CN106647632B - The prediction technique of CFRP and titanium alloy laminated construction reaming knife service life - Google Patents

Abstract

The invention provides a method for predicting the service life of a reaming tool with a laminated structure of CFRP and titanium alloy, and relates to the technical field of laminated assembly of carbon fiber composite material and titanium alloy. This method establishes the CFRP and titanium alloy laminated structure reaming hole size error analysis model, the reamer flank wear (VB value) analysis model, uses a variety of indicators to evaluate the reamer tool life, and comprehensively considers the laminated structure reaming In the process, the hole size accuracy and the flank wear of the reaming tool are constrained, and the effective service life of the reamer is predicted and analyzed based on the current structural parameters of the reamer and the parameters of the hole making process. The method provided by the invention has high accuracy in predicting the service life of the reamer, can effectively predict the maximum number of holes to be reamed in a laminated structure, reduce the failure rate and scrap rate of parts caused by exceeding the tool life, and make the holes The tool exerts its maximum reaming capacity.

Description

Prediction method of reaming tool life with CFRP and titanium alloy laminated structure

technical field

The invention relates to the technical field of laminated assembly of carbon fiber composite material and titanium alloy, in particular to a method for predicting the service life of a reaming tool with a laminated structure of CFRP and titanium alloy.

Background technique

Carbon fiber composite material (CFRP) has a series of advantages such as low density, high strength, high specific strength, and good vibration absorption, and has been widely used in aerospace, automobile, missile and other fields. For example, 90% of the fuselage surface of the Boeing 787 is made of carbon fiber composite materials. my country's new aviation aircraft is also gradually increasing the proportion of carbon fiber composite materials used. The application ratio of aviation aircraft composite materials and titanium alloys has become an important indicator to measure its advanced nature. one.

With the widespread use of carbon fiber composite materials in advanced aerospace vehicles, the demand for hole making of carbon fiber composite materials and titanium alloy laminated assembly structures is increasing. Boeing 787 passenger aircraft assembly needs to process 4 million carbon fiber composite materials and titanium alloy laminated structural holes. Due to the difficult-to-machine characteristics of carbon fiber composite materials and titanium alloys and their mutual constraints and influences, there are prominent problems in the hole-making process, such as low hole-making tool life, difficulty in ensuring hole-making quality, and difficulty in controlling the scrap rate of parts. According to reports, during the aircraft assembly process at home and abroad, the number of scrapped carbon fiber composite parts due to composite delamination/tearing defects caused by hole making accounts for more than 60% of all scrapped parts.

The reaming conditions of the carbon fiber composite material and titanium alloy laminated structure are complex, and the structural parameters of the reamer and the reaming process parameters have a great influence on the life of the reamer, and the service life of the reamer is difficult to predict accurately. Due to the lack of an effective life prediction method for reaming tools with laminated structures, it is difficult for the operator to judge when the reamer will reach the limit of its service life under the current reaming conditions. In order to avoid the low qualified rate and high part scrap rate caused by exceeding the effective service life of the tool, the number of holes can only be reduced based on experience, which greatly reduces the effective service life of the reaming tool and artificially increases the cost of hole making.

Aiming at the prediction method of reaming tool life with carbon fiber composite material and titanium alloy laminated structure, a lot of research work has been carried out at home and abroad, and a reamer life prediction method for reaming quality, flank wear and other evaluation indicators is proposed. These prediction methods have the following deficiencies: (1) The existing prediction methods are only applicable to the single reaming condition of carbon fiber composite materials, and no effective reamer life prediction method under the condition of reaming of carbon fiber composite materials and titanium alloy laminated structures is proposed. Considering the effect of titanium alloy material on reaming tool wear during the reaming process of laminated structures and the obstruction of composite materials on titanium alloy reaming chip removal, these prediction methods are not suitable for laminated structures; (2) Existing prediction methods The service life is predicted based on a single tool life evaluation index, and the prediction results cannot comprehensively reflect the hole diameter error and tool flank wear in the reaming process after reaching the service life limit.

Contents of the invention

Aiming at the defects of the prior art, the present invention provides a method for predicting the life of a reaming tool with a laminated structure of CFRP and titanium alloy, which can effectively predict CFRP and The maximum number of holes made by titanium alloy laminated structure reaming reduces the failure rate and scrap rate of parts caused by exceeding the tool life, and enables the hole making tool to exert the maximum reaming ability.

