Current situation and suggestions of three proofin

The current situation and suggestions of three prevention packaging of military electronic equipment

this paper summarizes the current situation of "Three Prevention" packaging of military electronic equipment, analyzes the problems existing in packaging design, material use, "Three Prevention" process and "Three Prevention" test, and puts forward suggestions on the standardization of "Three Prevention" packaging

preface

in modern war, electronic equipment has increasingly shown its combat effectiveness and progressiveness. In order to ensure the higher reliability of military electronic equipment used in various environments, in addition to the quality assurance of the equipment itself, packaging technology and quality are key factors. Especially in moisture-proof, mildew proof and corrosion prevention. Through investigation, we found that due to the backward packaging technology, the "Three Prevention" performance is not qualified, and the products appear corrosion and mildew when unpacked. Some components are less than 10% qualified after unpacking, and the product performance and service life are affected, even scrapped before use. This not only reduces the reliability of equipment in the harsh and urgent wartime environment, or even fails, resulting in the delay of fighters, but also causes the country to suffer huge losses of more than 10 billion yuan per year for this reason, which is really sad. Therefore, it is urgent to improve and update the "Three Prevention" packaging technology. For this reason, I will only outline some views on the current understanding of the packaging of electronic products

I. current situation and problems of "Three Prevention" packaging

in recent years, China's military packaging has made progress in relying on technological progress and developing the packaging industry. However, it is worrying that there are many problems in the "Three Prevention" packaging design and the adoption of new materials and new processes. Full attention should be paid. 221 steel protective door

1. Packaging design is a part of the overall product design

a factory produces military radar, and when the product is completed, it is delivered to the packaging workshop for packaging. As the military has anti vibration requirements for the packaging, the boxed equipment is tested on the safety road of high-energy density battery in level III public security. After the test, the equipment broke down, and the maintenance and packaging improvement were carried out respectively. Then test again → fault → maintenance → improvement. Only after such a cycle for several times can it leave the factory. Although the manufacturer is responsible for the products, the products have been tested and repaired for many times. Due to the small production batch, the equipment still delivered to the army after renovation inevitably has "hidden dangers" left after destructive tests

we don't think such packaging meets the requirements. Packaging design is a part of the overall design of products. If shockproof and impact resistant packaging is considered in the initial design of products, and the factors such as packaging storage and transportation environment, seismic grade, protective materials and so on are designed in it, the waste of manpower, material resources and time can be greatly reduced and the reliability of packaging can be improved. The product packaging design must not wait until the product is finished before considering or hastily carry out some tests, that is, delivery for use. It is found in the investigation that the manufacturer pays attention to the mechanical environmental performance test of packaging and despises the climate environmental adaptability test. The performance of mechanical environment can be found in the process of transportation, loading and unloading and transit, which is a short-term effect. The adaptability to climate and environment requires that the package can be exposed to moisture, mildew and corrosion during long-term storage. This is a long-term effect. The short-term effect is obvious, which is one of the reasons why manufacturers and users do not pay attention to the "Three Prevention" test. Many manufacturers carry out tests on transportation vehicles with specified road grade and specified distance according to standards (such as the above example), to test the shockproof and impact resistance of packages, but rarely carry out "Three Prevention" tests, especially for large products. Therefore, it is necessary to formulate unified "Three Prevention" packaging test methods and standards, and carry out research on the "Three Prevention" measures of products, so as to comprehensively improve the packaging quality. This case shows that:

(1) packaging design is not included in the overall design of the product, and packaging work is not paid due attention

(2) packaging design tends to focus on the test of direct damage such as vibration and impact, and pay insufficient attention to indirect slow and chronic damage. Therefore, the "Three Prevention" performance of packaging is usually ignored

2. "Three Prevention" packaging is an organic component of product packaging

some manufacturers, out of the desire to improve the quality of product packaging, overemphasize some direct damage factors in the environment, or some process measures are improperly selected, which affects other protective effects. Ignoring that the packaging is a whole, every protective measure must be in accordance with the overall requirements, and must not hinder the overall cooperation. For indirect damage that is not obvious in the short term, blindly quote other people's mature protective processes to use on the products, hoping to obtain satisfactory results, but things backfire, and often get the opposite results. Due to the adoption of a variety of measures, some measures are contradictory, sometimes have adverse effects, and sometimes the adopted process will not get the desired results. For example, the deoxidized packaging in the inner packaging can play the role of corrosion inhibition and mold prevention. Mold prevention treatment is carried out in the packaging, and the process is repeated. Moreover, due to the improper selection of mold inhibitor, the adverse consequences of metal corrosion are caused. Theoretically speaking, nitrogen filled packaging can play a role in mold prevention, but according to the current domestic reflection, there are technical problems in nitrogen filled packaging, which can not meet the requirements of mold prevention. Due to the lack of unified research and complete research data, some manufacturers just want to use more "new processes" in packaging, but they can't get satisfactory results

according to the above, we believe that the research on packaging technology lacks complete and in-depth research, and cannot provide systematic data to guide production and avoid errors in the use of some processes. Some corrosion inhibiting volatile fungicides can achieve double-layer effect when combined with silica gel. Therefore, when several process measures are adopted, the relationship between processes that interfere with and promote each other needs to be further studied. Strengthening the basic research of technology is the premise to ensure the quality of technology, and there should be special units to study this aspect

