After the batch die-casting is completed, it is necessary to check the final product, the mold burned portion, and confirm the shape of the important precision portion. It is also necessary to confirm that the mold does not conform to the part during die-casting or to replace and adjust the portion that consumes more.
Confirmation of mold status before use
1. If the mold is scratched, worn, sunken, protruding, etc., the operator first reports the leader of the pull, and the pull leader decides whether to correct it.
2. The mold core pin has no bending or cracking.
3. Confirm that the exhaust bag, exhaust vent, etc. are not blocked; if there is any abnormality, clean it immediately.
4. Determine whether there are residual aluminum chips on the parting surface and the inner surface of the mold; if there is any abnormality, it should be cleaned.
5. Confirm whether the mold ejector is broken or not, and whether the activity is flexible. If it is broken, it is necessary to inform the pull group to open the bill to replace it. If there is any difference, it can be lubricated with diesel oil or engine oil.
6. Confirm whether the plunger head is flexible or not. If there is any abnormality, the fault will be caused by the following reasons: the plunger head is worn; the material tube is seriously worn; the sprue sleeve is seriously worn; the pellet oil is too little or not; The mouth sleeve and the material tube are different; during the production process, the cooling water is not smooth, the temperature of the plunger head is too high, and the expansion is severe, and the plunger head cooling water inlet pipe and the outlet pipe are installed oppositely, resulting in unsmooth water flow. , the flow rate of the water is too small; the connection joint is distorted, loose; the plunger is bent, etc.
Important reminder: Everyone often forgets to install a cold water pipe after installing the mold. When the mold temperature is too high and the mold needs to be cooled, the mold cooling water pipe can only be temporarily installed, which wastes a lot of time and affects the quality of the product and the state of the mold.
Correct preheating The aluminum alloy die-casting mold should be preheated to 150 °C before use. The heating should be gentle and uniform. When preheating, the coolant should be gradually used to obtain an equilibrium state, and if it is quenched, the mold will be severely cracked. When the die-casting mold with the metal core is heated, it needs to be carried out slowly to synchronize the temperature rise of the core seat with the expansion. When preheating, generally the front 2-3 mold preheating tube and sprue sleeve, no shot, and then preheat the mold cavity in low speed state, the general hot mold 5-10 mold. Before each mold is preheated, apply a certain amount of mold release paste, etc., generally do not use spray gun spray. Cold water in the mold cannot be opened when the mold is preheated.
The use of cooling water The temperature control of the mold is high, which is conducive to the filling of the aluminum liquid in the mold and is conducive to the formation of the casting. However, when the mold temperature is close to 300 ° C, it will produce obvious aluminum adhesion, making the surface of the casting rough or missing. Need to grind the mold frequently. At the same time, the casting is opened without being sufficiently cooled within a predetermined time. The casting is not fully formed due to insufficient cooling and the mold release gap, plus the phenomenon of sticking aluminum. When the mold is released, the module and the pin will be subjected to excessive force and the crack will be damaged (the sound when opening the touch will also increase significantly). Too low mold temperature control will affect the fluidity of the aluminum liquid and cause cold casting of the casting. We hope that the temperature of each part of the mold does not differ too much. Otherwise, the mold cavity will be cracked due to the uneven expansion and contraction of the mold, and the tiny crack will expand due to the stress concentration phenomenon and the infiltration of the aluminum liquid, so that the module partially cracks and directly affects the service life of the mold. The aluminum liquid with a large wall thickness of the workpiece solidifies slowly, and the mold temperature can be slightly lower; the rib, the boss portion or the thin wall is used to prevent cold separation, and the fluidity of the aluminum liquid is to be improved. The mold temperature should be relatively increased.
On the spot, the temperature of the mold is generally determined from the appearance of the casting. The temperature of the mold is high. The appearance of the casting generally occurs in the following cases: strain, casting whitening is not bright, casting surface is peeling, surface foaming, etc. Near the mouth, the casting is thicker and the part of the mold is protruding. In the above situation, the on-site operation needs to pay attention to properly opening the mold cooling water at the corresponding part, increasing the spray of the corresponding part. The mold temperature is low, the surface is not smooth, the surface is black, the surface is cold and so on. In these cases, the mold cooling water is generally adjusted to reduce the spray at the corresponding part.
During the operation of the mold maintenance mold, there will be some sudden failures during the use of the mold, such as: sticking mold, sticking aluminum, batch seam, punch stuck in the sprue sleeve, the slider stuck can not be pulled out, top The rod cannot be ejected or returned to the position. The following examples are analyzed and processed. The common problem is the sticking mold. There are several reasons for the sticking mold: the mold temperature is too high, the roughness of the corresponding part of the mold is large, and the response part of the mold is inclined. In this case, firstly cool the mold part, then use a file to clean, after cleaning, pay attention to check the mold condition, remember to inform the mold master and the team leader to view. In the event of a mold failure, the team leader and the mold master should be notified to record in the shift record book to remind the off-duty personnel to pay attention.
During the die-casting process, burrs often appear on the surface of the mold and the sliding surface, which not only affects the accuracy of the product, but also causes the mold to malfunction. Therefore, it is necessary to remove the aluminum slag and other impurities every time (the burr-free die-casting is required) When cleaning during the die casting process, use a tool such as an air gun or a chisel, but be careful not to scratch the surface of the mold. Pay attention to the quality of the product and the condition of the mold, whether the casting has defects, poor cast aluminum, cracks in the ejector of the mold, and whether the slag bag and the venting groove are blocked.
After the completion of the die-casting, the mold condition is confirmed. After the completion of the batch die-casting, it is necessary to check the final product, the mold burned portion, and confirm the shape of the important precision part. It is also necessary to confirm that the mold does not conform to the part during the die-casting or to the part that consumes more. Replace and adjust. Pay particular attention to the blockage of the cooling tube caused by the use of hard water, which needs to be checked frequently. The problems detected should be reflected to the team leader and the mold master for easy repair.
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