Welded razor blade assembly

Abstract

A razor blade assembly (14) is disclosed that includes a razor blade (18), a blade support (16), and one or more weld regions 30 joining the razor blade to the blade support, each weld region having a length and a width, wherein the width W 30 is about 0.05 mm to about 0.15 mm. Also provided is a razor blade assembly that includes a razor blade, a blade support, and one or more weld regions joining the razor blade to the blade support, each weld region including a depth and a width, wherein the depth D 30 is about 0.10 mm to about 0.20 mm.

Description

Technical Field

[0001] The present invention relates generally to welded razor blade assemblies, and more particularly to razor blade assemblies made using keyhole welding and methods thereof. Background Technology

[0002] Razor blade assemblies include razor blades that are joined to a blade support, wherein the blade support is used to mount the razor blade assembly into a razor blade holder. In current razor blade assemblies, conducted laser welding is commonly used to join the razor blades to the blade support. Conducted laser welding relies on surface heating of the component to create a molten pool of material, the width and depth of which are expanded through conduction and convection processes until the molten pool reaches the underlying substrate and forms a welding area that bonds or joins the component to the substrate.

[0003] Welded areas formed by conducted laser welding typically consist of relatively shallow, circular cross-sections that narrow with depth. Therefore, these welded areas often have limited machining allowances. Achieving stronger welds using conducted laser welding usually requires increasing the size of the welded area, especially its depth, which typically necessitates longer welding times and results in a wider welded area. However, the increased heat associated with longer welding times can introduce numerous process variations that can lead to defects such as thermal deformation of the part. Furthermore, achieving consistently high-quality welds with conducted laser welding requires relatively complex control strategies and frequent maintenance, including cleaning and inspection, sampling, and destructive testing to ensure optimal operation. These tasks increase costs and workload, and 100% effectiveness in maintaining quality and consistency is often not achievable. Summary of the Invention

[0004] According to one aspect of this disclosure, a razor blade assembly is provided, comprising: a razor blade; a blade support; and one or more welding regions that join the razor blade to the blade support, each welding region having a length and a width, wherein the width is from about 0.05 mm to about 0.15 mm.

[0005] According to another aspect of this disclosure, a razor blade assembly is provided, comprising: a razor blade; a blade support; and one or more welding regions that join the razor blade to the blade support, each welding region including a depth and a width, wherein the depth is from about 0.10 mm to about 0.20 mm. Attached Figure Description

[0006] Although the specification concludes with claims that are particularly pointed out and clearly stated to form the subject matter of the invention, it is believed that the invention will be better understood from the following description taken in conjunction with the accompanying drawings, in which similar reference numerals are used to indicate substantially the same elements, and wherein:

[0007] Figure 1 This is a perspective view of a razor blade holder including a razor blade assembly according to the present disclosure;

[0008] Figure 2 According to this disclosure, a welded area formed using a keyhole welding process is provided. Figure 1 A top-view schematic diagram of the razor blade assembly;

[0009] Figure 3A It was taken from line 3A-3A. Figure 2 Cross section of the razor blade assembly;

[0010] Figure 3B It was taken from line 3B-3B. Figure 2 Cross section of the razor blade assembly;

[0011] Figure 4 It is based on the similarity of this disclosure Figure 3A The cross-section shows the angled welded area;

[0012] Figure 5 This is a top view schematic diagram of a razor blade assembly having a welded area formed using a conventional conductive laser welding process;

[0013] Figure 6 It is a section taken along line 6-6. Figure 5 Cross section of the razor blade assembly;

[0014] Figure 7 This is a schematic diagram of an exemplary laser scanning apparatus for performing keyhole welding according to the present disclosure;

[0015] Figure 8 This illustrates the interface between the laser beam and the workpiece according to this disclosure. Figure 7 A magnified view of a portion and a graph showing the shape of the laser pulse;

[0016] Figure 9 and Figure 10 This is a flowchart illustrating an exemplary method of joining a razor blade to a blade support to form a razor blade assembly according to the present disclosure. Detailed Implementation

[0017] This disclosure relates to a keyhole welding process for forming razor blade assemblies comprising a razor blade and a blade support. Compared to welds produced by conventional conducted laser welding techniques, welds produced by keyhole welding are much narrower, with their width remaining substantially uniform along the entire depth of the weld. The weld is also deeper relative to its width, resulting in a stronger weld. The keyhole welding process is faster, requires less heat input, and produces higher quality and more consistent welds. The keyhole welding process also allows for greater variation in laser beam parameters and eliminates the need for many of the complex, maintenance-intensive components found in conventional conducted laser welding machines, reducing costly machine downtime and failure modes.

