High-precision seamless mortise and tenon joint splicing method for purple light wingceltis furniture

Abstract

The invention discloses a high-precision seamless mortise and tenon joint splicing method for purple light wingceltis furniture, which belongs to the technical field of wood processing and comprises the following steps: S1, wood pretreatment and stabilization treatment; wood is screened; the wood is subjected to multi-stage thermal stabilization treatment; dewaxing treatment is carried out, surface floating wax is removed through pressurized steam, deep wax is reserved, and pores are sealed; performing low-temperature curing, naturally balancing until the water content of the wood is 6% + / -0.5%, and realizing the stability of a molecular structure; s2, seamless splicing is carried out through a dovetail tenon-row tenon-zongzi corner tenon composite structure; and S3, stress release is performed after splicing is completed. According to the high-precision seamless mortise and tenon joint splicing method for the purple-light sandalwood furniture, the problems that due to the characteristics of high density, high hardness, easy deformation and the like of the purple-light sandalwood, splicing gaps are obvious, and stability is insufficient are solved, and the seamless effect and durability of the purple-light sandalwood furniture are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of wood processing technology, and in particular to a high-precision seamless mortise and tenon splicing method for rosewood furniture. Background Technology

[0002] Traditional furniture made from Dalbergia melanoxylon (scientific name: East African blackwood) is characterized by its high hardness and air-dry density of 1.25-1.33 g / cm³. 3 With its extremely high hardness, sandalwood is prone to cracking and has a natural defect of being hollow ("nine out of ten sandalwood trees are hollow"), making it difficult to control the gaps in the joints. Traditional techniques require leaving expansion joints to accommodate wood shrinkage, but this affects the aesthetics. Seamless frame structures rely on wood stability treatments and precise mortise and tenon joint design. In current technologies, wood treatments mostly use conventional drying or waxing processes, but these have problems such as large fluctuations in moisture content (leading to significant thermal expansion and contraction) and insufficient precision in mortise and tenon joint fitting (seams often exceed 0.3mm), which easily expose the joints, affecting both aesthetics and stability. Summary of the Invention

[0003] The purpose of this invention is to provide a high-precision seamless mortise and tenon splicing method for purple sandalwood furniture, which aims to solve the problems of obvious splicing gaps and insufficient stability caused by the high density, high hardness and easy deformation of purple sandalwood, and significantly improve the seamless effect and durability of purple sandalwood furniture.

[0004] To achieve the above objectives, this invention provides a high-precision seamless mortise and tenon joint method for rosewood furniture, comprising the following steps: Step S1: Wood pretreatment and stabilization treatment; Step S101: Screening timber; Step S102: Perform multi-stage heat stabilization treatment on the wood; Step S103: Dewaxing treatment, using pressurized steam to remove surface wax while retaining deep wax to seal pores; Step S104: Low-temperature curing, naturally balancing the wood moisture content to 6% ± 0.5%, achieving molecular structure stability; Step S2: Seamless splicing is achieved through a composite structure of dovetail tenon, mortise and tenon, and corner tenon; Step S3: After splicing is completed, perform stress relief operation.

[0005] Preferably, step S101 specifically includes: Heartwood of *Pterocarpus santalinus* logs with a diameter ≥20cm was selected, and hollow pieces and sapwood were removed; the moisture content of the wood was controlled using a gradient drying method, specifically: The first stage (30℃) involves removing free water until the moisture content reaches 15%. The second stage (40℃) involves removing bound water to the target moisture content of 10-12%, and monitoring the process in real time using a moisture analyzer.

[0006] Preferably, the multi-stage thermal stabilization treatment in step S102 specifically includes the following sub-steps: Step S1021: Mix microcrystalline wax and beeswax in a 9:1 ratio and place the mixture in a wax boiling machine at a melting temperature of 80-85℃. Step S1022: Cut the wood according to the drawing. The size of the parts before cutting should be 0.4-0.6cm larger than the size of the drawing, so that the wax can penetrate into the wood faster after cutting. Step S1023: When the wax liquid temperature is 95℃, immerse the wood in the wax liquid in the wax boiling machine and keep it for 4-6 hours; Step S1024: Gradually raise the temperature to 120℃ by increasing it by 1℃ every two days, and maintain this temperature for two days; Step S1025: Gradually reduce the temperature to 100°C, then remove the wood and allow it to return to room temperature.

