Processing technology of pneumatic ball valve
After the completion of vulcanization, pneumatic ball valves often need to stop some post-processing before they can become qualified waste products. This includes: ① the trimming of mold products to make the appearance of products bright and the overall dimensions meet the requirements; ② After some special processes, such as the disposal of the appearance of the products, the application performance of products for special purposes has been improved; ③ For products containing fabric framework, such as tape, tire, etc., stop hot stretching and cooling and cool under inflation pressure after vulcanization to ensure the stability of product size, shape and good application performance.
When the mold is vulcanized, the rubber will flow out along the parting surface and other parts of the mold, forming an overflow rubber edge, also known as burr or flash. The number and thickness of the rubber edge depend on the structure and precision of the mold, the parallelism of the platen of the platen vulcanizer, and the amount of residual rubber filled. Today's products consumed by borderless molds have very thin adhesive edges, which can sometimes be removed when the mold is lifted or wiped quietly. However, this kind of mold has high cost and is easy to damage. Most mold products need to be repaired after vulcanization.
1. Manual finishing
Manual trimming is an ancient trimming method, which includes manually punching the rubber edge with a punch; Use scissors, scrapers and other tools to remove the glue edge. The quality and speed of manually trimmed products will also vary from person to person. The geometric dimensions of the finished products requested to be trimmed must meet the requirements of the product drawings, without scratches, scratches and deformation. Before trimming, the trimming parts and technical requirements must be clearly defined, and correct trimming methods and tools must be controlled.
2. Mechanical finishing
Mechanical trimming refers to the process of using various special machines and corresponding process methods to stop trimming the mold products. It is currently a more advanced method of repair.
(1) Mechanical punching trimming removes the glue edge of products with the help of pressure machine, punching die and punching knife. This method is applicable to products and model products whose rubber edges can be placed on the bottom plate of the punching die or punching knife, such as bottle stoppers, leather cups, etc. For products with high glue content and low hardness, the impact cutting method is generally used to cut the edges, which can reduce the uneven edges and side dents after cutting due to the large elasticity of the products; For products with lower glue content and higher hardness, the knife edge die can be directly used for punching. In addition, punching can also be divided into cold cutting and hot cutting. Cold cutting refers to punching under room temperature. The punching pressure of the requested equipment is high, and the punching quality is good; Hot cutting refers to cutting at a high temperature - f. During punching, avoid contact with products at high temperature for too long, which will affect the output and quality.
(2) Mechanical cutting trimming is applicable to trimming of products with large overall dimensions, and cutting tools are used. All cutting machines on one side are special machines, and different products use different cutters. For example, if there are rubber strips with different lengths at the air hole and exhaust line of the tire after vulcanization, the rubber strips must be cut off with grooved tools under the condition of tire rotation.
(3) Mechanical grinding trimming For mould pneumatic ball valves with inner holes and outer circles, grinding squares are usually used. The cutting tool to be ground is a grinding wheel with certain particle size. The precision of grinding trimming is low, and the grinding surface is rough, which may contain residual sand particles, affecting the application effect.