[0018] refer to Figure 1 It shows a razor blade holder 10, which may include a blade holder housing 12 having one or more razor blade assemblies 14 according to this disclosure. Although Figure 1 Three razor blade assemblies 14 are shown, but it should be understood that any number (more or less) of razor blade assemblies 14 can be installed within the razor blade holder 10. Each razor blade assembly 14 may include a blade support 16 coupled to a razor blade 18. As shown, the razor blade assembly 14 may be installed within the blade holder housing 12 and secured with clamps 20a and 20b. The blade holder housing 12 may also include a top cover 22 located near the rear of the blade holder housing 12 and one or more protective structures 24 located near the front of the blade holder housing 12. The top cover 22 may include one or more lubrication members (not shown). The razor blade holder 10 may be part of a razor system and may be detachably or permanently mounted to a handle (not shown). As described in detail herein, each razor blade assembly 14 may include one or more welding areas 30 for engaging a razor blade 18 to a corresponding blade support 16. The longitudinal length L of each razor blade 18 is... 18 On the longitudinal axis A parallel to the razor blade holder 10 10 Extending in the direction of, and each razor blade assembly 14 may include a longitudinal length L along the respective razor blade 18. 18 Multiple welded areas spaced apart 30. Figure 1 It should be understood that a portion of the razor blade 18 is shielded by clamps 20a and 20b, such that the longitudinal length L of each razor blade 18 is... 18 It can be greater than the longitudinal length of the visible portion of the razor blade 18.

[0019] Figure 2 yes Figure 1 A detailed top view of the welding area 30 of one of the razor blade assemblies 14 shown in the figure, and Figure 3A and Figure 3B yes Figure 2 A cross-sectional view of the corresponding part. Figure 4Another exemplary welded area 30' is similar to Figure 3A A cross-sectional view. (Reference) Figure 3A and Figure 4 The razor blade 18 includes a blade tip 18a, a trailing edge 18b, an upper surface 18c, and a lower surface 18d. The width W of the razor blade 18 is... 18 The thickness T of the razor blade 18 (measured from the blade tip 18a to the rear edge 18b) can be between approximately 0.20 mm and approximately 1.50 mm (±0.05 mm). 18 (Measured, for example, between the upper surface 18c and the lower surface 18d) can range from about 0.025 mm to about 0.125 mm, and in some examples is about 0.075 mm (±0.005 mm). In some examples, a portion of the razor blade 18 (e.g., a portion of the trailing edge 18b opposite the blade tip 18a) can be twisted or broken off after being attached to the blade support 16 to obtain the desired width W of the razor blade 18. 18 The blade support 16 includes an upper surface 16a, a lower surface 16b, and a front surface 16c. The thickness T of the blade support 16 is... 16 (As measured between the upper surface 16a and the lower surface 16b) may be between about 0.10 mm and about 0.30 mm (±0.05 mm).

[0020] like Figure 1 and Figure 2 As best seen, the welding area 30 may include a longitudinal length L along the razor blade 18. 18 A portion of an elongated shape. The length L of the welded area 30. 30 It can be from about 0.25 mm to about 2.0 mm, and in some examples it is about 0.70 mm (±0.05 mm). The width W of the weld area 30 30 It can be from about 0.05 mm to about 0.15 mm (±0.005 mm). In some examples, the length L of the weld area 30 is... 30 Greater than width W 30 To define an elongated shape, for example, a long axis (i.e., along length L) 30 The extended axis is greater than the shorter axis (i.e., along the width W). 30 The shape of the extended axis. In some cases, elongated shapes may include substantially straight, parallel sides with rounded or curved ends to form a rhombus shape, such as... Figure 1 and Figure 2 As shown. In other cases, the elongated shape may also include an elliptical or oval shape, wherein essentially all sides of the elongated shape are curved (not shown). In some specific examples, the length-to-width ratio of the welded area 30 may be greater than about 5:1 (±0.1).

[0021] like Figure 3A As best viewed, the weld area 30 extends from the upper surface 18c of the razor blade 18 into the blade support 16 to define the depth D of the weld area 30. 30 Depth D 30 The thickness can be between about 0.10 mm and about 0.20 mm (±0.05 mm). In some examples, the welded area 30 may extend slightly into the blade support 16, for example, by a amount greater than or equal to the thickness T of the blade support 16. 16 Approximately 5% to less than or equal to approximately 15% (±1%) of its thickness. In other examples, the welded area 30 may extend through the thickness T of the blade support 16. 16 At least half, for example, the thickness T of the blade support 16. 16 Approximately 50% to approximately 75% (±1%) of the welded area 30. 30 It can usually be larger than the width W. 30 In some specific examples, the depth-to-width ratio of the welded area 30 may be greater than approximately 2:1, and in other examples, greater than approximately 3:1 (±0.1). Figure 2 and Figure 3A As shown, the welding area 30 may be formed at or near the center point of the razor blade 18, such as along the width W of the razor blade 18. 18 The direction of extension is determined by this. It should be understood that the welding area 30 can also be formed along the width W of the razor blade 18. 18 (e.g., towards the blade tip 18a or rear edge 18b) at any other desired location. As described below relative to... Figure 4 To describe in more detail, Figure 3A The welding area 30 should be aligned with the front surface of the blade support 16 (not shown; see [link]). Figure 4 The 16c) in the middle are separated.

