Heading work "Lathe lathe assembly with NSR"

Contents

Contents

1 Lathe assembly cutter with NSR

1.1 Task

1.2 Analysis of analogues and justification of selection of NSR attachment mechanism

1.3 Calculation of geometric parameters

1.3.1 Determination of number of plate faces and selection of NSR

1.3.2 Determining the position of the plate in space

1.4 Power calculation of the prefabricated cutter

1.4.1 Calculation of cutting forces

1.4.2 Test calculation of the housing for stiffness

1.5 Description of cutter design and its operation

List of sources used

Applications

1 lathe assembly cutter with cmp

1.1 Task

Operation - swelling;

Cutter type - pass-through;

The main angle in the plan is sound= 75 °;

Supply direction - right;

Material to be processed - BTZ1;

Processing type - finished;

The height of the centers is 20 mm;

1.2 Analysis of analogues and justification of selection of NSR attachment mechanism

When analyzing various tool designs, it was found that not all versions of the basing and fastening schemes currently used in tool designs are presented in the already existing GOST classification and according to the international ISO system.

In this course work, it is necessary to analyze the mechanisms for fixing the SMP, consider the advantages and disadvantages from the point of view of fixing the plate. It is known from the task for heading work that the prefabricated cutter must be designed for finishing, this means that it must meet the following main requirements: accuracy of NSR positioning (it is necessary to attach to the corner slot), free chip release on the front surface, recommended negative angle A (all points of the cutting edge are above the top).

During the information search, 3 analogues of the mechanisms for fixing the SMP in the cutting tool were selected.

Analogue 1 (Appendix A, Patent No. 780970).

The first analogue is a cutting tool, in which the SMP is positioned through a central hole on the pin, is pressed against the support surface by a grip. An intermediate element serves as a thrust surface in the structure.

Advantages of this design:

- The main advantage of this structure is the pressing of the NSR to the support surface. It is economical and technological, since all surfaces are made on the passage, and the holes are through.

Design disadvantages:

The disadvantage is the absence of an angular slot in this attachment in which the NSR is positioned, and also there is no constancy of the thrust surface, since the intermediate element is able to move depending on the tightening force of the grip, and the pin will not be able to ensure the accuracy of the positioning of the plate, which will negatively affect the accuracy of processing of the product.

Analogue 2 (Appendix B, Patent No. 795733).

The second analogue is a cutter, in the seat of the holder of which there is a prismatic element with a pin, on which a cutting insert with a central hole is installed.

Advantages of this design:

- The advantage of this fastening mechanism is the stability of the thrust surface, all the surfaces of the cutting tool are made on the passage and are technological.

Design disadvantages:

The main disadvantage is the variability of the height of the support surface, which entails a change in the height of the tool vertex and a change in the geometry of the cutter embedded in the design, as well as the lack of pressing to the support surface .

- There is no corner slot where the finishing tool plate is to be based.

Analogue 3 (Appendix B, Patent No. 1202730).

The third analogue is a cutter consisting of a body, in the seat of which the cutting insert is fixed with a pin with a cut parallel to the axis of the plate hole. The NSR is fixed using a threaded part of the pin interacting with a nut equipped with internal and external threads.

Advantages of this design:

The advantage of this fastening method is the free release of chips on the front surface, the constancy of the supporting and thrust surfaces, the fastening mechanism is compact and well applicable in the boring tool.

Design disadvantages:

The main disadvantages are the lack of clamping to the support surface and the absence of an angular slot in which the NSR would be positioned, but the clamping to the support surface can be compensated by an equal cutting force that will press the plate against the cutter body, and the angular slot in this attachment method can be realized.

We choose patent No. 1202730, since it is most suitable for finishing processing in terms of positioning accuracy, compactness and chip release.

1.5 Description of cutter design and its operation

The cutter is used for internal finishing of various parts. During processing, the workpiece rotates about its axis (the main cutting movement), the cutter is brought to the workpiece, and due to the feeding movement along the axis of the part, a layer of material is removed.

This cutter is lathe, bore, bent, right. With mechanical attachment of a replaceable polyhedral square plate with a central hole for attaching a hard alloy plate, for example BK8.

Plate is attached to holder by means of pin with thread, which has eccentric conical surface, being pressed into thrust surfaces of angular slot. Due to the eccentric conical surface, both the angular groove and the support surface are pressed.

The fastening mechanism consists in the following: a nut equipped with internal and external threads is installed from below into the holder housing with external threads, at the same time the pin itself is twisted into the internal thread of the nut. The internal and external threads have different thread pitch, for example, the pitch of the external and internal threads is 1 mm and 1, 25 mm, respectively, which makes it possible to determine when the nut is twisted into the holder body by 1 mm, the pin with respect to the holder body is shifted by 0, 25 mm. Therefore, this relationship and fastening method allows the pin to be moved and secured in the holder body.

In this construction, a simple pattern of securing the cutting insert is provided. The pin is the main fastener. It is placed in the body of the tool holder. When the pin is inserted, the cutting insert is pressed and fixed by a grip on the base surfaces of the holder body. This design allows you to replace or rotate the cutting insert without removing the cutter from the cutter holder.

Державка.cdw

Резец сборный с СМП.cdw

Спецификация.spw