TWI473680B - Drilling apparatus and method for suppressing delamination of composite laminates - Google Patents

Description

Drilling device and method for inhibiting delamination of composite laminate

The invention relates to a drilling device and a method for suppressing delamination of a composite material layer, in particular to a method for providing active supporting force to a workpiece composed of a composite material laminate.

Structural members of various composite materials have been widely used in various industrial fields. Due to the excellent mechanical properties of the composite, such as high strength to weight ratio, high fracture toughness and outstanding corrosion resistance, it replaces a variety of metal materials. In recent years, composite laminates have been widely used in the aerospace industry, such as the Boeing 787 Dream-liner and the Airbus A350 (English name: Airbus A350). The composite laminate is used in excess of 50% of its overall aircraft weight. When manufacturing various transportation vehicles and aircraft component devices, it is important to maintain the stability and rigidity of their structures in order to achieve their design and safety. The drilling quality requirements for a variety of composite structural materials are also one of the major components of the overall manufacturing and assembly process. For example, an aerospace industry's market demand report shows that approximately 50 million holes must be drilled each year on the body components of the jetliner using automated manufacturing procedures. However, the quality of the drilling of composite parts should be ensured in an automated manufacturing process and the manufacturing costs can be minimized.

In the various assembly and production operations of composite parts, in order to achieve the purpose of using riveted joints and bolt joints, it is generally more economical to use drill bits for mechanical drilling. However, after drilling composite parts, defects and damage such as delamination, burrs, microcracks, bulges, chipping and fiber detachment are often found. The delamination of the composite laminar workpiece in the drilling and drilling of the drill bit seems to be the most serious, and the delamination phenomenon under the action of fatigue load will have a service life. This results in a reduction in the ride strength and requires additional manufacturing procedures to reinforce.

Many previous studies, including the results of several studies by inventors He Chenhong and Cao Zhongyu, have proved that axial thrust is an important factor in delamination induced by drilling, and the magnitude of axial thrust mainly depends on the bit material, bit geometry and Feed rate at the time of drilling. The analytical model of borehole induced delamination is constructed by using linear elastic fracture mechanics. The model establishment shows the relationship between the axial thrust of the borehole and the properties of the composite material and the delamination of the composite laminate. In this case, the induced delamination inside the composite laminate workpiece is avoided, which is to reduce the axial thrust of the drilling. He Chenhong and Cao Zhongyu also summarized a variety of analytical models for a variety of special drills, such as candle core drills, saw drills, pipe drills, step drills, and summed up the critical axial thrust models of a variety of special drill bits, and can be applied to a variety of composite laminates. The delamination-free drilling process. He Chenhong and Cao Zhongyu pointed out that reducing the axial thrust or dispersing the axial thrust from the center of the drill bit can reduce the delamination. However, a variety of composite materials consider the quality of their drilling, usually with a low feed drilling procedure to reduce the generation of axial thrust, which is not the most ideal processing method.

In addition to the above-mentioned emphasis on reducing the axial thrust of various drill bits, there is another solution to suppress delamination when drilling multiple composite materials, that is, using a passive backing plate (sacrificial plate) when drilling composite materials. ). This method is common in some manufacturing industries and is called “passive” support. Passive support uses a sacrificial plate to support the back of the composite laminate to avoid deformation and delamination of the drilled surface. However, the use of passive struts as a bracing force to support composite laminate workpieces during drilling is not an ideal processing method considering the cost, speed and maintenance factors of the overall manufacturing process. The use of passive struts or sacrificial plates will inevitably result in wastage, waste or scratches, which inevitably increases production costs, especially in the processing of composite laminates for a variety of large design parts. Furthermore, if you have to drill continuously, you must constantly monitor and Adjusting the various positions of the passive struts or sacrificial plates to provide the correct bracing force to the composite laminate workpiece during drilling, avoiding the repeated use of multiple perforations or unsupported areas in the consumable area, which will inevitably Increase the cost, speed, and operational steps of the manufacturing process.

According to the above description of the field of composite drilling, it is necessary to provide a suitable solution for suppressing delamination caused by drilling a composite material in a multilayer form. In other words, it is necessary to provide a drilling device or an effective method to overcome the disadvantages of the prior art and to inhibit the delamination or cracking of the composite material after drilling or completing the drilling to improve the drilling production rate of the composite laminate. Reduce manufacturing costs.

