JP2003164979A - Surface treatment method and surface treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treatment method and a surface treatment device capable of preventing an occurrence of an unfilled defect (so-called thickness irregularity) caused by insufficient pressing of a shoulder part of a rotary tool and ensuring stable depth of a modified layer regardless of dimensional irregularity of a metallic material to be treated. <P>SOLUTION: The surface treatment method forms the modified layer by applying a friction stir treatment to a surface of the metallic material to be treated by pressing the surface part with the shoulder part while pressing a probe of the rotary tool mounted on a machining device. When the friction stir treatment is conducted by pressing the rotary tool on the surface part of the metallic material to be treated in a press-on direction at a constant feeding amount, the height of the surface part and the height of a machining standard face of the metallic material to be treated are measured Q2 and Q3, the pressing depth of the shoulder part is calculated Q7 by these measurement values and shape data of the rotary tool, and the value of the pressing depth is compared Q8 with the depth standard value capable of avoiding the generation of unfilled defect. Based on the comparison Q8, when the value of pressing depth is larger than the depth standard value capable of avoiding the occurrence of unfilled defect, the friction stir treatment by the rotary tool is applied Q9 to the surface part of the metallic material to be treated. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface of a metal workpiece (so-called work) such as a cylinder head of a diesel engine, which is pushed by a probe at the tip of a rotary tool attached to a processing apparatus and is pressed by a shoulder portion. Friction stir processing is performed by pressing the part to form a modified layer,
The present invention relates to a surface treatment method and a surface treatment apparatus that enhance thermal fatigue strength.

[0002]

2. Description of the Related Art Conventionally, as a method for surface-treating light metals such as aluminum, aluminum alloys, magnesium and magnesium alloys, and metal-made objects (so-called workpieces) made of light alloys, as shown in FIG. While pushing the probe 81 of the rotating tool 80 that is rotated at a high speed into the surface portion 82a of the metal object 82 to be processed, the shoulder portion 8
By pressing the surface portion 82a with 3, and moving the rotary tool 80 along the surface while maintaining such a pressed state,
A so-called friction stir treatment is known in which the surface of the object to be treated 82 made of metal and the region in the vicinity thereof are modified to form a modified layer 84 to improve mechanical properties, particularly thermal fatigue strength.

For example, Japanese Patent Laid-Open No. 2000-15426 discloses a surface treatment of a sealing surface (a mating surface) of a cylinder block of an aluminum alloy cylinder head of an engine.
It is disclosed that the friction stir processing as described above is applied.

Further, Japanese Unexamined Patent Publication No. 2001-32058 discloses that the friction stir processing as described above is applied to the surface of the combustion chamber in the aluminum alloy cylinder head of the diesel engine.

In the friction stir processing method described above, the rotating tool 80 rotating at a high speed is brought into contact with and pressed against the surface of the object 82 to be processed, so that the friction heat generated at that time and the probe 81 are generated.
The stirring action of (1) softens the rotating tool 80 contacting portion on the surface of the member and the area in the vicinity thereof to generate plastic flow.
Then, the material portion in the plastic state (plastic fluidized bed) is agitated in the non-melted state, so that the surface of the member and the region in the vicinity thereof are modified.

When the surface modification treatment by the friction stir treatment is applied to the surface portion of the cast member made of a light alloy such as aluminum alloy,
The metal structure of the surface is made finer and internal unfilled defects due to porosity can be greatly reduced, and mechanical properties such as elongation and toughness as well as fatigue strength (thermal fatigue strength) are improved. be able to.

In particular, the valve bridge portion between the intake and exhaust ports in the cylinder head of a diesel engine repeats volume expansion due to combustion in the cylinder when the engine is driven and volume contraction due to cooling when the engine is stopped. Therefore, it is a portion where cracks are likely to occur due to thermal fatigue, and it is extremely effective to increase the thermal fatigue strength by subjecting such a portion to the friction stir treatment described above.

Therefore, in the past, the object to be processed made of metal
The pushing depth (position) of the tip of the probe 81 of the rotary tool 80 is made constant with respect to the surface of (so-called work), and the pushing depth of the bottom surface of the shoulder portion 83 (shoulder bottom pushing depth) is set to a certain value or more. Although the treatment method is adopted, the above-mentioned probe tip pushing depth and shoulder bottom pushing depth vary depending on the work size variation, so unfilled defects (so-called wall thickness) occur due to insufficient pushing and reforming. There was a problem that the depth of the layer fluctuated and became unstable.

Hereinafter, this problem will be described by exemplifying reforming of a cylinder head of an in-line four-cylinder diesel engine. FIG. 13 is a plan view showing the cylinder head 85 as viewed from the combustion chamber side, where 86 is an intake port and 87 is an intake port.
Is an exhaust port, 89 is an opening of a water jacket, 9
Reference numerals 0 and 91 are reference holes serving as reference surfaces when finishing processing is performed after the friction stir processing, P11, P12, P13, and P1.
Reference numeral 4 is a start point for performing friction stir processing on the valve bridge portion in each cylinder, and X1, X2, X3 are separation distances in the cylinder row direction at the start points P11, P12, P13, P14.

Further, FIGS. 14, 15, and 16 show a cylinder head 85 having a slight difference in size (that is, dimensional variation).
Shows the respective works W1, W2, W3, the upper side in the figure is the surface on the combustion chamber side that is subjected to friction stir processing, and the lower side in the figure is the cylinder head cover side that is fixedly mounted on the NC processing device and becomes the processing reference surface. Is the aspect of.

Therefore, the rotary tool 8 is adjusted so that the pushing position Lp of the front end of the plug becomes a constant value of, for example, 20.317 mm.
While pushing 0 into each of the works W1, W2, W3, the shoulder portion 83 presses the surface of each of the works W1, W2, W3 to perform friction stir processing.