[0022] In some examples, such as Figure 1 As shown, the welded areas 30 may include substantially similar characteristics (e.g., depth, width, length, location, etc.) across all razor blade assemblies 14, such that all welded areas 30 within the razor blade holder 10 are uniform. In other examples, the welded areas 30 of one or more razor blade assemblies 14 may include one or more different characteristics (e.g., depth, width, length, and / or location) compared to the welded areas 30 in one or more other razor blade assemblies 14 within the razor blade holder 10. Alternatively or additionally, one or more welded areas 30 within a single razor blade assembly 14 may include different characteristics compared to one or more other welded areas 30 within the razor blade assembly 14.

[0023] Because keyhole welding is used to form the welding area 30, the width W of the welding area 30 is...30 Along the weld area 30, essentially the entire depth D 30 and / or length L 30 It can be uniform. For example, the width W of the welding area 30. 30 Along the depth D of 80%, 85%, or 90% or more of the welding area 30 30 and / or length L 30 It can be uniform. (Reference) Figure 3A The welding area 30 may include a first sidewall 30a and a second sidewall 30b. The width W of the welding area 30 is defined. 30 The first sidewall 30a and the second sidewall 30b are substantially parallel to each other (e.g., ±5°). Figure 3A In the example shown, the first sidewall 30a and the second sidewall 30b extend through the razor blade 18 and into the blade support 16 in a direction substantially perpendicular to the upper surface 18c and lower surface 18d of the razor blade 18 (e.g., at an angle of approximately 90° (±5°) to the upper surface 18c and lower surface 18d). A portion of the first sidewall 30a and the second sidewall 30b may be substantially straight. For example, as shown... Figure 3A As shown, the cross-sectional profile of the welding area 30 can define an elongated "U" shape, wherein the portions of the first sidewall 30a and the second sidewall 30b extending from the upper surface 18c of the razor blade 18 to a point near the bottom or root (not separately indicated) of the welding area 30 (e.g., the location where the first sidewall 30a and the second sidewall 30b begin to bend toward each other) are substantially straight.

[0024] refer to Figure 3A and Figure 3B The upper surface of the welding area 30 may define a welding surface 30c, which may include at least a height H extending above the upper surface 18c of the razor blade 18. 30 The part. For example... Figure 3B Best visible from the center, height H 30 The entire length L spanning the welding area 30 30 The weld area may not be uniform. Typically, no point on the weld surface 30c will protrude more than 0.025 mm above the upper surface 18c of the razor blade 18, and preferably more than 0.0075 mm. One or more parameters of the keyhole welding process can be adjusted to minimize the weld area 30 protruding above the upper surface 18c of the razor blade 18.

[0025] exist Figure 4In the example shown, the welding area 30' may include a first sidewall 30a' and a second sidewall 30b' extending parallel to each other but at an acute angle α to the upper surface 18c of the razor blade 18 through the razor blade 18 (and into the blade support 16). The angle α may be between about 45° and less than about 90°, or between about 50° and about 70° (±1°). In some examples, the angle α may be about 60° (±1°). Similar to... Figure 3A The first sidewall 30a and the second sidewall 30b of the welding area 30 in the middle, Figure 4 A portion of the first sidewall 30a' and the second sidewall 30b' in the welding area 30' can be substantially straight. Because the first sidewall 30a' and the second sidewall 30b' are at an angle, one sidewall (e.g., the first sidewall 30a') can be shorter than the other sidewall (e.g., the second sidewall 30b'). Although the first sidewall 30a' and the second sidewall 30b' are in... Figure 4 The image shows the first sidewall 30a' and the second sidewall 30b' inclined toward the blade tip 18a, but it should be understood that the first sidewall 30a' and the second sidewall 30b' may also be inclined toward the rear edge 18b. The welding area 30' may otherwise include substantially similar features. Figure 2 and Figure 3A The characteristics of the welded area 30 include its length, width, and depth (not shown), as well as the length-to-width ratio and the depth-to-width ratio. As described above relative to... Figure 3A The welding area 30 is discussed in more detail. Figure 4 The welding area 30' may include a welding surface 30c' that extends only slightly above the upper surface 18c of the razor blade 18, for example, extending no more than 0.025 mm in height (not shown), and preferably no more than 0.0075 mm. The blade support 16 and the razor blade 18 may also include substantially similar components. Figure 2 and Figure 3A The characteristics of the blade support 16 and the razor blade 18, including width, length and thickness (not indicated).

[0026] When, for example, the width of razor blade 18 (not indicated; see...) Figure 2 W in 18 ) and / or the thickness of the blade support 16 (not indicated; see Figure 3A T in 16An angled weld region 30' may be particularly useful when it falls within the lower limit of the scope described herein. Forming an angled weld region 30' helps ensure that the weld region 30' fully penetrates into the blade support 16 and is included in the necessary contact area between the weld region 30', the razor blade 18, and the blade support 16 to produce the desired weld retention strength. The weld region 30' can be formed at any desired location between the blade tip 18a and the trailing edge 18b of the razor blade 18, for example, at or near the center point of the razor blade 18, as described above relative to... Figure 2 and Figure 3A The welding region 30' is discussed. The angle α and position of the welding region 30' relative to the blade support 16 and the razor blade 18 should be selected such that the welding region 30' is spaced apart from the front surface 16c of the blade support 16, that is, no part of the welding region 30' should contact or extend across or beyond the front surface 16c. Contact between the welding region 30' and the front surface 16c of the blade support 16 may result in a weak weld, which may cause the razor blade 18 to undesirably detach from the blade support 16.