[0007] Preferably, the dovetail tenon-groove tenon-corner tenon composite structure in step S2 includes a double-shoulder dovetail tenon, a side grove tenon, and a 45° corner tenon. The double-shoulder dovetail tenon is placed on the back of the wooden panel, and the back of the wooden panel is provided with a dovetail mortise that matches the double-shoulder dovetail tenon. The gap between the tenon width of the double-shoulder dovetail tenon and the mortise of the dovetail mortise is ≤0.01mm.

[0008] Preferably, the side tenon is specifically arranged in parallel with a row of trapezoidal tenons along the wood panel and the wood joint surface. Multiple trapezoidal tenons are arranged at intervals to disperse shear stress. The side tenon is provided with a side mortise parallel to the outside of the side tenon, and a row of trapezoidal mortises is provided inside the side mortise. The trapezoidal tenons and trapezoidal mortises are matched.

[0009] Preferably, the two ends of the side tenon are provided with 45° tenons, and two adjacent 45° tenons interlock to form a 90° tenon-and-mortise connection, and are reinforced with wooden wedges to eliminate micro gaps at the corners.

[0010] Furthermore, stress release specifically involves placing the assembled finished product in a constant temperature and humidity room (temperature 25±2℃, humidity 50±5%) for 30 days to ensure that the splicing seams are seamless.

[0011] Therefore, the present invention adopts the above-mentioned high-precision seamless mortise and tenon splicing method for purple sandalwood furniture, and the technical effects are as follows.

[0012] Seamless visual effect: Through wax sealing and multi-stage stabilization treatment, combined with high-precision mortise and tenon design, the splicing seam is ≤0.01mm, achieving a seamless visual effect.

[0013] Improved mechanical properties: The tensile strength of the dovetail tenon is increased by 30%, and the torsional stiffness of the dovetail tenon is twice that of the traditional right-angle tenon.

[0014] Strong environmental adaptability: Moisture content can be precisely controlled to 6%, wood shrinkage rate ≤0.1%, adaptable to environmental changes from -10℃ to 40℃.

[0015] Synergistic processing technology: Combining wax boiling and sealing, multi-stage thermal stabilization, and mortise and tenon mechanical design, this systematically solves the processing problems of purple sandalwood.

[0016] Mortise and tenon composite structure: a combination design of dovetail tenon, row tenon and mortise and tenon, which takes into account both strength and seamless aesthetics.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating an embodiment of a high-precision seamless mortise and tenon joint method for purple sandalwood furniture according to the present invention; Figure 2 This is a schematic diagram of the dovetail tenon structure of an embodiment of the high-precision seamless mortise and tenon splicing method for purple sandalwood furniture of the present invention; Figure 3 This is a schematic diagram of the overall splicing of an embodiment of the high-precision seamless mortise and tenon splicing method for purple sandalwood furniture according to the present invention.

[0019] Figure Labels 1. Double-sloping dovetail tenon; 2. Wood panel; 3. Dovetail mortise; 4. Trapezoidal tenon; 5. Side mortise; 6. Trapezoidal mortise; 7. 45° corner tenon. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms "comprising" or "including," or similar terms as used in this invention, mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects.

[0022] Example 1: like Figure 1 As shown, this invention provides a high-precision seamless mortise and tenon joint method for purple sandalwood furniture, comprising the following steps: Step S1: Wood pretreatment and stabilization treatment; Step S101: Screening timber, the specific steps of which are as follows: Heartwood (deep purplish-brown with black streaks) of purple sandalwood logs with a diameter ≥20cm was selected, and hollow parts and sapwood were removed; the moisture content of the wood was controlled using a gradient drying method, specifically: The first stage (30℃) involves removing free water until the moisture content reaches 15%. The second stage (40℃) involves removing bound water to the target moisture content of 10-12%, and monitoring the process in real time using a moisture analyzer.

