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Guiding technical document JB/Z206—84
（JB/T 8827-99）
Shockproof packaging of electromechanical products
Published on 1984-01-26
Ministry of the Machinery Industry of the People's Republic of China
Guiding technical document of the Ministry of Machinery Industry of the People's Republic of China Shockproof packaging of electromechanical products
JB/Z206-—84
This guiding technical document is applicable to the shockproof packaging of mechanical and electrical products. It can also be used as a reference for products such as instruments and meters. 1 Purpose
To protect the products to be packed, under the influence of external forces such as impact and vibration generated during transportation and loading and unloading, it should still meet the requirements of professional product standards.
2 Shockproof packaging
2.1 Design requirements
The design of shockproof packaging should take into account the characteristics of the product, transportation, loading and unloading conditions, meet the test requirements specified in Chapter 3, and must consider the following points:
a. Product characteristics include product performance, shape, volume, weight and quantity (especially considering whether there are protruding or easily damaged parts, easily bruised surfaces, brittleness), etc. b. Transportation, loading and unloading and storage conditions include transportation area, transportation and loading and unloading machinery, loading and unloading times, drop height, impact direction and storage conditions, etc.
c. Materials include (inner and outer packaging, cushioning, support, bonding, velvet, etc.) material types, characteristics, prices, sources and processability, etc.
d. Shockproof methods include the mechanical basis of cushioning and vibration isolation, design techniques, etc. e. Generalization and standardization.
2.2 General steps in shockproof packaging design
a. Determine the overall structure of the packaging. For example, whether inner packaging containers, floating packaging, anti-falling packaging, flat packaging, and whether collective packaging can be used are required.
b. Select the type of cushioning material, determine the cushioning method (full cushioning, two-end cushioning, four-corner cushioning or octagonal cushioning, etc.) and its size.
Determine the method of fixing the product in the packaging container. c.
d. Carry out packaging tests according to the provisions of Chapter 3. Check whether the shockproof performance of the packaging meets the requirements. 2.3 General principles of shockproof packaging design
2.3.1 The product should be fixed in the packaging container. Its protruding and vulnerable parts should be supported. If there are multiple products in the same packaging container, they should be fixed and isolated, and no collision between products is allowed. 2.3.2 The static pressure on the cushioning pad should be appropriate. The area of the cushioning pad should be determined according to the weight of the product or inner packaging and the characteristics of the cushioning material, and reasonable adjustments should be made when necessary.
2.3.3 The packaging structure should be as simple as possible. Various factors should be considered comprehensively during design. For example, the seismic resistance of the product itself, whether the vulnerable parts can be removed for seismic treatment, etc. 2.4 Selection of buffer materials
Depending on the use occasion, purpose, economy and importance, the requirements for buffer materials are different, and the following characteristics must be considered to select materials that meet the requirements: a. Buffering refers to the ability of the buffer material to absorb impact energy. b. Elastic stability and recovery refers to whether the elasticity of the buffer material will decrease and recover under the long-term effect of the product weight. Ministry of Machinery Industry of the People's Republic of China 1984-01-26 Issued 1
JB/Z206—84
Breakage and wear resistance refer to the strength and wear resistance of the buffer material. d. Specific gravity. www.bzxz.net
Water resistance, oil resistance, acid and alkali corrosion resistance and mildew resistance. e.
Temperature stability refers to whether the buffer material will become brittle or soften when the temperature changes. f.
Dust content and water content.
Processability refers to whether the cushioning material has processing properties such as easy forming and easy bonding. h.
2.5 Calculation of cushioning pad size
2.5.1 The contact area A of the cushioning pad (referring to the contact area between one surface and the product or the inner packaging) is calculated according to formula (1): A
Where: A-
-contact area, cm2;
-gravity of the product or the product plus the inner packaging, kgf, G
-brittleness value of the product;
(1)
Um Maximum stress of the cushioning pad, kgf/cm2. When determining the maximum stress m of the cushioning pad, attention should be paid to making the value of the cushioning coefficient C as small as possible, so that the thickness of the cushioning material can be reduced. However, sometimes the cushioning area A is determined by the size of the inner packaging container and the outer packaging container. In this case, the maximum stress can be calculated based on the determined cushioning area A, product weight W and brittleness value G, and then the appropriate cushioning material can be selected based on αm. 2.5.2 The thickness t of the cushion pad is calculated according to formula (2): G
Where: t—
Thickness of the cushion pad, cm
C——Cushioning coefficient;
h—Equivalent drop height, cm.
