Mold exhaust can represent the overall structure of the mold to the greatest extent

In the manufacture of molds, mold venting is a very important part. Mold exhaust can represent the overall structure of the mold to the greatest extent. Even if a good mold does not have good exhaust gas, it is impossible to produce a product with stable quality. A good mold should have good airtightness and ensure that the gas is freely discharged, instead of the gas being highly compressed. So what is the standard for mold exhaust? Let me introduce it to you. First of all, to understand the unreasonable exhaust will produce the following defects: 1, gas accumulation will etch the mold surface and the parting line; 2, color problems: the appearance of color difference, make the color black or bright; biting the flower surface is not bright 3, to increase mold polishing: wasting time, money and steel corrosion; 4, it is impossible to make the product meet the standards required by the customer; 5, will produce too much bonding line (this combination is not strong, and not beautiful 6, will waste too much injection pressure, increase the difficulty of the injection molding machine; 7, need to use too high barrel temperature (increased the difficulty of the injection molding machine, temperature control disorders, material performance deviation, increase cycle time) 8, will reduce the level of materials; 9, will reduce the product roundness and lead to product deformation; 10, the high-pressure gas in the cavity will increase the instability of the cycle, will often need to adjust the machine to solve the quality problem 11.

Increasing the work of technicians, QA, operators and model room personnel. Finally, let's take a look at the reasonable exhaust technology requirements: To do the exhaust structure as much as possible, the depth is within the plastic overflow value, the whole week exhaust is the best, but to keep 1/2 of the steel in the mold clamping Compensate for pressure online. If it is impossible to exhaust the whole week due to the irregularity of the PL surface, the better method is to use a 12mm wide exhaust vent to the master mold, and the gas must eventually be discharged into the atmosphere, and the exhaust gas should be processed as much as possible with a flat bottom chamfering cutter. Groove, if you must use a spherical milling cutter, you must calculate the depth of the processing and the depth of the flat bottom can be used. The length of the exhaust seal is one of the most easily overlooked by most people, and it is related to the proper exhaust problem.

There are many different size specifications on this issue. The material supplier's specifications are from 3 to 5 mm, and experience has proved that if the length is greater than 3 mm, it will no longer play a good role. Therefore, for safety reasons, we set the standard to be 3mm, the exhaust depth is determined by the molding material, if in doubt, the processing specifications can be consulted. One of the most common misconceptions is that too much venting leads to a cloak. In fact, the opposite direction is correct. Unreasonable venting requires excessive pressure. When gas is allowed to escape, the compound will go out with the gas. The only cause of excessive exhaust is that the pleat is too deep. It is usually best to use all the thimbles to vent. This is especially important for large plastic parts. This is of course determined by the diameter of the thimble. If this is not possible, the surface should be vented with the appropriate length and depth. Slow down the thimble to fit the gap, and the flow path, especially the large or long flow path, must be opened and vented. Another common problem is that when the part cannot be exhausted all the way, the Thin-wall injection molding final filling position and the second filling position must be taken into consideration. The two must be vented. Deep bone position, column position and small needle dispensing position or thin plastic position must be specially considered for exhausting, or with flat thimble, semi-needle structure or with exhaust steel, or even vacuum exhaust. So what do you need to pay attention to? A part can't be exhausted too much, although the mold line can do it, this will bring the following problems related to the exhaust: there is not enough steel to withstand the pressure on the mold line, the exhaust on the parting surface is pressed The best exhaust will eventually disappear. After a certain material circulation, if there is not enough steel to compensate the pressure on the mold line, the mold will bite together, and the air tank will wear, and the mold line should avoid the mold. The reduction of the clamping part is one of the biggest problems encountered by the large model. For the molds of the front and rear mold inserts, the front and rear mold cores cannot be clamped before the mold split surface is closed. The correct way is to clamp the mold at the same time with the pressure block between the mold plates AB. I hope my introduction is useful to you.