Welding method of injection molding machine rack

Abstract

The invention relates to a welding method for a rack of an injection molding machine, which comprises the following steps: S1, an upper frame, a lower frame and a stand column of the rack are assembled, the upper frame and the lower frame are arranged at an interval up and down and extend along the transverse direction, the stand column is arranged between the upper frame and the lower frame along the vertical direction, a top plate is arranged on the upper frame, and a bottom plate is arranged on the lower frame; s2, at least one square timber is longitudinally cushioned at the bottom of the lower truss, and the square timber is used for resisting pre-deformation of the rack; s3, welding an adjusting sizing block on the top surface of the upper truss; s4, the stand columns are welded to the upper truss and the lower truss correspondingly; s5, the lower trusses, the upper trusses and the bottom areas of the lower trusses are welded; and S6, the remaining part of the rack is welded till a finished product is obtained. The welding sequence of the injection molding machine rack is adjusted, overall deformation caused by stress concentration can be avoided in the mode that the frame is welded firstly and then the connecting parts are welded, and meanwhile the torsion resistance of the rack is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of injection molding equipment, and particularly relates to a welding method for an injection molding machine frame. Background Art

[0002] With the continuous development of the plastic processing industry, plastic products are widely used in industrial production. At the same time, injection molding machines are also used more and more widely. An injection molding machine includes an injection component, a mold clamping component, a hydraulic component, etc. The injection molding machine frame is mainly used to support the core structural components of the entire injection molding machine, and is usually made of high-strength steel plates by welding or cast iron casting. However, during the welding process, the surface of the frame is prone to deformation, which will affect the performance of the entire injection molding machine and the product quality.

[0003] For example, a Chinese utility model patent "An Injection Molding Machine Frame" with a patent number of ZL201020033110.5 (publication number CN201664983U) discloses such a frame, which includes an oil pan, a bolster plate, a panel and columns. The bolster plates are welded on both sides of the frame, and the welded parts are located at the bottom of the panel. The panel is prepared by secondary bending of a whole plate, which reduces the processing and preparation of materials. Only one kind of plate is needed to be folded into different shapes required by the size. There are no weld points on the surface of the panel, and it is not easy to deform. However, although this method avoids welding deformation, the bent panel lacks local strengthening of weld points, and the overall torsional resistance is poor. Under the high-frequency vibration or impact load of the injection molding machine, it will still deform.

[0004] Therefore, it is necessary to further improve the welding method of the injection molding machine frame. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a welding method for an injection molding machine frame that can prevent deformation and has high torsional resistance in view of the above-mentioned prior art status.

[0006] The technical solution adopted by the present invention to solve the above technical problems is as follows: The welding method for the injection molding machine frame is characterized by including the following steps:

[0007] S1. Assemble the upper beam, lower beam and columns of the frame. The upper beam and the lower beam are arranged at intervals up and down and extend horizontally. The columns are arranged vertically between the upper beam and the lower beam. A top plate is provided on the upper beam, and a bottom plate is provided on the lower beam;

[0008] S2. Longitudinally pad at least one square wooden block at the bottom of the lower beam. The square wooden block is used to resist the pre-deformation of the frame;

[0009] S3. Weld adjusting shims on the top surface of the upper beam;

[0010] S4. Weld the columns to the upper beam and the lower beam respectively;

[0011] S5. Weld between each of the lower frames, between the upper frames, and the bottom area of the lower frames;

[0012] S6. Weld the remaining part of the frame until it becomes a finished product.

[0013] To ensure the structural accuracy, preferably, in step S1, spot welding is used to basically fix the upper frame, the lower frame, and the columns. Among them, before formally welding the frame, each component of the frame needs to be pre-assembled, and spot welding is performed at non-critical positions. On the one hand, it can preliminarily position and fix the frame, and on the other hand, it can reserve an adjustment space for subsequent welding.

[0014] To pre-compensate for the welding deformation amount, preferably, the square timber in step S2 is vertically arranged with respect to the lower frame, and the thickness t1 of the square timber ranges from 80 to 120 mm. Among them, the lower frame of the frame will undergo welding deformation after welding. By setting the square timber, it can play a supporting role for the whole frame, thereby reducing the deformation amount. When the thickness t1 of the square timber is less than 80 mm, the supporting force is insufficient; when the thickness of the square timber is greater than 120 mm, it will cause pre-deformation of the lower frame, and secondary correction is required later.

[0015] To achieve static leveling, preferably, at least seven adjusting shims in step S3 are provided, and each of the adjusting shims is welded at intervals on the top end of the upper frame. Among them, the number of shims needs to be determined according to the weight, stiffness, and load distribution of the frame. There is an uneven situation on the upper surface of the upper frame. By setting multiple shims with different thicknesses, the frame can reach a horizontal state during installation.

[0016] To achieve precise leveling, preferably, the thickness t2 of each of the adjusting shims ranges from 30 to 35 mm. Among them, when the thickness of the adjusting shim is less than 30 mm, the adjusting shim is too thin, resulting in insufficient adjustment margin, making it difficult to compensate for the uneven foundation or the manufacturing tolerance of the frame, resulting in local suspension and uneven load distribution; when the thickness of the adjusting shim is greater than 35 mm, it may cause micro-deformation during high-pressure mold clamping or injection, resulting in deviation of the template parallelism and affecting the product precision.

