EXPERIMENTAL INVESTIGATION OF METAL SURFACE PURITY USING A PROFILOGRAPH PROFILOMETER

ABSTRAСT

In the article, the purity class of metal processing depends on the degree of unevenness of its surface. It is calculated as the height of the irregularities and the purity of the surface of their repetition. This indicator is influenced by two main factors: the method of exposure and the agent used. There are four categories of purity in the treatment of drugs. With the naked eye, you can only see the roughness. It is obtained by manual processing with a lot of labor or by mechanical processing at the initial stage of machine processing. The data shows that surface defects can be detected only with the help of additional measuring instruments.

АННОТАЦИЯ

В статье класс чистоты обработки металла зависит от степени неровности его поверхности. Рассчитывается как высота неровностей и чистота поверхности их повторения. На этот показатель влияют два основных фактора: способ воздействия и используемое средство. Существует четыре категории чистоты обработки препаратов. Невооруженным глазом можно увидеть только грубую неровность. Его получают ручной обработкой с применением большого труда или механической обработкой на начальном этапе машинной обработки. Приводятся данные о том, что дефекты поверхности можно обнаружить только с помощью дополнительных измерительных приборов.

Keywords: irregularities, surface irregularities, Preparation, machining, surface defects, profilograph profilometer, micrometer, profile, measurement.

Ключевые слова: неровности, неровности поверхности, Подготовка, механическая обработка, дефекты поверхности, профилограф-профилометр, микрометр, профиль, измерение.

Introduction. The purity class of metal processing depends on the degree of unevenness of its surface. It is calculated as the height of the irregularities and the surface purity of their repetition. This indicator is influenced by two main factors: the method of exposure and the tool used. There are four categories of preparation processing cleanliness. Only coarse unevenness can be seen with the naked eye. It is obtained by manual processing with the help of large labor or mechanical processing at the initial stage of machine processing. Surface defects are determined using only additional measuring tools [3,4,5].

Theory part. Surface purity is a set of surface irregularities of relatively small size determined using base length. Measured in micrometer (µm). Surface purity refers to the microgeometry of a solid and defines its most important performance qualities. First of all, abrasion resistance, strength, joint density (Hermeticism), chemical stagnation, appearance. Depending on the operating conditions of the surface, the surface purity parameter is determined when designing machine details, there is also a relationship between maximum size deviation and surface purity.

Figure 1. Surface purity parameters

L-base length is the length of the baseline used to quantify irregularities and its parameters. Surface cleanliness is assessed along the line and at a certain length. in this case, the middle line of the profile is taken as the main line.

The midline of the M profile is said to be the base line, which has a nominal profile shape and within the base length the average arithmetic deviation of the profile from that line is transferred so that Ra is minimal.

GOST 2789-73 normalizes the following surface purity parameters.

By height (vertical)

1.  - moderate arithmetic deviation of the profile.

2.   - the height of the profile unevenness at ten points.

3.Rmax is the distance between the height and dip lines of the profile at the boundary of the base length.

Ra, Rz and Rmax 0,01; 0,03; 0,08; 0,25; 0,80; 2,5; 8; 25 the main length at which mm can take values from the row is determined by L;.

Stepped (horizontal)

4.           - the average step of profile irregularities by peaks, where N is the number of profile Maxima.

5.   - The mean step of profile height on the midline, where k is the number of cases of the profile, l0≤l is the length of the main longitudinal central line segment bounded by the first and last odd intersection of the profile along the midline.

Step by height -the relative corresponding base length of the profile (in percentage), where p is the value of the cross — sectional level of the profile, from the row: 10; 15; 20; 30; 40; 50; 60; 70; 80; 90%..

Experimental part. As equipment for the experiment, the hommelwerke profilograph-profilometer, Thunder samples, a preparation for measuring surface roughness.

Profilograph-profilometer is one of the most universal contact tools for measuring surface roughness parameters. Device linear sliding device 1, Thunder-measuring head 2 for measuring accuracy, measuring head 3 for measuring profile, measuring Column 4, granite table 5 insulated from vibration, measuring Table 6, processing and Control Unit 7, emergency lock button 8 and device launch 9, software shown on Monitor 10, a device for microvint adjustment of the deviation of the measuring probe Action Line.

Figure 2. Profilograph-an overview of the profilometer

Profilograph-profilometer allows you to take profilograms and measure the parameters of surface purity with accuracy, depending on the parameters of the Trinity. This laboratory uses a tku 300/600 triad with a sensitivity of 40 nm and a step resolution of 1 µm.

After installing and starting the computer, to run the profiler-profiler processing and control program, it is necessary to start the TURBO RAUHEIT program. After launching the new program, the main protocol window will appear.

