The process flow of stainless steel jewelry casting

ตอนนี้, the lost wax casting process is mainly used for stainless steel jewelry, and its specific process is: 1. Plate making Lost wax casting requires wax plates, while batch production of wax plates requires rubber molds pressed with silver plates. It is the most demanding process in the production of stainless steel jewelry, requiring the surface, hollow parts, and back of the silver plate to be smooth and free of scratches. It also requires the structure of each part of the silver plate to be reasonable, the position and size of the diamond inlay to be accurate, and some require pre-processing of the inlay parts. Only after preparing the silver plate can we enter the lost wax casting process. Please be advised that the main plate making techniques currently used are: hand carved wax plate, computer carved wax plate, and hand raised silver plate. The three processes each have their own advantages and complement each other. Hand carved wax plates are made by carving the shape on the design drawing with paraffin wax, and then pouring out the silver plate using the method of lost wax casting; The difference between computer wax carving and manual wax carving is that it combines computer 3D software with a wax spraying machine to create a wax mold shape, and then uses the method of wax casting to pour out the silver plate; Handmade silver plate refers to the process where the plate maker directly handcrafts the model on the design drawing. Due to its fast plate making speed, easy modification during the wax carving process, and relatively low tool wear, manual wax carving plates are widely used. 2. Lost wax casting Lost wax casting, commonly known as reverse casting, is an important means of producing stainless steel jewelry at present. (1) Pressing rubber mold Precautions and process for pressing rubber molds: 1) The mold frame and raw film should be cleaned, and do not touch the surface of the raw film directly with your hands. 2) To ensure that there is no adhesion between the original version and the rubber, silver plates should be used first, and copper plates should be silver plated first. 3) Determine the appropriate vulcanization temperature and time, which basically follow a functional relationship and are related to the thickness, length, width, and complexity of the original mold. The molding temperature is usually set at around 150 degrees. If the thickness of the rubber mold is 3 layers (about 10mm), the general vulcanization time is 20-25 minutes. If it is 4 layers (about 13mm), the vulcanization time can be 30-35 minutes. And so on. At the same time, the vulcanization temperature is also related to the complexity of the original version. If the original version is complex and small, the vulcanization temperature should be lowered and the vulcanization time extended. 4) When pressing the mold, it is necessary to ensure that there is no gap between the original version and the raw film. Fill the gaps, concave areas, and stone inlay areas on the first plate by inserting, wrapping, and filling them with small rubber particles, and press them tightly with a sharp object (such as tweezers). 5) Preheat first. After the vulcanization time is up, quickly remove the rubber mold. The pressed rubber mold should not deform, be smooth, and have a straight water line. It is best to let it cool naturally until it is not hot to the touch, and then use a sharp surgical knife to open the rubber mold while it is still hot. (2) Opening glue molds and wax injection molds 1) Opening the adhesive mold: The technical requirements for opening adhesive molds are very high. Because the quality of the glue mold directly affects the quality of the wax mold and metal blank. The tools for opening adhesive molds are relatively simple, including surgical knives, tweezers, scissors, pointed nose pliers, ฯลฯ. The adhesive mold usually adopts the four foot positioning method, that is to say. The opened rubber mold has four legs that are fixed to each other, and the part between the four legs is cut in a straight line or a curved line. Attention should be paid to inspecting the opened rubber mold. There should be no defects such as obvious broken patterns, missing corners, adhesion, ฯลฯ. inside the mold, which may cause defects in the wax mold. เพราะฉะนั้น, these defective areas should be repaired, such as cutting open uncut positions and using a wax welder to weld the broken patterns, missing corners, ฯลฯ. 2) Wax injection mold: After the rubber mold is opened, the wax injection operation can be carried out. Attention should be paid to mastering factors such as wax temperature, pressure, and the tightness of the adhesive film during wax injection operation. 