Ultra-long thin-wall truss type guide rail machining process

Abstract

The invention discloses an ultra-long thin-wall truss type guide rail machining technology, and belongs to the technical field of guide rail machining. The ultra-long thin-wall truss type guide rail machining technology comprises the following operation steps that S1, a welding positioning tool is designed; s2, the welding process is simplified; s3, the welding stress is released, and post-welding deformation is controlled; s4, machining deformation control measures are taken; s5, the rough and uneven rough reference is replaced by the fine reference plane; s6, reasonably selecting a cutter; s7, cutting amount selection; according to the machining technology for the ultra-long thin-wall truss type guide rail, the technology for controlling welding and machining deformation of the guide rail is developed, and the deformation amount is controlled according to the principle that thermal deformation is controlled by reasonably releasing thermal stress through positioning and clamping; according to the clamping and aligning device, a lacing wire capable of improving manufacturability is used as a supporting force bearing point, aligning and clamping are facilitated, meanwhile, deformation of a workpiece after loosening due to clamping extrusion force is avoided, and the problems that an original technology is large in deformation amount, low in production efficiency, large in wall thickness difference, poor in quality and low in percent of pass are solved.

Description

Technical Field

[0001] The invention specifically relates to a processing technology for an ultra-long thin-wall truss type guide rail, and belongs to the technical field of guide rail processing. Background Art

[0002] Extra-long thin-walled guide rails in large truss types are characterized by light weight, material saving and compact structure, which are widely used in weight-reducing equipment components. However, large truss thin-walled parts have poor rigidity and strength, and are easily deformed during welding and processing. Thin-walled guide rails with a length of 8 meters weigh less than 360kg and lack mature processing technology.

[0003] After large truss-type structural parts are welded and formed, they will encounter welding problems such as spatial irregular deformation due to thermal stress and processing deformation caused by cutting stress during the processing. As a result, there are problems with the quality reliability, processing operability, large wall thickness difference, and low production efficiency of such welding parts. As a result, the welding and machining quality of the guide rails are poor, and the welding and machining deformation cannot meet the technical requirements, resulting in a poor overall product qualification rate.

[0004] Guide rails generally require mobility and lightness, which will be accompanied by poor rigidity, poor structural processability, low manufacturing efficiency, high cost, and corresponding increase in process technology difficulty. Such parts have large long diameter, thin wall, high precision, and high requirements for welding and machining processes. In particular, the raceway surface with extremely poor rigidity is prone to deformation. The traditional process methods are welding, correction, tempering, correction, machining, correction, etc. However, guide rails with a long diameter of 8 meters face the problems of difficult correction, low operability, heavy workload and low efficiency.

[0005] For example, an ultra-long thin-walled guide rail has a long diameter of 8528mm, a large amount of welding, and many welding points. After welding, a 120° V-groove and a 17±0.5mm T-groove with a length of 8410mm are processed to ensure that the edge between the V-groove and the T-groove is 4±0.3mm;

[0006] Among them: welding is difficult, and the two plates with a size of 85x22x8410mm used for processing the V-groove and T-groove raceway surface after welding have a large long diameter and are difficult to position;

[0007] Large deformation: After welding, the workpiece is bent into a wave shape, with a single-side deformation of 16mm. It is difficult to correct the workpiece and cannot meet the design requirements;

[0008] Large wall thickness difference: The theoretical wall thickness of the T-slot after processing is 4.5mm. The wall thickness of the parts that can be processed by calibration marking is mostly 2mm, and the wall thickness of some areas is 1mm. The wall thickness difference is 7-8mm, and the deformation cannot be controlled;

[0009] Difficulty in clamping and alignment, difficult clamping of part shapes, poor processing rigidity: no good support surface, clamping point and alignment surface for clamping;

[0010] Large cutting amount: In order to control deformation, the machining allowance meets the requirements of borrowing machining. The single plate uses 22mm thick steel plate and the cutting amount is 17.5mm;

[0011] Serious vibration during processing: Serious vibration during length and shape processing, uncontrolled deformation during processing, 2mm deformation after processing, need to be corrected again;

[0012] The correction work is difficult: there are no good process measures to ensure deformation, and correction is required before and after tempering and machining; the milling method is traditional and the processing efficiency is low.