[0017] In order to reduce the residual stress of welding, preferably, the columns in step S4 are welded to the upper and lower frames by multi-layer and multi-pass welding. The welding sequence is to weld the inner welds first and then the outer welds, and the interpass temperature is controlled between 80°C and 120°C. Among them, the columns of the injection molding machine belong to high-load welded parts. The multi-layer and multi-pass welding method can avoid local severe shrinkage caused by concentrated high temperature, thus preventing the frame from bending deformation. In addition, when the interpass temperature is greater than 120°C, the fluidity of the molten pool is too strong, which is likely to cause undercut or weld bead; when the interpass temperature is less than 80°C, the weld cools too quickly, increasing the hardening tendency.

[0018] For the convenience of operation, preferably, in step S5, the whole frame needs to be turned 180°, and the bottom plate at the bottom of the lower frame is welded. Then, the first longitudinal beam between adjacent upper frames and the second longitudinal beam between adjacent lower frames are welded. Among them, the width of the bottom plate of the frame is the same as that of the top plate. Turning the whole frame can facilitate the welding operation of the operators. The multi-layer and multi-pass welding method is adopted between the bottom plate and the lower frame. After the operation is completed, the first longitudinal beam and the second longitudinal beam are welded. The first longitudinal beam and the second longitudinal beam are made of solid square steel, which is mainly used to improve the overall rigidity of the frame.

[0019] In order to improve the rigidity of the frame, preferably, each part of the frame is inspected in turn, and the welding defects and each corner are welded. Among them, welding the corner can change the force transmission from linear to area diffusion, avoiding stress concentration, thus significantly improving the frame's ability to resist torsional deformation.

[0020] Compared with the prior art, the advantages of the present invention are as follows: By adjusting the welding sequence of the injection molding machine frame, after pre-assembling the frame, square timbers are set at the bottom surface of the lower frame to resist welding deformation. Then, shims for leveling and correction are welded on the top surface of the upper frame. Subsequently, the areas between the columns, the bottom plate, and between the lower and upper frames are welded in turn. Finally, the corners of the frame are welded. The method of welding the frame first and then the connecting parts can avoid overall deformation caused by stress concentration and improve the torsional resistance of the frame at the same time. The method is simple and easy to implement, and the cost increase is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a three-dimensional structural schematic diagram of an embodiment of the present invention;

[0022] Figure 2 is a front view of an embodiment of the present invention;

[0023] Figure 3 is an exploded structural schematic diagram of an embodiment of the present invention;

[0024] Figure 4 is a top view of an embodiment of the present invention.

[0025] In the figure: 1. upper frame; 2. lower frame; 3. column; 4. top plate; 5. bottom plate; 6. square timber; 7. adjusting shim; 8. first longitudinal beam; 9. second longitudinal beam. Specific implementation mode

[0026] The present invention will be further described in detail below in conjunction with the embodiments with reference to the drawings.

[0027] As Figures 1 to 4 shown, it is a preferred embodiment of the present invention. The welding method of the injection molding machine frame includes the following steps:

[0028] S1. Assemble the upper frame 1, lower frame 2 and column 3 of the frame. The upper frame 1 and the lower frame 2 are arranged at intervals up and down and extend horizontally. The column 3 is arranged vertically between the upper frame 1 and the lower frame 2. A top plate 4 is arranged on the upper frame 1, and a bottom plate 5 is arranged on the lower frame 2;

[0029] S2. At least one square timber 6 is longitudinally padded at the bottom of the lower frame 2. The square timber is used to resist the pre-deformation of the frame;

[0030] S3. Weld the adjusting shim 7 on the top surface of the upper frame 1;

[0031] S4. Weld the column 3 to the upper frame 1 and the lower frame 2 respectively;

[0032] S5. Weld between each lower frame 2, between the upper frames 1 and the bottom area of the lower frame 2;

[0033] S6. Weld the remaining part of the frame until it becomes a finished product.

[0034] In order to ensure the structural accuracy, referring to Figure 1 , before the frame is formally welded, it is necessary to pre-assemble each component of the frame and carry out spot welding at non-critical positions. On the one hand, it can carry out preliminary positioning and fixing of the frame, and on the other hand, it can reserve adjustment space for subsequent welding.

[0035] Referring to Figure 2 , the square timber 6 in step S2 is vertically arranged with the lower frame 2. The thickness t1 of the square timber 6 ranges from 80 to 120 mm. After the frame is welded, the lower frame 2 will undergo welding deformation. By setting the square timber 6, it can play a supporting role for the whole frame, thereby reducing the deformation amount. When the thickness t1 of the square timber 6 is less than 80 mm, the supporting force is insufficient; when the thickness of the square timber 6 is greater than 120 mm, it will cause pre-deformation of the lower frame 2, and secondary correction is required later. In this embodiment, the preferred thickness of the square timber 6 is 100 mm. At this time, the thickness of the square timber 6 can meet the requirements of both the supporting force and the anti-deformation at the same time.

