JPH02264810A - Measuring coating thickness and instrument for the same - Google Patents

Abstract

PURPOSE:To enable a real coating thickness to be measured by detecting a stage difference between the surfaces of a fresh coating formed by a flame sprayer and of parent material. CONSTITUTION:A coating 5 is formed on the whole surface 2a of a parent material 2 by continuing the flame spray of a coating material 4 while moving a flame spray gun 12 in parallel to the axis of the parent material 2. Initially, the tips of the contacts 7b and 8b of distance sensors 7 and 8, respectively, are brought into contact with the surface 2a which is not yet coated and both the sensors 7 and 8 measure a distance D3 to the surface 2a. When a region on which the coating 5 is formed has been passed by the distance sensor 7, the contact 7b is pushed up by the coating 5 whereby a distance D2 to the surface 5a of the coating 5 is measured. Since the contact 8a of the distance sensor 8 positioned ahead of the flame spray gun 12 in the moving direction thereof is still in contact with the surface 2a, the sensor 8 measures a distance D3. The distances D2 and D3 are outputted to arithmetic means as electric signals, a difference between the distances D2 and D3 is calculated and a result is detected as a coating thickness for one pass of the coating 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method and apparatus for measuring the thickness of a coating, and in particular, to measuring the thickness of a coating formed by thermally spraying a coating material onto a base material. The present invention relates to a film thickness measuring method and apparatus that are suitably used when measuring a coating material during a thermal spraying process.

[Prior Art] Conventionally, coating formation by thermal spraying involves moving a thermal spray gun along the base material multiple times to melt the coating material and spray the base material (hereinafter, one end of the base material). One movement from one end to the other end is called one pass ≧ By forming a film with a thickness of several tens of microns on the base material per pass, the final film will have a thickness of several tens of microns to several hundred microns. We are trying to obtain the desired film thickness.

As a method for measuring the thickness of a coating formed on a base material, for example, when a coating is formed on the circumferential surface of a cylindrical body, the following method is adopted.

First, thermal spraying is interrupted at an intermediate stage during the entire bath, and an intermediate check is performed by measuring the outer diameter of the coating formed up to this stage with a micrometer or the like.

Based on this information, the thermal spraying conditions for the subsequent stage are set and the thermal spraying is restarted.After all the baths are completed, the outer diameter of the coating is measured again, and based on the comparison with the set coating thickness, the thermal spraying is over or under-sprayed. to determine whether it is necessary to continue thermal spraying.

Next, after the base material temperature has decreased to room temperature, the outer diameter of the coating is measured, and the final film thickness is calculated by subtracting the outer diameter of the base material at room temperature from the measured value.

[Problems to be Solved by the Invention] By the way, when the thickness of the film is measured by the method described above, the following problems occur.

In other words, at both the intermediate stage of thermal spraying and the final stage of the entire bath, the base material temperature is as high as 100° to 200° and is in a state of thermal expansion, and the temperature distribution is in the radial and axial directions. Due to the non-uniformity, it is difficult to accurately estimate the amount of shrinkage at these stages when the base material temperature drops to room temperature.

Such defects become more noticeable as the outer diameter of the base material increases.

Due to the above-mentioned problem, it is not possible to judge whether the actual film thickness is too large or too short without waiting for the final measurement results at room temperature. re-spraying, and if excessive, post-processing such as polishing or cutting is required.

However, in re-spraying, the preheating time of the base material and the heat removal time after thermal spraying are long, several tens of hours, which has a large impact on productivity and costs. Because the hardness of the film formed is high, it takes more time and cost than thermal spraying.

In addition, when measuring the outer diameter of the coating at an intermediate stage, the base material temperature and the environmental temperature will drop due to the interruption of thermal spraying, so if thermal spraying is restarted and a new coating is laminated, the existing coating will overlap with the new coating. There is a risk that the adhesion between the film and the film formed on the film may decrease, causing peeling between the two.

Therefore, it has been desired to address the above-mentioned problems in the prior art, and the present invention is intended to solve these remaining problems in the prior art.

