Device suitable for forming titanium alloy sheet metal part

Abstract

The utility model provides a device suitable for titanium alloy sheet metal part forming, which comprises a pre-forming tool used for carrying out pre-heating preliminary forming on a part, improving the part forming quality and increasing the part machining qualification rate; the hot pressing forming tool is used for avoiding wrinkling of the part in the hot pressing process; the forming device is improved, a rubber bag hydraulic pre-forming process is added, the part forming quality is improved, and the part machining qualification rate is increased; the tool structure is improved, and the quality problems of wrinkling and the like in the part hot-pressing process are solved by additionally arranging reinforcing ribs with proper sizes on the hot-pressing tool; the hot forming parameters related to the hot pressing technology comprise the forming temperature, the forming pressure, the preheating time and the pressure maintaining time, and the problems of springback deformation and the like occurring in the part forming process are solved.

Description

Technical Field

[0001] This application belongs to the field of sheet metal technology, and in particular relates to an apparatus suitable for forming titanium alloy sheet metal parts. Background Technology

[0002] The forming of complex titanium alloy sheet metal parts is difficult and the forming process is prone to quality defects such as wrinkling and cracking. Therefore, it is necessary to find devices to assist in the forming process, improve the overall quality of the parts, and reduce quality and safety risks. Utility Model Content

[0003] Purpose of the utility model: To address the problems existing in the prior art, this invention provides a device that adds a rubber bladder for hydraulic pre-forming during the part forming process and then performs hot pressing shaping, which can significantly improve the surface quality of the parts, ensure a part qualification rate of over 98%, and achieve good surface quality.

[0004] This application provides an apparatus suitable for forming titanium alloy sheet metal parts, the apparatus comprising:

[0005] Preforming fixtures are used to preheat and initially shape parts, thereby improving the forming quality of parts and increasing the pass rate of part processing.

[0006] Hot pressing forming fixtures are used to prevent wrinkling of parts during the hot pressing process.

[0007] Preferably, the preforming tooling includes:

[0008] Workbench;

[0009] A rigid die is disposed on the worktable;

[0010] A rubber block is disposed within the rigid die; wherein a sheet metal is disposed on the rigid die, and the sheet metal is positioned above the rubber block;

[0011] The equipment rubber, under the pressure of the rubber bladder, squeezes the sheet material until the part is completely molded.

[0012] Preferably, the preforming tooling further includes:

[0013] Rolling mill is used to smooth and polish parts to prevent wrinkling.

[0014] Preferably, the hot pressing forming fixture is a deep drawing fixture structure.

[0015] Preferably, the deep-drawing tooling structure includes:

[0016] Hot pressing die;

[0017] The hot pressing punch presses the hot pressing die down at a preset pressing rate until the hot pressing die and the hot pressing punch are in contact. After they are in contact, the temperature and pressure are kept stable until the forming time is reached.

[0018] Preferably, the drawing tooling structure further includes:

[0019] The blank holder controls the material flow of the part during the forming process by adjusting the blank holder force, thereby preventing wrinkling of the part during the forming process.

[0020] The beneficial technical effects of this application are as follows:

[0021] This application improves the forming process by adding a rubber bladder hydraulic preforming process to improve the forming quality of the parts and increase the part processing qualification rate; it also improves the tooling structure by adding appropriately sized reinforcing ribs to the hot pressing tooling to eliminate quality problems such as wrinkling during the hot pressing process; and it improves the thermoforming parameters involved in the hot pressing process, including forming temperature, forming pressure, preheating time, and holding time, to eliminate problems such as springback deformation that occur during the forming process. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the rubber bladder hydroforming process provided in the embodiments of this application;

[0023] Figure 2 This is a schematic diagram of the titanium alloy hot-drawing tooling provided in the embodiments of this application;

[0024] Wherein: 1—Hot pressing die; 2—Guide plate; 3—Pressure ring; 4—Hot pressing punch; 5—Screw; 6—Spin-in lifting bar; 7—Positioning pin; 8—Screw; 9—Ejector seat; 10—Machine tool ejector; 11—Worktable; 12—Rigid die; 13—Equipment rubber; 14—Rubber bladder; 15—Rubber block; 16—Sheet material. Detailed Implementation

[0025] Please see Figures 1-2 The technical solution provided in this application is as follows:

[0026] 1. A process method suitable for forming titanium alloy sheet metal parts, comprising the following steps:

[0027] 1.1 Material Requisition

[0028] According to the drawing requirements, collect the corresponding materials, and at the same time verify that the grade, specifications, and condition of the raw materials for the parts are consistent with the drawing requirements. Inspect the surface quality of the materials, and ensure there are no quality defects such as scratches, corrosion, or bulging.

[0029] 1.2 Preparation of unfolded material

[0030] 1.2.1 Cutting materials according to the sample:

[0031] a) Collect materials according to the drawing requirements.

[0032] b) Prepare the unfolded material according to the dimensions and shape of the unfolded template.

[0033] c) Drill positioning holes, pin holes, etc. according to the template.

[0034] 1.2.2 Laser cutting blanking:

[0035] a) Collect materials according to the requirements of the drawings.

[0036] b) Confirm that the equipment used is in good working order; confirm that the auxiliary gas used for laser cutting meets the requirements and has a certificate of conformity; confirm that the laser head, nozzle and focusing lens are in good working order to avoid contamination or damage to the focusing lens; confirm that the laser center and the nozzle center are aligned.

[0037] c) Adjust the scaling parameters.