In order to overcome the above disadvantages, it is an object of the present invention to provide a drilling apparatus for suppressing delamination of a composite material layer, which provides an "active" supporting force to a workpiece composed of a composite material, so that the active supporting force can be drilled. It effectively suppresses the delamination of the composite laminate workpiece, and does not inhibit the axial thrust or feed rate of the drill bit and cause the breakage of multiple passive plates.

Another object of the present invention is to provide a method for suppressing delamination of a composite material layer, which provides an "active" support force to a workpiece composed of a composite material, so that the active support force can effectively suppress the composite material during drilling. The delamination of the laminate workpiece does not inhibit the axial thrust or feed rate of the drill bit and cause the breakage of multiple passive plates. Among them, the active supporting force is related to the axial thrust of the drill bit at the position of the drilling surface when drilling, and is also related to the size of the delamination during drilling.

Another object of the present invention is to provide an active supporting mechanism capable of providing an active supporting force whose active supporting force is related to the axial thrust of the drill bit, and the axial thrust is applied to the composite layer. The thrust of the drilled surface of the plate workpiece, and the position of the thrust force and the drill bit Inch or bit radius related.

It is still another object of the present invention to provide a method for inhibiting delamination of a composite laminate which, when drilled, obtains a critical axial thrust F _B ^* when the composite laminate workpiece begins to crack. An active urging force is applied by the mechanism for providing the active struts described above to offset the axial thrust F _{B of the} drilling device to avoid delamination of the composite laminate workpiece. The active struts can maintain or inhibit delamination or crack formation as compared to a composite laminate to which no active struts are applied.

The present invention provides a drilling apparatus for suppressing delamination of a composite material layer for suppressing delamination of a composite material. The drilling device of the present invention comprises: a workpiece composed of a composite material, wherein the composite laminate workpiece comprises a drilling surface and a drilling surface; and the supporting base is disposed on the drilling surface of the composite material layer workpiece. For accommodating the composite laminate workpiece thereon; a drill bit for drilling the composite laminate workpiece with an axial thrust F _B having a peripheral portion of the drill radius C, the drill collar On one side of the drilling face of the composite laminate workpiece, and advancing toward the first direction of the drilling face at a feed rate; and an active urging mechanism for providing the drilled face of the composite laminate workpiece An active buckling force R, the active buckling force R is applied along a contact zone facing the drilling face in a second direction and at a distance δ from the outer periphery of the drill bit.

The active force applying mechanism further comprises a contact frame at least partially contacting the drilling surface of the composite laminate workpiece in the contact area, and driving the contact frame to face the composite layer in the second direction An adjustable power generator that advances the drilling surface of the plate workpiece. The active brace R has a force value associated with the axial thrust F _{B of the} drill bit that is used to inhibit delamination of the composite laminate workpiece.

The invention provides a method for suppressing delamination of a composite material layer, which can provide an active supporting force for drilling a plurality of composite materials. The method comprises the following steps: providing a workpiece of a composite material forming a laminate having a drilling surface and a drilling surface; fixing the composite laminate workpiece to a supporting base to make the composite layer The drilled surface of the plate workpiece abuts against the support base; a drill having a radius C is provided, and the composite laminate workpiece can be drilled by an axial thrust F _B on the drilling surface of the composite laminate workpiece And traveling at a feed rate in a first direction toward the drilled face; providing an active buckling force R to the drilled face of the composite laminate workpiece, the active support R being along the workpiece facing the composite laminate The second direction of the drilling face is applied to the contact zone at a distance δ from the outer periphery of the drill bit.

In addition, the present invention further provides a method for suppressing delamination of a composite material layer, and provides an adjustable active struts force to obtain a critical axial thrust F _B when a delamination of the composite laminate workpiece begins to occur. ^* . When the drilling is applied and the active urging force is applied to offset the axial thrust of the composite laminate workpiece, delamination of the composite laminate workpiece can be avoided. The critical axial thrust F _B ^* is also obtained as the critical crack generating energy value G _IC per unit area, the bending stiffness of the reinforced composite material M, the bit radius C, the force application distance δ, the active supporting force R and the delamination range. A related.

The above summary refers to a number of preferred embodiments of the invention and is for illustrative purposes only. The various embodiments of the invention can be embodied in many different forms and should be considered as part of the scope of the invention.

