Standards And Requirements For Thousand-level Mechanical Transmission Dust-free Workshops

Standards and requirements for thousand-level mechanical transmission dust-free workshops

What is the biggest pitfall in the thousand-level mechanical transmission dust-free workshop? In fact, it is not that too much thought was spent on purchasing equipment. The really critical part is the critical data set after set. Even if it's just one number off, the entire production line will have to stop immediately.

How many dust particles are allowed in the air?

According to the standard GB/T 16292, for the requirements of a thousand-level workshop, the number of particulate matter with a particle size greater than or equal to 0.5 microns must be less than or equal to 35,200 per cubic meter, and for the number of particles with a particle size greater than or equal to 1 micron, it cannot be more than 8,320. In addition, the number of particles with a particle size greater than or equal to 5 microns cannot exceed 293.

For example, in 2025, there was a factory in Suzhou that produced gears. Because the particulate matter above 1 micron in its value exceeded the standard by 12 percentage points, the payment for the goods was deducted for a whole quarter.

The limit for planktonic bacteria is set at 5 to 100 CFU per cubic meter, while the detection result of settled bacteria in a 90 mm diameter petri dish for 30 minutes is no more than 1 to 3 each. Don't think that these bacterial test contents are not important, because if the customer finds that there are unqualified items in the microbiological test report during the factory inspection, the entire batch of orders will be directly rejected.

How to determine temperature, humidity and ventilation

The temperature is 24±2℃ and the humidity is 55±5%. Its purpose is to lock the viscosity of the lubricating oil and the clearance of the bearing to prevent them from drifting. The number of air changes should be maintained at ≥50 times/h. A reducer factory in Dongguan lowered it to 38 times in 2024. The purpose was to save electricity bills, but the result was that the rework rate doubled.

The distance between the air supply vents must not exceed 1.2 meters, because if this value is exceeded, local vortex conditions will be formed, which will make the settling of particulate matter more serious. Sufficient margin must be left for the space on the return air side. This requires accurate calculation of the reasonable distribution of air volume during the design stage.

If the fresh air volume is not enough and the positive pressure is insufficient, it will collapse.

The outdoor positive pressure must be maintained at 15 Pascals and above, the fresh air volume ranges from 10% to 30% of the total air supply volume, and the fresh air volume per person per hour must not be less than 40 cubic meters.

There is a factory in Shanghai that produces spindles. After expanding production and merging production lines in 2025, it did not recalculate the fresh air pipeline. As a result, the positive pressure dropped to 6 Pascals, and dust from the corridor outside poured in. The engineer stationed at the factory shouted stop on the spot.

The size of the exhaust air volume will change dynamically with the level of heat load and the number of people present. Therefore, it is recommended that you do an air volume balance test every six months. Don't wait until customers complain before you think of measuring it.

Don't worry about static electricity and lighting

When the chips rub against the belt, static electricity will be generated. When the voltage of this static electricity is high, it can reach tens of thousands of volts, causing the fine dust to be sucked over and stick tightly to the working surface of the gear. To solve this problem, you can lay an anti-static floor with a surface resistance ranging from 10⁶ to 10⁹Ω, install ion air curtains at key working positions, and require personnel to wear ESD bracelets.

The design standard for lamps in the lighting system is 500 to 1000 lux. The lamps are required to have a fully sealed structure and cannot have grilles. At the same time, the corners of the housing must be rounded.

There is a factory in Shenzhen that makes harmonic reducers. In 2024, it chose the LED product with a grille because it saves trouble. As a result, after half a year, dust accumulated on the grille and fell off, staining the transmission surface. In the end, the entire batch of products was scrapped.

Noise and access management

Background noise needs to be controlled within a weighted weight of 65 decibels. If it exceeds a weighted weight of 75 decibels, earplugs must be equipped. High-noise equipment should be concentrated in independent compartments. Low-speed operation and vibration isolation base solutions are preferred.

When personnel enter the workshop, they need to change into clean clothes, shoe covers and gloves, and be released after an air shower of fifteen seconds or more. Items are transferred through transfer windows with interlocking functions. Records of the number of people coming in and out every day, disinfection status records, and temperature and humidity records will be archived so that they can be checked one by one during the customer's audit.

Acceptance and daily monitoring

The building envelope is made of colored steel or stainless steel, and the ground is constructed using epoxy self-leveling technology. All joints must be sealed with silicone. In the final acceptance stage, the particle concentration needs to be monitored continuously for 72 hours. It must be ensured that the data of three different shifts all meet relevant standards. Only when such conditions are met can it be allowed to enter the production process.

After the production activities are officially launched, equipment such as particle counters, differential pressure meters, and temperature and humidity recorders need to be configured, and then the data collected by these equipment can be uploaded to the MES system, so that an alarm can be issued immediately when a problem is discovered. A third-party inspection must be carried out every month, and a comprehensive verification of the overall air balance status must be completed once a year. This is to ensure that all possible problems are blocked before they are dealt with as customer complaints.

Please provide the number of air changes and positive pressure values ​​obtained in the latest actual measurement in your workshop, and please publish the specific numerical content directly in the comment area. If you think this information has practical reference value, give it a like, and then forward it to the workshop director for review.