Bucket Teeth In New Design

Now we are offering new design in bucket teeth. Certainly we have compared the bucket teeth between external and internal. Working conditions of bucket tooth in mining excavator, failure analysis of bucket teeth all have been considered into. New design for bucket teeth had better reduce the digging resistance as far as possible. Beside we also add the designing of material volume in effective working parts of tooth tip.

There are some characteristics in new designing. For example, our new design has been changed symmetrical location of the center line. That makes the wear surface consistent with abrasion surface in mining process. So it will present a smooth continuous curve. This could reduce the resistance in digging.

On the other hand, our new design for bucket teeth has increased effective material volume and  \geometric size in tip. When the material volume has been increased upon 15%, the total bucket teeth weight will be not increased or increased little. With this new designing, the service life of bucket teeth will be improved 30%. Above all, we can know that increasing effective working volume of material and reduce digging resistance could improve the service life of bucket teeth.

Article From: http://www.nbtt.cc/Daewoo-Bucket-Teeth/18SA%2820mm%29-99.html

Assembling Bucket Lip And Tooth

Electric excavator is the main equipment in mining production. Assembling bucket tooth and lip in this equipment is very important. Because more firm assembling, more safe working. So we should know how to assemble the bucket tooth and lip firmly.

While you are installing new electric excavator, you should mapping the geometry size of assembly binding site between bucket tooth cavity and the bucket lip at first. And making as a model. Then repeating examination and correction with the physical. Finally drawing a pattern.

We can use bucket tooth model to test the new assembling position. If there is any wear, we can take some measures to solve the problem of wear. Sometimes we could do surfacing welding for wear parts and burnish until it coincide with model. Then installing a new bucket tooth.

With above operations, electric excavator can keep careful examination and diligent in repair for a long term. At the same time, the bucket tooth and bucket lip could cooperation with each other successfully. Certainly the safety and efficiency of electric excavator have been improved. On the contrary, if you have not installed the bucket tooth and bucket lip badly, that may be result in serious accidents.

Technical Elements To Bucket Teeth Conjunction

There are many technical elements that effect the conjunction of bucket teeth. Such as drawings cooperation scale, coating and so on. Precise cooperation scale can ensure the bucket teeth cooperate closely. The metal has been shortened to 2%-3% freely. With the condition of sand hinder, shortening will be less than 2%. When you coating the bucket teeth, you should be very careful. Coating evenly and control the coating layer thickness of the sand mold and core strictly.

Tooth tip and tooth seat had better do heat treatment in the production process. Because the fallen oxide skin will affect the platform scale. Certainly due to the casting structure is not same, the casting shortening will be reduced after the molten steel poured into the mold casting. The operation technical of casting in the process has an influence on cooperation scale. After the expansion steel pulling into the sand mold, the mold can produce phase change and even has effect on casting cooperation scale.

The final cooperation state of bucket tooth is result in above factors. So the key to solve cooperation doubt is precise designing size, strict processing controlling and known about reasonable casting technology of scale.

Reduce Tooth Breakage Rate

Bucket teeth of some excavators will be broken after working for a period of time while the excavators are mining and dumping. These phenomenons will not only effect the production task, but also increase production costs.

The main reasons to cause bucket teeth broken are that bucket tooth do not match, ore block is too large or the operational guidance is not perfect. Durable bucket teeth have wear resistance, they are very suitable for loading hard stones. The work place of self sharpening bucket teeth need inserted into the soil. For example, digging or loading sand need to use this one.

In order to reduce tooth breakage rate, we suggest operators use matching bucket teeth. Reducing the fragmentation of ore. Technical staff should try to reduce the fragmentation of ore, so that we can achieve the desired effect. Besides every operator had better own a complete operation manual. Some company even organize all operators learning and examination. And it also needs to be inspect in the following scene. After you have done the works above all carefully, the tooth breakage rate would be reduced.

Molding Process For Bucket Teeth

Now bucket teeth are made by sand casting, investment casting and squeeze casting. Different castings have different characteristic.

Molding material for sand casting is cheap and easy to get. The mold manufacturing is also easy. But there is always some defaults on bucket teeth surface. Such as sticky sand, sand inclusion, shrinkage hole, shrinkage porosity and so on.

Investment casting has high size precision, rough surface and small machining allowance. But it needs to set high riser for feeding. So that process yield rate will be decreased.

It is applying pressure to metal liquid continuous in the squeeze casting process. It can make the metal liquid solidified quickly. The grain refinement is better. Bucket teeth product has higher compactness because it solidification under pressure. Without using sand mold and sand core can prevent causing casting defaults at the same time, the product quality will be good, the process yield and production efficiency will be higher. While as a new kind of material forming technology, squeeze casting is usually in simple process, high material utilization rate, small machining allowance. Squeeze casting can save energy and without any waste discharge.

Improving The Design In Bucket Teeth Center

In the analysis of total service life of bucket teeth, we must design the center position of bucket teeth by wear rule to solve the problem of large resistance in the early using stage. So bucket teeth center must be higher than installing center in designing. If the bucket teeth has been moved high, the slope on the bucket teeth will become smaller. At this time, its wear should be decreased and it is easy to shovel the ore.

Don’t move the center up too much. Because mostly moving up will make the service life of the bucket teeth decrease. But move the center up about 40mm will be better.

There are separate gas hole, blowhole and reaction blowhole in the kneading castings. In the constitute process of shrinkage hole and shrinkage porosity, mostly accompanied by gas separation. If it has too high gas content or too much gas all will increase the shrinkage or porosity composition. We can easily see that the stomatal distribution is random and often with large hole. They are mostly spherical and balls. So we can determine that porosity is belongs to the blowhole.

Why Does Bucket Teeth Casting Cause Hot Cracks

One day, worker find that there is transverse crack below the pulp cavity hole of bucket tooth. It is easy to be found on the casting surface. The crack section of is in serious oxidation and without any metallic luster. The crack shape is tortuous and irregular. The crack on the casting surface has large width and even present lacerate. So we can ensure that crack  belongs to thermal crack in essence.

Thermal crack is caused during the solidified process and the casting is in the plastic deformation statue. Metal liquid start to freeze under the wall heat transfer effect from the casting surface. Then appear a large number of dendrite and build a complete skeleton. If the casting frozen without any hindrance, bucket tooth casting shrinkage free and the internal  produce stress gradually. If the contracts of dendrite layer is limited by type and core, the dendrite layer will own tensile stress. When the tensile stress is more than the film strength limit. The dendrite will be pulled open. In order to ensure the casting not cause hot crack, there must be enough metal liquid and flow to the crack position.

There is a tensile stress in the core pulling process. At the same time, artifacts will produced resistance in the core pulling direction due to the runner has been solidified at this time. This resistance is an opposite direction of the tensile stress. If these two tensile stress have bigger effect than the yield stress under high temperature, it will make the bucket teeth pulled open and even form thermal crack.