The protocol form is configured through the form menu, where it is necessary to select the type of the profile display graph, as well as select the parameters Ra, Rz, Rmax from a wide list of possible parameters, turning on the description of the surface purity parameters. After that, it is necessary to adjust the measurement parameters by pressing the F7 key, where it is necessary to select the length of the surface to be checked, the step, the measurement range, the speed of movement and the type of triplet.Then the measurement control menu is entered by pressing F6 [4].

In the measurement control menu, it is possible to move at four possible speeds along the three axes, but keep in mind that approaching the tip in manual mode can damage the tip of the tip and even the entire measurement head, so automatic approach mode should be used when about 4-5 mm is left on the surface for contactization.

In addition, before starting measurements, it is necessary to use the adjusting microvint to ensure the parallelism of the center line and the measuring tip line of Motion (see Figure 1, paragraph 11), but this should be done only with the participation of the teacher, since the slope can also hit the tip to the measured surface and cause the profiler to break.

Figure 3. Program ekraninig structure

1. Functional button panel; 2. Menu bar; 3. Title Row; 4. Working area of the program with a list of elements; 5. Passing lines; 6. Current status bar

Figure 4. Measurement control panel

0 functional buttons panel.

1 state of the Trinity sensor indicators

Graphical representation of the 1A profile shift

2 devices for tracking and displaying all connected components

3 moving back and forth of the positioning device (Y - positioner), that is, approaching and moving away

4 move the measuring column up and down

5 move the push device back and forth

6 Advanced Functional button panel

7 adjusting the speed of positioning the Arrows

8 show measured values (change during measurement)

Figure 5. Functional button panel

F1 contextual information calling

F3 coarse leveling (using oblique device, automatic or wavy oblique device)

Starting to take F5 size

Reverse movement of the F6 transmission device

F8 automatic zero reduction

F11 resizing cancellation

Return to the main mode menu “Measure” ("measure") by closing the F12 Settings window.

After adjusting the device and receiving measurements, it is necessary to go to the initial program window, where the values of the measured profilogram and controlled surface cleanliness parameters are displayed from the measurements control panel. Profilogram *.it is possible to export to the ASC format, where the first column will have a vertical step, and the second column will have a profile height.

It is convenient to work with this format, since the data obtained from it can be used in various software environments. (Profile - > export profile in ASCII).

Processing measurement results. In addition to the built-in processing algorithms provided by the Profiler-profiler program, measurement results can be exported to other programs, such as MS Excel. To do this, it is necessary to select the "Open" item of the menu,*.the ASC format uses "separator data format", "separator Mark - space", "shared data format"when selecting a measurement results file and importing texts. However, the data obtained is not perceived by Excel as numbers, since the decimal symbol provided by this environment is a comma rather than a dot, so by selecting "Find and replace" and all points are replaced by commas. (Note that the data may change slightly after the value of 100 in the first cell, so the entire table must be checked to make sure the columns at the beginning and end of the file are compatible.)

There are two ways to define the center line and further calculate the surface purity parameters. The first, the most obvious, appears to be the simplest and is done by Excel tools built into the trend line, by constructing which simply subtracts its value from the height value of the actual profile points, and thus removes the additive organizer associated with the impossibility of setting the multiplicative and the equidistant mean line of measurement at a distance equally.

The RA parameter can then be calculated using the above formula .

A clear mistake in the described approach is that the automatically obtained regression line is constructed not by minimizing the distance from profile points to a straight line along the normal, but by minimizing the distance from straight points along the Y-axis to the desired line.

The second, more canonical method requires the construction of the middle line independently using the least squares method, but the distance to this line is obtained along the normal. To implement this algorithm, it will be necessary to connect a package for data analysis and search for solutions (for different versions of Excel, the connection method differs, but in general it is not difficult to find the necessary information on the Internet).

Thus, in the MS Excel 2010 version, the “Excel Options” -> “Add-Ins” item from the main menu is selected, making the “Analysis Pack” and “Solution Search” Applications active.

Then two cells (for a straight line of type y=kx+m) determine the distance from the profile points to the center line points, choosing the parameters of the straight line K and m separately. These magnitudes then become variables when choosing an intermediate straight line using the least squares method. By default, it is possible to set the values m and n from the regression line calculated by Excel. Then the values of y are calculated.

Using the distance formula from the point to the line known from analytic geometry, ∂=|y-kx-m|/√(k^2+1), calculates these distances from the non-optimized line to the profile points. By squaring these distances, these differences are squared and minimized using a solution search package by selecting a target cell containing k and M. Then the average line obtained must also be removed from the results obtained. The calculation of the RA parameter is carried out in a similar way to the first case: 

Conclusions. With this method, labor efficiency is achieved by determining the purity of the surface.  It is achieved to improve the accuracy of the product quality and improve the surface quality. It is convenient to work with this format, since the data obtained from it can be used in various software environments [4].

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