How To Reduce The Break Bucket Tooth

After a period of work, some excavator seems to frequently meet the occurrence of bucket tooth’s broken teeth phenomenon, which not only affects the production tasks, but also increase the cost of production. The main reasons causing the high rate of broken tooth are that the bucket teeth don't match, ore block is too large, or the operation guidance is not perfect.

Usually there are three kinds of excavator teeth type for the users to choose, standard bucket tooth, durable bucket tooth and self sharpening tooth bucket. Standard bucket tooth can be used in most cases. Durable bucket tooth doesn’t need to meet the requirement of insertion, but it should work with the stones after split. And self sharpening bucket tooth should insert into the soil, doing the work such as excavating or loading of sand or clay. In order to avoid the broken teeth phenomenon, first of all, we should be sure to use the supporting bucket tooth. At the same time we should pay attention to reduce the huge lump ore, in order to achieve the expected effect. And also do not forget to improve the operation instruction. It is better to make a new operating manual, according to the original operating manual coming with the excavator and the actual situation.

To Improve The Brand Effect Of Chinese Bucket Tooth

The development of hardware accessories industry makes the bucket teeth industry capacity growing, and it also has enhanced China's hardware industry, and laid the foundation for the overall level of hardware industry and the international market share. However, in the development process of China's bucket tooth products, ignoring the problem of the industrial structure, productivity and other aspects makes the industry into a stagnant dilemma.

The low-end bucket teeth can not support the future, and paying much attention to the design and technology innovation is an important way for the future industrial development. We should try our best to promote science and technology innovation construction of the products, build the transformation and upgrading of traditional industries and accelerate the training speed of the platform. At the same time, building the industry leading enterprises, and setting up the influential national brand are also very important for making China bucket tooth industry bigger and stronger.

Three Molding Processes Of Bucket Teeth

The present production of bucket teeth mainly uses three molding processes, sand mold casting, investment casting and squeeze casting.

Molding material for sand casting is cheap and easy to get, so this kind of molding process is very easy and cheap. Investment casting can produce castings with high size accuracy, low surface roughness, and small machining allowance, but it needs setting high riser for feeding, thereby the process yield will be reduced. Squeeze casting process is to apply constant pressure to the metal liquid in the forming process of, making the liquid metal rapidly solidified. It can produce castings with well grain refinement, and because of the solidification under pressure, the compactness of bucket teeth products is higher. And it does not need to set the great riser to feeding, which can avoid the generation of shrinkage defect. Products always have good quality, high process yield rate and high production efficiency. At the same time as a new material forming technology, extrusion casting also has advantages of simple process, high material utilization efficiency, small machining allowance, no waste emissions and so on.

Why There Are Heat Cracks On Tooth Casting

There appear irregular cracks on some tooth casting, which are called the heat cracks. Then how the heat cracks come about?

The heat cracks appear during the process of solidification, when the casting is in the plastic property and deformation state. The shape of these cracks is tortuous and irregular. And its formation is mainly caused by the uneven shrinkage of the forming components. In the filling process of the parts, the matters such as the uneven distribution of mold temperature field, a relatively low forming pressure, and ineffectively feeding, will cause the uneven shrinkage of the forming parts. In the casting process, the solidification time of different casting parts are not the same, due to which there will exists two tensile stress in the opposite direction during the core pulling. If the two tensile stresses is greater than the stress effect of material under high temperature, the bucket tooth workpiece will break in the weak point, and then the heat cracks come about.

Fixing Method For Bucket Tooth And Bucket Lip After Assembly

In the whole process of using an electric excavator, maintaining long-term careful examination and being diligent in repair can always keep the bucket tooth closely matched with the bucket lip, so as to help the electric excavator shovel works and operates safely and efficiently.

Firstly, at the time of the installation of new electric excavator, accurate mapping size of outer assembly binding geometry parts of the inside bucket teeth and the bucket lip, and make out templates. Then after repeated testing and physical modification, finally draw the pattern out.

In the working process, use the bucket tooth model to test if the bucket tooth new parts assembly parts is qualified, with bucket lip model in the late using process of bucket to test the wear volume of the bucket lip. If the bucket lip has any wear or tear, use the intermittent time of maintenance and repair or replacement of bucket tooth equipment to bead weld on the wear parts of the surfacing, and polished it anastomose to the model, and then install the new bucket tooth.

Why The Excavator Bucket Tooth Casting Has Stomata

The stomata in bucket teeth casting is formed in the process of squeeze casting. In the process of liquid metal filling, the gas which has not been discharged will be entrapped into the liquid metal, and subsequently float. The floating rate of the gas is mainly related to the liquid metal viscosity. With the decrease of temperature, the liquid metal viscosity increases. When the liquid metal viscosity increases to a certain extent, the bubble buoyancy velocity tends to zero, then the bubble stops floating up but stay in the liquid metal. Then the stomata are informed.

The main reason for this situation is the unsmooth exhaust of casting mold. Gas in the cavity can not be discharged smoothly. In the filling process, the gas will be stored between the mold cavity and the liquid metal. Since the liquid metal can not completely dissolve the gas, and the part of the metal liquid which firstly contacts air will form a thin solidification shell in advance, the gas is which has not been discharged will gather in a certain internal region and finally the stomata appear. At the same time, as the squeeze casting is under high pressure to do the filling and solidification of liquid metal, the gas above will be compressed rapidly, thus creating conditions for the formation of bucket tooth stomata.

Abrasion Of Bucket Tooth Influences Cutting Force

According to the degree of abrasion of bucket teeth, we divided the bucket tooth into 3 levels. Level zero wear, i.e. the new bucket tooth without abrasion; the intermediate, namely the bucket tooth whose radial abrasion length is 6mm or so and the average abrasion surface is about 22mm; the heavy wear, namely the bucket tooth whose radial abrasion is more than or equal to 15mm and the average length of the wear surface is more than or equal to about 30mm.

The experiment proved that abrasion has the following effects of cutting force of bucket tooth. First, the cutting force increased, especially heavy wear, line cutting force is 6 times larger than that before the wear. Second, the normal force increased with the bucket tooth becoming dull due to the abrasion. The normal force of the intermediate wear increases about 3 times, while that of the heavy wear increased 8 times. Third, from a macro perspective, in the cutting process, with the intermediate or heavy wear the vibration of the machine itself is bad, and the digging resistance increases significantly. Obviously, it is extremely unreasonable of excavator working in such bad condition, and this will cause damage to the transmission parts, make the equipment power greatly overload, shorten the machine service life, and also reduce production capacity.