[0013] Therefore, it is necessary to propose an ultra-long thin-walled truss guide rail processing technology to solve the above problems. Summary of the invention

[0014] The purpose of the present invention is to provide an ultra-long thin-walled truss guide rail processing technology to address the deficiencies of the prior art, so as to solve the problems of large deformation, low production efficiency, large wall thickness difference, poor quality and low pass rate in the original process.

[0015] A super-long thin-wall truss guide rail processing process includes the following steps:

[0016] S1: Design welding positioning tooling: fix the two base plates, then perform welding, fix the two plates on the welding tooling, the tooling controls the position of the two plates, lock the two sides with bolts, weld other parts on the tooling and the two plates, the tooling controls welding deformation and reasonably releases thermal stress;

[0017] S2: Simplify the welding process: reduce the thermal stress on the two plates, weld the frame separately, and finally weld the frame to the two fixed plates. During tempering, the tooling needs to temper the product together;

[0018] S3: Release welding stress and control post-weld deformation: temper with tooling after welding;

[0019] S4: Machining deformation control measures: During the machining process, it is necessary to consider the deformation of the guide rail, the irregularity of the guide rail, and the difficulty of clamping and alignment due to the shape, and make corresponding optimizations. The optimization measures include:

[0020] Pre-welding reduction: On the basis of certain control of welding deformation, the processing allowance is reduced. When processing the V-shaped groove and the inner raceway surface of the two plates with a size of 85x22x8410mm, the bevel and straight groove are planed out in a single piece, and the processing allowance is 4mm;

[0021] Solid line simulation detection, detection of guide rail straightness: theoretically, after the long thin-walled guide rail is processed, only 4.5mm is left on one side of the inner cavity wall. Check the straightness of the guide rail in advance, and use borrowed processing to prevent the inner wall from being milled through due to the deformation of welding deformation in subsequent processing. Use iron blocks to tighten and straighten the two ends of the straight line to check the straightness of the long guide rail. If the deformation on both sides is large and the processing allowance is insufficient, rework correction or borrowed processing is performed;

[0022] Use tie bars to simplify clamping: weld tie bars on the bottom of the two plates before processing, spot weld tie bars at the parts with poor rigidity of the workpiece, add process bumps to enable the pressure plate to clamp the action point, control the deformation of the V-groove and the inner raceway surface caused by cutting stress during processing, and weld process tie bars on both sides of the track to solve the clamping problem;

[0023] Combination of multiple clamping methods such as pressing, pushing and clamping can reduce workpiece deformation: the use of precision machining reference surface, clamping of pressure plate and side pushing can avoid the problem of using the blank surface as the reference surface, unstable clamping and poor processing rigidity. At the same time, after adding process bumps through spot welding, the clamping rigidity is ensured and the position of the workpiece is prevented from changing. The pressing point of the pressure plate is consistent with the direction of the pressing force, the force point is lower than the pressing point, and the clamping force for rough machining is large to ensure sufficient cutting force.