The invention provides a drilling device for suppressing delamination of a composite material layer, suppressing delamination of the composite material, and providing a method for supplying an active supporting force when drilling the composite material, It can effectively suppress the delamination or cracking of the composite laminate workpiece during drilling. In order to clarify the utility of the active support or active support force when drilling a composite laminate workpiece, a basic mode of common axial thrust induced delamination is provided to illustrate the utility and serve as a comparative basis. Referring to Figure 1, as shown in Figure 1, a model of the axial thrust of the borehole in the composite laminate workpiece 2 is induced to delamination. Under normal conditions, when a drill bit 4 applies an axial thrust F to a composite laminate workpiece 2, and the composite laminate workpiece 2 does not exert an active reinforcement R to offset the axial thrust F, Part of the drilled face of the composite laminate workpiece 2 is deformed or separated to form a delamination D. In other words, the drill bit 4 pushes the uncut laminate of the composite laminate workpiece 2 and deforms it downward by the axial thrust F. When the axial thrust F is larger, the deformation of the laminate below the composite laminate workpiece 2 is greater. Under the action of a certain level of axial thrust F, when the bond strength between the laminates can no longer prevent the flexural deformation, cracks between the laminates occur.

See FIG. 2, as shown in FIG. 2 is a model of delamination caused by drilling axial thrust, within the composite laminates of the workpiece 2 there is a critical axial thrust F _A drilling (F _A with To indicate the critical axial thrust under the condition that no active buckling force is applied, and delamination occurs beyond the critical axial thrust F _A . Accordingly, the present invention provides a method of inhibiting delamination of a composite laminate, and includes values of critical axial thrust and critical axial thrust described later. Further, in accordance with the present invention, a drilling apparatus capable of providing an adjustable active struts R, in a control mechanism, produces a feed rate along the axial movement of the drill bit 4 and a desired borehole axial direction. Thrust value. Cracks are produced primarily in accordance with the rupture in the model. The critical value is the critical axial thrust F ^* at the time of delamination. The critical axial thrust F ^* can be obtained by theoretical analysis of equation (1):

Where E and v are the Young's coefficient and Poisson's ratio of the material, respectively, G _IC generates energy for the critical crack per unit area of the model, and H _T is the thickness of the laminate that has not been cut under the tool.

In addition to the above-mentioned critical axial thrust F ^* theoretical value for drilling a composite laminate workpiece without applying an active supporting force, the present invention provides a method for suppressing delamination of a composite laminate, mainly to reduce The axial thrust during drilling results in delamination of the composite laminate workpiece, which in turn increases critical axial thrust or maintains critical axial thrust and is suitable for drilling operations in a variety of industries and maintains comparable production levels. It is very important to confirm the true effect of the axial thrust when drilling to cause delamination, and to control the axial thrust to further suppress delamination. The present invention provides a new method for applying an adjustable active brace R instead of the previously mentioned passive pad or sacrificial plate, thereby more accurately offsetting the axial thrust F caused by the delamination of the drilled face. An ejection effect produced by _B.

Referring to FIG. 3, a schematic view of the present invention is shown in FIG. 3. A drilling apparatus 10 provides an active supporting force R to a workpiece 20 in the form of a plate. The workpiece 20 in the form of a laminate is a delaminated model. The various associations can be as detailed below. The following power drive is an active force applying mechanism that applies active buckling force R, such as an electromagnetic drive, a hydraulic drive, a pneumatic drive, a motor to drive the drive and the mechanical drive. As shown in Fig. 3, B is shown as applying a radius of annular force; in other words, the active force applying mechanism may further comprise a continuous annular or annular contact frame containing a periphery of a radius B of a ring. The hollow part surrounded by the part. The center of the ring or ring is a bit radius C. F _B is an axial thrust with active support, X is the displacement, the thickness H of the composite laminate workpiece, and A is the delamination range.

