Solid wood special-shaped part machining method based on curved surface generation path

Abstract

The invention discloses a solid wood special-shaped part classification method based on a curved surface generation path, and the method comprises the following steps: obtaining the attribute indexes of an existing solid wood special-shaped part, and carrying out the transverse cutting of the solid wood special-shaped part, the method comprises the following steps: determining a cross section of a part, classifying and defining the curved surface according to a path of generating the curved surface along the longitudinal direction of the cross section, dividing the curved surface into an extruded curved surface and a swept curved surface, matching the curved surface of the part with the curved surface to obtain an extruded part and a swept part, and defining and classifying the curved surface according to the path of generating the curved surface by rotating the cross section along a central axis. If the cross section and the longitudinal extension direction of the part are both complex curves, the part is defined as a free-form curved surface, and the part curved surface is matched with the free-form curved surface to obtain a free-form part, and if the cross section and the longitudinal extension direction of the part are both complex curves, the free-form part is defined as the free-form curved surface; the invention aims at solving the standard production bottleneck caused by diversity of special-shaped parts in furniture enterprises.

Description

Technical Field

[0001] The present invention relates to the technical field of furniture production, and in particular to a method for classifying special-shaped solid wood parts based on a curved surface generation path. Background Art

[0002] In order to meet the requirements of function and shape, some furniture parts need to be made into various shapes or curved surfaces. These parts are called "special-shaped parts". Because there are a large number of curved surfaces, special-shaped parts are more complicated in structural expression and production and processing.

[0003] A survey on the current status of special-shaped parts processing in the domestic furniture manufacturing industry shows that most furniture companies currently still generally use semi-mechanized, semi-manual, or even purely manual processing, and the choice of machinery is mainly based on ordinary milling machines, which also leads to relatively low production efficiency. Although equipment such as CNC machining centers have significant advantages in processing efficiency, precision, and safety, they are subject to high equipment purchase and maintenance costs, coupled with the objective limitations of the technical literacy of practitioners. As a result, the traditional model of manual loading + milling machine processing still dominates the industry. Due to the complex and diverse geometric shapes of special-shaped parts, the actual production process also leads to problems such as frequent machine replacement, frequent tool changes, and repeated processing paths, which greatly increase production costs. Summary of the Invention

[0004] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid blurring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0005] Therefore, the purpose of the present invention is to provide a classification method for solid wood special-shaped parts based on a surface generation path, aiming to break the standardization production bottleneck caused by the diversity of special-shaped parts in furniture companies.

[0006] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0007] A method for classifying special-shaped solid wood parts based on a surface generation path, comprising the following steps:

[0008] S1. Obtaining attribute indicators of existing solid wood special-shaped parts, wherein the attribute indicators include size, structure, process, and application scenario;

[0009] S2. Cross-cut the special-shaped solid wood parts to determine their cross-sections;

[0010] S3. Classify and define the surfaces according to the paths of the cross-sections along the longitudinal direction, into extruded surfaces and swept surfaces, and match the part surfaces with the paths to obtain extruded parts and swept parts;

[0011] S4. Define and classify the surfaces according to the paths of the surfaces generated by rotating the cross section along the central axis, into rotational surfaces and spiral surfaces, and match the part surfaces with the paths to obtain rotational parts and spiral parts;

[0012] S5. If the cross section and longitudinal extension direction of the component are both complex curves, they are defined as free-form surfaces. The component surface is matched with them to obtain a free-form part.

[0013] S6. Match the required new special-shaped component surface with the above-classified surfaces to obtain corresponding extruded parts, swept parts, rotational parts, spiral parts and free-form parts.

[0014] As a preferred solution of the solid wood special-shaped parts classification method based on the surface generation path described in the present invention, in step S1, the attribute indicators of the solid wood special-shaped parts specifically include: length, width, height, shape characteristics, processing flow, and the type of furniture to which they belong and their application scenarios, to ensure subsequent classification judgment standards.

[0015] As a preferred solution of the method for classifying special-shaped solid wood parts based on a curved surface generation path described in the present invention, in step S2, the special-shaped parts are cross-cut to determine their cross-sections as follows: the longest direction of the part is defined as the longitudinal direction, and the part is cut vertically along the longitudinal direction to obtain its cross-section.