However, since the work size varies, even if the probe tip pushing position Lp is kept constant, the shoulder bottom pushing depth Ds corresponding to the dimension between the work surface and the bottom of the shoulder portion 83 is As indicated by the numerical values in the figure, it fluctuates in the range of 0.419 to 1.3331 mm, and between the bottom surface of the reference holes 90 and 91 and the tip of the probe 81 when removing the surface irregularities after the friction stir processing by finishing. The standard of the depth of the modified layer corresponding to the depth of the gap is 2.241-
Since it fluctuates within the range of 3.609 mm, and these fluctuations fluctuate not only between the respective starting points P11, P12, P13 and P14 but also between the respective works W1, W2 and W3, the shoulder bottom pushing depth Ds (stirring). (A significant depth to restrain the material that has been struck and prevent it from protruding to the surface)
There is a problem that unfilled defects (so-called deficiency) are generated due to the lack of oxygen, and the depth of the modified layer fluctuates and becomes unstable.

[0013]

DISCLOSURE OF THE INVENTION The present invention can prevent the occurrence of unfilled defects (so-called wall thickness) due to insufficient pushing of the shoulder portion of a rotary tool, regardless of the dimensional variation of the object to be processed, and it is stable. An object of the present invention is to provide a surface treatment method and a surface treatment apparatus capable of ensuring the depth of the modified layer.

[0014]

According to the surface treatment method of the present invention, friction is generated by pressing a surface portion of a metal workpiece to be processed by a shoulder portion while pushing a probe of a rotary tool attached to a processing apparatus. A surface treatment method of performing a stirring treatment to form a modified layer, wherein the rotary tool is pushed into a surface portion of a metal workpiece with a constant feed amount in a pushing direction, and friction stir treatment is performed on the metal workpiece. The height of the surface of the processed object and the height of the reference surface for processing are measured, and the indentation depth of the shoulder part is calculated from these measured values and the shape data of the rotary tool, and the value of the indentation depth and the occurrence of unfilled defects are avoided. When the indentation depth value is larger than the depth reference value at which the occurrence of unfilled defects can be avoided by comparing with the possible depth reference value, friction stirring of the rotating tool on the surface of the metal workpiece is performed. It is to be processed.

The height of the surface portion of the metal workpiece having the above construction can be set to a height between the bottom surface and the top surface of the work, and the machining reference surface height is the bottom surface of the work and the hole of the reference hole. It can be set to a height between the bottom surface, the shape data of the rotating tool can be set to the probe length, and the depth reference value that can avoid the occurrence of unfilled defects is the lower limit of the shoulder bottom indentation depth. Can be set.

According to the above construction, first, the object to be treated made of metal is made.
The surface height of the (so-called work) and the machining reference surface height are measured, and the indentation depth of the shoulder part is obtained from this measurement value and the shape data of the rotary tool, and then the indentation depth value and unfilled The friction stir processing is executed when the indentation depth is large, by comparison with the depth reference value that can avoid the occurrence of defects (so-called flesh thickness).

As a result, even if the metal workpiece has dimensional variations, the shoulder portion of the rotary tool is not insufficiently pushed, the occurrence of unfilled defects due to the insufficient pushing can be prevented, and a stable modification is possible. The depth of the stratum can be secured.

According to one embodiment of the present invention, when the value of the indentation depth is smaller than the depth reference value capable of avoiding the occurrence of unfilled defects by the above comparison, the correction amount is added to the constant feed amount of the rotary tool, The indentation depth of the shoulder part is calculated again from this added feed amount, and the surface after friction stir processing is calculated based on the value of this indentation depth and the surface machining allowance calculated from the surface height and the machining reference surface height. Determine whether the unevenness can be removed by finishing processing, and if it can be removed, perform friction stir processing of the rotary tool on the surface part of the metal workpiece,
When it cannot be removed, the friction stir processing is stopped.

The value of the finishing machining allowance of the above construction can be set to the value of the finishing machining allowance capable of avoiding the rough residue which removes the surface irregularities (roughness) after the friction stir processing by the finishing machining.

According to the above construction, when the pushing depth value of the shoulder portion is smaller than the depth reference value at which the occurrence of unfilled defects can be avoided, the correction amount is first added to the constant feed amount of the rotary tool. Then, the indentation depth of the shoulder part is obtained again by this added feed amount, and it is judged whether the surface irregularities can be removed during the finishing process from the obtained indentation depth value and the finishing machining allowance value. When the removal is possible, the friction stir processing is executed by the rotary tool under the correction amount addition condition, and when the removal is not possible, the friction stirring processing is stopped (or prohibited) and, for example, the work is delivered.

As a result, the friction stir processing is performed only on the object to be treated on the metal whose surface irregularities can be removed by adding the correction amount, and the size of the object to be treated NG on which the surface irregularities cannot be removed even if the correction is applied. Since the product is not subjected to friction stir processing, the production quality can be stabilized.

In one embodiment of the present invention, the height of the surface of the metal workpiece and the height of the machining reference surface are measured at a plurality of points, and the shoulder is determined by the measured values at the respective measurement points and the shape data of the rotary tool. The indentation depth of the part is calculated for each measurement point.

According to the above construction, by measuring a plurality of points, it is possible to perform appropriate measurement corresponding to the dimensional variation in the lengthwise direction of the object to be processed, an appropriate evaluation for each measurement point, and an appropriate evaluation. Can be processed.

That is, since accurate determination and evaluation cannot be performed with only one measurement point, measurement at a plurality of points and calculation for each measurement point are executed.

In one embodiment of the present invention, the metal object to be treated is set in a cylinder head of a diesel engine, and a reforming layer is formed between intake and exhaust ports of the cylinder head.

According to the above construction, regardless of the dimensional variation of the cylinder head of the diesel engine, it is possible to prevent an unfilled defect due to insufficient pushing of the shoulder portion of the rotary tool, and to secure a stable depth of the reformed layer. be able to.
In particular, it is possible to increase the thermal fatigue strength of the so-called valve bridge portion between the intake and exhaust ports where repeated stress is applied.

