Selective Laser Sintering - Sls Stereo Light Curing Molding - Sla
It mainly uses photosensitive resin as a raw material, and utilizes the characteristic that liquid photosensitive resin will cure quickly under ultraviolet laser beam irradiation. The photosensitive resin is generally liquid, and it immediately initiates a polymerization reaction and completes curing when irradiated with a certain wavelength of ultraviolet light (250 nm to 400 nm). SLA focuses on the surface of the light-curing material by focusing ultraviolet light of a specific wavelength and intensity to solidify it sequentially from point to line and from line to surface, thereby completing the drawing of a layered cross-section.
Selective Laser Sintering - Sls,Sls 3D Printing Service,Laser Sintering 3D Printing,Selective Laser Printing Ningbo Rongna Technology Co.,Ltd , https://www.machiningcustom.com
The inspection examined the surface quality of steel castings, stem diameter measurement, and wall thickness measurement of 90 batches of valve products produced by 90 companies in nine provinces and municipalities directly under the Central Government in Jiangsu, Shanghai and Zhejiang. There are 72 batches that meet the requirements of the testing standards. The passing rate of detection is 80%. There are 18 batches of products that do not meet the requirements of the standard. The detection rate of unqualified products is 20%.
This inspection is based on GB/T12234-200 "steel valve for stud connection valve cover for petroleum and natural gas industry", JB/T7746-2005 "compact steel valve", GB/T8464-2008 "iron and copper "Threaded connection valve", GB/T12232-2005 "Flanged connection iron gate valve", GB/T12233-2006 "iron stop valve and lift check valve" and other standard requirements. Of the 18 batches of unqualified products that were inspected, seven batches of industrial valves and 11 batches of plumbing valves involved 6 items, including 1 low-pressure seal test, 8 stem diameter measurement, and wall thickness. Measure 10 times, the valve body material composition analysis 2 items, high pressure seal test 2 items, shell test 1 item.
Valve quality problems are mainly reflected in the poor surface quality of cast steel parts, the measurement of stem diameter and wall thickness of the valve body are not up to standard, low pressure seal, upper seal, high pressure seal, shell and other tests are not up to standard, and the valve body material composition analysis is not up to standard. , Pipe thread accuracy is poor, the wall thickness of the valve casting blanks is poor, the quality of the surface roughness of the casting is poor, the internal and external leakage of the general valve is serious, and even some valves can not guarantee a reliable work within a maintenance period.
Some people in the industry pointed out that many companies clearly have a quality assurance system, but they are not actually implemented in actual work, and quality management is arbitrary. Although the overall level of China's valve industry has been greatly improved, but the product quality is not yet stable, such as run, run, drip, leakage phenomenon often occurs in domestic valves. There are also individual users blindly pursuing low prices, one-sided reduction of engineering project technical requirements, coupled with the homogenization of low-end products in the same industry, leading to a decline in the quality of some companies.
Experts reminded the majority of manufacturers that quality is still the main problem in the industry. To be invincible in the market, we must ensure the good quality of products, and do a good job of product quality management. The ISO9001 quality system does not go through the court and really falls into place. Real place.
Valve product quality national supervision spot check result
On July 28, the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China announced the results of national supervision and inspection of valve product quality. There were 18 batches of products that did not meet the requirements of the standards, and the rate of detection of unqualified products was 20%.