[0016] As a preferred embodiment of the method for classifying special-shaped solid wood parts based on a surface generation path described in the present invention, in step S3, the extruded surface is specifically defined as follows: a surface generated by extrapolating one or several curves in a cross section along a straight line in a certain direction is defined as an extruded surface, and parts with such a surface are classified as extruded parts. It is found that such parts are linear in the longitudinal direction and regular in the cross section. The expression of the extruded surface is as follows:

[0017] S(u,v)=C(u)+vd,v∈[0,1];

[0018] Among them, S(u,v) is the surface parameter equation, C(u) is the cross-sectional curve equation, and d is the straight line equation with a fixed direction.

[0019] As a preferred embodiment of the method for classifying special-shaped solid wood parts based on a surface generation path according to the present invention, in step S3, the swept surface is specifically defined as follows: a surface generated by rotating a cross-sectional curve along a central axis accompanied by translation or twisting is defined as a spiral surface, and parts having such a surface are classified as spiral parts. It is concluded that the outer contour of such parts is spiral, and the cross section is composed of a circle and a regular arc. The expression of the swept surface is as follows:

[0020] S(u,v)=r(v)+T(v)C(u);

[0021] Among them, S(u,v) is the surface parameter equation, r(u) is the path curve equation, T(v) represents the direction transformation equation as v changes, and C(u) is the equation of the cross-sectional curve in the local coordinate system.

[0022] As a preferred embodiment of the method for classifying special-shaped solid wood parts based on a surface generation path according to the present invention, in step S4, the rotational surface is specifically defined as follows: the surface generated by rotating the outer contour curve of the cross section along the central axis is defined as a rotational surface, and parts with such a surface are classified as rotational parts. It is concluded that such parts are composed of a combination of square, circular, polygonal, and spherical geometric bodies. The expression of the rotational surface is as follows:

[0023] S(u,θ)=(x(u)cosθ,x(u)sinθ,y(u)),θ∈[0,2π);

[0024] Among them, S(u,θ) is the parametric equation of the rotational surface, and r(u)=(x(u),y(u)) is the parametric equation of the cross-sectional outer contour curve in the plane.

[0025] As a preferred embodiment of the method for classifying special-shaped solid wood parts based on a surface generation path according to the present invention, in step S4, the spiral surface is specifically defined as follows: a surface generated by rotating a cross-sectional curve along a central axis accompanied by translation or twisting is defined as a spiral surface, and parts having such a surface are classified as spiral parts. It is concluded that the outer contour of such parts is spiral, and the cross section is composed of a circle and a regular arc. The expression of the spiral surface is as follows:

[0026] S(u,θ)=(r(θ)cosθ,r(θ)sinθ,h(θ));

[0027] Where S(u,θ) is the parametric equation of the spiral surface, θ is the rotation angle, and r(θ) and h(θ) represent the equations of how the radius and height change with θ.

[0028] As a preferred embodiment of the method for classifying special-shaped solid wood parts based on a surface generation path according to the present invention, in step S5, a free-form surface is specifically defined as follows: a surface that is complex in multiple directions and generated in different ways is defined as a free-form surface, and parts with such surfaces are classified as free-form parts. It is found that such parts have complex curves in both longitudinal and cross-sectional shapes, wherein the expression of the free-form surface is:

[0029]

[0030] Among them, P i,j is the control point grid ((m+1)*(n+1) points), B i,m (u) and B j,n (v) is the Bernstein basis function, which is specifically defined as:

[0031]

[0032] Or the expression for the free-form surface is:

[0033]

[0034] Among them, P i,j is the control point grid, w i,j The weight corresponding to each control point (w i,j >0), N i,p (u) and N j,q (u) is the non-uniform B-spline basis function, defined by the knot vector and degree.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. This invention rapidly classifies part surfaces by defining different surfaces, along with the cross-sectional profile and longitudinal displacement direction of the part, thereby significantly improving part classification efficiency. The diverse surface definitions ensure that this method can cover the vast majority of parts and respond quickly even to a large number of different parts.

[0037] 2. Directly compatible with CNC / 3D printing, surface mathematical models can be directly converted into G-code to drive CNC equipment (e.g., swept surfaces for CNC milling path planning), reducing manual intervention. Multiple solutions can be quickly generated by adjusting parameters (e.g., changing section curves in lofted surfaces), accelerating design verification cycles and enabling efficient iterative optimization.