In the surface treatment apparatus according to the present invention, friction stir processing is performed by pressing the probe of the rotary tool attached to the processing apparatus onto the surface of the object to be treated and pressing the surface with the shoulder portion. A surface treatment device for forming a quality layer, the measuring means for measuring the height of the surface portion and the processing reference surface height of the metal workpiece, the measurement value measured by the measuring means, and the shape of the rotary tool. Calculation means for calculating the indentation depth of the shoulder portion with the data, comparison means for comparing the value of the indentation depth and the depth reference value for avoiding the occurrence of unfilled defects, and based on the comparison result of the comparison means When the value of the indentation depth is larger than the depth reference value at which the occurrence of unfilled defects can be avoided, the friction stir treatment of the rotary tool is performed on the surface portion of the metal workpiece.

According to the above construction, first, the measuring means measures the height of the surface portion of the object to be processed (so-called work) made of metal and the height of the reference surface for machining, and the calculating means calculates the measured value and the rotary tool. The indentation depth of the shoulder part is obtained from the shape data of the
The depth reference value capable of avoiding the occurrence of (so-called wall deficiency) is compared, and the friction stir processing is executed when the indentation depth is large according to the comparison result.

As a result, regardless of the dimensional variation of the metal workpiece, the shoulder portion of the rotary tool does not have insufficient indentation, it is possible to prevent the occurrence of unfilled defects due to insufficient indentation, and a stable modified layer. It is possible to secure the impossibility.

In one embodiment of the present invention, a correction means is added to a constant feed amount of the rotary tool, and arithmetic means for calculating the pushing depth of the shoulder portion again from the added feed amount is provided, and the comparison means is provided. When the value of the indentation depth is smaller than the depth reference value at which the occurrence of unfilled defects can be avoided based on the comparison result of, the indentation depth of the shoulder portion is calculated again by the above calculating means, and the indentation depth value and the surface are calculated. A determination means for determining whether or not the surface unevenness after the friction stir processing can be removed by the finishing processing based on the value of the finishing processing cost calculated by the section height and the processing reference surface height is provided. When it can be removed based on the above, the friction stir processing of the rotary tool is performed on the surface portion of the metal workpiece, and when it cannot be removed, the friction stirring processing is stopped.

According to the above construction, when the value of the indentation depth of the shoulder portion is smaller than the reference value of the depth at which the occurrence of unfilled defects can be avoided, the calculation means described above corrects the feed amount of the rotary tool to a constant feed amount. Then, the indentation depth of the shoulder portion is calculated again based on this added feed amount, and then the judgment means determines whether the surface unevenness can be removed during the finishing process from the value of the indentation depth and the value of the finishing allowance. Based on the judgment result, when the surface irregularities can be removed, the friction stir processing is executed with the rotating tool under the correction amount addition condition, and when the surface irregularities cannot be removed, the friction stir processing is stopped (or prohibited). , For example, paying out the work.

As a result, the size NG of the metal object to be treated in which the surface irregularities cannot be removed by performing friction stir processing only on the object to be treated in which the surface irregularities can be removed by adding the correction amount Since the product is not subjected to friction stir processing, the production quality can be stabilized.

In one embodiment of the present invention, the metal treated portion is set in a cylinder head of a diesel engine, and the surface height and the machining reference surface height are measured at a plurality of positions spaced in the cylinder row direction. It is configured to do so.

According to the above construction, since the surface height and the processing reference surface height are measured at a plurality of locations separated in the cylinder row direction, the cylinder head has a normal dimension (however, the surface roughness is corrected to correct the surface roughness). (Including a work that can be removed), a good modified layer can be obtained in each cylinder.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. The drawings show a surface treatment method and a surface treatment apparatus. First, the configuration of a cylinder head (cast work) made of an aluminum alloy as a metal object to be surface-treated will be described with reference to FIG.

FIG. 1 is a plan view showing the cylinder head 1 as viewed from the combustion chamber side. The cylinder head 1 of this in-line four-cylinder type diesel engine has two cylinder heads.
Two intake ports 2 and 2 and two exhaust ports 3 and 3 are formed.

Further, an opening 4 communicating with the inner water jacket is opened in the surface portion 1a on the combustion chamber side, and reference holes 5A and 5B are used as reference surfaces when finishing is performed after the friction stir processing. Are simultaneously formed when the cylinder head 1 is cast.

Further, in FIG. 1, P1, P2, P3
P4 is a starting point for performing friction stir processing on the valve bridge portion between the intake and exhaust ports 2 and 3 in each cylinder, X
1, X2, X3 are start points P1, P2, P3, P4
Is the separation distance in the cylinder column direction.

The cylinder head 1 is provided with tension bolt holes 6 ... Formed after the friction stir processing,
The cylinder head 1 and the cylinder block are fastened by a tension bolt (not shown) inserted through the tension bolt hole 6.

Therefore, in this embodiment, after friction stir processing of the valve bridge portion from the above-mentioned starting points P1, P2, P3 and P4 along the processing path shown by the arrow in FIG.
The processing is set to end at the position of the tension bolt hole 6.

Next, a specific structure of the rotary tool will be described with reference to FIG. This rotary tool 7 is an NC processing device 8
It is attached to a main shaft 9 (see FIG. 4) and rotates at a high speed, and a shank 10 has a shoulder portion 11 for pressing the surface portion 1a, and a cylinder head 1 integrally formed with the shoulder portion 11. Probe 1 that is pressed into the surface portion 1a of the surface and frictionally stirs the surface layer portion (surface or its vicinity)
2 and are provided.

The above-mentioned probe 12 is formed with a left-hand thread, while a predetermined probe length L is set between the shoulder bottom surface 11a and the tip of the probe 12. Next, the relative relationship between the cylinder head 1 and the rotary tool 7 and the contents of various reference symbols used in the following description will be described with reference to FIG.