Referring to Figure 4, there is shown a schematic view of a drilling apparatus 10 as shown in Figure 4 which inhibits delamination of the composite material. The drilling apparatus 10 includes: a workpiece 20 in the form of a laminate composed of a composite material having a thickness H between a drilling surface 22 and a drilling surface 24 relative to one of the drilling surfaces 22; a support base 30. A drilling face 24 of the workpiece 20 in the form of a laminate thereof to provide a workpiece 20 in the form of a receiving laminate thereon and to limit the displacement of the workpiece 20 in the form of a laminate; a drill bit 42 for the laminate The workpiece 20 of the form is drilled with an axial thrust F _B which is disposed on and perpendicular to the drilling face 22 and the drilling face 24 of the workpiece 20 in the form of a lamination having a peripheral portion P of the drill radius C. The drill bit is disposed on one side of the drilling face 22 of the workpiece 20 in the form of a laminate, and advances toward the first displacement direction X of the drilling face 24 at a feed rate and along the drill axis O; and an active urging mechanism 50, applying an active supporting force R to the drilling face 24 of the workpiece 20 in the form of a laminate, the active supporting force R being in a second displacement direction parallel to the drilling axis O of the drill bit 42, and located at a distance from the drill bit 42 The peripheral portion P is applied to a contact region of a biasing distance δ, and the active biasing mechanism 50 further includes a contact. The frame 52, the contact frame 52 is at least partially in contact with the drilled surface 24 of the workpiece 20 in the form of a laminate in contact with the contact area, and includes an adjustable power generator 54 that can drive the contact frame 52 and advancing it in the second direction toward the drilling face 22 of the workpiece 20 in the form of a lamination; wherein the active buckling force R has a force value associated with the axial thrust F _{B of the} drill bit 42, the force value suppressing layer The workpiece 20 in the form of a plate is delaminated. It can be seen that the drill bit 42 is disposed on the collet 44 of a hub unit 40, and the hub unit 40 is coupled to the drilling apparatus 10.

Referring to FIG. 5, a schematic view of the active urging mechanism 50 provided in the drilling apparatus 10 is shown in FIG. The active urging mechanism 50 can provide an active struts R to the workpiece 20 drilling face 24 in the form of a lamination, which is parallel to a second displacement direction of the drill axis O of the drill bit 42 and from the periphery P of the drill bit 42. There is a supporting force applied to a contact zone of a force application distance δ. Furthermore, This contact location is on the drilled face 24 of the workpiece 20 in the form of a laminate. As described above, in the embodiment, the active urging mechanism 50 further includes a contact frame 52 that is at least partially in contact with the drilled surface 24 of the workpiece 20 in the form of a laminate in the contact area. The active force applying mechanism 50 also includes an adjustable power generator 54 that can drive the contact frame 52 and displace it in a second direction upwardly toward the drilling surface of the workpiece 20 in the form of a laminate. 22 forward.

Referring to FIGS. 6A through 6D, a plurality of different embodiments of the contact frame 52 in the aforementioned active force applying mechanism 50 are shown in FIG. The shape of the contact frame 52 is an annular body, and the annular body can be composed of a metal wire or a metal strip having a relatively small thickness or diameter. As shown in Fig. 6A, in an embodiment, the contact frame 52 of the active urging mechanism 50 is a continuous annular body having a hollow portion surrounded by a peripheral portion of the annular urging radius B. The sum is equal to the sum of the bit radius C of the drill bit 42 and the applied force distance δ of the contact zone. In another embodiment, the contact frame 52 of the active force applying mechanism 50 includes a plurality of contact points (not shown) having a plurality of contact points spaced apart from each other and surrounding one having a radius of the annular force B. The annular body is equal to the sum of the bit radius C of the drill bit 42 and the applied force distance δ of the contact zone. It can be seen that a contact frame 52 that is disposed around or substantially closed annular configuration has a variety of shapes or configurations, such as viewed from above or below the contact frame 52, as shown in Figure 6B, rectangular ring, Figure 6C. The triangular ring shown or the hexagonal ring shown in Figure 6D.

It is known from the energy conservation principle combined with the axial thrust analysis applied to the active supporting force that the drilling displacement distance (dX) and the axial thrust F are related to the work done by the composite laminate workpiece 2 when delamination occurs. Coupling, an energy balance formula is obtained by the displacement distance between the plate and the crack generated between the laminates (2): G _IC dA=FdX-dU (2) where dU represents a small amount of strain energy and dA is the area of the delamination crack increments.

Formula (3) and formula (4) show a laminate theory, which can be used to determine the displacement and stored strain energy of the annular plate below the drill bit:

Where M = EH _T ³ /12(1- v ² ) represents the bending stiffness of the reinforced composite. As shown in the formula (5) and the description, the formula (3) and the formula (4) are differentiated into A and the result is brought into the formula (2), and a critical axial thrust F _B ^{* is obtained} , and the critical axial thrust is obtained. F _B ^* is the critical axial thrust when a suppression mechanism begins to crack: Where R = γ F _B , δ = BC = ξ C represents the difference between the radius (B) of the suppression load and the radius C of the bit, and S = C / A. In formula F _B ^* and Formula (1) (5) in a ratio of F ^* as follows:

As can be seen from the above, in the embodiment of the drilling apparatus 10, the force value of the active urging force R is related to the bit radius C of the drill bit 42, and also to the urging distance δ of the contact zone of the active urging mechanism 50.