[0038] 3. Parameter libraries can be built, standardizing parameters such as sweep paths and rotation axes to form reusable design modules and establish standardized model libraries. With cross-category versatility, the same classification method can be applied to different furniture types, eliminating the limitations of part application scenarios and types, offering high flexibility and a wide range of classifications.

[0039] 4. Surface geometry is clearly defined through mathematical equations, enabling precise description and adjustment of shapes, avoiding the errors often associated with empirical estimation in traditional classification. Complex morphologies can be supported, enabling the generation of complex topological structures such as minimal surfaces and hyperbolic paraboloids that are difficult to achieve with traditional processes. Mathematical models accurately calculate the surface area, precisely calculate material requirements, optimize processing plans, reduce solid wood waste, and provide a common language between designers and engineers, minimizing communication errors. Simulation analysis is supported, and surfaces based on mathematical models can be directly imported into finite element analysis software. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort. Among them:

[0041] Figure 1 This is a flow chart of a method for classifying special-shaped solid wood parts based on a curved surface generation path according to the present invention;

[0042] Figure 2 A schematic cross-sectional view of an extruded part provided by the present invention;

[0043] Figure 3 A schematic diagram of an extruded part provided by the present invention;

[0044] Figure 4 A schematic cross-sectional view of a swept-shaped part provided by the present invention;

[0045] Figure 5 A schematic diagram of a swept-shaped part provided by the present invention;

[0046] Figure 6 A schematic cross-sectional view of a rotary part provided by the present invention;

[0047] Figure 7 A schematic diagram of a rotary part provided by the present invention;

[0048] Figure 8 A schematic diagram of a spiral part provided by the present invention;

[0049] Figure 9 A schematic cross-sectional view of a free-form part provided by the present invention;

[0050] Figure 10 Schematic diagram of the free-form part provided by the present invention. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0052] The present invention provides a solid wood special-shaped parts classification method based on a curved surface generation path, aiming to solve the standardization production bottleneck caused by the diversity of special-shaped parts in furniture companies.

[0053] like Figure 1 As shown in the figure, the solid wood special-shaped parts classification method based on the surface generation path has the following steps:

[0054] S1. Obtain the attribute indicators of existing solid wood special-shaped parts, which include size, structure, process and application scenarios. More specifically, the attribute indicators of solid wood special-shaped parts include: length, width, height, shape characteristics, processing flow, and the type of furniture they belong to and their application scenarios, to ensure the subsequent classification judgment standards.

[0055] S2. Cross-cut the special-shaped solid wood parts to determine their cross-sections. More specifically, define the longest direction of the parts as the longitudinal direction, and cut the parts vertically along the longitudinal direction to obtain their cross-sections.

[0056] S3. Classify and define the surfaces according to the paths of the cross-sections along the longitudinal direction, into extruded surfaces and swept surfaces, and match the part surfaces with the paths to obtain extruded parts and swept parts;

[0057] The specific definition of the extruded surface is as follows: the surface generated by extrapolating one or several curves in the cross section along a straight line in a certain direction is defined as the extruded surface, such as Figure 2 As shown in , parts with such surfaces are classified as extruded parts, such as Figure 3 As shown, it is concluded that this type of part has a straight longitudinal shape and a regular cross-section. It is mostly used for straight handrails, long guardrails, skirtings, etc. The expression of the extruded surface is as follows:

[0058] S(u,v)=C(u)+vd,v∈[0,1];

[0059] Among them, S(u,v) is the surface parameter equation, C(u) is the cross-sectional curve equation, and d is the straight line equation with a fixed direction;

[0060] The specific definition of a swept surface is as follows: The surface generated by rotating the cross-section curve along the central axis while accompanied by translation or twisting is defined as a spiral surface, such as Figure 4As shown in , parts with such surfaces are divided into spiral parts, such as Figure 5 As shown, the outer contour of this type of part is spiral, and the cross section is composed of circles and regular arcs. It is mostly used for curved armrests, curved supports, curved backrests, etc. Among them, the expression of the swept surface is as follows:

[0061] S(u,v)=r(v)+T(v)C(u);

[0062] Among them, S(u,v) is the surface parameter equation, r(u) is the path curve equation, T(v) represents the direction transformation equation as v changes, and C(u) is the equation of the cross-sectional curve in the local coordinate system.