In FIG. 3, F is the work height (surface height) between the lower surface 1b on the head cover side of the cylinder head 1 and the surface on the combustion chamber side, and S is the bottom surface of the reference holes 5A and 5B and the cylinder head 1. Processing reference surface height between the lower surface 1b of the
Is the depth at which the bottom surface 11a of the shoulder portion 11 is pushed into the inside of the cylinder head 1 from the surface of the cylinder head 1.
(Pushing depth of shoulder part), Lp is the probe tip pushing position corresponding to the height between the tip of the plug 12 and the lower surface 1b of the cylinder block 1, and δ is the surface of the cylinder block 1 and the tip of the probe 12. It is a probe tip pushing depth reference position corresponding to the depth between.

Next, the structure of the surface treatment apparatus will be described with reference to FIG. This surface treatment device pushes the surface portion 1a with the shoulder portion 11 while pushing the probe 12 of the rotary tool 7 mounted on the spindle 9 of the NC processing device 8 into the surface portion 1a of the cylinder head 1 as shown in FIG. This is an apparatus for forming a modified layer by performing friction stir processing by performing.

As shown in FIG. 4, this surface treatment apparatus has a CPU 20 as a control means, and the CPU 20 has a work height detection sensor 13 and a reference surface height detection sensor 1.
4, the input unit 15, and the identification information marking device 16 are connected. The work height detection sensor 13 described above is composed of a contact type dial gauge or a non-contact type laser displacement meter, and measures the work height F (see FIG. 3) at the start points P1 and P4 shown in FIG.

The above-mentioned reference surface height detecting sensor 14 is composed of a contact type dial gauge or a non-contact type laser displacement meter, and the processing reference surface height S (FIG. 3) is formed in the reference holes 5A and 5B shown in FIG. See). The above-mentioned input unit 15 is composed of a keyboard or the like and is used for input processing of pre-input information.

Here, the above-mentioned pre-input information is the heights F and S.
Measurement position, the positions of start points P1 to P4 of the friction stir processing, the probe length L as the shape data of the rotary tool 7,
Probe tip indentation depth reference position δ (see FIG. 3), shoulder bottom indentation depth Std (which is the lower limit of the shoulder bottom indentation depth Ds, and henceforth abbreviated as the lower limit). It is a finishing removal allowance α, etc., which can avoid rough residue as a finishing processing allowance when removing the surface irregularities after the friction stir processing during the finishing processing.

The CPU 20 described above, based on the necessary input information from the work height detection sensor 13, the reference surface height detection sensor 14, and the input unit 15, according to the program stored in the ROM 17, the sequencer of the NC processing device 8. 18,
Driving control of the identification information marking device 16 and RAM
Reference numeral 19 stores necessary data and the like. Here, the identification information marking device 16 is for marking a predetermined portion of the cylinder head 1 when the friction stir processing is performed on the cylinder head 1 with a value obtained by adding a correction amount described later so that the fact can be recognized. Is.

The NC processing device 8 described above includes the sequencer 1
8, NC controller 21, Z-axis servomotor 22, Y
It has an axis servo motor 23, an X axis servo motor 24, a spindle motor 25, a spindle 9, and a rotary tool 7. The spindle motor 25 drives the rotary tool 7 via the spindle 9, and the Z axis servo motor 22 drives the rotary tool 7. Position control in the vertical direction (height direction) of the Y-axis servomotor 23 and the X-axis servomotor 2
Reference numeral 4 controls the position of the rotary tool 7 in the front-rear direction and the left-right direction in order to obtain the processing path of the friction stir processing as shown in FIG.

Further, the CPU 20 described above has the work height detecting sensor 13 and the reference surface height detecting sensor 14 as measuring means.
Measured values (work height F, machining reference surface height S
Reference) and the shape data of the rotary tool 7 (see probe length L)
By means of calculating the shoulder bottom indentation depth Ds (see step Q7 of the flowchart shown in FIG. 5)
And the comparing means (see step S8 in the flowchart shown in FIG. 5) for comparing the shoulder bottom indentation depth Ds and the lower limit value Std, and the comparing means (step Q8).
When the shoulder bottom indentation depth Ds is larger than the lower limit value Std (see YES in step Q8).
(See the determination), the surface 1a of the cylinder head 1 is configured to be subjected to friction stir processing of the rotary tool.

Further, the above-mentioned CPU 20 uses the rotary tool 7
A calculation means for adding a correction amount to the constant feed amount of and calculating again the shoulder bottom indentation depth Ds from the added feed amount (see step Q12 of the flowchart shown in FIG. 5).
And the value of the finishing machining allowance, that is, the finishing machining allowance α calculated by the shoulder bottom indentation depth Ds, the work height F, and the machining reference surface height S, can the surface unevenness after the friction stir processing be removed by the finishing machining? Judgment means for judging whether or not
(See step Q10 of the flowchart shown in FIG. 5), and when the shoulder bottom indentation depth Ds is smaller than the lower limit value Std based on the comparison result of the above-mentioned comparison means (see step Q8), the above calculation means (step (See Q12), the shoulder bottom indentation depth Ds is calculated again, and the surface irregularities can be removed by the finishing process from the finish bottom allowance α calculated by the shoulder bottom indentation depth Ds and the heights F and S in consideration of this correction amount. Whether or not the above-mentioned determination means (step Q1
0)), and when surface irregularities can be removed based on this determination result (see NO determination in step Q10), the friction stir processing of the rotary tool 7 is applied to the surface 1a of the cylinder head 1 to obtain the surface irregularities. When can not be removed (Step Q10
In the case of YES determination), the friction stir processing is stopped. The above-mentioned step Q10 may be configured so as to serve as both the determination means and the calculation means.

Moreover, in this embodiment, the work height F of the cylinder head 1 is set to the starting points P1 and P2 shown in FIG.
And the machining reference surface height S of the cylinder head 1 is measured at a plurality of reference holes 5A and 5B shown in FIG. 1, and the measured values at the plurality of measurement points and the rotary tool 7 are measured.
The bottom surface indentation depth Ds of the shoulder is calculated for each cylinder based on the shape data. Here, the above CPU
It goes without saying that other means such as a personal computer may be used instead of the 20, ROM 17, RAM 19, and input section 15.

