In the manufacture of Crate Mould, mould exhaust is a v […]
In the manufacture of Crate Mould, mould exhaust is a very important link. Exhaust of crate mould can represent the whole structure of mould to the greatest extent. What should be paid attention to when designing the exhaust of the crate mould?
1. Try to exhaust with all thimbles, which is especially important for large plastic parts. This, of course, depends on the diameter of the thimbles. If this is not possible, grind flat exhaust, use appropriate length and depth, and slow down the fit clearance of the thimbles. Flow passages, especially large or long flow passages, must be vented.
2. When the parts cannot be fully vented, the last glue filling position and the second last glue filling position must be taken into account, and these two positions must be vented. Special consideration shall be given to venting for deep bone position, column position, small needle dispensing position or thin glue position, or flat thimble, semi-needle structure, venting steel or even vacuum venting.
3. The exhaust structure of the whole circle should be made as much as possible, the depth is within the plastic overflow boundary value, and the exhaust of the whole circle is the best, but 1/2 of the steel should be left to compensate the pressure on the mold closing line. If full-cycle exhaust cannot be performed due to irregular PL surface, the better method is to use a 12mm wide exhaust slot to the master mold, and the gas must eventually be exhausted to the atmosphere.
4. Use flat-bottomed milling cutter with chamfer as much as possible to process the exhaust groove. If spherical milling cutter is required, the processing depth should be calculated to be consistent with the depth processed by flat-bottomed. The length of exhaust sealant is the most easily ignored by most people and is related to the appropriate exhaust problem. Experience has proved that if the length is greater than 3mm, it will no longer play a good role. Therefore, to be on the safe side, we set the standard at 3mm, and the exhaust depth depends on the molding material. In case of doubt, please refer to the processing specifications.
5. Excessive pressure is required for unreasonable exhaust. When the gas is allowed to exhaust, the rubber compound will go out with the gas. The only reason for excessive exhaust is that the depth of the gas tank is too deep.