Referring again to FIGS. 4 and 5, according to an embodiment, the adjustable power generator 54 can be used to drive the contact frame 52 of the active force applying mechanism 50, and is a power driver in the form of an electromagnetic driver, and can be powered according to the power. Or the power input is adjusted to reach its output. Also included are other types of power drives that are within the spirit of the present invention, such as hydraulic drives, pneumatic drives, motor driven drives, mechanical drives.

Please refer to Figure 7, as shown in Figure 7 for critical axial thrust and different gamma and enthalpy values as the active support force of the suppression mechanism is different. As can be seen from Fig. 7, the critical axial thrust F _B ^* increases as the active support force R increases. When the drill bit reaches the lowermost laminate, the active support R can help to prevent delamination cracks, so a higher drilling axial thrust F _B is required to cause delamination. That is to say, when the critical axial thrust F _B ^{* is} higher, delamination is less likely to occur. When the active supporting force R is applied to the extent of the axial thrust F _B of the borehole, the critical axial thrust F _B ^* will rise more than 100% more than when there is no active supporting force.

Therefore, an advantage of the present invention is that, when drilling can be performed at a faster feed rate, it is possible to shorten the production cycle or reduce the manufacturing cost without worrying about delamination. However, in actual operation, the force value of the active buckling force R is limited to γ < 2 due to the jig rigidity required for the workpiece 20 in the form of a layer to be drilled. In other words, the ratio γ will be less than or equal to 2, so that the force value of the active struts R of the drilled surface of the workpiece 20 mounted in the form of the laminate will be less than or equal to the drilled surface of the workpiece 20 mounted in the form of a laminate. The axial thrust of the drill bit is twice the F _B . This effect is more pronounced when the S value is larger, ie the crack is produced much larger than the drill bit size. The results also show that the formation of delamination is more difficult when the active support force R is larger; therefore, the advantage of the present invention is to maintain and reduce the occurrence of delamination defects caused by drilling.

In addition, as pointed out by Di Paolo et al., when the size of the delamination is smaller than the drill bit, the delamination phenomenon can be ignored. As shown in Fig. 7, the relationship between the ratio of borehole and critical axial thrust F _B ^{* and the} ratio of borehole to delamination is shown in Fig. 7, compared with the influence of active support force R, critical axial direction. The thrust F _B ^* does not change with the position of the active buckling force R.

In accordance with another embodiment of the present invention, a method of actively supporting R is provided and a plurality of composite materials are drilled. According to an embodiment of the above-described characteristics of the drilling apparatus 10 of the present invention, please refer to FIGS. 4 and 5 again. The method comprises the steps of providing a workpiece 20 in the form of a laminate having a thickness H defined by a drilling surface 22 and with respect to the drilling surface 24; the workpiece 20 in the form of a laminate is fixed to Supporting the base 30 and having the drilled surface 24 of the workpiece 20 in the form of a laminate against the support base 30 to limit the displacement of the workpiece 20 in the form of a laminate; a drill bit 42 for an axial thrust F _B on the laminate The drilled face 22 of the form workpiece 20 is drilled and advanced at a feed rate toward the first displacement direction of the drill face 24 and along the drill axis O, and the drill axis O is perpendicular to the workpiece 20 in the form of a laminate. The drilling face 22 and the drilling face 24, wherein the drill bit 42 has a peripheral portion P of the drill radius C and a drill shaft O; and provides an active buckling force R to the drilled face 24 of the workpiece 20 in the form of a laminate, which is parallel to The drill shaft O of the drill bit 42 is applied in a second displacement direction and is applied to a contact zone having a biasing distance δ from the peripheral portion P of the drill bit 42.