[0024] S5: The precision datum plane replaces the uneven rough datum: reduce the compression deformation, increase the contact area between the bottom surface of the workpiece and the worktable, improve the processing stability, first mill the process clamping datum surface, increase the contact area between the bottom surface of the workpiece and the worktable;

[0025] S6: Reasonable selection of tools and cutting parameters: Reasonable selection of tool materials, parameters and cutting parameters, tool selection, parameter selection, low helix angle is suitable for milling grooves, cutting torque is not large, axial tension is not large, if a milling cutter with a large helix angle is selected, the blade is more likely to break, the axial tension is large, the residual material is subject to a large cutting compound force and the vibration amplitude increases, so the tool life is short, the first knife cuts into the layer, consider cutting from the top of the T-slot, and use the depth direction offset tool compensation method to facilitate the discharge of iron chips, and at the same time, the support of the residual material is the basis for cutting;

[0026] S7: Cutting amount selection: Use reasonable processing amount to ensure processing accuracy. In rough processing: the cutting amount can be appropriately increased under the conditions allowed by the machine tool. At the same time, the vibration phenomenon in the processing process can be used to release the vibration stress of the workpiece. In fine processing: use faster cutting speed, smaller feed rate, and lower cutting speed to ensure processing accuracy and surface quality;

[0027] S8: Reasonable selection of processing equipment and optimal processing and cutting methods: When processing, you need to use a CNC gantry milling machine with good rigidity and sufficient power. You need to increase the rigidity of the tool and workpiece, increase the cross-sectional area of ​​the tool bar, and pay attention to the tool direction and cutting sequence to avoid the impact and effect on subsequent cutting processing after processing has caused greater damage to the rigidity of the parts.

[0028] Preferably, in step S4, when borrowing tie rods to simplify clamping, the workbench only needs to install support studs, the studs support the process tie rods, align the lines and parts, and use pressure plates to press the process tie rods. When processing in large quantities, it only needs to align and press according to the alignment lines.

[0029] Preferably, in step S4, when a combination of multiple clamping methods such as pressing, pushing and clamping is used, when the clamping force is small during fine machining, it is necessary to reduce the deformation of the workpiece due to external force, and the process reinforcement is subjected to force to control the machining deformation. The process reinforcement needs to be spot welded to avoid welding thermal stress deformation, and the process reinforcement is used to bear force during clamping and machining to avoid deformation during machining.

[0030] Preferably, in step S6, the workpiece material is a Q235 welding structural part, and an indexable slot milling cutter with good performance is selected, and the blade is YBG302.

[0031] Preferably, in step S7, when processing the guide rail body, a lubricating emulsion mainly for cooling is selected, and sufficient flow is ensured to reduce deformation caused by cutting heat.

[0032] Technical effects and advantages of the present invention:

[0033] (1) This process is to develop a process technology for controlling the welding and machining deformation of the guide rail. It uses the principle of reasonably releasing thermal stress through positioning and clamping to control the deformation. The clamping and alignment uses the tie rods that improve the processability as the support force points to facilitate alignment and clamping. At the same time, it avoids the deformation of the workpiece after release due to the clamping extrusion pressure, thus solving the problems of large deformation, low production efficiency, large wall thickness difference, poor quality and low qualified rate in the original process.

[0034] (2) The ultra-long thin-walled truss rail processing technology develops the process technology for controlling rail welding and machining deformation, forming a set of mature welding forming technology for large truss-type welded structural parts and a mechanical processing process system for trusses and rails with a large aspect ratio, which can greatly improve the consistency of the rail wall thickness difference and increase production efficiency by 3 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the process flow of the present invention;

[0036] Figure 2 Schematic diagram of the process of machining deformation control measures of the present invention

[0037] Figure 3 It is a schematic diagram of the welding process optimization idea of ​​the present invention;

[0038] Figure 4 Schematic diagram of the machining process optimization idea of ​​the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] See also Figure 1-Figure 4 As shown, a processing technology for an ultra-long thin-walled truss guide rail includes S1: designing a welding positioning tool: fixing two base plates and then welding them, fixing the two plates on the welding tool, the tool controls the positions of the two plates, locking the two sides with bolts, welding other parts to the tool and the two plates, and controlling welding deformation and reasonably releasing thermal stress.

