Molded silicone rubber is one of the most simple methods in fast molds. Silicon is usually used to print 3D prototype prototype, but the life is very short, only 10-30 or so. It has a very good flexibility and replication performance, with a silicone mold can not consider the draft angle, will not affect the dimensional accuracy, a very good separation, do not have the upper and lower mold can be directly the overall casting, Mold line for cutting, remove the master mold on it.
Room temperature vulcanized silicone rubber is divided into two types of addition and condensation. Raw materials and formulations using special mold silica gel, Mold Making Silicone Rubber the strains sold in double packaging, A component is the compound, B component is the catalyst. Preparation, to consider the room temperature, mold strength and hardness, in order to determine the proportion of AB component weight preparation. Room temperature at 20-25 degrees, A: B = 100: 1.5; room low (but not less than 10 degrees), the appropriate increase in B component 0.1-0.3; room temperature is high, then reduce the B group 0.1-0.3 Copies. The specific method is: according to the mold volume to determine the total amount, and then A, B components in proportion to accurately measure, Mold Making Silicone Rubber placed in the vessel evenly stirred, Serve.
1. Mold silica gel operation method
1. Mold silica gel and curing agent stir evenly. Mold silica gel appearance is the flow of liquid, A component is silica gel, B component is curing agent, for example, take 100 grams of silica gel, add 2 grams of curing agent (Note: silica gel and curing agent must be stirred even if there is no mixing evenly, Mold will appear curing dry uneven situation, and the impact of mold silicone rubber life, and the number of times the mold, or even cause mold scrapped.
2. Vacuum exhaust bubble treatment. Mold Making Silicone Rubber Silica gel and curing agent after mixing evenly, the vacuum exhaust bubble section. Vacuum time should not be too long, generally not more than 10 minutes, otherwise, silica gel curing cross-linking reaction, can not be painted or perfusion, Mold Making Silicone Rubber resulting in material waste.
3. Brush the operation process. (In the brush or perfusion before the mother mold on the release agent or release agent), the brush must be uniform, 30 minutes after a layer of sticky Sand cloth or glass fiber cloth to increase the strength and tension of the mold; and then a second brushing, and then paste a layer of gauze or fiberglass cloth, and then silica gel brushing, after this treatment out of the mold with life and mold Many times, long life, cost savings, improve efficiency.
4. The production of external mold. The general method is: the mold around the plastic board or wood surrounded by a kind of gypsum will be filled with mold can be used, another external mold is the way to use resin brushing, brushing a layer of resin, painted Brush a layer of glass fiber cloth, and then brushing and then paste, Mold Making Silicone Rubber repeated two or three layers can be completed outside the mold.
5. Silicone (silicone, silicone) and curing agent ratio reflects the situation. Proposed curing agent can not add more than 5%, the greater the proportion of curing agent, the faster curing time, the more brittle mold, short life. But also according to product and process requirements, the appropriate amount of silicone oil, mold making better, pay attention to silicone oil should not be excessive (5% -10%), otherwise, Mold Making Silicone Rubber affect the molding silicone rubber tensile strength and hardness.
Second, mold making silicone rubber precautions
1.B component is a catalyst, easy to tide hydrolysis, it should be covered with cover after the cover.
2.A, B components once mixed, the chemical reaction immediately began, the viscosity gradually increased, can not be suspended, in order to avoid waste, should be based on the amount, with the use with, with a good use should be immediately after, can not be delayed.
3.A, B group of the ratio, related to the speed of chemical reactions and mold performance. The more B components, the faster the reaction, the higher the strength and hardness of the product, Mold Making Silicone Rubber but the toughness decreases, so the weighing requirements are accurate.
4. Before preparation, should be A group of ingredients up and down mixing evenly, and then weighing.
5. Casting method suitable for relief, brushing method for the production of three-dimensional mold. Pouring relief type of mold, should be made longer than the width of the original carving long and wide 4-6CM border. Border to be flat, the inside to be smooth. Pour, the border will be placed on a clean glass plate, and then the prototype on the box, leaving 2-3CM on each side of the gap (mold silicone 25-35 yuan / KG).