A method for predicting the life of a CFRP and titanium alloy laminated reaming tool, the specific steps are as follows:

Step 1. Set the dimensional accuracy standard of the laminated structure reaming hole;

Step 2. Set the bluntness standard of the laminated reamer reamer as the flank wear value VB of the reamer is not greater than 0.06mm;

Step 3. Set and input the initial number of reaming holes;

Step 4, according to the mapping relationship model of the aperture size error changing with the number of reaming holes in the stable reaming stage of the laminated structure, calculate the aperture size error under the current geometric parameters of the reamer structure, the reaming process parameters and the number of reaming holes; The mapping relationship model of aperture size error with the number of reaming holes is shown in formula (1);

D＝1.214N+0.15216+D _f (1)

Among them, D is the aperture size error, N is the number of reaming holes, D _f is the correction value of the aperture size error, and the calculation of D _f is shown in formula (2);

Among them, k _r is the main deflection angle of the reamer, α _r is the back angle of the outer edge of the reamer, Vc is the cutting speed of the reamer, and fr is the feed rate of the reamer per revolution;

Step 5. If the aperture size error calculated in step 4 is smaller than the aperture size accuracy set in step 1, proceed to step 6, otherwise execute step 9;

Step 6. According to the mapping relationship model of the reamer flank wear value changing with the number of reaming holes in the stable initial stage of reaming with stacked structures, calculate the reaming under the conditions of the current geometric parameters of the reamer structure, reaming process parameters and the number of reaming holes Knife flank wear value VB; The mapping relationship model of the reamer flank wear value changing with the number of reaming holes is as shown in formula (3);

VB＝0.001333N-0.01333+VB _f (3)

Among them, VB is the flank wear value of the reamer, VB _f is the flank wear correction value, and the calculation of VB _f is shown in formula (4);

Step 7. If the VB value calculated in step 6 is smaller than the blunt standard VB value set in step 2, proceed to step 8, otherwise proceed to step 9;

Step 8, increase the number of reaming holes by 1, return to step 4;

Step 9: The predictive analysis process ends, the life of the reaming tool with stacked structure is set as the current number of reaming holes, and the life of the reaming tool, the error of the hole diameter and the wear value VB of the flank of the reamer are output.

It can be seen from the above-mentioned technical scheme that the beneficial effect of the present invention is that: the CFRP and titanium alloy laminated structure reaming tool life prediction method provided by the present invention establishes the CFRP and titanium alloy laminated structure reaming hole size error analysis model, reaming The analysis model of tool flank wear (VB value) uses various indicators to evaluate the tool life of the reamer, and comprehensively considers the two constraints of aperture size accuracy and reamer tool flank wear during the reaming process of the laminated structure. Knife structure parameters and hole making process parameters, predict and analyze the effective service life of the reamer, the prediction result of the service life of the reamer is highly accurate, and can effectively predict the maximum number of holes made by the laminated structure reaming, reducing the damage caused by exceeding the tool life The unqualified rate and scrap rate of parts can be reduced, and the hole-making tool can be used to maximize the reaming capacity.

Description of drawings

Fig. 1 is the flow chart of the method for predicting the life of a CFRP and titanium alloy laminated reaming tool provided by an embodiment of the present invention;

Fig. 2 is a schematic diagram of the variation of the hole size error and the flank wear value VB with the number of reamed holes in the tool life prediction analysis process provided by the embodiment of the present invention.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Taking the reaming process of T300 carbon fiber composite material and TC6 titanium alloy laminated structure as an example, the reaming conditions and accuracy requirements of the laminated structure are as follows:

(1) Structural geometric parameters of the reamer: the diameter is 6.6mm, the main deflection angle is 45 degrees, and the rear edge angle is 12 degrees;

(2) The tool material is K6UF (tungsten carbide);

(3) Reaming process parameters: cutting speed is 20m/min, feed rate is 0.03mm/r;

(4) Reaming hole size accuracy requirements: the hole size meets the H9 accuracy;

(5) The thickness of the T300 composite material plate is 5mm, and the thickness of the TC6 titanium alloy plate is 3mm.

As shown in FIG. 1 , the method of this embodiment is as follows.

Step 1. Set the dimensional accuracy standard of the laminated structure reaming hole.

According to the present embodiment, the dimensional accuracy of the reaming hole needs to meet the H9 accuracy requirement, and the dimensional tolerance of the hole with a diameter of 6.6 mm is 0.036 mm, that is, D _max =0.036 mm.

Step 2. Set the bluntness standard of the laminated structure reamer.

Considering the reaming quality and the grinding and damage of the reamer comprehensively, the bluntness standard of the laminated reamer reamer is set so that the wear value VB of the reamer flank is not greater than 0.06mm, that is, VB _max = 0.06mm.

Step 3. Set and input the initial number of reaming holes as 5.

Step 4, according to the mapping relationship model of the aperture size error changing with the number of reaming holes in the stable reaming stage of the laminated structure, calculate the aperture size error under the current geometric parameters of the reamer structure, the reaming process parameters and the number of reaming holes; The mapping relationship model of aperture size error with the number of reaming holes is shown in formula (1);

D＝1.214N+0.15216+D _f (1)

Among them, D is the aperture size error, N is the number of reaming holes, D _f is the correction value of the aperture size error, and the calculation of D _f is shown in formula (2);

Among them, k _r is the main deflection angle of the reamer, α _r is the relief angle of the outer edge of the reamer, Vc is the cutting speed of the reamer, and fr is the feed rate of the reamer per revolution.

In this embodiment, the current aperture size error calculated according to the above-mentioned mapping relationship model of the variation of the aperture size error with the number of reaming holes is 0.0041 mm.