[0027] For comparison, Figure 5 and Figure 6 These are similar top and cross-sectional views of a razor blade assembly 114 formed using a conventional conductive laser welding process. The razor blade assembly 114 includes a blade support 116 attached to a razor blade 118. The razor blade 118 may be substantially similar to... Figures 1 to 4 The razor blade 18 shown may include a blade tip 118a, a trailing edge 118b, an upper surface 118c, a lower surface 118d, and a width W. 118 and thickness T 118 The blade support 116 can be substantially similar to... Figures 1 to 4 The blade support 16 shown may include an upper surface 116a, a lower surface 116b, and a thickness T. 116 .

[0028] Razor blade 118 through including length L 130 Width W 130 and depth D 130 One or more conventional welding areas 130 are joined to the blade support 116. The welding area 130 may include a slightly elongated shape, wherein the length L... 130 Greater than width W 130 .However, Figure 5 The length-to-width ratio of the welding area 130 is basically less than Figure 2The length-to-width ratio of the welding area 30 in the weld. For example, compared to a length-to-width ratio of welding area 30 / 30' greater than approximately 5:1, the length-to-width ratio of the welding area 130 formed using conductive laser welding is typically approximately 2:1. Furthermore, Figure 6 The depth-to-width ratio of the welding area 130 is significantly smaller than that of the welding area 130. Figure 3A and Figure 4 The ratio of depth to width of the welding area 30. For example, the ratio of depth to width of the welding area 130 is typically about 1:2, compared to a ratio greater than about 2:1 for the welding area 30 / 30'. Relative to width W 130 The welding area 130 extends relatively little into the blade support 116. As described in more detail herein, in order to achieve deeper welds using guided laser welding, the width W of the welding area 130 must typically be increased accordingly. 130 For example, such as Figure 6 As shown, in order to obtain depth D using conductive laser welding 130' Similar to Figure 3A and Figure 3B Depth D of the welding area 30 The welding area 130' (shown as dashed lines) (e.g., depth D) 130' It is depth D 130 Approximately twice the width of the welded area (W), which is 130'. 130' The area must be increased accordingly (e.g., at least doubled) to form a very wide welding area 130'.

[0029] Unlike Figure 3A and Figure 4 Welding area 30 in the middle, Figure 6 The width W of the welding area 130 in the middle 130 Along depth D 130 It is non-uniform. Specifically, the welded area 130 may include a semi-circular cross-section with circular walls that curve inward toward each other, such that the width W 130 Basically, with depth D 130 The width W of the welding area 130 decreases continuously. 130 The depth can be maximized at the upper surface 118c of the razor blade 118 and can be continuously reduced to the maximum depth D. 130 The point. It can be seen that the width W of the 130' welding area. 130' The same applies.

[0030] refer to Figure 7The illustration shows an exemplary laser scanning apparatus 200 for performing keyhole welding (some parts are magnified for detail and are not drawn to scale). A laser beam 202 generated by a laser 204 is transmitted via an output fiber optic cable 206 connected to a laser head 208. In some examples, the laser 204 may be a single-mode laser. A collimator 210 collimates the laser beam 202 generated by the laser 204 to produce a collimated laser beam 203, and a lens 212 focuses the collimated laser beam 203 to produce a focused laser beam 205. The collimator 210 may optionally include one or more actuators and / or mirrors (not shown) for guiding and moving the collimated laser beam 203. The lens 212 may include a single-element lens or a multi-element lens. In some examples, the lens 212 may include an F-θ lens, and in one specific example, the lens 212 may include a telecentric F-θ lens. In other examples, the lens 212 may include diffractive optics or holographic optics.

[0031] Mirror 214 is coupled to actuator 220 such that mirror 214 is translatable and / or rotatable to guide focused laser beam 205 to workpieces 216, 218 and create weld area 230 along the welding direction indicated by arrow A. Actuator 220 may include, for example, a galvanometer mirror scanner. Actuator 220 causes mirror 214 to move in, for example, a direction indicated by arrow B, which changes the angle and / or position of focused laser beam 205 relative to workpieces 216, 218. In some examples, galvanometer mirror scanner may include a 2-axis scanner or a 3-axis scanner. Although one mirror 214 is shown, it should be understood that laser scanning device 200 may include two or more mirrors 214. Furthermore, although one actuator 220 is shown, it should be understood that laser scanning device 200 may include two or more actuators 220 to enable mirror 214 to move about two or more different axes. The laser scanning device 200 may also include an imaging system 222 positioned to monitor one or more parameters of the workpieces 216, 218 and the welding area 230. One or more nozzles 232, coupled to a gas supply source (not shown), may direct a protective gas, such as helium, argon, or nitrogen, to the welding area 230. It should be understood that... Figure 7 The laser scanning device 200 shown is an example, and other suitable laser scanning devices can be used. For example, Figure 7 A front objective scanner is shown, but a rear objective scanner can also be used, wherein lens 212 is located in front of mirror 214 and is coupled to a servo system or other actuator.

