SU1704928A1 - Method of machining parts on numerically controlled machine - Google Patents

Abstract

This invention relates to machining of parts by cutting. The purpose of the invention is to improve the accuracy of processing. Rough, semi-finishing and control transitions are carried out. Then the actual dimensions of the surface of the part with intermediate dimensions are compared, and the program is adjusted by the amount of the deviations obtained. The remainder of the program (final processing) is performed with modes equal to the control transition processing modes. 1 tab., 1 Il.

Description

The invention relates to the field of machining of parts by cutting, in particular, to processing on CNC machines.

The aim of the invention is to improve the accuracy of machining parts on CNC machines.

The drawing shows a part of the surface of the part A with a scheme of distribution of allowances for transitions and the ratio of modes during processing by the proposed method.

(. t3.4 tl.2,1 S3.4 Sl.2; V3.).

When this is indicated: Z - total allowance, mm; ti. t2 is the depth of cut with chernogue and semi-finish processing, respectively. mm: 1z. t4 is the depth of cut at the control transition and final processing, respectively, mm; Si, 82 - feed for roughing and milling, respectively, mm / rev; $ h, 5h - feed at the control transition and final about 6 rl C1 from to sootootstenno. mm / OO: Vi, V / 2 - cutting speed with roughing yolocho; to processing and control pyrohode; V3, V4 - at the control transition and final processing, respectively, m / min.

Depending on the size of the allowance Z and the accuracy of the workpiece, semi-finish processing may be absent.

In this case, before the control treatment transition, the allowance layer is equal in size and + 12 (rough processing).

When pretreating the cutting depth (ti, 12) and feed (Si, 82), there are more cutting depths (1z, ti) and feeds (5z. SA) at the control transition and final processing.

The cutting speeds during pretreatment (Vi, U2 can have different ratios with speeds (V3. Ai) at the control transition and final processing depending on the force re:; lmi, rigidity of the machine, the degree of oibration, 12) and the boat h (51. 82).

VI

ABOUT

 Yu

About 00

The method is carried out as follows.

The part is installed and processed according to the program surface A. The roughing, semi-finishing treatment with the modes ti, Si, Vi is carried out; 12, 82, V2, respectively, and the control processing transition with the modes h, 8h, VG.

After the control transition, a technological shutdown is provided in the program.

The operator measures the actual dimensions of the part surface, obtained after the control transition, and compares them with the intermediate dimensions specified in the process and makes adjustments to the program by the amount of deviations received and performs the rest of the program — final processing with modes equal to the control transition processing, i.e. 1z TA: Uz-V4.

The performed correction of the program after the control transition of the treatment ensures the high accuracy of the surface of the workpiece, since all the factors affecting the accuracy of the processing, including the accuracy of the control system, are the same for the control transition and final processing.

In the correction program includes the installation tool in the original zero position.

Such a method of processing allows to eliminate the permanent errors of the technological system of AIDS and thereby increase the accuracy of processing.

This is especially important for machining high-precision parts from hard-to-machine materials or, when machining from different installations is unacceptable due to the high precision of the relative position of the surfaces of the parts.

Depending on the degree of stability of the errors associated with the accuracy of -. preparations and dimensional tool wear, program correction and can be performed on each part or on a batch of parts.

Example .. On a 16KZOF2 type CNC lathe, a half-cut machining, a machining control transition, and a final machining of the stepped external and internal surfaces of the part are performed. Material - alloy 8Т6. The misalignment of these surfaces is 0.03 mm. Zagotokz pre-processed in rough with allowances for an outer diameter of 5 mm (2.5 mm per side), an internal diameter of 6 mm (3 mm per side).

Past roughing was installed on a CNC lathe.

Then semi-finishing processing was performed at a speed of m / min and a feed of 3 mm / rev. In this case, the 0 dM allowance was removed - 1 mm, no dD - 2 mm.

After the semi-finishing treatment, a control transfer was carried out at a speed of m / min and a feed rate of 3 times 0.1 mm / rev and the stock allowance of 0.5 mm was removed. 5 Then the technological shutdown of the machine was carried out and measurements of the inner and outer diameter of the sleeve were made. Instead of the programmed, 95 ± 0 .05 mm,, 05 ± 0.05 mm 0 (middle tolerance floor 0.1), the following dimensions were obtained .04 mm: dn - 134.0.

After the correction of the program was completed, the final processing of the part was carried out at a speed of m / min, a feed of $ 4 0.1 mm / rev, and a stock allowance of 0.5 mm was removed. After final processing, the actual dimensions of the part were measured. The obtained dimensions are outer diameter 0 dn 149.06 mm, inner diameter, 08; fit into the drawing tolerances.

To obtain comparative data, the part was processed using the basic technology of turning: without a control transition of processing and adjustment of the program before final processing. An analysis of the processing performed shows that when calculating the processing program at the control transition in the middle of the tolerance field, an error was obtained with you-. pad from the floor tolerance on the diameter of the outer dH + 0.04 mm, on the diameter of the inner do size was obtained at the boundary of the marginal minus 5 deviation, i.e. in the absence of a control processing transition, after the final processing, the size of the inner diameter does not fit into the tolerance specified by the drawing, which will lead to 0.

Data processing are summarized in the table. The use of the proposed method of machining parts on CNC machines expands the technological capabilities of the machine tool 5 and in terms of improving the accuracy of machining high-precision surfaces. The method is suitable for all types of machine tools with a flexible (programmable) control system, in particular for CNC machines.

Claims (1)

Formula of the Invention A method of processing parts on CNC machines, including performing several passes on a general control program without re-installing a part, including performing a control and then measuring the deviation of dimensions from the specified process and making corrections to the program. to improve accuracy, the control pass is performed before the final pass with the modes set for the final pass.