In addition, the above is a method for providing an active supporting force R when drilling a composite material according to the present invention. The active supporting force R is a force value, the force value thereof and the axial thrust F _{B of the} drill bit 42 and the biasing distance of the contact zone. δ is correlated and delamination of the workpiece 20 in the form of a laminate can be suppressed. Moreover, another embodiment of the present invention provides an active supporting force R to the composite material during drilling, and the contact frame 52 disposed on the active force applying mechanism 50 is also a continuous annular body having a radius of the annular supporting force. A hollow portion surrounded by one of the peripheral portions B, the annular support radius B is equal to the sum of the bit radius C of the drill bit 42 and the biasing distance δ of the contact zone. From this, it can be seen that the greater the active support force R, the more difficult the formation of the delamination; therefore, the advantage of the present invention is to maintain and reduce the occurrence of delamination defects caused by drilling.

To further provide relevant experimental data and analysis as an example to support the advantages of the present invention, the following experimental data and analysis are for illustrative purposes only, to demonstrate the principles of the present invention and should not be Limit it.

When designing an experiment to demonstrate the principles of the present invention, first, the composite material used would require a pre-impregnated fabric (WFC 200) formed from a carbon fiber epoxy resin using an autoclave. The stacking procedure for the laminate is [0/90]8S. The carbon fiber reinforced plastic (CFRP) laminate has a thickness of 4 mm and 16 layers of fibers are composed of 55% by volume. Carbon fiber reinforced plastic (CFRP) laminates were placed on a water-cooled diamond saw table for multiple 60 mm x 60 mm sample cuts. Multiple drilling experiments were performed on a vertical machining center, in which a piezoelectric dynamometer (Kistler 9273) and two charge amplifiers (Kistler 5007) were used to measure the axial thrust and recorded in the computer. A number of high-speed steel twist drills are required for the entire experiment. All experiments were carried out without coolant, spindle speed 1000 rpm, and feed rate of 30-120 mm/min. A tubular solenoid valve electromagnet is used to transmit the pressure load. The pressure load can be easily accomplished on the machine table. When the composite laminate workpiece is fixed above the device and the drilling is initiated, the magnetic drive force is also activated. When the drilling is completed, its holding force is turned off. The drilling apparatus of the present invention provides active support when performing drilling operations. The DC voltage used in the present invention is 0 (i.e., no support), 10V and 24V, and ξ is 0.05, 0.1, and 0.2. This experiment uses an adjustable electromagnetic actuator as the adjustable power generator 54 of the active force applying mechanism 50 in the embodiment. Please refer to Figure 8. Figure 8 shows the linear relationship between the active support force and the supply voltage generated by the solenoid valve or driver. The delamination was measured using an ultrasonic C-scan device (AIT-5112) with a scanning bridge with a resolution of 0.025 mm, an ultrasonic pulse wave generation and receiver (AIT-2230) With a digital oscilloscope. This study can obtain a large number of high-contrast images from each scan, where each image is composed of 150 × 150 pixels. It can be seen that other types of power drives, such as hydraulic drives, pneumatic drives, motor driven drives, and mechanical drives, can also be used.

Referring to Figure 9, the axial thrust F _B as shown in Figure 9 increases as the feed rate increases. Due to the rise in structural rigidity below the drill bit 42, the application of the active buckling force R results in an increase in the drilling force of an axial thrust F _B . The closer the application position of the active urging force R is to the drill bit 42 (i.e., the smaller the enthalpy value), the stronger the overall structure is affected by the borehole. This effect is slightly enhanced when the feed rate is higher; therefore, the axial thrust F _B increases as the active buckling force R increases, and is greater than the simple bore without the brace. As shown in Fig. 10, the relationship between the delamination range and the feed rate is mainly related to the fact that, in the case of using multiple feed rates without providing support, the delamination is often caused, and vice versa. When the active buckling force R is applied and at a high feed rate, the delamination range A can be suppressed to 60-80%. When the feed rate is increased with the active support force R, the delamination phenomenon is further reduced. When the application position of the active urging force R is closer to the drill bit 42 (i.e., the enthalpy value is equal to 0.05), the delamination can be more effectively suppressed. On the other hand, the active struts R (the enthalpy values are equal to 0.1 and 0.2) are applied at a distance from the drill bit 42, and at different high feed rates, the amount of delamination A produced is also increased. As shown in Fig. 11 a and b, the influence of the utilization of the active supporting force R on the drilling surface during drilling is illustrated, wherein Fig. 11b shows that the use of the active supporting force R significantly inhibits the delamination phenomenon. produce.