[0032] Workpieces 216 and 218 can be mounted to the stage 224 and fixed in a given position relative to each other. The lower workpiece 216 can be a blade support, and the upper workpiece 218 can be a razor blade, wherein the laser beam 205 is guided to the upper surface 218c of the razor blade 218. The laser head 208 and / or the stage 224 may optionally include one or more corresponding actuators 226 and 228 that enable the laser head 208 and / or the stage 224 and the workpieces 216 and 218 to move relative to each other in the X, Y, and / or Z directions to advance the laser beam 205 along the razor blade 218. The actuators 226 and 228 may include, for example, linear motors, voice coils, or other linear translations. The actuators 226 and 228 may also enable the laser head 208 and / or the stage 224 and the workpieces 216 / 218 to tilt or pivot relative to each other. Although in Figure 7 The welding direction indicated by arrow A is shown as proceeding from left to right, but it should be understood that the laser scanning device 200 can be configured to perform welding in any desired direction, such as along the direction extending into or out of the page.

[0033] In some examples, the laser head 208 may be fixed such that the laser head 208 does not move relative to the stage 224 and the workpieces 216, 218, wherein the stage 224 and the workpieces 216, 218 may move relative to the laser head 208. In other examples, the stage 224 and the workpieces 216, 218 may be fixed such that the stage 224 and the workpieces 216, 218 do not move relative to the laser head 208, and the laser head 208 may move relative to the stage 224 and the workpieces 216, 218, for example, the laser head 208 may be coupled to a movable stage (not shown). In yet another example, both the laser head 208 and the stage 224, as well as the workpieces 216, 218, may be movable, such that the laser head 208 and the stage 224, as well as the workpieces 216, 218, may move relative to each other.

[0034] The laser scanning device 200 may also include a controller 234 electrically connected to one or more components of the laser scanning device 200. For example, such as Figure 7As shown, controller 234 is coupled to laser 204, imaging system 222, and actuators 220, 226. Controller 234 may be part of a control system that receives data relating to one or more components and / or workpieces 216, 218 of the laser scanning device 200 and the welding area 230, and controls the operation of the components of the laser scanning device 200. Controller 234 may also be coupled to, for example, actuator 228 and / or nozzle 232, and any additional actuators or other components. The laser scanning device 200 may be positioned at laser welding station 236, wherein actuator 228 may include a moving belt or chain that feeds multiple stands 224 carrying workpieces 216, 218 into the laser welding station 236 for welding.

[0035] The controller 234 can change one or more parameters of the laser scanning device 200 to control one or more characteristics of the welding area 230. For example, the laser 204 can provide an adjustable power output that can be changed by altering the input voltage reaching the laser 204, which changes the power density of the laser beam 205. In some examples, as the laser beam 205 advances along the razor blade 218, the laser beam 205 at a first power output (e.g., during the start-up phase) can be applied to the razor blade 218 to begin forming a keyhole. Afterward, the first power output can be reduced to a second (lower) power output, and the laser beam 205 at the second power output can be applied to the razor blade 218 to form the welding area 230 that bonds the razor blade 218 to the blade support 216 (e.g., during the welding phase; see also). Figure 8 The first power output may be, for example, between about 50% and about 500% (±5%) larger than the second power output. These steps may be repeated as needed to form one or more additional weld areas 230.

[0036] In some examples, multiple welded areas 230 can be started at one end of the razor blade 218 and then extended along the longitudinal length of the razor blade 218 (not shown; see [link]). Figure 1 The weld area 230 is formed by extending in a certain direction. In other examples, multiple weld areas 230 can be formed using alternating weld patterns. In some cases, the first weld area may be formed at the longitudinal center or midpoint of the razor blade 218, the second weld area may be formed to the right of the first weld area, the third weld area may be formed to the left of the first weld area, the fourth weld area may be formed to the right of the second weld area, the fifth weld area may be formed to the left of the third weld area, and so on, until the desired number of weld areas 230 have been formed. Other alternating patterns may be used as needed. Using alternating weld patterns can help to distribute the heat generated by welding more evenly, which can reduce thermal deformation of the blade support 216 and / or the razor blade 218.

[0037] The duration of the applied laser beam can also be varied to obtain the desired length and / or depth of the weld area 230. For example, the first time period during which a laser beam 205 with a first power output is applied to the razor blade 218 may differ from the second time period during which a laser beam 205 with a second power output is applied to the razor blade 218. The first time period may be between about 0.05 milliseconds (msec) and about 0.20 msec (±0.005 msec). In some examples, the second time period may be longer than the first time period, and in some specific examples, the ratio of the first time period to the second time period is greater than about 5:1 (±0.1).

