is supported by the posture control plate 11 via the flange portion 15 by being movably fitted in an assembly hole 18 provided in the posture control plate 11. 15 is assembled to the posture control plate 11 so that the upper side protrudes from the upper surface of the posture control plate 11 and the lower side from the flange portion 15 protrudes from the lower surface of the posture control plate. That is, the impact receiving base 12 is assembled to the attitude control plate 11 in a state where it is separated from the attitude control plate 11 with respect to the impact acceleration received when the collision surface 19 collides with the collision receiving table 4 due to the fall of the drop table 3. ing.

  As shown in FIG. 4, the jumping receiver 13 is formed in a hook shape in which the jumping receiving part 22 protrudes in the horizontal direction from the rising part 21 rising on the upper surface of the attitude control plate 11. The receiving portion 22 is provided with a buffer 23 and is provided on the upper surface of the attitude control plate 11 along the impact receiving base 12. The bounce-up receiver 13 is an element for suppressing the bounce-up base 12 from jumping up due to the reaction of the impact receiving base 12 colliding with the collision receiving base 4. The flange portion 15 of the impact receiving base 12 is pressed from above through the function to smoothly stop the impact receiving base 12 from jumping up. With respect to such a jump-up receiver 13, by using an oil damper for the buffer body 23, the jump-up stop of the shock receiver base 12 can be performed more smoothly.

  The collision cradle 4 is an element that receives a drop collision of the drop table 3, more specifically, a drop collision of the impact receiving base 12 on the drop table 3. As shown in FIG. The upper surface is formed as a collision receiving surface 24. A surface 25 is placed on the collision receiving surface 24 as necessary. The surface 25 is formed of a material having a high buffering property, for example, a low resilience rubber or felt. By using such a surface 25, the width of the sine half wave in the impact acceleration can be adjusted. The width of the sine half wave correlates with the buffering property of the surface 25, and the buffering property of the surface 25 is determined by the material and thickness of the surface 25. Therefore, the surface 25 is prepared in various types with different materials and thicknesses, and is selected and used according to the impact acceleration conditions of the drop test.

  The drop receiver 5 is an element that suppresses the rebound of the shock receiver base 12 through receiving the fall of the attitude control plate 11. As shown in FIG. 1, the drop receiver 5 is an operating portion 26 that is formed to be movable up and down using an air cylinder. The drop receiving portion 27 is assembled at the upper end, and is provided along the collision cradle 4.

  Next, a drop test performed by the above drop test apparatus 1 will be described. In order to perform the drop test, first, the substrate B is fixed to the fixing surface 16 of the impact receiving base 12 with fixing screws 17. Then, the control system is operated to cause the drop table 3 to start the first drop from a predetermined drop height position. Here, the drop height position correlates with the G value of the impact acceleration, and in the case of 1500 G, is about 500 mm. The drop table 3 that has started to drop falls freely while being guided by both guide rods 2 and 2. Finally, the impact receiving base 12 collides with the impact receiving surface 24 of the impact receiving base 4 or the surface 25 mounted thereon at the impact surface 19, so that impact acceleration is applied to the substrate B through the impact receiving base 12.

  The impact receiving base 12 that has collided with the collision receiving base 4 jumps up by the reaction. During this time, the attitude control plate 11 continues to fall in a state separated from the impact receiving base 12, and is finally received by the drop receiver 5 and stops dropping. That is, the drop receiver 5 starts the ascending operation of the operating portion 26 in accordance with the timing at which the impact receiver base 12 collides with the collision receiving base 4 and raises the drop receiver 27 to a predetermined height position. 5 stops the attitude control plate 11 from the lower side so as to absorb the drop impact by the cushioning property of the cylinder. On the other hand, the impact receiving base 12 that has been bounced up is smoothly stopped by being softly received by the bounce-up receptacle 13 (the state shown by the imaginary line in FIG. 4), and then slightly falls, and the flange portion 15 And return to the state supported by the attitude control plate 11 and stabilize. That is, by supporting the posture control plate 11 at an appropriate height position with the drop receiver 5 and supporting the posture control plate 11 in this state to stabilize the shock receiver base 12, rebound of the shock receiver base 12 is suppressed. That is. When the impact receiving base 12 is stabilized in this way, the drop table 3 rises and returns to a predetermined drop height position. When the first drop is completed as described above, the same drop test is repeated on the same substrate B as many times as necessary.