[0023] Step S102: The wood undergoes high-temperature waxing to seal the pores and multi-stage heat stabilization treatment; the specific multi-stage steps are as follows: The first stage involves mixing microcrystalline wax and beeswax in a 9:1 ratio and then placing the mixture in a wax boiling machine at a melting temperature of 80-85℃. The second stage involves cutting the wood according to the drawings. The dimensions of the parts before cutting are 0.4-0.6cm larger than the dimensions in the drawings, so that the wax can penetrate into the wood more quickly after cutting. The third stage involves immersing the wood in the wax solution at a temperature of 95°C for 4-6 hours. The fourth stage involves gradually raising the temperature to 120°C by increasing it by 1°C every two days, and maintaining this temperature for two days. The fifth stage involves gradually lowering the temperature to 100°C, and then removing the wood to allow it to return to room temperature.

[0024] Through the above five stages of operation, the wax penetrates to a depth of 1.5-2 cm inside the wood. This wax seals the wood's pores and micropores, blocking moisture exchange pathways and reducing moisture absorption. Simultaneously, the wood's moisture content is controlled below 6%, thus ensuring the overall structural stability of the wood.

[0025] Step S103: Dewaxing treatment, using pressurized steam (pressure 0.4Mpa, temperature 120℃) to remove surface wax while retaining deep wax to seal pores; Step S104: Low-temperature curing, naturally balancing the wood moisture content to 6% ± 0.5%, achieving molecular structure stability; Step S2: Seamless splicing is achieved through a composite structure of dovetail tenon, mortise and tenon, and corner tenon; The dovetail-tenon-corner joint composite structure includes a double-sloping dovetail tenon 1, side tenons, and a 45° corner tenon 7, such as... Figure 2 As shown. The double-shoulder dovetail tenon 1 is placed on the back of the wooden panel 2. The back of the wooden panel 2 is provided with a dovetail mortise 3 that matches the double-shoulder dovetail tenon 1. The tenon width of the double-shoulder dovetail tenon 1 and the mortise gap of the dovetail mortise 3 are ≤0.01mm. Precision milling with a special-shaped cutter ensures vertical strength. The spacing between each double-shoulder dovetail tenon 1 does not exceed 40cm, which reduces the overall area of ​​the finished wooden product, increases tensile strength, reduces the degree of thermal expansion and contraction, and makes the finished wooden product less prone to deformation.

[0026] The side tenon joints are specifically a row of trapezoidal tenons 4 arranged parallel to the wood panel 2 and the wood joint surface. Multiple trapezoidal tenons 4 are spaced apart to distribute shear stress, such as... Figure 3 As shown, a side tenon 5 is provided parallel to the outer side of the side tenon, and a row of trapezoidal mortises 6 is provided inside the side tenon 5. The trapezoidal tenon 4 matches the trapezoidal mortises 6, ensuring the connection stability between the side tenon and the side tenon 5.

[0027] The two ends of the side tenon 5 are provided with 45° tenon 7. The two adjacent 45° tenon 7 interlock to form a 90° tenon-and-mortise connection. With the help of wooden wedges for pressure and curing, the corner gaps are eliminated. Thus, the seamless splicing of the finished wood products is achieved through the above-mentioned tenon-and-mortise structure.

[0028] Step S3: After the splicing is completed, stress is released. Specifically, the spliced ​​finished product is placed in a constant temperature and humidity room (temperature 25±2℃, humidity 50±5%) for 30 days to ensure that there are no traces in the subsequent splicing seams.