[Means for Solving the Problems] The present invention provides two inventions, a coating measuring method and an apparatus, which can effectively solve the above-mentioned problems, and the coating measuring method according to the first aspect includes: A film thickness measuring method for measuring the film thickness of a coating formed on the surface of a base material by a coating material sprayed from a thermal spraying device that is moved along the base material, the method comprising: a new coating formed by the thermal spraying device; The method is characterized in that the thickness of the coating is measured by detecting a step difference between the surface of the substrate and the surface of the base material or the previously formed coating.

Further, the film thickness measuring device 4 for the film related to the second t♂ is as follows:
A film thickness measuring device for measuring the film thickness of a coating formed on the surface of a base material by a coating material sprayed from a thermal spraying device that is moved along the base material, the device being a base provided at intervals along the movement direction of the thermal spraying device, and a distance between the surface of the coating formed on the base material and the base or the base material; It is characterized by comprising a pair of distance sensors that detect the distance between the base and the base, and a calculation means that calculates the difference between the measured distances between the two based on output signals from these distance sensors.

[Operation] According to the first aspect of the present invention, there is a difference in level between the surface of the new coating formed by the thermal spraying device and the surface of the base material on which the new coating is formed or the surface of the coating previously formed. By measuring , the position of the coating surface relative to the base material surface is detected.

As a result, even when thermal expansion and contraction occurs in the base material,
Since the position of the new coating surface is detected with reference to the base material surface, the actual thickness of the coating can be measured regardless of thermal expansion and contraction of the base material.

According to the second aspect, when a new coating is sequentially formed on the surface of the base material by the thermal spraying device, one distance sensor located at the rear in the moving direction of the thermal spraying device detects the surface position of the new coating. is detected, and at the same time, the position of the base material surface or the previously formed coating surface located in front of the moving direction of the thermal spraying device is detected by the other distance sensor.

Then, the distance between the base material surface or the previously formed coating surface and the new coating surface, that is, the coating thickness, is measured by calculating the difference between the detection values from both distance sensors using the calculation means. , the film thickness measuring method according to the first aspect is effectively implemented.

[Example] Hereinafter, one embodiment of the present invention will be described based on the drawings. .

First, prior to explaining the first aspect of the present invention, this first aspect
An example of a film thickness measuring device according to the second aspect, which is suitably used to implement the aspect, will be described.

In the figure, reference numeral 1 indicates a film thickness measuring device according to this embodiment, and this film thickness measuring device 1 is applied to forming a film on a cylindrical base material 2. This is a film thickness measuring device for measuring the film thickness t of the coating 5 formed on the surface 2a of the base material 2 by the coating material 4 sprayed from the moving thermal spraying device 3. From prescribed use 1
! A base 6 placed at an IDI, and on this base 6,
The distance between the surface 5a of the coating 5 formed on the base material 2 and the base 6 or the distance between the base material 2 and the base 6 is provided at intervals along the moving direction of the thermal spraying device 3. A pair of distance sensors 7 and 8 to detect and these distance sensors 7 and 8
The general configuration includes a calculation means 9 that calculates the difference between the measured distances D2 and D3 based on an output signal from the calculation means 9, and a control unit 10 electrically connected to the calculation means 9.

Next, these details will be explained.

The base material 2 is supported by a clamp mechanism 11 at both ends thereof, and the clamp mechanism 11
This allows it to rotate at a constant speed in a constant direction around the axis.

The thermal spraying device 3 is disposed at a position facing the surface 2a of the base material 2 at a predetermined distance (D4) from the surface 2a of the base material 2, and melts the powder coating material 4 to coat the surface. 2a
A manipulator 13 that reciprocates the thermal spraying gun 12 parallel to the axis of the base material 2, and a hopper 14 that supplies the coating material 4 in powder form to the thermal spraying gun 12.

The manibulator 13 and the hopper 14 move the thermal spray gun 12 based on commands from the control unit 10, and also adjust the amount of coating material 4 supplied to the thermal spray gun 12. .

In this embodiment, the base 6 is disposed in a fixed state at one end of the base material 2 (the left end in the figure, the end on which the coating 5 is started to be formed). , the distance from the base material 2 is maintained.