Next, the surface treatment method will be described with reference to the flow chart shown in FIG. First, step Q
1 (advance information input means) inputs various kinds of advance input information to the CPU 20 by operating the input unit 15.

That is, the measuring positions of the heights F and S, the starting position of the friction stir processing (see starting points P1 to P4 shown in FIG. 1), the probe length L, the probe tip pushing depth reference position δ, the lower limit value Std, Inputting information for finishing allowance α
Input to the CPU 20.

Next, at step Q2, the work height F at the starting points P1 and P4 is detected by the work height detection sensor 13.
Is measured and the measured value is input to the CPU 20. Next, in step Q3, the reference surface height detection sensor 14 causes the reference hole 5
The processing reference surface height S at the portions A and 5B is measured, and the measured value is input to the CPU 20.

Next, in step Q4, the CPU 20 calculates the work height F at each of the starting points P1 to P4. In this case, the work height F at the starting points P1 and P4
For, the measured value may be used as it is.

Next, in step Q5, the CPU 20 estimates and calculates the machining reference surface height S at each of the starting points P1 to P4. Next, in step Q6, the CPU 20 obtains the probe tip pushing position Lp for each cylinder.

The calculated value Lpi of the probe tip pushing position can be obtained by adding the probe tip pushing depth reference position δ to the calculated reference surface height Si. Here, i of the calculated value Lpi is the position L of the first cylinder in the case of the first cylinder.
p means the position Lp of the second cylinder in the case of the second cylinder, and the same applies to i used in the following description.
Next, in step Q7, the CPU 20 obtains the shoulder bottom indentation depth Ds for each cylinder. The calculated value Dsi of the shoulder bottom indentation depth is obtained by the following [Equation 1].

[Equation 1] Dsi = Fi-Lpi-L However, Fi is the calculated value of the work height Lpi is the calculated value of the probe tip pushing position L is the probe length

Next, in step Q8, the CPU 20 determines whether or not the shoulder bottom indentation depth Dsi obtained by the above calculation is larger than the lower limit value Std of the depth at which the occurrence of unfilled defects can be avoided, and a YES determination is made. When the workpiece size is normal, the process proceeds to the next step Q9, while when the NO determination is made (when the workpiece size is NG, however, it includes the one in which the rough portion is eliminated by applying the correction), another step Q10 is performed. Move to.

At the above-mentioned step Q9, the CPU 20 outputs a command to the NC processing device 8 to perform the friction stir processing with the probe tip pushing amount Lpi obtained at step Q6 as a calculated value. On the other hand, in step Q10 described above, the CPU 2
A value of 0 determines whether or not there will be rough spots. That is, next, [Equation 2]
It is determined whether or not there is a rough residue depending on whether or not the value indicated by is zero or more.

[Equation 2] (Std-Dsi + α)-(Fi-Si) where Std is the lower limit value Dsi is the calculated value of the shoulder bottom indentation depth α is the roughing avoidable finishing allowance Fi is the work height. The calculated value Si is the calculated value of the machining reference surface height. Here, when (Std-Dsi + α)-(Fi-Si) <0, it remains rough and (Std-Dsi + α)-(Fi-Si) ≧ 0.
At the time of, it does not remain rough.

Then, if it is determined in the above-mentioned step Q10 that there will be rough residue (YES determination), the next step Q10
When it is determined that no rough residue occurs (NO determination), the process proceeds to another step Q12.

At the above-mentioned step Q11, the CPU 20 stops the friction stir processing corresponding to the work size NG product,
In response to this, a command is output to the NC processing device 8 so that the work (see the cylinder head 1) is discharged.

On the other hand, in step Q12, the CPU 20 corrects the pushing position Lp of the probe tip so that the pushing depth Ds of the shoulder bottom surface becomes the lower limit value Std. This correction is executed based on the following [Equation 3].

[Equation 3] Corrected probe tip pushing position = Lpi + (Std-Ds
i) where Lpi is the calculated value of the probe tip indentation position Std is the lower limit value Dsi is the calculated value of the shoulder bottom indentation depth

Next, at step Q13, the CPU 20 makes the identification information marking device 16 mark the identification information on the cylinder head 1 so that the CPU 20 recognizes that the correction amount (Std-Dsi) has been added. Command is output to.

The NC processing device 8 receives the determination result according to the flowchart of FIG.
Work, work size that can avoid rough residue by correction NG
The processing corresponding to each product is executed.

For example, if any one of the four cylinders has the size NG, the work is paid out even if the size of the remaining three cylinders is proper, and all the cylinders have the size OK. In some cases, the friction stir processing is executed based on the calculation data of the probe tip pushing-in position Lp in step Q6, one of the four cylinders requires correction, and the remaining cylinders require correction. If not, based on the calculation data of the probe tip pushing position Lp corrected in step Q12 for the cylinders requiring correction, and for the cylinders not requiring correction, the probe tip pushing position Lp is calculated in step Q6. Friction stir processing is executed based on the data.

FIG. 6 shows a work W1 having the same size as that of FIG. 14, which is surface-treated by the method of the above-described embodiment (however, a process based on the command of step Q9), and FIG. 7 shows a work W2 having the same size as that of FIG. Surface treatment by the method of the above embodiment
(However, the processing based on the command in step Q9) is performed, and FIG. 8 shows the workpiece W3 having the same dimensions as in FIG. 16, but after the NO determination in step Q8 and the NO determination in step Q10, the correction is performed in step Q12. Then, the surface treatment is performed as shown in FIG.

As shown by the numerical values shown in FIGS. 6, 7, and 9, the shoulder bottom indentation depth Ds is 0.5 to 0.
It was in the range of 973 mm, and a sufficient amount of indentation could be secured, and the target of the modified layer depth was in the range of 2.676 to 2.88 mm, and a stable improved layer depth could be secured.

