Common problems, causes and solutions of die casting mould

1. Ejector

Problem points: the thimble is stuck or broken, the thimble position is pointed, the thimble position has many materials, the thimble print is too deep in the product surface, and the projection of the thimble print is too high.

Cause analysis: 1. The hole diameter of the thimble hole is too small or the inner surface of the thimble hole is rough, and the thimble assembly is too tight.

2. The sealing level of the thimble hole is too deep or there is no void avoidance position.

3. The hole diameter of the thimble hole is too large during processing, or it is processed into a special-shaped hole, and the thimble assembly is too loose.

4. During mold production, the maintenance of the thimble is not good, the surface of the thimble is greasy, and there is no thimble oil on the thimble; The ejector pin hole is worn.

5. During mold production, the Die Casting was closed before it was taken out, and the ejector pin was damaged.

6. During the processing and assembly of the thimble, the countersunk position of the thimble has an empty position, the protruded surface of the thimble is inconsistent, and the thimble is not positioned.

7. The thimble cup head and thimble plate are not marked, and the thimble is installed incorrectly.

8. The garbage pin on the ejector plate is too high or too low.

9. The thimble plate is too thin, the strength is not enough, and the middle bracket is not added to the thimble plate, causing deformation of the thimble plate.

10. The quality and strength of the thimble are not good enough, the heat resistant thimble of Datong standard is not selected, or the thimble exceeds its service life.

11. The mold core material is poor, the strength is not enough, and the thimble hole is worn

12. Diameter Φ The thimble with standard specification is not used for the thimble less than 3mm.

Solution: 1. During the processing of the thimble hole, the clearance of the thimble hole shall be controlled within 0.015mm on one side (e.g Φ For 6mm thimble, the corresponding thimble hole size must be Φ 6mm+0.03/0) to ensure smooth ejection after assembly of thimble.

2. The sealing depth of the ejector pin hole on the mold core is below 25~30mm, and the ejector pin is processed to avoid vacancy.

3. During the processing of the counterbore of the thimble, no taper plane is allowed. After the thimble is assembled, the thimble shall be controlled to be 0~0.05mm higher than the die core surface. When the thimble surface is inclined (curved surface) or pull level, the thimble must be positioned.

4. Diameter Φ The thimble less than 3mm shall be the supporting thimble, and the heat resistant thimble of Datong standard shall be used.

5. During mold production, pay attention to the maintenance of the thimble.

6. During mold production, the machine shall be shut down in time in case of abnormal conditions.

7. When replacing the thimble, be careful not to damage the mold core cavity. When the thimble is stuck, gently knock it out; otherwise, send it to the mold factory for wire cutting or electric discharge processing and take it out.

8. Do not install the thimble incorrectly, and check it after completion.

2. Core pin/insert

Problem points: Broken core pin/insert, bent core pin/insert, worn core pin/insert, and crushed core pin/insert.

Cause analysis: 1. The core pin/insert material is defective, the hardness is too high or too low, or the core pin/insert exceeds its service life.

2. The draft angle of core pin/insert is too small or the size is too long.

3. No clearance is left for the core pin/insert at the contact position.

4. During mold production, the operation method is improper, and the release agent is unevenly sprayed (too little or too much).

5. During mold production, the Die Castings were closed before being taken out, and the pins/inserts were damaged.

6. In case of die sticking during die production, use the thimble to knock out the insertion pin/insert.

7. In case of die sticking during die production, soak the needle/insert with hydrochloric acid.

Solution: 1. The needle/insert with good material shall be used. The hardness of the needle/insert surface after heat treatment shall reach HRC48~52 °, or the needle/insert shall be nitrided and titanium plated.

2. The draft angle of the core pin/insert is ≥ 1 degree/single side (rear mold), the draft angle is ≥ 1.5 degree/single side (front mold), the length is ≤ 10~15mm, and the head of the core pin/insert is chamfered with a R fillet.