3) Repairing wax molds and planting wax trees Repairing wax molds: In general, the wax molds taken out after wax injection may have some problems to varying degrees. For defects such as flying edges, multiple edges, pinch marks, unclear flower heads, or overlapping edges, surgical blades can be used to smooth them out; For sand holes, broken claws can be repaired with a wax welding tool; Small holes that are not accessible can be penetrated by soldering needles; The deformation of wax molds can be corrected in hot water at 40-50 ℃. If the hand size is incorrect, you should directly change the finger ring when repairing wax. Planting wax trees: The pre made wax molds are sequentially welded in layers along the circumference onto a wax rod using a wax welder, resulting in a wax tree that resembles a large tree in shape. (3) Gypsum casting and baking Gypsum casting: Cover the planted wax tree with a stainless steel tube along with the chassis; Mix the corresponding weight of gypsum powder and water to form gypsum slurry. After the first vacuum pumping, slowly inject the gypsum slurry along the inner wall of the steel bell. Do not pour the gypsum slurry directly onto the wax tree. Continue vacuuming for the second time until the gypsum slurry is about 1cm below the wax tree. Then let it stand naturally for 12-24 hours to ensure the solidification of the gypsum. Baking gypsum: The baking of gypsum molds is an important process to ensure the normal progress of casting. Its main functions are dewaxing, drying, and casting insulation. In general, the dewaxing temperature is 0-250 ℃ and the holding time is 1.5-2 hours; The drying temperature is 250-600 ℃, and the insulation time is 2-3 hours; Heating up to 600-900 ℃ midway, with a holding time of 2-3 hours; The casting temperature is 900-1000 ℃, and the insulation time is 2-4 hours. (4) Melting steel and casting Stainless steel smelting is not just about simple melting, but also involves the smelting process to ensure that the metal poured into the mold meets the expected requirements in terms of temperature, chemical composition, and purity. เพราะฉะนั้น, a quality control testing process must be carried out during the melting process, and the purity of the liquid metal must meet the pouring requirements before pouring can be allowed. As the baking of the gypsum mold approaches its end, the stainless steel begins to melt and maintain its molten state. After the gypsum mold is insulated, inject the stainless steel liquid from the water outlet to complete the casting. (5) Blasting, cleaning, and sawing of gypsum molds The cast gypsum mold is in a high temperature state. After being taken out of the casting machine, it should be left to stand naturally for 30-60 minutes, and then placed in cold water for frying and washing. After the gypsum explodes due to shrinkage, the steel tree is taken out, and large pieces of gypsum are brushed off with a steel brush. The steel tree is then sprayed with a high-pressure cleaning gun to remove the remaining gypsum until the surface of the steel tree is clean. The accessories on the steel tree are cut along the bottom of the water outlet or cut with a cutting machine, and then rolled in a drum for 20-30 minutes before being taken out. After cleaning and electrolyzing, it can be delivered to the warehouse or proceed to the next process. (6) Mold holding and inlay The touch process of stainless steel jewelry refers to the process step after wax loss casting and before inlay. Due to shrinkage and deformation caused by casting, the surface of the mold often has problems such as sand holes, bulges, heavy edges, dents, and even fractures, which require repair and correction. The usual process sequence is: shaping – grinding the water mouth – checking and repairing cracks and sand holes – correcting the shape – sanding (or rubber wheel). (7) Polishing Polishing is the most important step in the surface treatment process of stainless steel jewelry, and it is a crucial process in the production of stainless steel jewelry. The polished surface of the jewelry should be extremely bright, giving people a dazzling beauty. Only by achieving a mirror like shining effect can it attract customers’ attention. Polishing is the general term for smoothing and polishing the surface of stainless steel jewelry. Polishing can only be carried out after the scratches, burrs, and edges on the surface of stainless steel jewelry have been completely polished. The polishing and finishing of stainless steel jewelry usually use “purple wax” และ “blue wax”. Purple wax “is a coarse abrasive that can quickly remove sandpaper marks or small scratches. If used correctly, it can polish metal surfaces very smoothly, but still lacks some brightness. Green wax can throw a bright light out of metal, and its function is only to polish it. In fact, the heat generated by high-speed friction can make the metal surface soft and fill the slightest scratches, achieving a very smooth level and thus having a shiny effect.