Thus, the surface treatment method of the above embodiment is
Surface part 1a of metal object (see cylinder head 1)
The probe 1 of the rotary tool 7 mounted on the NC processing device 8
A surface treatment method in which a friction stir treatment is performed by pressing the surface portion 1a with the shoulder portion 11 while pushing in 2 to form a modified layer, and the rotary tool 7 is made of metal at a constant feed amount in the pushing direction. The surface height (see the work height F) and the machining reference surface height of the metal workpiece (see the cylinder head 1) when the friction stir processing is performed by pushing the surface 1a of the workpiece (see the cylinder head 1) Measure S (Step Q
2 and Q3), the indentation depth of the shoulder portion 11 (see shoulder bottom indentation depth Ds) is calculated from these measured values and the shape data of the rotary tool 7 (see step Q7), and the value of the indentation depth Ds is calculated. And a depth reference value (see lower limit value Std) at which the occurrence of unfilled defects can be avoided (see step Q8),
By this comparison, when the value of the indentation depth Ds is larger than the depth reference value (see lower limit value Std) at which the occurrence of unfilled defects can be avoided (see YES determination in step Q8), the metal workpiece
The surface portion 1a of the cylinder head 1 is subjected to friction stir processing of the rotary tool 7.

According to this structure, first, the object to be processed made of metal
The surface height of the cylinder head 1 (see the work height F) and the machining reference surface height S are measured, and the pushing depth Ds of the shoulder portion 11 is determined from the measured value and the shape data of the rotary tool 7. Then, the value of indentation depth Ds and unfilled defect
The friction stir processing is executed when the indentation depth Ds is large by comparison with a depth reference value (see lower limit value Std) capable of avoiding the occurrence of (so-called wall deficiency).

As a result, even if the metal workpiece (see cylinder head 1) has dimensional variations, the rotary tool 7
Insufficient indentation of the shoulder portion 11 can prevent the occurrence of unfilled defects (so-called flesh thickness) due to the insufficient indentation, and can secure a stable depth of the modified layer.

Further, when the value of the indentation depth Ds is smaller than the depth reference value (see the lower limit value Std) at which the occurrence of unfilled defects can be avoided by the above comparison (see step Q8), a constant feed amount of the rotary tool 7 is obtained. The correction amount (see Std-Dsi) is added, the pushing depth Ds of the shoulder portion is calculated again from the added feed amount, and the value of the pushing depth Ds and the surface height (see the work height F) and Based on the value of the finishing machining allowance (refer to finishing machining allowance α) calculated by the machining reference surface height S, it is determined whether or not the surface irregularities after the friction stir processing can be removed by the finishing machining. The surface 1a of the object to be processed (see the cylinder head 1) is subjected to friction stir processing of the rotary tool 7, and when it cannot be removed, the friction stir processing is stopped.

According to this configuration, the value of the indentation depth Ds of the shoulder portion 11 is the depth reference value that can avoid the occurrence of unfilled defects.
If it is smaller than (lower limit value Std), first turn tool 7
The correction amount (see Std-Dsi) is added to the constant feed amount of, and the pushing depth Ds of the shoulder portion 11 is obtained again by the added feed amount, and the obtained pushing depth Ds value and finish It is determined from the value of the machining allowance (refer to the finishing allowance α) whether or not the surface irregularities can be removed during the finish machining, and when the removal is possible, the friction stir processing is executed by the rotary tool 7 under the correction amount addition condition, When it cannot be removed, the friction stir processing is stopped.
(Or prohibited), and the work is paid out, for example.

As a result, the friction stir processing is performed only on the object to be processed (refer to the cylinder head 1) made of metal which can remove the surface irregularities by adding the correction amount (refer to Std-Dsi).
Since the friction stir processing is not performed for the size NG product of the metal processing object that cannot remove the surface unevenness even after the correction, the manufacturing quality can be stabilized.

Moreover, the surface height (see the work height F) and the machining reference surface height S of the metal workpiece (see the cylinder head 1) are measured at a plurality of points, and the measured values at the respective measurement points are shown. The indentation depth Ds of the shoulder portion 11 is calculated for each measurement location based on the shape data of the rotary tool 7 (see the probe length L).

According to this structure, by measuring a plurality of points, it is possible to perform appropriate measurement corresponding to the dimensional variation in the length direction (see the cylinder row direction) of the object to be processed (see the cylinder head 1), and Appropriate evaluation for each measurement location and processing according to the evaluation can be performed. That is, since accurate determination and evaluation cannot be performed with only one measurement point, measurement at a plurality of points and calculation for each measurement point are executed.

Further, the above-mentioned object to be treated made of metal is set in the cylinder head 1 of the diesel engine, and a reforming layer is provided between the intake and exhaust ports of the cylinder head 1 (see the valve bridge portion between the intake and exhaust ports 2 and 3). To form.

According to this structure, regardless of the dimensional variation of the cylinder head 1 of the diesel engine, it is possible to prevent an unfilled defect due to insufficient pushing of the shoulder portion 11 of the rotary tool 7, and to ensure a stable depth of the reformed layer. Can be secured. Especially between the intake and exhaust ports where stress is repeatedly applied.
(Refer between the intake and exhaust ports 2 and 3) The thermal fatigue strength of the so-called valve bridge can be increased.

In the surface treatment apparatus of the above-mentioned embodiment, the surface 12a of the object to be treated (see the cylinder head 1) is pushed by the probe 12 of the rotary tool 7 mounted on the NC processing apparatus 8 while the surface of the shoulder 1 is pushed by the shoulder portion 11. A surface treatment apparatus for performing a friction stir processing by pressing the portion 1a to form a modified layer, the height of the surface portion of the above-mentioned metal object (see cylinder head 1) (see work height F). And measuring means (see sensors 13 and 14) for measuring the machining reference surface height S, and measurement values measured by the measuring means (see sensors 13 and 14) and shape data of the rotary tool 7 (see probe length L). The calculation means (see step Q7) for calculating the indentation depth of the shoulder portion 11 (see the shoulder bottom indentation depth Ds), the value of the indentation depth Ds, and the depth reference value for avoiding the occurrence of unfilled defects ( Lower limit value Std) Comparison means for (step Q
8) and the value of the indentation depth Ds is larger than the depth reference value (see lower limit value Std) at which the occurrence of unfilled defects can be avoided based on the comparison result of the comparison means (see step Q8) (step Q8). (Refer to YES judgment)
The surface portion 1a of the cylinder head 1 is subjected to friction stir processing of the rotary tool 7.