3. A clearance of 0.05~0.10 mm shall be reserved for the core pin/insert in the contact position.

4. During mold production, pay attention to the maintenance of the needle insert/insert.

5. During mold production, the machine shall be shut down in time in case of abnormal conditions.

6. When replacing the insert pin/insert: be careful not to damage the mold core cavity. When the insert pin/insert is stuck, gently knock it out, otherwise, send it to the mold factory for wire cutting or discharge machining to take it out.

7. It is prohibited to soak the core pin/insert with hydrochloric acid.

8. When assembling the core pin/insert, it shall not be wrongly installed and shall be checked after completion.

3. Mold core

Problem points: the surface of the cavity is not smooth and clean, the mold is burned, the surface of the cavity is eroded by water, the surface of the cavity is corroded, the surface of the cavity is cracked, the surface of the cavity is crushed, the mold core is deformed, the mold flies, and the mold core leaks oil.

Solution: 1. The tool pattern or spark pattern on the surface of the mold core cavity is not saved or not in place.

2. The mold core material or heat treatment problem, the mold core surface hardness is too high or too low.

3. The mold core material exceeds the service life.

4. During mold production, the operation method is improper, and the release agent is unevenly sprayed (too little or too much).

5. During mold production, the maintenance was not good, the magnesium chips on the mold core surface were not cleaned in time, and there were foreign matters on the mold core surface.

6. During mold production, the die is closed before the thimble returns (the thimble is broken or stuck), or the die casting is not taken out and the die core is damaged.

7. In case of die sticking during die production, use the thimble to knock the cavity surface of the die core.

8. In case of die sticking during mold production, soak the surface of mold core cavity with hydrochloric acid.

9. During mold core processing, the thimble, insert pin and insert touch the oil circuit, or the oil circuit is not blocked properly.

10. The thread of the oil pipe connector is worn, and the raw material belt is not wrapped and tightened when connecting the oil pipe.

Treatment method: 1. The surface of the mold core cavity is properly saved.

2. The mold core with good material shall be used. The hardness of the mold core surface after heat treatment shall reach HRC46~50 °, or the mold core surface shall be nitrided and titanium plated.

3. When the mold is produced to 10000 beer, the mold core shall be tempered.

4. Pay attention to the maintenance of mold core during mold production.

5. During mold production, the machine shall be shut down in time in case of abnormal conditions.

6. When disassembling and assembling the mold core: be careful not to damage the surface of the mold core cavity.

7. It is prohibited to soak the surface of mold core cavity with hydrochloric acid.

8. After the mold core is assembled, check whether the oil pipe is smooth and whether there is oil leakage.

4. Sprue sleeve/splitter cone

Problem points: the fitting position between the gate bushing and the nozzle is damaged, the nozzle is stuck to the front mold, the gate bushing is flaring, the inner hole of the gate bushing is strained, the clamp head, the gate bushing leaks (oil leaks), the splitter cone leaks, and the gate bushing or the splitter cone is damaged.

Cause analysis: 1. The material or heat treatment of the sprue sleeve/splitter cone is poor, and the surface hardness is not enough.

2. The inner hole surface of the sprue bushing is not smooth and clean.

3. The fit clearance between the sprue sleeve and the splitter cone is too large, and the mold fitting is not in place.

4. The inner hole size is too large (or too small) during the processing of gate bushing.

5. The inner hole of gate bushing is worn.

6. The joint thread of the sprue sleeve/splitter cone cooling water circuit is worn, and the raw material belt is not wrapped and tightened when connecting the oil pipe.

7. Mold production: improper operation method, uneven spraying of release agent (too little or too much).

8. During mold production, the die casting was closed before it was taken out, and the surface of the sprue sleeve/splitter cone was damaged.

Solution: 1. Use a good material sprue sleeve/splitter cone, and the hardness of the surface of the sprue sleeve/splitter cone after heat treatment shall reach HRC48~52 °, or nitriding and titanium plating the surface of the inner hole of the sprue sleeve.

2. The mold saving of the inner hole surface of the sprue bushing is in place.

3. The machining dimension of the inner hole of the gate bushing shall be within the tolerance requirements.

4. During mold production, pay attention to the maintenance of the sprue sleeve/splitter cone.

5. During mold production, the machine shall be shut down in time in case of abnormal conditions.

6. When disassembling and assembling the sprue sleeve/splitter cone, knock it out gently, and be careful not to damage the inner hole surface of the sprue sleeve.