[0038] Adjustable additional parameters of the laser scanning device 200 may include the scanning speed or speed profile within the welding area 230, the scanning speed or speed profile between welding areas 230, and the focal length F (see [reference]). Figure 7 The angle of the laser beam 205 relative to the upper surface 218c of the razor blade 218 (e.g., to form) Figure 4 The angled welding area 30' shown in the diagram, spot size, pulse length, shielding gas type and flow rate, pulse power or pulse shape, or laser beam parameter product can be selected. The scanning speed of the laser beam 205 within the welding area 230, and the duration of the applied laser beam, can be selected to form, for example, Figure 1 , Figure 3A and Figure 3B The elliptical or rhomboid weld area shown has the characteristics described herein. For example, the scanning speed of the laser beam 205 and / or other parameters may be selected such that the width of the weld area 230 is uniform along substantially the entire depth, as described herein. Figure 7 Not shown in the image; see also Figure 3A and Figure 3B The symbol W in the attached icon 30 and D 30 ).

[0039] In some examples, the laser beam 205 can be advanced along the razor blade 218 at a speed of at least 800 mm / s, and in some examples, at a speed of at least 1000 mm / s. For example, at a scan rate of 1000 mm / s, a weld area 230 with a length of 0.70 mm can be formed within 0.70 msec (0.05 msec to 0.20 msec at the first power output and 0.50 msec to 0.65 msec at the second power output). The highest scan rate among the multiple weld areas 230 can be selected such that the scan rate is uniform within each additional weld area 230, and thermal deformation of the razor blade 218 and the blade support 216 is minimized. In some examples, the scan rate of the laser beam 205 can be kept substantially constant throughout the welding process. In other examples, the scan rate of the laser beam 205 can be varied during the welding process. For example, the scanning speed of the laser beam 205 within the welding area 230 may be different from the scanning speed between welding areas 230 and / or the scanning speed of the laser beam 205 during the startup phase (i.e., under the first power output) may be different from the scanning speed during the welding phase (i.e., under the second power output).

[0040] Figure 8 yes Figure 7 An enlarged view of the interface between workpieces 216, 218 and laser beam 205 is provided, in which a graph is provided to show the correspondence between the power output of laser 204 and the formation of weld region 230. Pulsing the laser during keyhole welding (e.g., by modulating the power output) can be used to optimize the parameters of weld region 230. Pulsing may be particularly useful to avoid or minimize the generation of protrusions 230a, 230b in the metal at the beginning and / or end of weld region 230, which may be generated due to metal jetting and sputtering, for example, during keyhole welding. Large protrusions 230a, 230b extending above the upper surface 218c of razor blade 218 may interfere with the stacking and / or feed of razor blade assemblies. Therefore, it is desirable to keep the upper surface 218c of razor blade 218 as flat as possible (i.e., planar) and substantially free of unevenness such as burrs, spikes, and other protrusions.

[0041] It was expected that the pulse shape, undergoing a lower-power start-up phase followed by a higher-power welding phase, would reduce bulging at the beginning and end of the welding area. However, surprisingly, it was found that the amount of bulging generated by the lower to higher pulse shapes extending above the upper surface of the razor blade interfered with the stacking / feeding of the razor blade assembly. It was found that, as... Figure 8As shown, the pulse pattern, which involves a short-duration, high-power start-up phase followed by a longer-duration, low-power welding phase, produces a welding region 230 with protrusions 230a and 230b that do not interfere with the stacking / feed of the razor blade assembly. For example, by following... Figure 8 The keyhole welding process performed using the parameters in the parameters produces a welded area comprising a protrusion extending no more than 0.025 mm above the surface of the razor blade, and preferably no more than 0.0075 mm.

[0042] Compared to weld zones of comparable depth produced using conventional guided laser welding, the weld zones produced according to this disclosure exhibit higher weld retention strength (i.e., the magnitude of the force required to separate the razor blade from the blade support after welding). It has been found that conventional weld zones (e.g., Figure 6 The retention strength of the welded region 130 in the present disclosure is significantly less than that of the welded region according to the present disclosure (e.g., Figure 3A , Figure 3B and Figure 4 The weld retention strength of the weld area (30 / 30') in the disclosed method is similar in depth and includes a weld joint with a similar (or smaller) surface area. The weld area produced using the keyhole welding method of this disclosure can exhibit a weld retention strength at least 30% or at least 50% greater than that produced using conventional conducted laser welding. In some examples, razor blade assemblies produced using conventional conducted laser welding can exhibit a weld retention strength between about 120 N and about 150 N, while comparable razor blade assemblies produced according to this disclosure can exhibit a weld retention strength between about 180 N and 200 N. In one example, the weld retention strength of a conventional razor blade assembly including a weld area produced using conventional conducted laser welding is 146.65 N (±8.04 N), and the weld retention strength of a razor blade assembly including a weld area produced according to this disclosure is 191.28 N (±5.81 N).