[0063] S4. Define and classify the surfaces according to the paths of the surfaces generated by rotating the cross section along the central axis, into rotational surfaces and spiral surfaces, and match the part surfaces with the paths to obtain rotational parts and spiral parts;

[0064] The specific definition of the rotational surface is as follows: the surface generated by rotating the outer contour curve of the cross section along the central axis is defined as the rotational surface, such as Figure 6 As shown in , parts with this type of surface are classified as rotational parts, such as Figure 7 As shown, it is concluded that this type of part is composed of several geometric bodies such as square, circle, polygon, and sphere. It is mostly used for turning furniture components, such as chair legs, table legs, and cylindrical components. Among them, the expression of the rotational surface is as follows:

[0065] S(u,θ)=(x(u)cosθ,x(u)sinθ,y(u)),θ∈[0,2π);

[0066] Where S(u,θ) is the parametric equation of the surface of revolution, r(u) = (x(u), y(u)) is the parametric equation of the cross-sectional outer contour curve in the plane;

[0067] The specific definition of spiral surface is as follows: The surface generated by rotating the cross-section curve along the central axis accompanied by translation or twisting is defined as a spiral surface. Parts with such surfaces are classified as spiral parts, such as Figure 8 As shown, the outer contour of this type of part is spiral, and the cross section is composed of circles and regular arcs. It is mostly used for torsion columns with carved patterns, spiral staircase columns, etc. The expression of the spiral surface is as follows:

[0068] S(u,θ)=(r(θ)cosθ,r(θ)sinθ,h(θ));

[0069] Where S(u,θ) is the parametric equation of the spiral surface, θ is the rotation angle, and r(θ) and h(θ) represent the equations of how the radius and height change with θ.

[0070] S5. If the cross section and longitudinal extension direction of the component are both complex curves, they are defined as free-form surfaces. The component surface is matched with them to obtain a free-form part.

[0071] The specific definition of free-form surface is as follows: a surface that is complex in multiple directions and generated in different ways is defined as a free-form surface, such as Figure 9 As shown in , parts with such surfaces are classified as free-form parts, such as Figure 10 As shown in the figure, it is concluded that this type of part has complex curves in both longitudinal and cross sections. It is mostly used for complex carvings, irregular curved backrests, and highly artistic curved furniture parts. The expression of the free-form surface is:

[0072]

[0073] Among them, P i,j is the control point grid ((m+1)*(n+1) points), B i,m (u) and B j,n (v) is the Bernstein basis function, which is specifically defined as:

[0074]

[0075] Or the expression for the free-form surface is:

[0076]

[0077] Among them, P i,j is the control point grid, w i,j The weight corresponding to each control point (w i,j >0), N i,p (u) and N j,q (u) is the non-uniform B-spline basis function, defined by the knot vector and degree.

[0078] S6. Match the required new special-shaped parts surface with the above-classified surfaces to obtain the corresponding extruded parts, swept parts, rotational parts, spiral parts and free-form parts.

[0079] Although the present invention has been described above with reference to embodiments, various modifications may be made thereto and equivalent components may be substituted without departing from the scope of the present invention. In particular, as long as there are no structural conflicts, the various features of the embodiments disclosed herein may be combined with each other in any manner, and the omission of an exhaustive description of such combinations in this specification is solely for the sake of space and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for classifying special-shaped solid wood parts based on a surface generation path, characterized in that: Here are the steps: S1. Obtaining attribute indicators of existing solid wood special-shaped parts, wherein the attribute indicators include size, structure, process, and application scenario; S2. Cross-cut the special-shaped solid wood parts to determine their cross-sections; S3. Classify and define the surfaces according to the paths of the cross-sections along the longitudinal direction, into extruded surfaces and swept surfaces, and match the part surfaces with the paths to obtain extruded parts and swept parts; S4. Define and classify the surfaces according to the paths of the surfaces generated by rotating the cross section along the central axis, into rotational surfaces and spiral surfaces, and match the part surfaces with the paths to obtain rotational parts and spiral parts; S5. If the cross section and longitudinal extension direction of the component are both complex curves, they are defined as free-form surfaces. The component surface is matched with them to obtain a free-form part. S6. Match the required new special-shaped component surface with the above-classified surfaces to obtain corresponding extruded parts, swept parts, rotational parts, spiral parts and free-form parts.