The distance sensors 7 and 8 are dial gauges used in this embodiment, and are fixed to the base 6 at their fixed parts 7a and 8a, and are mounted to the fixed parts 7a and 8a so that they can move relative to each other. The contacts 7b and 8b are kept in constant contact with the surface 2a of the base material 2 or the surface 5a of the coating 5.

Therefore, since the distance D1 between the base 6 and the surface 2a of the base material 2 is set constant, each distance sensor 7, 8 can detect the distance from the fixed part 7a, 8a of each contactor 7b, 8b. The amount of protrusion is the measured distance D2 and D3 of each distance sensor 7 and 8
be replaced as

On the other hand, the distance between the distance sensors 7 and 8 is set to about three times the spray width W of the coating material 4 sprayed by the spray gun 12.

Next, an embodiment of the second aspect of the present invention will be described along with the operation of the film thickness measuring device 1 having the above structure.

First, prior to spraying the coating material 4 onto the base material 2, the base material 2 is preheated.

Next, the thermal spray gun 12 is moved to one end of the base material 2 and aligned, and then the thermal spray gun 1 is moved while rotating the base material 2.
By thermally spraying the coating material 4 melted from 2 onto the surface 2a of the base material 2, the surface 2 of the base material 2 is
A coating 5 is formed over the entire circumference of a.

Following this thermal spraying operation, the thermal spraying gun 12 is moved parallel to the axis of the base material 2 as shown by the arrow (A) in FIG. 1 while continuing to spray the coating material 4 on the base material. A coating 5 for one bath is formed on the entire surface 2a of 2.

On the other hand, the two-way separation sensors 7 and 8 of the film thickness measuring device 1 initially
Is the tip of each contact 7b and 8b vermilion? ! Both are brought into contact with the surface 2a of the base material 2 in the covered state, and the distance D3 to the surface 2a of the base material 2 is measured.

Then, as described above, the coating 5 extends from one end to the other end.
As the formation of the new coating 5 progresses, as shown in FIG. By pushing up the contact 7b of No. 7, the distance D2 to the surface 5a of the new coating 5 is measured.

Here, the distance sensor 8 located in front of the moving direction of the thermal spray gaff 12 detects the distance D3 to the surface 2a of the base material 2 because its contact 8a is still in contact with the surface 2a of the base material 2. Measuring.

Each of the distances D2 and D3 measured in this way is output as an electric signal to the calculation means 9, and the calculation means 9 calculates the difference between the two paths MD2 and the distance D3, and the calculation result is used as a new It is detected as the film thickness t of one bus of the coating 5.

On the other hand, as shown in FIG. 2, a transition region C with non-uniform thickness is formed at one end of the new coating 5 (the right end in FIG. 2). The measurement value of the part is ignored, for example by a timer.

After completing the operation of forming the coating 5 in the direction from one end of the base material 2 to the other end, the thermal spray gun 12 is moved in the opposite direction as shown by the arrow (b) in FIG. While doing so, the coating 5 of the second bath is formed on the surface 5a of the coating 50 formed in the first bath.

At this time, while the formation of the new coating 5 of the second bus progresses to the bottom thereof, the distance sensors 7 and 8 are activated.
8, the surface 5 of the coating 5 formed in the first bath.
As the formation of a new coating 5 progresses, each distance sensor 7 and 8 is operated in the reverse order of the first bus, and the distance D2 to the second bus is measured. The film thickness of No. 5 is measured.

The film thickness t measured for each of these passes is integrated in the calculating means 9, and at the time when film formation is completed one bus before the final pass, the film thickness T measured in advance is calculated.
Based on the comparison result, a signal is output to the control unit 10 and color hopper 14, and the thermal spray gun 1 is
By adjusting the amount of coating material 4 supplied to coating material 2, the thickness of the film to be formed in the final pass is controlled.

When the film thickness t of the coating 5 is measured in this way, the film thickness t is measured based on the difference between the surface 5a of the newly formed coating 5 and the surface 5a of the base material 2 or the coating 5 previously formed. Therefore, the distance between the front surface 5a and the back surface of the coating 5 to be formed is measured, and as a result, the actual film thickness t is measured.