[0043] Generally, compared to conduction laser welding, keyhole welding according to this disclosure produces stronger welds and is generally less susceptible to process variations. Keyhole welding is faster and more efficient, enabling greater output and lower costs, and allowing for greater variation in laser characteristics. Some conventional techniques utilize welding masks to control the position of the weld area and / or act as heat sinks. The increased efficiency of keyhole welding allows for a reduction in the total amount of energy (i.e., heat) applied to the workpiece, thereby reducing thermal deformation and eliminating the need for masks. The use of galvanometer scanners and other precision scanners provides a more precise and consistent laser beam placement, further eliminating the need for masks to define the weld area. The use of precision scanners also reduces or eliminates the need for mechanical linkages to move the laser head and / or workpiece stage, which are more prone to failure, require considerable maintenance, and can lead to weld defects and weld interruptions.

[0044] Compared to weld zones produced using conventional conducted laser welding, the depth-to-width ratio of the weld zone produced according to this disclosure is significantly higher (e.g., greater than about 2:1 for keyhole welding and greater than about 1:1 for conducted laser welding). Increasing the depth of the weld zone produced by conducted laser welding requires increasing the total volume of molten material, and each increase in weld zone depth typically requires an increase in width of equal or greater. The heat required to achieve this increase in depth often results in unacceptable amounts of thermal deformation of the workpiece. In the case of keyhole welding, increasing the depth of the weld zone typically requires little or no increase in width and reduces thermal deformation of the workpiece. Unlike conventional conducted laser welding, which relies on surface heating and rarely allows or does not allow directionality except perpendicular to the workpiece surface, keyhole welding allows for the formation of precise welds angled to the workpiece surface.

[0045] Keyhole welding typically offers greater flexibility when manufacturing razor blade assemblies. Razor blade assemblies made using conventional guided laser welding typically include 13 weld zones of a given length, width, and depth, and possess a given weld retention strength. Razor blade assemblies including weld zones according to this disclosure can achieve comparable weld retention strength, for example, with a smaller amount of longer, deeper, and / or angled total weld zone, without causing unwanted thermal deformation or significantly increasing the width of the weld zone. Keyhole welding can be used in conjunction with, for example, narrower razor blades and / or blade supports, which allows for the mounting of a greater number of razor blade assemblies per razor blade holder.

[0046] Figure 9 and Figure 10 This is a flowchart illustrating an exemplary method of joining a razor blade to a blade support to form a razor blade assembly according to the present disclosure. Reference Figure 9An exemplary method 300 for joining a razor blade to a blade support to form a razor blade assembly includes, at step 302, guiding a laser beam with adjustable power output at an upper surface of the razor blade. At step 304, while advancing the laser beam along the razor blade, applying the laser beam at a first power output to the razor blade. Step 306 includes reducing the first power output of the laser beam to a second power output, and step 308 includes applying the laser beam at the second power output to the razor to form a welding area for joining the razor blade to the blade support, after which method 300 may terminate.

[0047] refer to Figure 10 An exemplary method 400 of joining a razor blade to a blade support to form a razor blade assembly includes, at step 402, selecting values ​​for one or more parameters for a laser scanning device, including at least one of spot size, scanning speed profile, pulse length or type and flow rate of protective gas, pulse power or product of laser beam parameters.

[0048] Step 404 includes operating a laser scanning device to apply a laser beam to the razor blade according to one or more selected values, and step 406 includes generating an elongated weld area that joins the razor blade and the blade support to form a razor blade assembly, wherein the elongated weld area includes at least one of the following: (i) a depth-to-width ratio greater than about 2:1, or (ii) a length-to-width ratio greater than about 5:1, after which the method may terminate.

[0049] The representative embodiments of this disclosure described above can be described as follows:

[0050] A. A razor blade assembly comprising:

[0051] Razor blades;

[0052] • Blade support; and

[0053] • One or more welding areas that join the razor blade to the blade support, each welding area having a length and a width, wherein the width is from about 0.05 mm to about 0.15 mm.

[0054] B. The razor blade assembly according to paragraph A, wherein the length of each welded area is greater than the width of each welded area to define an elongated shape.

[0055] C. The razor blade assembly according to paragraph A or B, wherein the length-to-width ratio of at least one of the one or more welded areas is greater than about 5:1.

[0056] D. The razor blade assembly according to any one of paragraphs A to C, wherein each welded area comprises a substantially elliptical or rhomboid shape.

[0057] E. The razor blade assembly according to any one of paragraphs A to D, wherein the width of the razor blade from end to rear is from about 0.20 mm to about 1.50 mm.

[0058] F. The razor blade assembly according to any one of paragraphs A through E, wherein each welded area further includes depth, and wherein the width of each welded area is uniform along substantially the entire length.

[0059] G. The razor blade assembly according to any one of paragraphs A through F, wherein one or more

[0060] The welding area includes a plurality of welding areas spaced apart along the longitudinal length of the razor blade. H. A razor blade assembly comprising:

[0061] Razor blades;

[0062] • Blade support; and

[0063] • One or more welding areas that join the razor blade to the blade support, each welding area including depth and width, wherein the depth is from about 0.10 mm to about 0.20 mm.