[0029] The specific implementation method is as follows: Taking the production of seamless rosewood painting tables as an example: 1. Material pretreatment: Take a 2.3m long and 25cm diameter purple sandalwood log, cut it into sections without hollow cores, cut it into pieces according to the drawing dimensions +0.8cm, and then perform wax boiling and multi-stage heat stabilization treatment until the moisture content is 6%, with the moisture meter showing an error of ±0.5%.

[0030] 2. Mortise and tenon processing: The double-sloping dovetail tenon 1 is processed by CNC machine tool, and the side tenon is processed by digital machining center.

[0031] 3. Assembly and verification: Laser positioning instrument assists in splicing, mirror polishing is followed by wax curing, and gap detector confirms that the gap accuracy is ≤0.01mm.

[0032] Example 2: Seamless multi-layer bookshelf made of purple sandalwood (small to medium-sized shelf furniture).

[0033] 1. Material pretreatment: Take a 1.8m long and 22cm diameter purple sandalwood log, cut sections without hollow cores or sapwood, and cut them according to the drawing dimensions +0.5cm (layer board thickness 2.5cm); the wax boiling stage is adjusted to "microcrystalline wax: beeswax = 8.5:1.5, melting temperature 82℃, immersion in wax at 95℃ for 5 hours, and then heat to 115℃ and keep warm for 2 days". After dewaxing and low-temperature curing, the moisture content is controlled at 5.8%±0.3% (verified by a moisture meter).

[0034] 2. Mortise and tenon processing: The spacing of the double-sloping dovetail tenon 1 is shortened to 30cm (to match the span of the shelf), and it is processed by a high-speed CNC milling machine. The gap between the tenon and the mortise is ≤0.04mm; the side tenons are small trapezoidal tenons (section size 1.5cm×1cm) with a spacing of 15cm; the 45° corner tenon 7 is trimmed by a five-axis linkage machining center.

[0035] 3. Assembly and verification: The laser rangefinder is used to assist in the horizontal positioning of the panels. After splicing, the panels are pressurized and cured for 24 hours using a press (pressure 0.3Mpa). After mirror polishing, the panels are waxed again for curing. The gap detector is used to check that the splice seam accuracy is ≤0.01mm. The panels are placed in a constant temperature and humidity chamber (25℃, 50% humidity) for 25 days to release stress.

[0036] Example 3: Seamless Purple Sandalwood Round-back Chair (Curved Irregular Furniture).

[0037] 1. Material pretreatment: Take a piece of purple sandalwood log with a length of 1.5m and a diameter of 20cm, select the curved sections without cracks, and cut it according to the dimensions of the curved surface drawing + 0.6cm (seat surface curvature R45cm); the wax boiling stage adopts the "segmented waxing method": first, the straight part is waxed at 95℃ for 4 hours, and after the curved surface is formed, it is waxed at 90℃ for 3 hours. After multi-stage heat stabilization treatment, the moisture content is 6.0%±0.4%.

[0038] 2. Mortise and tenon processing: The double-sloping dovetail tenon 1 is adapted to the curvature of the curved surface and is processed by contour milling. The tenon gap is ≤0.01mm and the interval is 35cm. The side tenon is changed to an arc-shaped trapezoidal tenon to fit the curved surface. The 45° mortise and tenon 7 is used at the connection between the chair leg and the seat. After cross locking, natural wood glue (shellac resin) is injected for reinforcement.

[0039] 3. Assembly and verification: A 3D scanner is used to assist in the positioning of the curved surface tenon and mortise. After splicing, it is fixed with a special clamp for 12 hours. The surface is then finely polished by hand until the surface roughness Ra ≤ 0.1μm. A gap detector is used to confirm that all splicing seams are ≤ 0.01mm. The surface is then left to stand in a constant temperature and humidity room for 30 days, during which the moisture content is tested every 10 days (fluctuation ≤ 0.3%).

[0040] Example 4: Seamless large-size office desk made of purple sandalwood (extra-long and extra-wide furniture).