Please refer to Fig. 12. As shown in Fig. 12, the delamination suppression effect of the active force R is low (R=13N), and there is almost no difference in the increase of the active struts R. The apparatus and method of the present invention have the advantages of drilling or manufacturing a variety of related composite materials. In a particular experimental setup, this method only needs to provide a low electromagnetic power to effectively suppress delamination during drilling. However, the phenomenon of delamination inhibition caused by the low force value of the active struts R can be attributed to the carbon fiber reinforced plastic (CFRP) and the epoxy resin used, which have a cutting force due to drilling. The plate is bent, causing brittle fracture and breakage.

Due to the experimental data and analysis described above, the axial thrust F _B can be regarded as an important factor in the generation of delamination when drilling a composite laminate. The invention is based on classical elastic mechanics, linear elastic fracture mechanics and energy conservation principle, and proposes the extensiveness of the relationship between the active supporting force R and the critical axial thrust F _B ^* when drilling a pair of composite material layers. analysis. As a result, it is revealed that the value of the critical axial thrust F _B ^* generated when an active supporting force R is applied is significantly increased as compared with the case where the active supporting force R is not applied. In other words, the application of the active buckling force R can prevent the delamination A generated on the drilling face of the composite laminate workpiece and inhibit the delamination damage, especially when drilling with high feed rate to shorten the production cycle. The invention further proves that the application of an active supporting force R has the effect of delamination suppression. Further, when the application position of the active urging force R is closer to the drill bit, the phenomenon of suppressing delamination is more remarkable, and the active urging force R to be applied is smaller.

While the invention has been particularly shown and described with reference to the particular embodiments of the invention, it is understood that By way of example, experimental data and analysis are provided for illustrative purposes only and should be considered to be limited to particular or specific settings of the experimental device used.

2‧‧‧Composite laminate workpiece

4‧‧‧ drill bit

O‧‧‧Drill shaft

D‧‧‧Lamination

10‧‧‧Drilling device

20‧‧‧Sheet in the form of a laminate

R‧‧‧Active support

B‧‧‧Ring support radius

C‧‧‧Drill radius

X‧‧‧ Displacement direction

A‧‧‧ delamination range

H‧‧‧thickness

P‧‧‧External Department

22‧‧‧Drilling surface

24‧‧‧Drilled face

30‧‧‧Support base

50‧‧‧Active force applying mechanism

40‧‧‧Axis unit

42‧‧‧ drill bit

44‧‧‧ chuck

52‧‧‧Contact frame

54‧‧‧Adjustable power generator

Figure 1 is a model of delamination induced by axial thrust composites.

Figure 2 is a model of the delamination induced by the axial thrust of the borehole.

Figure 3 is a schematic view of the present invention.

Figure 4 is a schematic view of the drilling device.

Figure 5 is a schematic view of the active force applying mechanism of the drilling device.

Figure 6A is a schematic view of the contact frame of the present invention.

Figure 6B is a schematic view of the contact frame of the present invention.

Figure 6C is a schematic view of the contact frame of the present invention.

Figure 6D is a schematic view of the contact frame of the present invention.

Figure 7 is a schematic diagram of the ratio of borehole to critical axial thrust and the ratio of drill bit to delamination.

Figure 8 is a schematic view of the active supporting force and the supply voltage of the present invention.

Figure 9 is a schematic view of the axial thrust and feed rate of the active support of the present invention.

Figure 10 is a schematic diagram of the delamination range and the feed rate.

Figure 11 is a schematic diagram of the delamination range and feed rate.

Figure 12 is an ultrasonic C-scan diagram.

2‧‧‧Composite laminate workpiece

4‧‧‧ drill bit

O‧‧‧Drill shaft

D‧‧‧Lamination

Claims (8)