2. The adoption of new packaging materials and the elimination of old packaging materials

packaging should achieve the purpose of moisture-proof, mold proof and corrosion-proof, and the inner packaging materials are required to have low moisture permeability and air permeability. Generally speaking, the basic material used for sealing packaging is mainly plastic film. This kind of material not only has various single-layer films, but also has a variety of plastic/plastic composite films and plastic/aluminum/plastic composite films. At present, plastic/aluminum/plastic composite membranes have the best oxygen and moisture resistance (oxygen and water vapor transmission are almost zero), but they are expensive and difficult to popularize. Therefore, at present, most of the packaging materials used for sealing and packaging are cheap plastic/plastic composite films

polyvinyl chloride film has been proved to have corrosive effect on metals, so it is forbidden to be used as packaging material for electronic products. But at present, many military factories are still in use, because the price is cheap. Involving funds, it is difficult to change at the moment. PVC releases organic gases, and the packaging in this environment will gradually deteriorate and discolor the materials and corrode the metals, and the air permeability and moisture permeability of the film are higher than those of ordinary plastic/plastic composite films (see the table below). The "Three Prevention" performance is poor, which is obviously extremely detrimental to the storage and transportation protection of military electronic equipment. It is true that the film is cheap, but the resulting losses cannot be compensated

foreign countries pay more attention to the research and determination of the protective properties of packaging materials. For example, France strictly detects and controls the content of harmful components of films used for military products and precision instrument packaging, in which the halogen content and sulfur content are less than 50ppm, and chloride and fluoride are also under certain control, otherwise it is strictly prohibited to use. Compared with that in China, there are differences. Generally, harmful elements are not determined for military packaging materials, let alone strictly controlled

II. Formulate complete and unified "Three Prevention" packaging specifications and standards

1. The "Three Prevention" standards lack

mil-std-810d and GJB150, which are mainly aimed at equipment and products. IEC68 and GB2423 are mainly for equipment and materials, and the packaging is difficult to adapt to the above standards in the face of both packaging and materials. China's national packaging standards mainly refer to ISO, and there are few "Three Prevention" standards. By the end of 1986, China had issued 228 military standards, of which only 6 were related to packaging standards. During the "Seventh Five Year Plan" period, there was a slight increase, but it was still quite lacking. The "Three Prevention" requirements of packaging are sometimes incompatible in the use of products. For example, the use of fungicides will often affect the corrosion and moisture resistance of products. But sometimes solving one problem in the "Three Prevention" can also solve another factor. For example, while solving the moisture-proof problem of products, it can solve some mold prevention problems. Some aniline mold inhibitors can protect some metals. Therefore, the "Three Prevention" is a related whole, and it is necessary to carry out unified research and formulate unified specifications. The sample material can be divided into metal and non-metal. At present, there is no systematic specification and complete standard in the "three proofing" packaging of military electronic equipment in China, which leads to no rules to follow in the packaging of manufacturers, resulting in the design and process not reaching the actual use effect, and the material selection and construction are blind and lax. Even if there are some standards, it is difficult to implement them due to the disconnection between standards and production. The lack of military "three defense" packaging standards is one of the important reasons for the backwardness of military packaging. It is an arduous task to systematically sort out packaging standards, formulate corresponding standards as soon as possible, and establish a complete and unified military "three defense" packaging system

2. revise standards to meet new requirements

at present, military electronic equipment is in the period of upgrading, and the formulation of product standards and product packaging standards can no longer be synchronized. Some original standards have not fully adapted to the new requirements and must be revised in time. For example, for some packaging mold test methods, the main indicators of this standard are consistent with gb2423.16-81, but gb2423.16 is mainly formulated for the mold test requirements of electrical and electronic products and materials, and packaging has its own special requirements. When conducting mold test, the first thing to encounter is whether to use packaging or materials for the test. Whether the package is tested with real object or simulation. China's packaging standards mainly rely on ISO standards, which should be mainly based on material testing. If the test is carried out on packages, not counting the size and the need for large-scale equipment, it is more important that the products have been tested by artificial mold growth test according to the regulations, and then a mold growth test is carried out in the packages, because mold is a destructive test, the test time is long, the cost is high, and the batch of military products is very small, Many factories will be deterred from testing with a finished product, so the "Three Prevention" test of packaging should adopt the test method that can reflect their own packaging characteristics, and cannot blindly copy the same type of domestic test method, otherwise it is difficult to popularize and apply even if there is a test method, such as the mold standard of packaging. We should strengthen the study of the characteristics of packaging and formulate suitable and feasible packaging "Three Prevention" standards

3. determine the basic environmental conditions

packaging must be affected by environmental factors during transportation and transit storage, which will cause changes in performance and quality of equipment packaging and equipment itself, and even damage. Therefore, when formulating and revising military "Three Prevention" packaging specifications, we should first study the environmental requirements of packaging and our