Note: The thickness t of the cushion pad has a certain relationship with the area A. If the area A is small, arbitrarily increasing the thickness t will not increase the cushioning effect. Generally, t and A are required to meet the following relationship: Amin> (1.33t)2
Where: Amin minimum load area, cm2. 2.6 Shockproof measures
2.6.1 When the entire surface of the product or inner packaging needs to be cushioned with cushioning material, thin strips, granules and sheets are mainly used (see Figure 1). These materials are particularly suitable for small batch packaging. For large batches, a former is generally used. Outer packaging container
Cushioning material
Product or inner packaging container
Full cushioning packaging
JB/Z206-84
2.6.2 When corner pads or side pads or both are used for products or inner packaging, it is suitable for large-volume packaging. However, special pads must be used, mainly block-shaped materials that are easy to process (see Figures 2 and 3). Corner pads
Product or inner packaging container
Figure 2 Corner pad packaging
Outer packaging container
Product or inner packaging container
Side pads
Figure 3 Side pad packaging
2.6.3 During transportation, for product packaging with large volume and weight in a specific direction and with external force acting on a specific surface, simplified packaging can be used in directions other than the specific direction.
2.6.4 When the brittleness value of the product varies greatly due to different directions, the material size in the specific direction can be appropriately adjusted. 2.6.5 In order to effectively utilize the cushioning material, in addition to adjusting the load area, the following methods can also be used: a.
When the load area is enlarged and the area in a specific direction needs to be enlarged, a pressure plate should be installed on this surface (see Figure b. When the load area is reduced, corner pads or side pads, or both, are generally used. In this case, the padding should be fixed (fixed on the inner packaging or outer packaging, or used together with the supporting material). 2.6.6 For products with protruding parts, the thickness of the cushioning material should be calculated from the outermost side of the protruding part to the inner side of the outer packaging container. 3
Cushioning material
JB/Z20684
Pressure plate
Product or inner packaging container
Figure 4 Packaging with adjusted pressure area
2.6.7 Products with irregular shapes , should be packed in molding materials, or supported firmly with combined cardboard grids, paperboard and other appropriate materials, and then protected with cushioning materials.
2.6.8 Products with small volume, light weight and large quantity should be separated by cushioning materials. 2.6.9 When the brittle value of a component in a large product is smaller than that of the entire product, the component should be removed and packaged separately. 2.6.10 For products with high shockproof requirements (such as precision electromechanical equipment, instruments, etc.), "floating packaging" can be used. The method is: first put the product in a carton, and use soft foam plastic pads on all sides between the product and the carton. The outside of the box is sewed with canvas or packed in a plywood box, and then hung in the outer packaging box with springs to suspend the product, so that the springs and foam plastics can play a buffering role. The length of the spring can be calculated according to the theory of impact and vibration, and the length should be moderate. 2.6.11If the product must be placed upwards and cannot be placed sideways or upside down, "anti-falling packaging" or "normal flat packaging" can be used. Simple "anti-falling packaging" is to make a corrugated cardboard box with a large bottom plate and a portable device on the top (see Figure 5). For wooden boxes and plywood boxes, wooden strips can be used to build a support at the bottom of the box, extending on all sides (see Figure 6). Figure 5
For products that have very strict requirements for flat placement, normal flat packaging can be used, and its packaging structure is shown in Figure 7. 4
JB/Z206-84
Buffering material
Bolt axis
Bolt axis
The outer packaging container is a wooden box, and the inner packaging container is a plywood box. When the product is placed in the inner packaging container, it must be stabilized with appropriate cushioning material. There is a wooden frame between the inner box and the outer box. The centers of the two ends of the wooden frame and the center of the end wall of the wooden box are connected from the outside to the inside with bolt axes (the wooden frame can rotate on the bolt axis). The centers of the two sides of the wooden frame and the two sides of the inner box are connected from the inside to the outside by bolt shafts (the inner box can rotate on the bolt shafts). The connection points on the side of the inner box should ensure that its center of gravity is below the wooden frame. The axes of the two sets of bolt shafts should be perpendicular to each other to form a cross axis. This kind of packaging can keep the original position of the inner box unchanged no matter how the outer box is placed during transportation. 2.6.12 In order to facilitate mechanical loading and unloading, for some relatively fragile products that are not easy to solve the shockproof problem of manual loading and unloading, collective packaging can be used to increase the packaging volume (length, width, height are not less than 70cm), or increase the packaging weight (gross weight is more than 200kg), which can avoid manual loading and unloading.
2.6.13 For packages using shockproof packaging, the indication signs should be correctly selected in accordance with the provisions of GB191-73 "Indication Signs for Storage and Transportation of Goods". For fragile products exposed to the outside (such as electric porcelain, etc.), lattice boxes can be used for packaging so that the loading and unloading personnel can see the fragile products in the box from outside.
