Common problems and solutions in arrow wax investment casting
Part 1. Sand cave
Generally divided into gasification sand caves and shrinking sand caves; gasification sand caves are spherical in shape and are as small as a pencil tip. Shrinking sand holes are angular, with crystalline surfaces in different sizes, and are mostly found in thick parts of precision castings.
Gasification sand cave:
1. Increase the time of losing wax. It is necessary to lengthen the stay at the highest temperature in order to remove the char.
2. Check the ventilation throat of the oven, and check the flame intensity if the oven is fired.
3. Check whether there is stone lamb powder accumulated on the surface of the old gold.
4. If you use a gun to melt the gold, check if there is too much oxygen mixed in.
5. Check whether the mould temperature is too high or the temperature detector displays incorrect temperature.
6. Too much old gold is used when reusing.
7. Check whether the temperature of Shijiao is too high.
Shrink sand hole:
1. Check whether the nozzle position is correct. The nozzle must be placed at the thickest position of the casting.
2. Check whether the nozzle thickness matches the shape and weight of the casting. Remember that the nozzle should enter the casting in a flared shape, and there should be no sharp turns.
3. Check if the temperature of Shilao is too high
4. Some castings should be designed with more water to make the metal easy to enter.
Part 2. Cracked
1. Check the quenching time; too fast will cause cracks.
2. Check the mold reversal temperature; alloys containing silicon deoxidizer require a higher temperature.
3. Check the stone lamb temperature; cracks found in thin parts may use too low stone lamb temperature.
4. Do not use hydrochloric acid to remove stone powder, because it will burst low-color castings.
5. Incorrect or inadequate placement of the nozzle, this kind of cracks are mostly found at the junction of the nozzle and the casting.
6. At the junction of the thick body and the thin body, there will be cracks in the thin body position, which is caused by different degrees of solidification speed. At this time, add more nozzle to the thick body part.
7. Excessive use of old gold will cause cracks.
8. Casting 18K with 10K or 14K patch will make the casting crack or fragile.
Part 3. Not completely filled
1. The molding temperature is too low.
2. The temperature of Shigao is too low.
3. The vacuum casting is not strong enough. Check the related equipment.
4. The speed used by the centrifuge is not strong enough.
5. The position of the nozzle is incorrectly placed.
6. Failure to complete the loss of wax will cause the air in Shigao to expand. Deform the casting
Part 4. Rough surface
1. The mold temperature is too high.
2. The temperature of Shigao is too high.
3. The prototype is rough.
4. The wax mold is rough, check whether there is too much release agent left in the rubber mold.
5. Check whether the stone lamb slurry is mixed with too much water.
6. Check whether the waiting time for stone lambs before waxing or steaming is insufficient.
7. The steaming time may be too long.
8. The Shigao Cup is heated too fast (Put the Shigao Cup into a high-temperature oven)
Part 5. Fins
1. The ratio of Shigao powder to water is incorrect.
2. The Shigao cup heats up too fast.
3. There is not enough waiting time in the Shigao cup before losing wax.
4. The treatment of mixed stone lamb pulp is too long.
5. Use expired or contaminated stone lamb powder.
Part 6. Watermark
1. There is a problem with the production of Shilao pulp. Before pouring the Shigao cup, the Shigao slurry must be continuously stirred to avoid water separation.
2. The waiting time before steaming is not long enough.
3. The steaming time is too long.
Part 7. There are blisters or bumps
1. Shilao pulp contains too little water.
2. It takes too long to make shigao paste, which makes shigao powder stubborn.
3. In the final stage of vacuuming, the vibration force is not enough.
4. The surface tension causes blisters on the surface of the wax mold.
Part 8. Rough oxide casting
1. In the process of lost wax, use too high temperature to overheat the stone lamb.
2. Excessive reuse of old gold.
3. Use borax with oxidation function to treat molten gold.
Part 9. There are unknown additions on the casting
1. Use damaged or contaminated crucibles.
2. Use contaminated metal.
3. Unidentified objects infiltrate when making stone lamb slurry.
4. After injecting the stone lamb slurry, the bottom was accidentally removed, causing the stone lao powder near the nozzle to peel off. Attached to the casting.
Ningbo Suijin Machinery Technology manufactures all kinds of lost wax investment castings and machining parts or called precision investment castings , material including carbon steel, alloy steel, and stainless steel. we also can according to the customers' requirement to compound the material,
Contact Person: Mr. Fred Zhang
Tel: 0086 574 28861663