[0041] S2: Simplify the welding process: reduce the thermal stress on the two plates, weld the frame separately, and finally weld the frame to the two fixed plates. During tempering, the tooling is required to temper the product together. After the tooling is used and the process flow is optimized, the deformation of the finished product is controlled within 2mm, which is 9 times smaller than the previous deformation of 16mm. The operating difficulty is also reduced and the efficiency is increased by 1 times. However, after tempering, it was found that the deformation had reached 4.5mm when it was transferred to the machining link. The only way is to strengthen the role of the welding tooling and temper the product together with the tooling.

[0042] S3: Release welding stress and control post-weld deformation: After welding, the tooling is tempered to release thermal stress and control deformation. The deformation of the finished parts is controlled within 1.5mm, which is more than 9 times smaller than before. The qualified rate of welded finished parts is 100% in one-time inspection, which is more than 2 times higher. After these three measures, the deformation of the welding process is controlled, the quality is guaranteed, and the operation intensity is also reduced.

[0043] S4: Machining deformation control measures: During the machining process, it is necessary to consider the deformation of the guide rail, the irregularity of the guide rail, and the difficulty of clamping and alignment due to the shape, and make corresponding optimizations. The optimization measures include:

[0044] Pre-welding reduction: On the basis of certain control of welding deformation, the processing allowance is reduced. When processing the V-shaped groove and the inner raceway surface, the two plates with the size of 85x22x8410mm are used to process the V-shaped groove and the inner raceway surface. The bevel angle and straight groove are planed out of the single piece, and the processing allowance is 4mm. The straight groove is shortened by 3.4 times compared with the previous processing amount;

[0045] Solid line simulation detection, detection of guide rail straightness: theoretically, after the long thin-walled guide rail is processed, only 4.5mm is left on one side of the inner cavity wall. Check the straightness of the guide rail in advance, and use borrowed processing to prevent the inner wall from being milled through due to the deformation of welding deformation in subsequent processing. Use iron blocks to tighten and straighten the two ends of the straight line to check the straightness of the long guide rail. If the deformation on both sides is large and the processing allowance is insufficient, rework correction or borrowed processing is performed;

[0046] Use tie bars to simplify clamping: weld process tie bars on the bottom of the two plates before processing, spot weld process tie bars at the parts with poor rigidity of the workpiece, add process bumps to press the plate pressure point position, control the deformation of the V-groove and the inner raceway surface due to cutting stress during processing, and weld process support tie bars on both sides of the track to solve the clamping problem. The workbench only needs to install support studs, the studs support the process tie bars, find the alignment line and parts, and use the pressure plate to press the process tie bars. When processing in large quantities, it only needs to align and press according to the alignment line;

[0047] Combination of multiple clamping methods such as pressing, pushing and clamping can reduce deformation of workpieces: the use of fine machining reference surface, pressure plate clamping and side pushing can avoid the problem of blank surface as reference surface, unstable clamping and poor processing rigidity. At the same time, after adding process bumps by spot welding, the clamping rigidity is guaranteed and the position of the workpiece is prevented from changing. The pressing action point of the pressure plate is consistent with the direction of the pressing force, and the force point is lower than the pressing point. The clamping force of rough machining is large to ensure sufficient cutting force. When the pressing force is small during fine machining, it is necessary to reduce the deformation of the workpiece due to external force, and the process reinforcement is stressed to control the machining deformation. The process reinforcement needs to be spot welded to avoid welding thermal stress deformation. The process reinforcement is stressed during clamping and processing to avoid deformation during machining. The process reinforcement is stressed during clamping and processing to avoid deformation during machining. The pass rate of one-time verification is increased from 50% to 100%, which is 1 times higher than before.

[0048] S5: The precision reference plane replaces the uneven rough reference plane: reduce the compression deformation, increase the contact area between the bottom surface of the workpiece and the worktable, improve the processing stability, first mill the process clamping reference plane, and increase the contact area between the bottom surface of the workpiece and the worktable.

