Basic principles of designing of cutting tools

Technical and economic feasibility of the use of a particular tool depends on the sizes and designs of items and received the type of production.


For processing holes in parts such as bushings, in mass production, rationally to use a special broach, while serial — boring cutter or countersink bit. At the same time, if the item is freestanding and relatively large size, it is advisable to apply a thin boring or a floating block cutters.< / span>


andselection Criteria of cutting tools,

high performance process of machining with optimum tool life;

its value


convenient and fast tool mounting on the machine;

the possibility of restoring the size of the work piece or use of its waste.< / span>


High performance processing with optimal resistance, durability and reliability of the tool provided by

a) through the application of modern tool materials and various methods of refining the surface layer of the working part of the tool;

6) by assigning the optimal geometric parameters and cutting schemes;

) as a result of increasing the total length of the cutting blades running at the same time the teeth of the tool;

g) through the use of existing combined, special and new designs of tools;

d) optimal rigidity and vibration resistance of tool design, etc.< / span>

the Relatively low cost of the cutting tools is achieved by the adaptability of their structures and the rational use of expensive tool materials due to the use in the manufacture of tools techniques such as welding, surfacing, welding, soldering, gluing, etc.< / span>

the Increase in tool life is ensured through the use of interchangeable or adjustable elements of the working part, and also due to some changes in the design tool. For example, the introduction in the design of the broach several groups of so-called replacement of the gauge of the teeth with a negative rake angle at the chamfer and the cylindrical land width / allows to increase the service life of the drive by 4-5 times with increasing its length by 5-10%.< / span>

the possibility of recovering the tools or use their waste is a big reserve to reduce the cost of production.< / span>

Design tool

large machine-building plants by restoring the dimensions of cutting tools with chrome plating, welding and other methods, as well as the result of alterations of the tool on the smaller size is met up to 20-25% of demand in it departments of the enterprise.

Convenient and fast tool mounting on the machine, depending on its type, as well as the substance of the transaction, the type of equipment and production can be done in different methods. In terms of single and small batch type production.

the Drill is mainly attached or directly in the machine spindle, or using a bushing. At the same time, the spindles multi-spindle drilling heads and modular machines in high volume production fastening it by means of a special adapter extension cable, and mass production on the automatic lines it is rational to apply bespodvalnyh the design of the instrument with a special compensating devices, as well as quick-change mount.

it Should be noted that in designing the instrument method of attachment machine it should be linked to fixture design and operational control.

So when you assign the length of the working part of the drill when drilling holes in the product in the conductor it is necessary to consider the height of the conductor sleeve and the clearance between the bushing and the workpiece.

At the same time, if drilling precedes reaming of the bores or threading using the same conductor, it should provide the possibility of controlling the drilled hole smooth calibre without removing parts of a conductor.

Equipping the technological process of machining of machine parts, mechanisms and devices for cutting and auxiliary tools, it is necessary to pay due attention to standardization, normalization and unification, allowing to reduce the time to prepare the launch of the new production, and reduce the costs associated with the use of tools. The standards for cutting tools can be divided into three groups. The first group should include the classification standards, podrazdelyayutsya cutting tools for operational and structural characteristics and sizes, as well as establishing the terminology and notation. Standards assortments and sizes should be attributed to the second group. They establish the dimensional characteristics of the tool, its geometrical parameters, but also permitted deviations and guidelines for use.

Standards and technical conditions belong to the third group.

the term unification is to understand the uniformity, i.e. when based on a comprehensive analysis of the applicability of the structural elements and geometrical parameters of the tools are excluded from treatment tools have limited application by their equivalent replacements on the parameters that have a wide use.

multiblade tools are pictured in the drawings only two or three teeth, the same screw groove milling cutters, drills and other tools to show straight lines at a certain angle and the total cross section to replace the ejection.

If you need the image of several similar tools, you draw one of them and the drawing give the letter designation of the dimensions of structural elements and geometric parameters of the tool, as well as the overall summary table of all the numerical values of sizes. The profile of a blade shaped tool, chip and stroiarsenal grooves are usually carried separately, but in same format on an enlarged scale. Projection of the tool on the drawing, usually given in 1:1 scale. in the drawings cutting. In addition to the graphical images of instruments, and sometimes in a separate application, identifies the technical requirements for the manufacturing of the instrument, its monitoring, testing and packaging. These specifications contain: guidance on the material, its hardness and method of treatment, marking, requirements to appearance of the tool and the classes of surface finish, dimensional tolerances etc.

as small-scale production, accept standard scan 0 40. In that case, if the large-scale production and application of feed or a standard scanner for some reason is not possible, the design of a special vertical drill with a ring shank design. For the case when the working part of the tool is made from tool steel, rationally with the aim of improving durability, to provide one method: low temperature leaching, electrolytic plating, etc. The size of the bore in the housing must be determined by calculation or taken on the basis of the recommendations of the technical literature. The number, shape and size of the teeth of the blades of a vertical drill, its design dimensions are determined by calculation or on the basis of the recommendations tables. The geometrical parameters of the working part appointed on the basis of the conditions of rational exploitation of a vertical drill.

In that case, if a core drill would be used on the automatic line, the design of the extension should provide a compensation device — a screw with a spherical head and locknut for installation of a vertical drill on the size of the outside of the machine, as well as its quick-change mount.

When making the working drawing of designed core drill will need to take into account the conventions provided for drawing the cutting tools.

If you wanted to give the two drawings of the same type of core drills, which differ only in the diameters D and the main angles in terms of CP, as stated above, it would suffice to draw one drawing. In this letter to outline the parameters D and D in the table to specify numeric values.

design Basics

On materials : Zhigalko N. I., Kiselev V. V. Proektirovanie and manufacture of cutting tools

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