[0041] 1. Material pretreatment: Take a 3.0m long and 30cm diameter purple sandalwood log, cut two sections without hollow cores and splice them together for pretreatment (total length 3.2m), cut the log according to the drawing dimensions + 1.0cm (table width 1.2m); extend the waxing stage to "wax immersion at 95℃ for 6 hours, raise the temperature by 1℃ over two days to 125℃ and keep it warm for 3 days", increase the dewaxing pressure to 0.5Mpa, and after low-temperature curing, the moisture content is 5.5%±0.2%.

[0042] 2. Mortise and tenon processing: The double-shoulder dovetail tenon 1 adopts "double row arrangement" (two rows of tenons are arranged alternately), with a row spacing of 20cm, a single tenon spacing of 30cm, and a gap between the tenon and the mortise ≤0.01mm; the side row tenon cross section size is 2cm×1.5cm, with a spacing of 20cm; the 45° zongjiao tenon 7 is equipped with a metal reinforcing plate (hidden), and the wooden wedge is used for pressure curing with a pressure of 0.4Mpa.

[0043] 3. Assembly and verification: Double-assisted splicing with laser positioning instrument and level, the overall weight is evenly distributed after splicing and left to stand for 48 hours. After mirror polishing, it is cured with wax three times. The gap detector detects that the splicing seam of the whole surface is ≤0.01mm. It is left to stand in a constant temperature and humidity room (24℃, 52% humidity) for 45 days to release stress. During this period, there is no deformation or crack.

[0044] Comparative Example 1: Single mortise and tenon structure (without composite mortise and tenon).

[0045] Variables: Only double-sloping dovetail tenon 1 is used, the side tenon and 45° mortise and tenon 7 are removed, and other parameters are the same as in Example 1.

[0046] Results: The seam accuracy was 0.08-0.12mm. After being placed in a constant temperature and humidity environment for 6 months, a 0.3mm crack appeared at the corner, the tensile strength decreased by 40%, and thermal expansion and contraction caused the center of the tabletop to bulge by 2mm.

[0047] Comparative Example 2: Stabilization without wax boiling (gradient drying only).

[0048] Variables: Wood pretreatment only involves gradient drying (moisture content 10-12%), omitting the wax boiling, multi-stage heat stabilization and dewaxing steps, and other parameters are consistent with Example 1.

[0049] Results: The initial precision of the splicing seam was 0.05mm. After 3 months, the moisture content increased to 15%, the surface showed signs of dampness, the splicing seam widened to 0.2mm, the wood moisture absorption rate reached 12%, and the deformation of the tabletop edge was 1.5mm.

[0050] Comparative Example 3: Shorten the stress release time.

[0051] Variable: The settling time of the constant temperature and humidity chamber after splicing is shortened to 10 days, and other parameters are consistent with those in Example 1.

[0052] Results: The initial splice seam accuracy was 0.02mm. After one month, stress concentration occurred at the tenon and mortise joints, resulting in a 0.1mm micro-seam. The corner splice seam widened to 0.08mm, and the overall flatness deviation was 0.8mm.

[0053] Comparative Example 4: Enlarging the mortise and tenon tolerance.

[0054] Variables: The gap of the double-shoulder dovetail tenon 1 is adjusted to ≤0.1mm, the angle tolerance of the 45° dovetail tenon 7 is ±1.0°, and other parameters are consistent with those in Example 1.

[0055] Results: The splicing seam accuracy was 0.05-0.07mm. After assembly, there were obvious micro-seams (visible to the naked eye) at the corners. The shear stress decreased by 35%. After being placed in a constant temperature and humidity environment for 12 months, the deformation reached 3mm, and the tenon and mortise joints loosened.

[0056] Comparative Example 5: No dewaxing treatment.

[0057] Variables: The pressurized steam dewaxing step was omitted in the wood pretreatment, and the surface wax was retained. Other parameters were the same as in Example 1.

[0058] Results: The surface wax caused the mortise and tenon joint gap to increase (actual gap 0.08mm), the splice seam accuracy was 0.06mm, and after 6 months the surface wax aged and fell off, the surface pores appeared, the splice seam widened to 0.15mm, and the wood moisture absorption rate reached 8%.