[0049] S6: Reasonable selection of tools and cutting parameters: Reasonable selection of tool materials, parameters and cutting parameters, tool selection, parameter selection, low helix angle is suitable for milling grooves, cutting torque is not large, axial tension is not large, if a milling cutter with a larger helix angle is selected, the blade is more likely to break, the axial tension is large, the residual material is subject to a large cutting compound force and the vibration amplitude increases, so the tool life is short, the first knife cuts into the layer, consider cutting from the top of the T-slot, and use the depth direction offset tool compensation method to facilitate the discharge of iron chips. At the same time, the support residual material is used as the basis for cutting. The workpiece material is Q235 welding structure, and the selection The indexable slot milling cutter with good performance has YBG302 blade, where the blade YBG302 is used to replace the original traditional three-sided milling cutter. The cutting efficiency and deformation reduction are compared as follows: measures to reduce self-excited vibration, cutting speed, feed rate and back cutting amount. Different parameters have a great influence on vibration. For example, too much back cutting amount or feed rate will cause the workpiece and tool to deform, and the vibration will increase significantly. Therefore, enhancing the vibration resistance of the processing system itself can reduce it, such as enhancing the rigidity of the machine tool and improving vibration. The tool has left the workpiece, which can greatly reduce the cutting force and cutting heat, improve the cutting quality, and improve the processing timeliness.

[0050] S7: Cutting amount selection: Use reasonable processing amount to ensure processing accuracy. In rough processing: Under the conditions allowed by the machine tool, the cutting amount can be appropriately increased. At the same time, the vibration phenomenon in the processing process can be used to release the vibration stress of the workpiece. In fine processing: Use faster cutting speed, smaller feed rate, and lower cutting speed to ensure processing accuracy and surface quality. When processing the guide rail body, use cooling-based lubricating emulsion and ensure sufficient flow to reduce deformation caused by cutting heat.

[0051] S8: Reasonable selection of processing equipment and optimal processing and cutting methods: When processing, you need to use a CNC gantry milling machine XKAV2840X120 with good rigidity and sufficient power. It is necessary to improve the rigidity of the tool and the workpiece, increase the cross-sectional area of ​​the tool bar, and pay attention to the tool direction and cutting sequence to avoid the impact and effect on subsequent cutting after the processing has caused greater damage to the rigidity of the parts. Among them, the application of the plunge milling method, also known as the Z-axis milling method, is one of the most effective processing methods to achieve high metal removal rates. It has a better improvement effect on grooving and workpieces with poor rigidity. In addition to improving processing efficiency, this processing can also reduce deformation and improve workpiece processing accuracy. The use of this method for segmented processing has great benefits for stress control.

[0052] Example:

[0053] The deformation of the guide rail is caused by the particularity of the structural shape: the long diameter of the guide rail is 8528mm, the welding volume is large, and there are many welding points. The deformation points are mainly the thermal stress deformation of two plates with a length of 8410mm after welding. After welding, a 120° V-groove and a 17±0.5mm T-groove with a length of 8410mm must be processed on these two plates to ensure that the edges between the V-groove and the T-groove are 4±0.3mm. The main deformation is the two plates used for the main purpose. The problem of thermal stress deformation of these two plates during welding and cutting stress deformation during machining is solved.

[0054] Therefore, it is necessary to start with the deformation problems of welding and machining respectively:

[0055] Welding process: avoid the welding thermal stress of other parts causing deformation again;

[0056] Use process equipment and other measures to control its deformation during this process;

[0057] The welding operation is facilitated by technological measures.

[0058] Machining process: The clamping process is subjected to compression force and deforms after the pressure plate is released;

[0059] The cutting amount during cutting is large and the cutting stress leads to deformation;

[0060] Reducing the labor intensity of workers with the help of technological measures;

[0061] The milling method measures low efficiency.