According to this structure, the height of the surface portion (see the work height F) of the object to be processed (see the cylinder head 1) and the height of the reference work surface are measured by the measuring means (see the sensors 13 and 14). The depth S is measured, the indentation depth Ds of the shoulder portion 11 is obtained from the measured value and the shape data of the rotary tool 7 by the above-mentioned calculation means (see step Q7), and then the comparison means.
In step Q8, the value of the indentation depth Ds is compared with the depth reference value (see lower limit value Std) that can avoid the occurrence of unfilled defects (so-called fillet), and the indentation depth is determined by this comparison result. When the value of Ds is large, the friction stir processing is executed.

As a result, there is no insufficient pushing of the shoulder portion 11 of the rotary tool 7 regardless of the dimensional variations of the metal workpiece (see the cylinder head 1), and there is no filling defect (so-called lack of wall thickness) due to the insufficient pushing. It is possible to prevent the occurrence of) and to ensure the stability of the modified layer.

Further, the correction amount is set to the constant feed amount of the rotary tool 7.
(See Std-Dsi), and the calculating means for calculating the pushing depth Ds of the shoulder portion 11 again from the added feed amount.
(See step Q12) is provided, and based on the comparison result of the comparing means (see step Q8), the value of the indentation depth Ds is the depth reference value (see lower limit value Std) at which the occurrence of unfilled defects can be avoided.
When it is smaller (see NO determination in step Q8), the indentation depth Ds of the shoulder portion 11 is calculated again by the calculation means (see step Q12), and the value of this indentation depth Ds and the surface portion height (workpiece height) are calculated. Judgment means for judging whether or not the surface unevenness after the friction stir processing can be removed by the finishing process based on the value of the finishing process allowance (refer to the finishing allowance α) calculated from the height F) and the machining reference surface height S. (Refer to step Q10), and when it can be removed based on the determination result of the determination means (see step Q10), the friction stir processing of the rotary tool 7 is performed on the surface portion 1a of the metal workpiece (see cylinder head 1). When it is not possible to remove it, the friction stir processing is stopped.

According to this structure, the value of the indentation depth Ds of the shoulder portion 11 is the reference value of the depth at which the occurrence of unfilled defects can be avoided.
When it is smaller than (lower limit value Std), the above calculation means
In step Q12, the correction amount (see Std-Dsi) is added to the constant feed amount of the rotary tool 7, and the pushing depth Ds of the shoulder portion 11 is obtained again by the added feed amount. In step Q10, it is determined from the value of the indentation depth Ds and the value of the finishing allowance (see the finishing allowance α) whether the surface irregularities can be removed during the finishing, and the surface irregularities are determined based on the determination result. When the removal is possible, the friction stir processing is executed by the rotary tool 7 under the correction amount addition condition, and when the surface irregularities cannot be removed, the friction stirring processing is stopped (or prohibited), and, for example, the work is discharged.

As a result, the friction stir processing is performed only on the object to be processed (see the cylinder head 1) made of metal whose surface unevenness can be removed by adding the correction amount, and the surface unevenness cannot be removed even if correction is applied. Since the friction stir processing is not performed for the NG product of the object to be processed (see the cylinder head 1), the manufacturing quality can be stabilized.

In addition, the above-mentioned metal treated portion is set in the cylinder head 1 of the diesel engine, and the height of the surface portion is set.
(Refer to the work height F) and the machining reference surface height S are configured to be measured at a plurality of locations separated in the cylinder row direction.

According to this structure, since the surface height (see work height F) and the machining reference surface height S are measured at a plurality of locations separated in the cylinder row direction, the cylinder head 1 having a normal size is measured. (However, when the friction stir processing is performed on the work in which the surface irregularities can be removed by performing the correction), a good modified layer can be obtained in each cylinder.

In the flowchart shown in FIG. 5, step Q10 may be configured so that it serves as both the determining means and the calculating means.

FIG. 10 shows another embodiment of the rotary tool. In the previous embodiment shown in FIG. 2, the left screw portion is formed on the outer peripheral portion of the probe 12, but in this embodiment shown in FIG. The probe 12 has a shape.

FIG. 11 shows still another embodiment of the rotary tool, and in this embodiment, the tip portion is formed as a prog 12 having a hemispherical curved surface shape. Even if configured in this manner, the above-described surface treatment method and apparatus provide substantially the same actions and effects as those of the previous embodiment.
0 and FIG. 11, the same parts as those in the previous figure are designated by the same reference numerals, and detailed description thereof will be omitted.

In the correspondence between the structure of the present invention and the above-described embodiment, the metal workpiece of the present invention corresponds to the aluminum alloy cylinder head 1 of the embodiment. Corresponding to the NC processing device 8, the surface height corresponds to the work height F, the indentation depth of the shoulder portion corresponds to the shoulder bottom indentation depth Ds, and the depth standard with which the occurrence of unfilled defects can be avoided The value corresponds to the lower limit value Std, and the correction amount is
Corresponding to Std-Dsi, the finishing machining allowance is α
The shape data of the rotary tool corresponds to the plow length L and the like, the space between the intake and exhaust ports corresponds to the valve bridge portion between the intake and exhaust ports 2 and 3, and the measuring means is the sensors 13 and 14.
The calculation means corresponds to step Q7 controlled by the CPU 20, the comparison means corresponds to step Q8, the calculation means corresponds to step Q12, and the determination means corresponds to step Q10. Is not limited to the configuration of the above-described embodiment.

[0094]

According to the present invention, it is possible to prevent the occurrence of an unfilled defect (so-called wall thickness) due to insufficient pushing of the shoulder portion of the rotary tool regardless of the dimensional variation of the metal workpiece, and to perform stable modification. This has the effect of ensuring the depth of the stratum corneum.