[0036] Referring to Figures 1 to 4, according to the weight, stiffness and load distribution of the frame in this embodiment, seven adjusting shims 7 are welded at intervals on the top surface of the upper beam 1. Since the upper surface of the upper beam 1 is uneven, by setting a plurality of adjusting shims 7 with different thicknesses, the frame can reach a horizontal state during installation. When the thickness of the adjusting shim 7 is less than 30 mm, the adjusting shim 7 is too thin at this time, resulting in insufficient adjustment margin, making it difficult to compensate for the unevenness of the foundation or the manufacturing tolerance of the frame, resulting in local suspension and uneven load distribution; when the thickness of the adjusting shim 7 is greater than 35 mm, it may cause micro-deformation during high-pressure clamping or injection, resulting in deviation of the template parallelism and affecting the product accuracy. Therefore, the thickness of the adjusting shim 7 in this embodiment is preferably 33 mm.

[0037] In step S4, the columns 3 are welded to the upper beam 1 and the lower beam 2 by means of multi-layer and multi-pass welding. The welding sequence is to weld the inner welds first and then the outer welds. The interlayer temperature is controlled at 80°C to 120°C. Since the columns 3 of the injection molding machine are high-load welded parts, the multi-layer and multi-pass welding method can avoid local severe shrinkage caused by high-temperature concentration, thereby causing the frame to bend and deform. In addition, the interlayer temperature in this embodiment is controlled at 100°C, which can not only avoid excessive interlayer temperature resulting in too strong fluidity of the molten pool, causing undercut or weld bead; but also avoid too small interlayer temperature resulting in too fast cooling of the weld, increasing the hardening tendency.

[0038] In step S5, the whole frame needs to be turned over by 180°. At this time, the bottom surface of the frame faces up, which is convenient for the operator to perform welding operations. Then, the bottom plate 5 at the bottom of the lower beam 2 is welded. The width of the bottom plate 5 is the same as that of the top plate 4. The bottom plate 5 and the lower beam 2 are welded by means of multi-layer and multi-pass welding. After the operation is completed, the first longitudinal beam 8 and the second longitudinal beam 9 are welded. The first longitudinal beam 8 and the second longitudinal beam 9 are made of solid square steel, which is mainly used to improve the overall rigidity of the frame. Subsequently, the whole frame is inspected, and the welded joints with missing welds and each corner are welded. Welding the corners can convert the force transmission from linear to area diffusion, avoid stress concentration, and thus significantly improve the frame's ability to resist torsional deformation.

Claims

1. A welding method for an injection molding machine frame, characterized in that: It includes the following steps: S1. Assemble the upper beam (1), lower beam (2) and columns (3) of the rack. The upper beam (1) and the lower beam (2) are arranged at intervals up and down and extend horizontally. The columns (3) are arranged vertically between the upper beam (1) and the lower beam (2). A top plate (4) is arranged on the upper beam (1), and a bottom plate (5) is arranged on the lower beam (2). S2. At least one square timber (6) is longitudinally laid at the bottom of the lower beam (2), and the square timber (6) is used to resist the pre-deformation of the rack. S3. Weld adjusting shims (7) on the top surface of the upper beam (1). S4. Weld the columns (3) to the upper beam (1) and the lower beam (2) respectively. S5. Weld between each of the lower beams (2), between the upper beams (1), and the bottom area of the lower beams (2). S6. Weld the remaining parts of the rack until it becomes a finished product.

2. The welding method of the injection molding machine frame according to claim 1, characterized in that: In step S1, spot welding is used to basically fix the upper beam (1), lower beam (2) and columns (3).

3. The welding method of the injection molding machine frame according to claim 1, characterized in that: The square timber (6) in step S2 is arranged perpendicular to the lower beam (2), and the thickness t1 of the square timber (6) ranges from 80 to 120 mm.

4. The welding method of the injection molding machine frame according to claim 1, characterized in that: At least seven adjusting shims (7) are provided in step S3, and each of the adjusting shims (7) is welded to the top surface of the upper beam (1) at intervals.

5. The welding method of the injection molding machine frame according to claim 4, characterized in that: The thickness t2 of each of the adjusting shims (7) ranges from 30 to 35 mm.

6. The welding method of the injection molding machine frame according to claim 1, characterized in that: In step S4, the columns (3) are welded to the upper beam (1) and the lower beam (2) by multi-layer and multi-pass welding. The welding sequence is to weld the inner welds first and then the outer welds, and the interlayer temperature is controlled below 120°C.

7. The welding method of the injection molding machine frame according to claim 1, characterized in that: In step S5, the whole rack needs to be turned over by 180°, and the bottom plate (5), square tubes and channel steels at the bottom of the lower beam (2) are welded, and then the first longitudinal beams (8) between the adjacent upper beams (1) and the second longitudinal beams (9) between the lower beams (2) are welded.

8. The welding method of the injection molding machine frame according to claim 1, characterized in that: Check each part of the rack in turn, and weld the places with missed welding and each corner.

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