Linyi Electronics Factory Cleanliness Testing Contents and Methods-
If a precision machining workshop cannot meet the cleanliness requirements, the cost of rework will be dozens of times higher than the inspection fee. This is a lesson that many electronic manufacturers and mechanical processing manufacturers in Linyi have experienced. Everyone has spent a lot of money in vain.
Red line of particle concentration in workshops of level 1000 and level 100
In a Class 1,000 dust-free workshop, the upper limit of particle concentration for 0.5 micron particles is 35,200 particles per cubic meter, while the upper limit for particle concentration for 5 micron particles is 2,930 particles per cubic meter. The requirements for Class 100 workshops are even more stringent, controlling 0.5 micron dust particles within 3,500 particles per cubic meter. The higher the level of the workshop, the fewer dust particles it tolerates, which means the dust-free effect is better.
The electronics factory's 100,000-level standard is divided into 0.5 micron dust particles. In the case of 100-level dust particles, the number must be less than 3.5. If it reaches the 1,000-level dust particle level, it must be less than 35 particles. If it reaches the 10,000-level dust particle level, it must be less than 350 particles. At present, most electronics factories and machining factories in Linyi implement standards above 100,000, so when testing, they must be based on this standard.
How to deal with illumination and power distribution?
The illumination of the main production lines in the clean area is no less than 300 lux, while the illumination of the airlock, aisles and auxiliary studios is between 200 and 300 lux. The distribution lines must be routed separately according to the load of the clean room and cannot be mixed with power electricity. This is done to avoid electromagnetic interference.
If the illumination is insufficient, it will directly have a negative impact on the assembly and detection accuracy of optical components. There are some old factories in Linyi. When these old factories were renovated, they neglected to upgrade the lighting. As a result, after the production line was put into production, it was found that the probability of rework was high. If you wanted to modify it again, you had to stop production for construction, which doubled the cost.
Where are the noise and temperature and humidity measurements?
The noise measurement point is located at a height of 1.2 meters from the ground. When the workshop area is less than 15 square meters, only one point in the center needs to be measured. If the area exceeds 15 square meters, four additional diagonal points need to be measured. These four points are each one meter away from the side walls, and the direction of the measurement points must face the cleanliness standards of each corner of the precision machining workshop. Temperature, humidity, and fresh air volume need to be recorded and archived simultaneously.
Precision machined parts are significantly sensitive to vibration and noise. Once these data exceed the standard, it will have a very direct impact, causing the grinding accuracy to be lowered. Therefore, when performing inspections, the precision machined workshop cleanliness standards must be measured on the spot with the equipment in operation. The data in the empty state can only be used as a reference and is not representative. Therefore, it cannot represent the specific situation under actual working conditions.
How to choose the air supply and return method
The selection of air supply methods for Class 100,000 clean rooms mainly includes three types: the perforated ceiling method, the high-efficiency filter with a diffusion plate installed on the ceiling, and the air supply method from the upper side wall. As for the layout of the return air, in most cases it is arranged at the lower part of the wall on one side, or evenly arranged inside the aisle, or it is chosen to be concentrated at the end as the return air outlet.
When carrying out factory renovation in Linyi, a very common situation is that the return air outlet is too close to the air supply outlet. In this case, the air flow is easily short-circuited. The result is that although the cleanliness of a certain part meets the standard, the overall cleanliness does not meet the standard. This results in the debugging time period being lengthened, and the manpower and material resources are in vain.
How to run in empty state
The so-called empty state refers to those facilities that are fully equipped and relevant pipelines have been connected and are in operation, but no specific production equipment has been installed, and no relevant materials and staff have been stored.
When testing, you must first collect and test the data in the empty state, and then compare these data with the data in the dynamic state. The operation process needs to be carried out with reference to the corresponding specifications such as GB 50073. Only when all this is done can the results be qualified for acceptance.
Biological laboratories also involve standards such as GB 19489 and GB 14925. It needs to be divided into two rounds: empty state and dynamic state to generate data. Only in this way can we provide a reliable basis for project acceptance. At the same time, it can also provide a reliable basis for subsequent maintenance work.
How to remedy failure
If the data in a local area does not meet the standard, the problem can usually be solved by strengthening sealing measures, adjusting the total air volume, or replacing high-efficiency filters. However, if the condition of the entire factory building is not up to standard, it is often necessary to redesign the organization of air flow. In this case, the construction period will be delayed by at least two to three weeks.
At this stage of construction, a lot of defects can actually be avoided. To take some common examples, such as the sealing area is not done well, or the filter is installed in the wrong direction, etc., if we intervene before the inspection, we will save at least 50% of the construction period and the corresponding manpower costs instead of waiting until afterwards to make rectifications.
When the workshop you were in last conducted a cleanliness testing operation, was this state called empty operation or dynamic operation? You are welcome to chat about relevant opinions and situations in the comment area. If you think this content is useful, please like it and forward it to your peers.
暂无评论内容