  In FIG. 5, the waveform of the impact acceleration measured in the board | substrate B by the drop test by the drop test apparatus 1 of this embodiment is shown. As can be seen in the figure, a sine half wave of 1500 G and 0.5 milliseconds is obtained with no disturbance and very high stability. For this reason, the reproducibility of impact acceleration is extremely high in repeated drop tests. Such a high reproducibility of the impact acceleration is brought about by the structure of the drop table 3. The structure of the drop table 3 that provides high reproducibility of the impact acceleration is a separation structure, that is, the drop table 3 is constituted by the attitude control plate 11 and the impact receiving base 12 that are separable with respect to the impact acceleration received in the case of a drop collision. The impact receiving base 12 that is directly subjected to impact acceleration is lightweight, has a high hardness and has a high impact propagation property, and is further characterized by a cylindrical shape. It can be said that even the additional requirement of being characterized.

  The characteristics of the impact receiving base 12 which is lightweight and has a large impact propagation property can be realized by forming the impact receiving base 12 with a plastic material. Among the plastics materials, there is ultra-high molecular weight polyethylene having a molecular weight of 1 million or more, which is preferably used. Furthermore, among the ultra-high molecular weight, an ultra-high molecular weight polyethylene plastic material having an average molecular weight of 5.5 million was suitable. As an example, the size of the impact receiving base 12 corresponding to the substrate size defined by the JESD22-B11 standard is a cylinder having a diameter of about 140 mm and a height of about 120 mm. This is an ultrahigh molecular weight polyethylene plastic material having a durometer hardness of 67. When formed, the weight is about 1.7 kg.

  The large impact propagation property of the impact receiving base 12 in the characteristic structure of the drop table 3 as described above also serves to reduce the fall height necessary for obtaining a predetermined G value in impact acceleration. Specifically, 1500 G is possible with a drop height of about 500 mm. This drop height is less than half that of a conventional drop test device. For this reason, the apparatus can be significantly reduced in size. The impact receiving base 12 is also characterized by its light weight, but this light weight contributes to the miniaturization of the device by allowing the impact-resistant structure of the device to be simplified, and further reduces the collision energy. This contributes to a significant reduction in the noise of the device.

  Here, in the case of impact acceleration load due to dropping, it is inevitable that a reverberant impact, that is, a damping impact is generated to some extent after an acceleration impact of a sine half wave is generated. If this damping impact is large, impact acceleration other than normal impact acceleration is applied to the substrate B, and the accuracy of the test is accordingly reduced. Therefore, it is important that the damping impact is as small as possible. As can be seen from FIG. 5, in the drop test apparatus 1 of the present embodiment, the damping impact is extremely small, and the requirements can be sufficiently satisfied in terms of low damping impact.

  Such low damping impact is provided by the bounce-up receiver 13 and the drop receiver 5. That is, by a series of operations in which the impact receiving base 12 bounced up by the collision is softly received by the rising receiver 13 and then the posture control plate 11 that is received at an appropriate height position by the drop receiver 5 stably supports the impact receiving base 12. The cause of the occurrence of the damping impact can be effectively eliminated, and as a result, a low damping impact property is realized.

It is a figure which simplifies and shows the structure of the drop test apparatus by one Embodiment. It is a figure which expands and shows the vicinity of a fall table. It is a figure which shows the planar structure of a fall table. It is a figure which shows the assembly | attachment structure to the attitude | position control plate of the impact receiving base in a fall table. It is a figure which shows the example of the waveform of the impact acceleration in the drop test apparatus by this invention.

Explanation of symbols

2 Guide rod 3 Drop table 4 Collision cradle 5 Drop receiver 11 Attitude control plate 12 Impact receiver base 13 Bounce-up receiver B Substrate (test object)

Claims (4)

A drop table guided by a vertically standing guide rod and falling, and a collision cradle that receives a drop collision of the drop table, the drop table having a test object fixed thereto, In a drop test apparatus that is adapted to apply a predetermined impact acceleration to the test object via the drop table by causing it to fall and collide with
The drop table includes a posture control plate and an impact receiving base, and the posture control plate is formed so as to be able to receive a drop guide by the guide rod in order to adjust the drop posture of the drop table. The base has an upper surface serving as a fixing surface for fixing the test object, and a lower surface serving as a collision surface that collides with the collision cradle. A drop test device, wherein the drop test device is assembled to the posture control plate in a state of being separated from the posture control plate. The impact receiving base is formed in a cylindrical shape as a whole, and a flange portion is provided at an intermediate position, and is formed on the posture control plate so as to be supported by the posture control plate via the flange portion. The drop test apparatus according to claim 1, wherein the impact acceleration is separated by movably fitting into the assembly hole. The drop test device according to claim 1, wherein the impact receiving base is formed of a plastic material. The attitude control plate is provided with a spring-up receiver for suppressing the shock receiver base from jumping up due to a reaction when the shock receiver base collides with the collision receiver. The drop test apparatus according to any one of claims 1 to 3, wherein a drop receiver that receives and stops the posture control plate is provided in the vicinity of the collision cradle .

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