1.1 East long modeling line work process
The static disk blank is produced on the AMF-II07 Dongjiu mainframe. The inner dimensions of the sandbox are 700mm×600mm×200mm. The working process of the machine is vertical sand shooting and horizontal classification.
In this modeling process, whether the equipment performance meets the requirements of the hardness of the mold parting surface, whether the demoulding is horizontal, stable, and whether the box is positioned accurately or not, plays a decisive role in the appearance quality of the blank.
2 defect analysis and improvement measures
The defect parts are respectively produced in the four-corner section of each type, which accounts for about 1/3 to 1/4 of the casting's one-week ratio.
2.2 Improvement measures Improvement measures are as follows:
Analyze its possible causes
1 Check the mold and template, and clean the mold;
2 Check the level of the core in the lower part, and use it after smoothing;
3 Test and record the hardness of the upper surface and adjust to the standard requirement of 85 or more.
2.3 Results verification
The mold plate is inspected by scribing, the parallelism of the upper and lower sides, and the verticality are all in accordance with the requirements; the mold has burrs and damage, and the repair meets the requirements for use; and the upper and lower shots are restored to increase the uniformity of sand shooting. Sex, so that the sand of the four corners can be effectively filled and the hardness tends to be uniform. After the production of two furnace blanks, the effect is not satisfactory, and the rough edges of the blanks still exist in a large amount.
3 Revised implementation plan For the analysis of the causes of product defects, it is often to find problems in the technical aspects or in the operation process. Since the comprehensive effect of the equipment is not well understood, and the influencing factors of the equipment are neglected, it is necessary to adjust the thinking and get out of the analysis misunderstanding.
3.1 The second cause analysis and the reasons for the measures are as follows:
1 The mold release resistance is large, and the demolding time of the casting is inconsistent for one week;
2 The distance from the template is too long, the speed of demoulding is too fast, and the shape is shaken.
The corresponding measures are as follows:
1 Adjust the equipment release program to make it smooth;
2 Check the distance of the stripping stroke to increase the smoothness of the contact.
3.2 Implementation results
The blank inspection results show that the casting pass rate has improved, but it is not obvious, and some of the furnace scrap rate is still as high as 50% to 70%.
4 equipment, comprehensive analysis of technology
4.1 Analysis
Summarizing the lessons of the previous two failures, decided to find a way to thoroughly check the integrity of the cavity after clamping, so propose measures: observe the degree of top damage by two methods, that is, one placed the core, one does not place the core . After the mold clamping, the cavity is transported from the main machine to the conveying line segment, and then removed, respectively, cut from the middle of the cavity, and the cross section is observed to observe the complete condition around the upper mold. The results show that the upper cavity of the lower core has been damaged, and the cavity without the lower core is intact. At this time, it can be concluded that the rotten type has a direct relationship with the core. In the case of eliminating the core size problem, there must be a problem with the upper or lower cavity. The cause of the bad edge can be summarized as follows:
1 The equipment is not tightly sealed, resulting in insufficient sand injection pressure, resulting in a relatively small amount of sand in the edge area of ​​the cavity where the amount of sand is small, resulting in loose cavity and low hardness in this part;
2, after the lower type is combined, the lower type is under the gravity of the upper type, the amount of sand eaten is small, and the part with low hardness will sink, especially after the pressure of the pressed iron (the total weight of the iron box) A total of 370kg), the cavity part adjacent to the core does not have enough supporting force to retreat, because the core is made of hot coated sand, the outer ring thickness is only 10mm, but its hardness is much higher than the type The cavity, at which point the core that does not have concession protrudes partially from the parting surface. If the hardness of the upper type is relatively high, it can only move toward the center direction without external force when it is pressed by the external force of the core. Since the displacement is small, most of the cavity does not drop sand, but The cavity forms a crack locally, as shown in Figure 7. After the pouring, the molten iron naturally penetrates into the gap of the mold, which causes the outer circumference of the casting to finally leave a mark of the burrs, resulting in a defective product.
4.2 Corrective measures and effects
The hardness was measured in different areas of the parting surface, and the above-mentioned speculation was confirmed by using the test result of the type B durometer, which was 45 to 70 in all directions and 85 or more in the middle portion.
Take the following measures:
1 Modify the mold, adjust the amount of sand in the cavity, so that the thickness of the sand mold with a minimum of 20mm on both sides of the lower mold is increased to 30mm, which improves the unevenness of hardness. Tests have shown that this increases the hardness around the cavity to more than 75.
2 Replace the upper and lower plate sealing strips to increase the tight pressure of the sand box.
3 Increase the template compaction block to increase the local hardness of the cavity.
After several improvements, the real cause of the defect was found. After the implementation of corrective measures, the trial production of the blank eliminates the phenomenon of smearing.
5 Conclusion
(1) The styling main engine and auxiliary machine of AMF-II07 Dongjiu production line are a complex system. The quality of blank quality depends to a large extent on whether the performance of the production equipment remains stable. The phenomenon of static disk smearing is related to the degradation of equipment performance. Therefore, it is necessary to pay attention to equipment sealing, sand shooting pressure, and motion positioning.
(2) The influence of casting equipment and process technology on the quality of blanks is cross-over and superimposed. Comprehensive analysis should be carried out when analyzing the causes of product defects. In the case that the process technology is not completely reasonable, due to the excellent performance of the equipment, the irrational force of the process can be weakened; conversely, the degradation of the performance of the equipment will make the degree of product defects caused by unreasonable process technology more serious. In the case of aging equipment, or repairs are not in place, it can have a fatal impact on product quality.
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