7. During mold production, check whether the oil path of the sprue sleeve/splitter cone is smooth and whether there is oil leakage (water leakage).

8. During mold production, check whether there is strain on the hammer, otherwise, replace the hammer in time.

5. Row position

Problem points: flying materials (product blades) and sliding blocks in the row position are stuck, the row position is damaged, and the row position core is eroded by water.

Cause analysis: 1. The strength of the front die wedge is not enough (or the front die wedge is not hardened), and the wedge surface is worn.

2. The overall dimension of the row position slider is too small, or the sealing level of the row position slider is not enough, resulting in collapse.

3. The sliding block and the sliding guide surface (or the sealing level of the sliding block) are too loose or tight, and are worn.

4. The matching between the sliding block and the guide surface at the T-slot position is too loose or tight, or the pressure strip strength of the sliding block is not enough and is worn.

5. The strength of the inclined guide pillar is not enough, or the inclined guide pillar is unbalanced.

6. During mold production, the ejector pin is not returned and the mold is closed (the ejector pin is broken, stuck, and the pull rod is not installed properly), or the die castings are not taken out and the mold is closed.

7. During mold production, the operation method is improper, and the release agent is unevenly sprayed (too little or too much).

8. During mold production, the maintenance is not good, the magnesium scraps on the line position are not cleaned in time, and there are too many magnesium scraps and oil stains in the guide chute.

9. During mold processing, the line position mold matching is not in place.

10. The row position is installed incorrectly.

11. The pull rod is missing or the travel of the pull rod is not adjusted properly.

Solution: 1. The front die wedge must be designed and processed with enough strength, and the front die wedge must be equipped with a hardening block.

2. During the design and processing of the line position slider, ensure that the overall dimension of the line position slider is sufficient, and the width distance of the line position slider seal level is greater than 25 mm.

3. Ensure that the fit clearance between the sliding block and the guide surface is reasonable.

4. The width and height of the T-slot position shall be ensured during the design and processing of the row position slider, and the pressure bar of the row position slider shall have sufficient strength.

5. The inclined guide pillar of Datong standard shall be used in the design and processing of the inclined guide pillar.

6. Marking and error proofing measures shall be taken for the row position slider.

7. When installing the mold, carefully check whether the pull rod assembly and adjustment are in place.

8. During mold production, the magnesium pin on the line position shall be cleaned in time, and the line position maintenance shall be in place.

9. During mold production, the machine shall be shut down in time in case of abnormal conditions.

6. Oil cylinder

Problem points: oil leakage at the sealing position of the oil cylinder and oil pipe joint.

Cause analysis: 1. The main reason is that the High Temperature Resistance of the oil cylinder is insufficient, which causes the damage of the oil cylinder seal ring during production and oil leakage of the oil cylinder.

2. The oil pipe connector is not connected properly.

Solution: 1. It is required to use high temperature resistant oil cylinder on the mold line, with a service life of more than 30000 mold times.

2. When repairing the oil cylinder, replace the black high temperature resistant oil cylinder seal ring.

3. Before mold production, check whether the screw thread of the oil pipe joint is worn, and wrap and tighten the raw material belt when connecting the oil pipe.

7. Exhaust plate

Problem points: flying materials, magnesium carbide, and collapse of exhaust plate.

Cause analysis: 1. The exhaust plates of front and rear formworks are not matched properly, the gap is too large, and the sealing level is not enough.

2. The exhaust plate and mold core are not matched properly, the gap is too large, and the exhaust plate is not fixed stably.

3. During mold production, the maintenance is not good, and the magnesium scraps on the exhaust plate are not cleaned in time.

Solution: 1. During mold processing, the exhaust plate shall be properly matched with the mold.

2. During mold production, the magnesium pin on the exhaust plate shall be cleaned in time and maintained in place.

3. During mold production, stop in time in case of abnormality