CNC Knowledge: Reasons for boring degraded performance!

When boring treatment performance decreases, the reason can be caused by a specific factor or the result of the combined action of several factors. These factors include the stability of the part, the size of the machining allowance, the rigidity of the tool system, the grade of insertion and the geometry, the cutting speed and the performance of the correspondence tool the food frequency. When you meet situations such as long treatment cycle time, the lifespan of the shortened tool or the poor quality of the parties, these factors must be analyzed and identified.
In a particular boring process, the influence of a factor can be more significant than others, but these factors can also be closely linked to each other. The change in one of these factors can mean that to achieve the desired result, the other factor must be modified at the same time. However, do not change two or more factors at a time when performing cutting tests.

Although the cone hole in the spindle isBt50、Bt40AndBT30All the machines can use the same annoying head, but not all machines can finish the same boredom process. The same goes for the boring depth. existBt50On the tool machine, the diameter of the hole can be bored75 mmKong Shen250——300 mmThe hole,Bt40Machine-tools can also use extensive bars to complete the treatment of this size beach, but less than40No conical machine tools supports this type of treatment.

Used machine pins and unstable lights are often factors that cannot be changed but must be treated. Sometimes these factors can completely fail a machining task, but the generally modification of the type of insertion or the cutting parameters will provide a solution.

2Treatment allowances are often not clear on the amount of margin which must be reserved for boring treatment. User cutting speed can cut/ /The food rate and the required machining allowance are more familiar, but these experiences do not always apply to boredom. This is particularly true in noisy boredom using boring tools.

The diameter of the drill bit is very close to the diameter of the final bore of the part(Stay0.5——0.75 mmBoring margin))It is not uncommon.

If there is an insufficient machining allowance and a loose diameter tolerance(A ten thousand more or less a ten thousand))Use a boring tool(Or remove the bore tool from one of the blade chucks))The treatment effect is better. On the other hand, for the parts with central holes, if the central hole is incorrect, there may be too much part of the piece to be cut.

Even if the diameter of the core hole is in the standard beach typical of the rough bore margin, a bias in the nucleus can ensure that the bore tool takes a larger amount of cutter on one side From the hole that the blade can withstand the load of chip.

3 and 3Rigidity of tool assembly when choosing a boring tool for a machining task, it is generally based on the boring diameter required and nominal depth, with little examination of the real boredom and of the additional overhang required(If necessary)). For example, in a sort of boring treatment, the boring depth is only50 mmBut the tool goes through the part and(Or))The luminaire may be necessary to reach the boredom200 mmlength of overhang.

This is linked to the required depth of boredom250 mmThe boring process is completely different. To maximize the rigidity of the tool and the range of use, a modular encouragement system can provide an unlimited number of module combinations. With the length of the required tool, it is important to first select a larger basic diameter of the bore bar, then reduce the diameter of the bore bar as needed, rather than adopt The same dimension of diameter throughout the length of the bore bar.

For a boring long overhang with a limited space, a full carbide removal rod can be considered(Instead of using several extensive stems)). This configuration offers higher rigidity and better control, but is generally limited to boring treatment with smaller diameters. For a long overhang, a modular boredom system which uses a larger connection size and reduces the diameter of the tool when necessary, has a more stable boredom system than a tool configuration which does not consider that the nominal bore length and the bore diameter.

4The blade and geometric grade blades are key contact points between the room and the tool. If the insert does not correspond to boring treatment, even if the boredom tool system is extremely rigid and precisely balanced with the boring head, it can be difficult to obtain ideal machining performance.

If the blade geometry cannot guarantee cutting stability, it will be useless to use the best blade note. The boring insert with pressed geometric shapes generally uses a relatively conservative chip circuit breaker, which can maintain a long service life in stable treatment conditions, but its radial cutting depth should be at least the arc radius of the Pointe.1/2。

In some boring processes with serious conditions(Like a deep hole or a long boring overhang, a long mosquito net of the chip material or machine tools and/ /Or the pliers causes unstable room tightening))The drilling insert with a geometric grinding shape can be cut more freely. For a specific bore treatment, the notes and blade coatings used are constantly upgraded. When the boring steel pieces, the most commonly used are the grades of cermet and three layers.

Coating carbide grades can also be used for the removal of melting, ceramic inserts of silicon nitride and certain cubic boron nitride if the treatment conditions are stable.(CBN)Notes can also be used for cast iron bore. Aluminum and other non -ferrous metallic materials can be bored with non -covered carbide inserts, which generally have a broken chip -to -chip table with large positive angles to avoid long strips of chips. For high -speed precision of these materials, polycrystalline diamond(PCD)A tip of blade or coated blade can also be a good choice.

It should be remembered that the stability cut is the first requirement to extend the lifespan of the blade.

5The reduction speed and the supply rate after all other factors are taken into account, it is also necessary to determine whether the cutting speed and the supply speed are appropriate. These cutting parameters are essential to achieve optimal free cutting conditions. The annoying state ideal is to adopt a very high cutting speed and a relatively moderate power rate, but this can also be limited by the above conditions. Rugue drilling2。

This calculation method is generally not correct: for the treatment of the bore with the same hole diameter, the power speed of the rough alternation tool can reach the fine work -study tool.4Indeed, for example, if the point radius of the fine disturbance tool0.2 mmOr0.4 mmA rough bore insert can be used0.8 mmPointe du Couteau radius.

The value of the radius of the arc of the tip of the double tool, and with the use of two inserts, the supply frequency can reach the relevance tool4Time. In general, rough bores does not require very fine

The surface finish is therefore a better rigid bore tool can be used to treat at a higher cutting speed. If the food rate of the boredom tool is too small, it will cause floating due to an inappropriate machining allowance. The rough work -study tool is used for boredom with larger loads, which requires cutting more part materials and a higher power rate.

The processors sometimes find it difficult to determine the appropriate surface cutting speed for fine drilling. Optimization of cutting speed is essential to extend the life of the blade. If high load boredom is carried out at very high cutting speeds, a large amount of cutting heat will be generated and the lifespan of the insert will be shortened.

Reducing flea load can reduce the cutting temperature, so the bore insert can be treated at a higher surface supply rate.