A drilling apparatus for suppressing delamination of a composite material layer, comprising: a workpiece composed of a composite material layer having a thickness, the thickness being a drilled surface and a drill opposite to the drilling surface The spacing between the exit faces is defined; a support base is disposed on the drilled surface of the composite laminate workpiece to receive the composite laminate workpiece thereon and to limit displacement of the composite laminate workpiece; a drill bit for drilling a hole in the composite laminate with an axial thrust F _B having a peripheral portion P of a drill radius C and a drilling surface and a drilling surface perpendicular to the workpiece of the composite laminate a drill shaft O; the drill bit is disposed on one side of the drilling face of the composite laminate workpiece and advancing toward the first direction of the drilling surface and along the drill axis O at a propulsion rate; An active force applying mechanism for applying an active supporting force R to the drilled surface of the composite laminate workpiece, the active supporting force R being in a second direction perpendicular to the drill axis O of the drill bit and Applying on a contact zone at a distance δ from the periphery of the drill bit The active force applying mechanism further includes a contact frame at least partially contacting the drilling surface of the composite laminate workpiece in the contact area, and a driving frame for driving the contact frame in the second direction An adjustable power generator advancing the drilling face of the composite laminate workpiece; and wherein the active support R has a force value associated with the axial thrust F _{B of} the drill bit to inhibit the composite laminate Delaminating the workpiece; wherein the axial thrust F _B has a critical axial thrust F _B ^* at the beginning of the crack initiation of the delamination, and the critical axial thrust F _B ^* is defined by: And G _{IC is the} energy value of the type I critical crack generated by a region; M is the bending stiffness of the reinforced composite material; the enthalpy is equal to the distance of the force applied divided by the radius of the bit (ξ=δ/C) The γ system is equivalent to the ratio of the active struts R to the axial thrust F _B (γ=R/F _B ); and the S system is obtained from the delamination range A and the bit radius C (S=C) /A). The drilling device for suppressing delamination of a composite material layer according to claim 1, wherein the contact frame of the active urging mechanism is a continuous annular body having a ring portion surrounding a hollow portion. The outer ring portion has a radius B which is equal to the sum of the bit radius C of the bit and the force applied distance δ of the contact zone. The drilling device for suppressing delamination of a composite material layer according to claim 1, wherein the contact frame of the active urging mechanism comprises a plurality of contact points, and the plurality of contact points are spaced apart from each other Surrounding the annular body having a radius B, the radius B is equal to the sum of the bit radius C of the drill bit and the applied force distance δ of the contact zone. The drilling device for suppressing delamination of a composite material layer according to claim 1, wherein the force value of the active urging force R is a contact radius of the drill bit of the drill bit and the active urging mechanism The force application distance δ is related to each other. The drilling apparatus for suppressing delamination of a composite material layer according to claim 1, wherein the adjustable power generator for driving the contact frame is selected from one of the following power drives: an electromagnetic drive, an oil Pressure drive, pneumatic drive, motor drive drive, mechanical drive. A method for inhibiting delamination of a composite laminate, the method comprising: providing a workpiece from a composite laminate having a thickness, the thickness being from a drilled surface and a The spacing between the drilled faces of the drilling face is defined; the composite laminate workpiece is fixed on a support base, and the drilled surface of the composite laminate workpiece is placed on the support base to limit the Directional displacement of the composite laminate workpiece; providing a drill bit for drilling a hole in the composite laminate with an axial thrust F _B having a peripheral portion P of a drill radius C and a perpendicular to the composite material a drilling surface of the drilling workpiece and a drilling axis O of the drilling surface; the drill is disposed on one side of the drilling surface of the composite laminate workpiece and is first to the drilling surface at a feed rate And advancing along the drill axis O; and applying an active buckling force R to the drilled face of the composite laminate workpiece, the active buckling force R being in a second direction perpendicular to the drill axis O of the drill bit And a distance δ between the outer portions of the drill bit The administration on the contact region; and wherein the axial thrust F _B having a critical axial force generated at the beginning of the delamination crack in F _B ^*, the critical axial thrust force F _B ^* of ^lines defined by the following: And G _IC refers to the energy value of the type I critical crack generated by a region; M refers to the bending stiffness of the reinforced composite material; the enthalpy is equal to the value of the applied force distance δ divided by the radius of the bit C (ξ=δ/ C); the γ system is equivalent to the ratio of the active struts R to the axial thrust F _B (γ=R/F _B ); and S is obtained from the delamination range A and the bit radius C (S= C/A). The method for inhibiting delamination of a composite material layer according to claim 6, wherein the active urging force R is applied by an active urging mechanism; the active urging mechanism includes at least a portion thereof The contact surface of the composite laminate workpiece is contacted by the contact area of the contact area, and an adjustable surface for driving the contact frame and advancing in the second direction toward the drilling surface of the composite laminate workpiece Power generator. The method for suppressing delamination of a composite material layer according to claim 6, wherein the active struts R have a force associated with the axial thrust F _{B of} the drill bit and the urging distance δ of the contact zone. Value to suppress delamination of the composite laminate workpiece.