3 Test
3.1 Test Items
All packages designed and manufactured according to this guidance technical document must be tested according to the items specified in Table 1. 3.2 Test Methods
3.2.1 Vibration Test
Properly fix the package on the table of the vibration test machine (additional vibration should be avoided). The center of gravity of the package is basically coincident with the center of the table of the vibration test machine. During the test, the vibration frequency is 3-4Hz, the maximum acceleration is 0.75±0.259, and the waveform is a sine wave. According to the characteristics of the product and transportation conditions, the vibration time is selected within 10, 20, 40, and 60 minutes. The basic value of the vibration test time for general road and rail transportation is 20 minutes.
3.2.2 Collision Test
Properly fix the package on the table of the collision test machine. During the test, the acceleration is 10±1g (100±10m/s2), the pulse duration is 11±2ms, the number of collisions is not less than 1000±10 times, and the waveform is approximately a half-sine wave. Table 1 Package test items
Package weight
Test items
Vibration or collision*
Road transport or simulated road transport**
Free fall
Face edge fall
Corner fall
Pendulum impact
3.2.3 Road transport test
<100kg
>100～1000kg
Put the package in the middle and rear of the truck, with the load being one third of the full load, and drive at a speed of 25～40km/h on the intermediate road surface of the third-class highway. The driving distance shall not be less than 200km. The road surface grade shall be in accordance with the provisions of JTJ1-81 "Highway Engineering Technical Standard": The intermediate road surface of the third-class highway is crushed and gravel road surface, irregular stone road surface, other granular road surface, etc. 3.2.4 Simulated highway transport test
On the simulated automobile transport test bench, the test is carried out according to the requirements of automobile transport of 200km. 3.2.5 Free drop test
After lifting the package weighing less than or equal to 100kg to a certain height, let it fall freely onto the test bench. According to the characteristics of the product and the loading and unloading conditions, the drop height is selected from 50, 100, 150, 200, 300, 400, 500, 600, 800, 1000, 1200mm. Each package is generally dropped 7 times in succession, and the drop position is a corner and the three faces and three edges that constitute the corner. For products that cannot be inverted, the bottom plane should be dropped 6 times in succession. Note: The test bench is a flat, hard cement floor or steel plate, and its overall weight is not less than 50 times the weight of the tested package. When the test bench is made of steel plate, its thickness should be not less than 13mm.
3.2.6 Face, edge and corner drop test
a. Face and edge drop test
Place the bottom edge of one end of the package on the ground (face drop test) or raise it by 100-150mm (edge drop test), lift the other end to the predetermined height (or make the box plane form a 30° inclination with the horizontal plane), and let it fall freely on a flat, hard cement floor or steel plate (as shown in Figure 8). The lifting height is selected within the drop height grade range of the free drop test. When the tested package cannot reach the predetermined lifting height, the package can be raised to the maximum height that will not cause it to tip over. Number of drops: For the face drop test, each bottom edge is placed on the ground and dropped twice; for the edge drop test, each bottom edge is dropped twice. b. Corner drop test
Raise the two adjacent corners of the package by 100mm and 200mm respectively, lift the corner corresponding to the corner raised by 200mm, reach the predetermined height, and drop it freely on a flat, hard cement floor or steel plate (as shown in Figure 9). The lifting height is selected within the height grade range of the free drop test. When the tested package cannot reach the predetermined lifting height, the package can be raised to the maximum height that will not cause it to tip over. Each bottom corner should be dropped twice. uost
Surface drop test
Note: For packages weighing 100-200kg, free drop tests can also be performed according to actual loading and unloading conditions. 3.2.7 Pendulum impact test
Edge drop test
Place the package on a table suspended by wire ropes at the four corners, and the collision surface (edge) of the package is flush with the front edge of the table or extends beyond the front edge of the table by no more than 50mm (as shown in Figure 10). When the table is stationary, its front edge should be in contact with the vertical collision surface, and the error should not be greater than 1. The vertical collision surface should be flat and have a certain rigidity. During the test, the table is pulled up to a height that can produce a predetermined horizontal impact speed and then released freely, so that the collision surface of the package impacts the vertical collision surface. During the impact, the error of the actual horizontal impact speed should not be greater than 5% of the predetermined horizontal impact speed. Each side (end) face is impacted twice. The horizontal impact speed is selected within 1.5, 1.8, 2.2, 2.7, 3.3, 4.0, 5.0m/s according to the product characteristics and transportation and loading and unloading conditions. The basic value of the horizontal impact speed for general road transportation is 1.5m/s. The basic value of horizontal impact velocity for railway transportation is 1.8m/s. Note: Without considering other resistances, the lifting height of the package during the test can be calculated by the formula hV2
(where: V is the predetermined horizontal impact velocity value). 2g
4 Inspection rules
Wire rope
Vertical collision surface
Package
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4.1 Packages with any of the following conditions shall be tested in accordance with the provisions of Article 3.1: When a new design;
b. When there are major changes in packaging materials, design, and technology. Number of packages used for testing: No less than three packages of the same type (except for products produced in small quantities). 4.2 After the tests specified in Chapter 3, if there is no obvious damage to the packaging box, no obvious deformation of the cushioning material, and the product contained meets the requirements of professional product standards, it is qualified. If one of the above items does not meet the requirements, the package is unqualified. 8
JB/Z206-84
Appendix A
Terms and Definitions
(Supplement)
A.1 Product brittleness value (G): The ratio of the maximum acceleration that a product can withstand to the acceleration of gravity when its function and physical state are not damaged is called the product brittleness value.