[Brief description of drawings]

FIG. 1 is a plan view of a cylinder head showing an example of a metal workpiece.

FIG. 2 is a side view of the rotary tool.

FIG. 3 is an explanatory diagram showing a relationship between a work and a rotary tool.

FIG. 4 is a block diagram showing a surface treatment apparatus of the present invention.

FIG. 5 is a flowchart showing a surface treatment method of the present invention.

FIG. 6 is an explanatory view showing a dimension of a work processed by the above method before finishing.

FIG. 7 is an explanatory diagram showing the dimensions of a work piece processed by the above method before finishing.

FIG. 8 is an explanatory diagram showing a work size before a correction amount is added.

FIG. 9 is an explanatory diagram showing a work size after the correction amount is added.

FIG. 10 is a side view showing another embodiment of the rotary tool.

FIG. 11 is a side view showing still another embodiment of the rotary tool.

FIG. 12 is an explanatory diagram of a friction stir processing method.

FIG. 13 is a plan view showing a state in which the cylinder head is viewed from the combustion chamber side.

FIG. 14 is an explanatory diagram showing variations in the shoulder bottom indentation depth and the modified layer depth standard according to the conventional method.

FIG. 15 is an explanatory diagram showing variations in the shoulder bottom indentation depth and the modified layer depth standard according to the conventional method.

FIG. 16 is an explanatory diagram showing variations in the shoulder bottom indentation depth and the modified layer depth standard according to the conventional method.

[Description of Reference Signs] 1 ... Cylinder head (metal object to be processed) 1a ... Surface part 2 ... Intake port 3 ... Exhaust port 7 ... Rotating tool 8 ... NC processing device (processing device) 11 ... Shoulder part 11a ... Shoulder bottom surface 12 ... probe 13 ... work height detection sensor (measurement means) 14 ... reference surface height detection sensor (measurement means) Q7 ... calculation means Q8 ... comparison means Q10 ... determination means Q12 ... calculation means F ... work height (surface height) S) S ... Machining reference surface height L ... Probe length (rotary tool shape data) Ds ... Shoulder bottom indentation depth (shoulder indentation depth)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3G024 AA01 FA00 GA16 HA07                 4E067 AA05 AA06 BG00 DA13 DC07                       DD02 EA07 EB00

Claims (7)

[Claims] 1. A surface on which a modified layer is formed by performing friction stir processing by pressing a probe of a rotary tool attached to a processing device onto the surface of a metal object to be processed and pressing the surface with a shoulder part. A processing method, wherein the rotary tool is pushed into a surface portion of a metal workpiece by a constant feed amount in a pushing direction to perform friction stir processing, the surface height of the metal workpiece and a processing reference surface height. The depth of the shoulder portion is calculated from these measured values and the shape data of the rotary tool, and the value of the depth of depression is compared with the depth reference value for avoiding the occurrence of unfilled defects. By comparison, when the indentation depth is larger than the depth reference value at which the occurrence of unfilled defects can be avoided, the surface treatment method of performing friction stir processing of the rotary tool on the surface portion of the metal workpiece. 2. When the value of the indentation depth is smaller than the reference depth value for avoiding the occurrence of unfilled defects as a result of the above comparison, a correction amount is added to the constant feed amount of the rotary tool, and the added feed amount is again used. The indentation depth of the shoulder part is calculated, and the surface unevenness after friction stir processing can be removed by finishing by the value of this indentation depth and the value of the finishing machining allowance calculated by the surface height and the machining reference surface height. The surface treatment method according to claim 1, wherein it is determined whether or not it is possible to remove, and when it can be removed, the friction stir processing of the rotary tool is applied to the surface of the object to be treated, and when it cannot be removed, the friction stirring processing is stopped. . 3. The height of the surface portion of the metal workpiece and the height of the machining reference surface are measured at a plurality of points, and the indentation depth of the shoulder portion is determined based on the measured values at the respective measurement points and the shape data of the rotary tool. The surface treatment method according to claim 1, wherein the surface treatment method is calculated for each measurement location. 4. The surface treatment method according to claim 1, wherein the metal object to be treated is set in a cylinder head of a diesel engine, and a reforming layer is formed between intake and exhaust ports of the cylinder head. 5. A surface on which a modified layer is formed by applying friction stir processing by pressing the surface of a metal tool to be processed with a shoulder of a rotary tool attached to a processing device and pressing the surface with a shoulder part. A processing device, measuring means for measuring the surface height and processing reference surface height of the metal object to be treated, and the measurement value measured by the measuring means and the shape data of the rotary tool Calculating means for calculating the indentation depth, comparing means for comparing the indentation depth value and the depth reference value for avoiding the occurrence of unfilled defects, and the indentation depth value based on the comparison result of the comparing means A surface treatment device for performing friction stir processing of a rotary tool on the surface portion of the metal object to be treated when is larger than the reference depth value for avoiding the occurrence of unfilled defects. 6. A calculation means for adding a correction amount to a constant feed amount of the rotary tool, and again calculating the pushing depth of the shoulder portion from the added feed amount, and pushing based on the comparison result of the comparing means. When the depth value is smaller than the depth reference value at which the occurrence of unfilled defects can be avoided, the indentation depth of the shoulder portion is calculated again by the above calculating means, and the indentation value, the surface portion height and the machining reference surface are calculated. A determining means for determining whether or not the surface unevenness after the friction stir processing can be removed by the finishing processing based on the value of the finishing machining allowance calculated by the height is provided, and when it can be removed based on the determination result of the determining means, The surface treatment apparatus according to claim 5, wherein the surface of the object to be treated is subjected to friction stir processing of the rotary tool, and when it cannot be removed, the friction stir processing is stopped. 7. A metal head to be treated is set on a cylinder head of a diesel engine, and the height of the surface portion and the processing reference surface height are measured at a plurality of positions spaced in the cylinder row direction. Or the surface treatment apparatus according to 6.