2. The method for classifying special-shaped solid wood parts based on curved surface generation path according to claim 1, characterized in that: In step S1, the attribute indicators of the solid wood special-shaped parts specifically include: length, width, height, shape characteristics, processing flow, and the type of furniture and its application scenario to ensure the subsequent classification judgment standards.

3. The method for classifying special-shaped solid wood parts based on curved surface generation path according to claim 1, characterized in that: In step S2, the special-shaped component is cross-cut to determine its cross section by defining the longest direction of the component as the longitudinal direction, and cutting the component vertically along the longitudinal direction to obtain its cross section.

4. The method for classifying special-shaped solid wood parts based on curved surface generation path according to claim 1, characterized in that: In step S3, the extruded surface is specifically defined as follows: a surface generated by extrapolating one or several curves in a cross section along a straight line in a certain direction is defined as an extruded surface. Parts with such a surface are classified as extruded parts. It is found that such parts are straight in the longitudinal direction and regular in the cross section. The expression of the extruded surface is as follows: S(u,v)=C(u)+vd,v∈[0,1]; Among them, S(u,v) is the surface parameter equation, C(u) is the cross-sectional curve equation, and d is the straight line equation with a fixed direction.

5. The method for classifying special-shaped solid wood parts based on curved surface generation path according to claim 1, characterized in that: In step S3, the swept surface is specifically defined as follows: a surface generated by rotating a cross-sectional curve along the central axis while accompanied by translation or twisting is defined as a spiral surface. Parts with such a surface are classified as spiral parts. It is concluded that the outer contour of such parts is spiral, and the cross-section consists of a circle and a regular arc. The expression of the swept surface is as follows: S(u,v)=r(v)+T(v)C(u); Among them, S(u,v) is the surface parameter equation, r(u) is the path curve equation, T(v) represents the direction transformation equation as v changes, and C(u) is the equation of the cross-sectional curve in the local coordinate system.

6. The method for classifying special-shaped solid wood parts based on curved surface generation path according to claim 1, characterized in that: In step S4, the specific definition of the rotational surface is as follows: the surface generated by rotating the outer contour curve of the cross section along the central axis is defined as a rotational surface. Parts with such a surface are classified as rotational parts. It is concluded that such parts are composed of a combination of squares, circles, polygons, and spheres. The expression of the rotational surface is as follows: S(u,θ)=(x(u)cosθ,x(u)sinθ,y(u)),θ∈[0,2π); Among them, S(u,θ) is the parametric equation of the rotational surface, and r(u)=(x(u),y(u)) is the parametric equation of the cross-sectional outer contour curve in the plane.

7. The method for classifying special-shaped solid wood parts based on curved surface generation path according to claim 1, characterized in that: In step S4, the spiral surface is specifically defined as follows: a surface generated by rotating a cross-sectional curve along the central axis accompanied by translation or twisting is defined as a spiral surface. Parts with such a surface are classified as spiral parts. It is concluded that the outer contour of such parts is spiral, and the cross-section consists of a circle and a regular arc. The expression of the spiral surface is as follows: S(u,θ)=(r(θ)cosθ,r(θ)sinθ,h(θ)); Where S(u,θ) is the parametric equation of the spiral surface, θ is the rotation angle, and r(θ) and h(θ) represent the equations of how the radius and height change with θ.

8. The method for classifying special-shaped solid wood parts based on curved surface generation path according to claim 1, characterized in that: In step S5, the free-form surface is specifically defined as follows: a surface that is complex in multiple directions and generated in different ways is defined as a free-form surface, and parts with such surfaces are classified as free-form parts. It is found that such parts have complex curves in both longitudinal and cross-sectional shapes. The expression of the free-form surface is: Among them, P i,j is the control point grid ((m+1)*(n+1) points), B i,m (u) and B j,n (v) is the Bernstein basis function, which is specifically defined as: Or the expression for the free-form surface is: Among them, P i,j is the control point grid, w i,j The weight corresponding to each control point (w i,j >0), N i,p (u) and N j,q (u) is the non-uniform B-spline basis function, defined by the knot vector and degree.

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