Moreover, since the film thickness t is measured with reference to the surface 2a of the base material 2 and the surface 5a of the coating 5 previously formed, even when the base material 2 undergoes thermal expansion, Alternatively, even in a state where misalignment occurs when rotating the base material 2, the reference plane for film thickness measurement changes following these displacements, and the film thickness measurement is performed based on this changed reference plane. Therefore, the measurement result of the film thickness t is not affected.

Therefore, it is possible to form a film with high precision, and post-processing after the film is formed is unnecessary or significantly reduced.

Furthermore, since the measurement operation is carried out simultaneously with the work of forming the coating 5, there is no interruption of the work, which is advantageous in terms of workability and production cost.

Furthermore, when the coatings S are laminated in multiple layers, the temperature conditions can be kept constant, and therefore, a decrease in adhesion between each layer, which has been considered a problem in the past, is suppressed, and peeling between the coatings 5 is suppressed. be done.

Note that the above-mentioned embodiments are merely examples, and various changes can be made based on the type of base material 2 to be applied, the type of coating to be formed, design requirements, etc.

For example, in the embodiment described above, the coating 5 is formed on the cylindrical base material 2, but the present invention can also be applied to a flat plate.

Further, the number of distance sensors is not limited to one pair, but three or more distance sensors may be installed.Furthermore, like the thermal spray gun 12, they may be moved relative to the base material.

Further, as the distance sensor, a laser displacement meter, a magnetic displacement meter, an ultrasonic displacement meter, or the like may be used.

By moving the distance sensor, the film thickness t can be controlled over the entire surface of the coating 5 to be formed, and by feeding this to the thermal spraying device, it is possible to form a uniform coating. Become.

Furthermore, in the above embodiment, an example was shown in which the final set film thickness T is obtained by adjusting the film thickness t formed in the final pass. It is also possible to compare the thickness and adjust the film thickness for each pass.

[Effects of the Invention] As explained above, according to the first aspect of the present invention, even when thermal expansion and contraction occurs in the base material on which the coating is formed, the surface of the base material and the coating previously formed are The new coating surface position is detected using the surface of the base material as a reference, and thereby the actual thickness of the coating is measured regardless of thermal expansion and contraction of the base material.

Therefore, it is possible to measure the film thickness with high precision, and with this, it is possible to form a uniform film by eliminating excess or deficiency of the film thickness, and to reduce the work such as post-processing. This provides excellent effects such as improving workability and reducing production costs.

Further, according to the second aspect, when a new coating is sequentially formed on the surface of the base material by the thermal spraying device, one distance sensor detects the surface position of the new coating, and at the same time, the other distance is detected. The sensor detects the position of the base material surface or the previously formed coating surface, and the calculation means calculates the difference between the detection values of the two path separation sensors. The distance between the formed coating surface and the new coating surface, i.e.
The film thickness can be measured, thereby making it possible to effectively implement the film thickness measuring method according to the first aspect.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a schematic plan view showing an example of a thermal spraying apparatus equipped with one embodiment, and FIG. 2 is an enlarged view of the main parts. 1... Film thickness measuring device, 2...
Base material, 3... Thermal spraying equipment, 4.
...Covering material, 5...Coating,
6... Base, 7.8... Distance sensor, 9
...Calculation means.

Claims (2)

[Claims] (1) A film thickness measuring method for measuring the film thickness of a coating formed on a base material by a coating material sprayed from a thermal spraying device that is moved along the base material, the coating being formed by the thermal spraying device. A method for measuring the thickness of a coating, characterized in that the thickness of the coating is measured by detecting a step between the surface of the new coating and the surface of the base material or the surface of the previously formed coating. (2) A film thickness measuring device for measuring the film thickness of a coating formed on the surface of the base material by a coating material sprayed from a thermal spraying device that is moved along the base material, the device comprising: A base placed at a predetermined distance, and on this base,
a pair of distance sensors that are provided at intervals along the moving direction of the thermal spraying device and detect the distance between the surface of the coating formed on the base material and the base or the distance between the base material and the base; A film thickness measuring device for a film, characterized in that it is equipped with a calculation means for calculating the difference between the measured distances based on the output signals from these distance sensors.