Step 5. If the aperture size error calculated in step 4 is smaller than the aperture size accuracy set in step 1, proceed to step 6, otherwise execute step 9.

In this embodiment, if the current aperture size error of 0.0041 mm is less than the dimensional accuracy tolerance of 0.036 mm, step 6 is performed.

Step 6. According to the mapping relationship model of the reamer flank wear value changing with the number of reaming holes in the stable initial stage of reaming with stacked structures, calculate the reaming under the conditions of the current geometric parameters of the reamer structure, reaming process parameters and the number of reaming holes Knife flank wear value VB; The mapping relationship model of the reamer flank wear value changing with the number of reaming holes is as shown in formula (3);

VB＝0.001333N-0.01333+VB _f (3)

Among them, VB is the flank wear value of the reamer, VB _f is the flank wear correction value, and the calculation of VB _f is shown in formula (4).

In this embodiment, the current VB value of the flank wear of the reamer calculated according to the above-mentioned mapping relationship model of the change of the flank wear value of the reamer with the number of reaming holes is 0.02 mm.

Step 7. If the VB value calculated in step 6 is smaller than the blunting standard VB value set in step 2, proceed to step 8; otherwise, proceed to step 9.

In this embodiment, if the current reamer flank wear VB value of 0.02 mm calculated in step 6 is less than the blunting standard VB _max =0.06 mm, then step 8 is performed.

Step 8: Increase the number of reaming holes by 1, return to step 4, and repeat step 4 to step 8 until the hole size accuracy is not met or the blunting standard is not met, then go to step 9.

Step 9: The predictive analysis process ends, the life of the reaming tool with stacked structure is set as the current number of reaming holes, and the life of the reaming tool, the error of the hole diameter and the wear value VB of the flank of the reamer are output.

During the execution process, the variation of hole size error and flank wear value VB with the number of reamed holes is shown in Figure 2. It can be seen from Figure 2 that when 42 holes are reamed, although the tool face wear still meets the relevant standards, the hole diameter The size error is 0.0361mm, which is greater than the set aperture size tolerance of 0.036mm, so the effective tool life prediction analysis result of the reamer is 41 reaming holes.

This example establishes the T300 and TC6 lamination structure reaming hole size error analysis model, the reamer flank wear (VB value) analysis model, and proposes a comprehensive consideration of the hole size accuracy and the reamer flank wear. The constrained tool life prediction method predicts and analyzes the effective service life of the reamer according to the current structural parameters of the reamer and the parameters of the hole making process. This method can effectively predict the maximum number of holes for reaming in laminated structures, reduce the failure rate and scrap rate of parts caused by exceeding the tool life, and enable the hole-making tool to maximize its reaming capacity.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some or all of the technical features; these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope defined by the claims of the present invention.

Claims (1)

1. the prediction technique of a kind of CFRP and titanium alloy laminated construction reaming knife service life, it is characterised in that：This method it is specific Steps are as follows：

Step 1, setting laminated construction fraising aperture size accuracy standard；

Step 2, setting laminated construction fraising reamer blunt standard are that reamer wear of the tool flank value VB is not more than 0.06mm；

Step 3 is arranged and inputs initial fraising quantity；

Step 4, the stage aperture size error that steadily reamed according to laminated construction are with the mapping relations model of fraising quantity variation, meter It calculates in current reamer geometrical parameters, fraising technological parameter and the aperture size error to ream under quantity term；The aperture Shown in mapping relations model such as formula (1) of the scale error with fraising quantity variation；

D=1.214N+0.15216+D_f (1)

Wherein, D is aperture size error, and N is fraising quantity, D_fFor aperture size error correction values, D_fCalculating such as formula (2) institute Show；

Wherein, k_rFor reamer tool cutting edge angle, α_rFor reamer outer rim relief angle, Vc is fraising cutting speed, and fr is fraising feed of every rotation；

If step 5, step 4, which calculate the aperture size error obtained, is less than the aperture size precision that step 1 is arranged, continue to hold Row step 6, it is no to then follow the steps 9；

Step 6, the steady starting stage reamer wear of the tool flank value that reamed according to laminated construction are closed with the mapping of fraising quantity variation It is model, calculates in current reamer geometrical parameters, fraising technological parameter and the reamer flank mill to ream under quantity term Damage value VB；Shown in mapping relations model such as formula (3) of the reamer wear of the tool flank value with fraising quantity variation；

VB=0.001333N-0.01333+VB_f (3)

Wherein, VB is reamer wear of the tool flank value, VB_fFor wear of the tool flank correction value, VB_fCalculating such as formula (4) shown in；

If step 7, step 6, which calculate the VB values obtained, is less than the blunt standard VB values that step 2 is arranged, step 8 is continued to execute, It is no to then follow the steps 9；

Step 8, fraising quantity increase by 1, return to step 4；

Step 9, forecast analysis process terminate, and the setting laminated construction reaming knife service life is current fraising quantity, output fraising knife Have service life, aperture size error and reamer wear of the tool flank value VB.