A.2 Equivalent drop height (h): In order to compare the impact degree caused by loading and unloading, the impact speed is regarded as the collision speed of a free fall, and the height of the free fall is calculated, which is the equivalent drop height (m). A.3 Static stress (o): The load per unit area applied to the cushioning material in a static state (kgf/cm2). A.4 Maximum stress (αm): The instantaneous maximum load (kgf/cm2) applied to the unit area of the buffer material due to the action of external force. A.5 Buffer coefficient (C): The ratio of any stress generated by the load to the amount of work per unit volume required to generate this stress, used to express the buffering capacity of the buffer material, is called the buffer coefficient. A.6 Maximum stress-buffer coefficient curve: In order to clarify the maximum stress range when the buffer coefficient reaches the optimal value, a curve is used to express the relationship between the maximum stress of the buffer coefficient.
A.7 Acceleration-static stress curve: During the dynamic load test, the static stress of the specimen and the acceleration generated by the heavy hammer (equivalent to the weight of the object) are plotted.
B.1 Types of test methods
JB/Z 206-84
Appendix B
Test method for determining brittleness
(Supplement)
When testing, one of the following two methods can be selected: B.1.1 Collision test method. When this method is used for testing, the collision test equipment must meet the following conditions: a. The collision waveform should be as close to a sine wave as possible. b. The duration of the collision pulse is adjustable below 20ms. c. The acceleration error is below 10%.
B.1.2 Free fall test method. When this method is used for testing, the drop test equipment must meet the following conditions: The drop height can be adjusted arbitrarily and easily.
The test sample can fall freely without any hindrance. It is convenient to manipulate and lift the test sample.
B.2 Selection of test samples
B.2.1 Products produced in large quantities
B.2.1.1 Due to the relationship between quantity, products with similar structures and sizes can be selected as products of the same type. B.2.1.2 For products of the same type but with large structural changes, products with special structures should be selected for testing. B.2.1.3 There should be at least three products of the same type. B.2.2 Simulation parts
When a product cannot be sampled for testing due to its high price, it is allowed to use a simulation part with similar structure, material, size, etc. to the product as a substitute.
B.3 Test method
B.3.1 Collision test method
B.3.1.1 Installation of acceleration sensor
Fix the sensitive axis of the sensor to the base of the product in line with the collision direction. B.3.1.2 Installation of the tested product
After adjusting the parameters of the collision table, rigidly fix the tested product on the collision table. B.3.1.3 Collision direction
Generally, the direction in which the product is most likely to be damaged when it is hit is selected for testing, but for products that are not allowed to be inverted, the test is carried out in their normal placement position. B.3.1.4 Test
The impact force applied should be from small to large, and the minimum impact force should be based on the principle of not damaging the tested product. After each test, an inspection shall be carried out. When it is confirmed that the product is not damaged, the impact force shall be increased and the test shall be carried out again until the product is damaged. B.3.2 Free drop test method
The steps for determining the brittleness value of the product by drop test are as follows: a. Select a set of pads with thickness that can be gradually reduced and suitable acceleration-static stress curve, and the maximum thickness is sufficient to prevent the product from being damaged when it falls from the specified drop height for the first time. Use the pads to make a rough shockproof packaging design. Install an accelerometer on the product during the test.
b. Perform a drop test on all six faces (and edges and corners if necessary) of the package from the specified drop height, and record the peak acceleration during each test.
c. Gradually reduce the pad thickness and repeat step b until the product is damaged. 10
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d. The peak value of acceleration recorded before damage can be used as the brittle value of the product (if the acceleration-static stress curve of the cushion material is known, they can be checked against each other). B.3.3 Determination of product brittle value Calculate the average value of all brittle values of the same type of product, take 80% of it as the reference value, and then take factors such as product strength deviation and price into account to determine the brittle value of the product.
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