[0062] The ultra-long thin-walled truss guide rail prepared by this process is compared with the ultra-long thin-walled truss guide rail commonly found on the market, wherein the ultra-long thin-walled truss guide rail prepared by this process is an example, and the ultra-long thin-walled truss guide rail commonly found on the market is a comparative example. The following is a comparison table:

[0063]

[0064] This process develops a process technology for controlling the deformation of guide rail welding and machining. The deformation is controlled by the principle of reasonably releasing thermal stress through positioning and clamping. The clamping and alignment uses the tie rods that improve the processability as the supporting force points to facilitate alignment and clamping, while preventing the workpiece from deforming after release due to the clamping extrusion force.

[0065] In order to solve the problems of large deformation, low production efficiency, large wall thickness difference, poor quality and low qualified rate in the original process, this process develops the process technology of controlling the welding and machining deformation of the guide rails, forming a set of mature welding forming technology for large truss-type welded structural parts and a mechanical processing process system for trusses and guide rails with a large aspect ratio, which can greatly improve the consistency of the guide rail wall thickness difference and thus improve production efficiency.

[0066] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0067] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A process for processing an ultra-long thin-walled truss guide rail, comprising the following steps: S1: Design welding positioning tooling: weld the two substrates and use the tooling to control the position of the two boards; S2: Simplify the welding process: weld the frame separately, and finally weld the frame to the two fixed plates; S3: Release welding stress to control deformation after welding: tempering with tooling after welding; S4: Set up corresponding control measures for machining deformation problems; S5: The fine datum plane replaces the uneven rough datum; S6: Selection of tools and cutting parameters; S7: Select cutting parameters: for rough machining: increase cutting parameters; for fine machining: use faster cutting speed, smaller feed rate, and lower cutting speed; S8: Rationally select processing equipment and processing cutting methods: improve the rigidity of the tool and workpiece, increase the cross-sectional area of ​​the tool bar, and use the plunge milling method for cutting.

2. The process for processing an ultra-long thin-walled truss guide rail according to claim 1, characterized in that: The optimization measures in step S4 include: pre-welding reduction: reducing the machining allowance, planing the bevel and straight grooves of the two single plates used for machining the V-groove and the inner raceway surface, and leaving the machining allowance.

3. The process for processing an ultra-long thin-walled truss guide rail according to claim 1, characterized in that: The optimization measures in step S4 include: solid line simulation detection, detection of the straightness of the guide rail, and if the deformation on both sides is found to be too large and the machining allowance is insufficient, rework correction or borrowing machining is performed.

4. The process for processing an ultra-long thin-walled truss guide rail according to claim 3, characterized in that: The optimization measures in step S4 also include: using tie rods and simplifying clamping.

5. The process for processing an ultra-long thin-walled truss guide rail according to claim 4, characterized in that: When borrowing tie rods to simplify clamping, the workbench is equipped with supporting studs, the studs hold the process tie rods, the alignment lines and parts are aligned, and the process tie rods are pressed with pressing plates; during large-scale processing, the alignment lines are aligned and pressed.

6. The process for processing an ultra-long thin-walled truss guide rail according to claim 5, characterized in that: The optimization measures in step S4 also include: applying a combination of multiple clamping methods such as pressing, pushing and clamping to act on the workpiece together.

7. The process for processing an ultra-long thin-walled truss guide rail according to claim 6, characterized in that: The combined application of the plurality of clamping methods such as pressing, pushing and clamping reduces the pressing force during fine machining, reduces deformation of the workpiece due to external forces, and reduces stress on the process reinforcement; the process reinforcement needs to be spot welded.

8. The process for processing an ultra-long thin-walled truss guide rail according to claim 1, characterized in that: In the step S6, the workpiece material is a Q235 welding structure, and an indexable slot milling cutter with good performance is selected.

9. The process for processing an ultra-long thin-walled truss guide rail according to claim 1, characterized in that: In step S7, a lubricating emulsion mainly used for cooling is selected during cutting.

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