What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
rivet is a nail-shaped object used to join two parts or components with a through hole and a cap on one end. In riveting, the riveted parts are connected by their own deformation or interference. There are many types of rivets, and they are informal. In today's product production, the slot holes on the same mounting surface often have different mounting slot depths. If a mechanical tool is used for quick screwing and installation, it will directly bring destructive effects to the brittle products, resulting in When the product is cracked and damaged, when connecting plastic shells, lightweight boards, insulating materials, circuit boards, or any other thin and light materials, the requirements for the installation process are also relatively high. The gripping force and bonding force of rivets are weaker than those of rivets that are screwed and installed by machinery. The bonding strength of rivets used in manual operations needs to be enhanced. The rivet structure needs to be improved and enhanced when installing thin, light-weight materials.
With the mass production of large-scale equipment, standardization, and the concept of lean production, it has become more and more important to improve the efficiency of the assembly stage. Nowadays, when assembling small equipment, power tools and automatic bolt supply devices are basically popular, but only for M3 and smaller However, large equipment is often fastened with M8 or larger diameter bolts, and it is still in the process of combining manual and air tools. Among them, the pre-installation of the flat and spring washers on the bolts is completely manual operation. When the bolts need to be tightened in large quantities, the shortcomings of low efficiency are particularly obvious, and the flat and spring washers are easy to be scattered when manually assembled, and there are mixed installations of different specifications. Problems such as less installation and missing installation will affect the processing quality.
(1) Galvanized (blue-white, multicolored, black) 1. Pretreatment: thermal degreasing tank (5 tanks) - electrolytic degreasing tank (3 tanks) - rust removal tank (4 tanks) 2. Electroplating: electroplating tank (20 tank) (ammonium chloride, zinc oxide, gloss, softener solution). 3. Post-treatment: Melting tank (1 tank) - Green medicine tank (1 tank) - (blue-white/multicolored/black) (2), blackening: 1. Pre-treatment: thermal degreasing tank (4 tanks) - rust removal Tank (4 tanks) 2. Blackening: blackening (5 tanks) (flake alkali, sodium nitrite solution) 3. Post-treatment: anti-rust oil (1 tank) (3), phosphating: 1. Pre-treatment: heat Degreasing tank (1 tank) - Derusting tank (1 tank) - Electrolytic degreasing tank (1 tank), - Surface treatment (1 tank) 2. Phosphating: Phosphating (forming a film) 3. Post-treatment: dipping in anti-rust oil (2 tanks) (4) Hot dip galvanizing: 1. Pretreatment: degreasing tank (1 tank) - rust removal tank (1 tank) - FLUX tank (1 tank) - drying 2. Hot dip galvanizing: hot Zinc immersion tank 3. Post-processing: centrifugal treatment - ammonia chloride cooling - water cooling
The lifting ring screws are generally not surface treated, but according to the requirements, surface treatment such as galvanized passivation and chrome plating can be carried out, and it is specified in GB5267-85. The chemical composition and mechanical properties of the material should be treated immediately after electro-galvanizing. The test methods are specified in GB699. During routine inspection, the grain size test may not be advanced, and the grain size test method shall be in accordance with the provisions of YB27. Thread inspection is performed with thread gauges and smooth limit gauges or universal energy tools.
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