[0064] I. The razor blade assembly as described in paragraph H, wherein the width of each welded area is from about 0.05 mm to about 0.15 mm.

[0065] J. The razor blade assembly according to paragraph H or I, wherein the depth-to-width ratio of at least one of the one or more welded areas is greater than about 2:1.

[0066] K. The razor blade assembly according to paragraphs H to J, wherein the weld surface of each welded area protrudes above the upper surface of the razor blade by no more than 0.025 mm.

[0067] L. A razor blade assembly according to any one of paragraphs H to K, wherein each welded area extends from the upper surface of the razor blade into the blade support.

[0068] M. The razor blade assembly according to paragraph L, wherein at least one of the one or more welding regions extends through at least half the thickness of the blade support.

[0069] N. The razor blade assembly according to paragraph L or M, wherein each welded area includes a first sidewall and a second sidewall, the first sidewall and the second sidewall being parallel to each other.

[0070] O. The razor blade assembly according to paragraph N, wherein the first sidewall and the second sidewall extend through the razor blade in a direction substantially perpendicular to the upper surface of the razor blade.

[0071] P. The razor blade assembly according to paragraph N or O, wherein the first sidewall and the second sidewall extend through the razor blade at an acute angle to the upper surface of the razor blade.

[0072] Q. The razor blade assembly described in any of paragraphs H to P, wherein the width of each welded area is uniform along substantially the entire depth.

[0073] R. The razor blade assembly according to any one of paragraphs H to Q, wherein the thickness of the blade support is from about 0.10 mm to about 0.30 mm.

[0074] The dimensions and values ​​disclosed herein should not be construed as strictly limited to the precise numerical values ​​cited. Rather, unless otherwise specified, each such dimension is intended to represent the stated value and a range around which it is functionally equivalent. For example, a dimension disclosed as “40 mm” is intended to represent “approximately 40 mm”.

[0075] Unless expressly excluded or otherwise limited, every reference cited herein, including any cross-references or related patents or patent applications, and any patent application or patent claiming priority to or benefiting from it, is incorporated herein by reference in its entirety. Reference to any reference is not an endorsement of it as prior art to any disclosed or protected art herein, nor is it an endorsement of any such invention, either on its own or in combination with any one or more references. Furthermore, where any meaning or definition of a term in this invention conflicts with any meaning or definition of the same term in referenced documents, the meaning or definition given to that term in this invention shall prevail.

[0076] While specific embodiments of the invention have been illustrated and described by way of example, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, it is intended that all such changes and modifications falling within the scope of the invention be covered by the appended claims.

Claims

1. A razor blade assembly, the razor blade assembly comprising: Razor blades; Blade support; and One or more welding areas that join the razor blade to the blade support, the one or more welding areas having a height, a length and a width, wherein the width is 0.05 mm to 0.15 mm, one or more welding areas or at least one of the welding areas is not uniform in height along the length, and wherein the one or more welding areas include a protrusion extending no more than 0.025 mm above the surface of the razor blade.

2. The razor blade assembly according to claim 1, wherein, The length of the one or more welded regions is greater than the width of the one or more welded regions to define an elongated shape.

3. The razor blade assembly according to claim 2, wherein, The length-to-width ratio of at least one of the one or more welding regions is greater than 5.1:

1.

4. The razor blade assembly according to claim 2, wherein, The one or more welding areas include a generally elliptical shape.

5. The razor blade assembly according to claim 1, wherein, The width of the razor blade from end to rear is 0.20 mm to 1.50 mm.

6. The razor blade assembly according to claim 1, wherein, The one or more welding areas include a plurality of welding areas spaced apart along the longitudinal length of the razor blade.

7. A razor blade assembly, the razor blade assembly comprising: Razor blades; Blade support; and One or more welding areas, each including one or more welded portions, the welding areas joining the razor blade to the blade support, wherein the welding areas include height, length, depth, and width, wherein the width is 0.05 mm to 0.15 mm and the depth is 0.10 mm to 0.20 mm, wherein one or more welding areas, or at least one of the welding areas, is not uniform in height along the length, and wherein the welding areas include a protrusion extending no more than 0.025 mm above the surface of the razor blade.

8. The razor blade assembly according to claim 7, wherein, The depth-to-width ratio of at least one of the one or more welding regions is greater than 2.1:

1.

9. The razor blade assembly according to claim 7, wherein, The distance by which the weld surface of one or more welded areas protrudes from the surface of the razor blade containing one or more welded areas does not exceed 0.025 mm.

10. The razor blade assembly of claim 7, wherein, At least one of the one or more welding regions extends from the surface of the razor blade containing the one or more welding regions into the blade support.

11. The razor blade assembly of claim 10, wherein, At least one of the one or more welding areas extends through at least half the thickness of the blade support.

12. The razor blade assembly of claim 10, wherein, The one or more welding areas include a first sidewall and a second sidewall, the first sidewall and the second sidewall being parallel to each other.

13. The razor blade assembly of claim 7, wherein, The thickness of the blade support is 0.10 mm to 0.30 mm.

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