[0059] Therefore, this invention employs the aforementioned high-precision seamless mortise and tenon joint method for purple sandalwood furniture. Through optimized material selection, wax-filled heat stabilization treatment, precise moisture content control, and a high-precision composite mortise and tenon joint design, the gap accuracy of purple sandalwood furniture is achieved to be ≤0.01mm, combining artistic aesthetics with structural stability. This method solves the problems of cracking and obvious gaps in traditional purple sandalwood furniture. It significantly improves the seamless effect and durability of furniture, and is suitable for the production of high-end rosewood furniture such as painting tables and cabinets.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-precision seamless mortise and tenon joint method for purple sandalwood furniture, characterized in that, Includes the following steps: Step S1: Wood pretreatment and stabilization treatment; Step S101: Screening timber; Step S102: Perform multi-stage heat stabilization treatment on the wood; Step S103: Dewaxing treatment, using pressurized steam to remove surface wax while retaining deep wax to seal pores; Step S104: Low-temperature curing, naturally balancing the wood moisture content to 6% ± 0.5%; Step S2: Seamless splicing is achieved through a composite structure of dovetail tenon, mortise and tenon, and corner tenon; Step S3: After splicing is completed, stress is released.

2. The high-precision seamless mortise and tenon joint method for purple sandalwood furniture according to claim 1, characterized in that, Step S101 is as follows: Heartwood of *Pterocarpus santalinus* logs with a diameter ≥20cm was selected, and hollow pieces and sapwood were removed; the moisture content of the wood was controlled using a gradient drying method, specifically: The first stage is at 30℃, removing free water to a moisture content of 15%; The second stage involves removing bound water at 40℃ to the target moisture content of 10-12%, and monitoring the process in real time using a moisture analyzer.

3. The high-precision seamless mortise and tenon joint method for purple sandalwood furniture according to claim 1, characterized in that, The multi-stage thermal stabilization process in step S102 specifically includes the following sub-steps: Step S1021: Mix microcrystalline wax and beeswax in a 9:1 ratio and place the mixture in a wax boiling machine at a melting temperature of 80-85℃. Step S1022: Cut the wood according to the drawing. The size of the parts before cutting should be 0.4-0.6cm larger than the size of the drawing, so that the wax can penetrate into the wood faster after cutting. Step S1023: When the wax liquid temperature is 95℃, immerse the wood in the wax liquid in the wax boiling machine and keep it for 4-6 hours; Step S1024: Gradually raise the temperature to 120℃ by increasing it by 1℃ every two days, and maintain this temperature for two days; Step S1025: Gradually reduce the temperature to 100°C, then remove the wood and allow it to cool to room temperature.

4. The high-precision seamless mortise and tenon joint method for purple sandalwood furniture according to claim 1, characterized in that, The dovetail tenon-groove tenon-corner tenon composite structure in step S2 includes a double-shoulder dovetail tenon, a side groove tenon, and a 45° corner tenon. The double-shoulder dovetail tenon is placed on the back of the wooden panel. The back of the wooden panel is provided with a dovetail mortise that matches the double-shoulder dovetail tenon. The gap between the tenon width of the double-shoulder dovetail tenon and the mortise of the dovetail mortise is ≤0.01mm.

5. The high-precision seamless mortise and tenon joint method for purple sandalwood furniture according to claim 4, characterized in that, The side tenon is specifically arranged as a row of trapezoidal tenons parallel to the wood panel and the wood joint surface. The side tenon is provided with a side mortise parallel to the outside of the side tenon, and a row of trapezoidal mortises is provided inside the side mortise. The trapezoidal tenons and trapezoidal mortises are matched.

6. The high-precision seamless mortise and tenon joint method for purple sandalwood furniture according to claim 5, characterized in that, The two ends of the side tenon are provided with 45° tenons, and two adjacent 45° tenons interlock to form a 90° tenon-and-mortise connection.

Images