[0038] d) During the milling process, analyze the cutting breakpoint of the part according to the process requirements, increase the process allowance, and leave room for the removal of process lugs and the edge of the heat-affected zone of the part in the form of compensation.

[0039] e) After milling, remove the part, remove surface metal shavings, and grind the edges of the part to remove the heat-affected zone.

[0040] 1.3 Preforming

[0041] 1.3.1 Equipment preparation: rubber bladder hydraulic press, rolling machine, etc.

[0042] 1.3.2 Tool preparation: wooden hammer, rubber board, etc.

[0043] 1.3.3 Tooling Preparation: Check the sharp edges and corners of the mold; sharp edges and corners in non-working areas must not be less than R10. In principle, the mold should not have holes other than those required for the process. If necessary, these should be plugged with hemispherical pins during the forming process. Use a scouring pad to remove oil and impurities from the mold surface. Place the mold stably on the forming table. If the mold height is greater than 75mm, a natural transition rubber pad ramp should be placed near the mold in areas not yet formed. The distance between the mold and the side wall of the worktable should be greater than 1.5 times the mold height, and a rubber pad should be filled between the side wall and the mold until it is the same height as the mold. If the mold has a cavity structure with a depth-to-width ratio greater than 1.5, the cavity must be filled with rubber. After placing the mold, clean the mold surface again to remove oil and impurities.

[0044] 1.3.4 Preparation of unfolded material: Place the unfolded material flat on the mold and fix it with pins; place the auxiliary rubber on the unfolded material and clean the impurities on the auxiliary rubber to prevent impurities from damaging the parts;

[0045] 1.3.5 Adjusting pressure: First, use a pressure of about 150 bar for a test, and then gradually increase the pressure until the part is completely attached to the mold; after each test, the part should be smoothed with a rolling mill according to the wrinkling condition of the part to prevent the part from having unqualified surface quality due to wrinkling.

[0046] 1.3.6 Cleaning parts: Clean impurities from the surface of parts after hydraulic treatment.

[0047] 1.4 Hot pressing

[0048] 1.4.1 Before forming, the part can be partially formed according to its complexity to prevent cracks and wrinkles in certain areas during the thermoforming process.

[0049] 1.4.2 Cleaning tools

[0050] i. Open the upper and lower molds of the tooling and use compressed air to remove dust and impurities from the surface of the molds;

[0051] ii. Use sandpaper to sand away the hard particles formed during sintering of the mold surface;

[0052] iii. Wipe the mold surface further with a clean cotton cloth to remove grease, metal, non-metal and other foreign matter adhering to its surface, and ensure that the mold surface is smooth and free of protrusions.

[0053] 1.4.3 Spray boron nitride lubricant on parts and tooling. For parts that are easily scratched, apply a protective coating first, and then apply boron nitride lubricant.

[0054] 1.4.4 Set hot pressing parameters. The main parameters of titanium alloy hot forming process include forming temperature, forming pressure, preheating time, and holding time. The forming temperature is controlled at about 590℃, the forming pressure is 100 bar, the preheating time is 5 min, and the holding time is 28 min.

[0055] 1.4.5 After selecting the molding pressure and time, the equipment presses down the upper mold at a rate of 1 mm / s until the upper and lower molds are in contact. After contact, the temperature and pressure are kept stable until the molding time is reached.

[0056] 1.4.6 After forming is completed, lift the upper mold at a constant speed. The part can only be removed after the upper and lower molds are completely separated.

[0057] When removing the part, it should be clamped at the front, back and middle positions to ensure that the part does not deform. The removed part can be placed in a heat preservation furnace to control the cooling rate and prevent the part from deforming due to excessive cooling.

[0058] 1.5 Lighting

[0059] For individual areas that may wrinkle during the hot pressing process of parts, a rolling mill can be used to roll the surface, thereby smoothing the surface of the parts and eliminating wrinkles.

[0060] 1.6 Thermal Shaping (Thermal Correction)

[0061] Following the hot pressing operation requirements and process parameter settings in section 1.4, perform hot forming on the polished parts to eliminate deformation and springback caused by uneven stress distribution on the part surface during polishing. Note that after forming, the removed parts should be placed in a holding furnace, and the cooling rate should be controlled to prevent deformation due to excessive cooling.

[0062] 1.7 Cutting

[0063] Cut the parts according to the mold cutting lines. Note that vibratory shears should not be used to cut the parts to prevent deformation.

[0064] 1.8 Final Inspection

[0065] Inspect the quantity of parts, forming dimensions, surface quality, fit to the mold, and the completeness of inspection records during the forming process.

[0066] 2. Design of titanium alloy hot pressing tooling structure:

[0067] For complex titanium alloy hot forming, the optimal tooling structure is a hot drawing tooling structure. This structure, with its added blank holder, allows for control of material flow during forming by adjusting the blank holder force, thus preventing surface quality issues such as wrinkling. However, for large, complex titanium alloy parts, the hot drawing tooling structure is unsuitable due to its complexity, large size, high manufacturing cost, long cycle time, and complex debugging process. Therefore, adding a reinforcing rib to the relatively simple hot press die can also control material flow. The reinforcing rib is positioned 80-100mm around the part's outer shape, with a width of 15mm and a depth of 5mm. The reinforcing rib can be reworked based on the die's debugging results. Simultaneously, the position and size of the reinforcing rib in the hot press die must be coordinated and consistent with the rubber bladder hydroforming tooling.

[0068] 3. Quality defects such as wrinkles and cracks are prone to occur during the forming process of titanium alloys. The following methods can eliminate wrinkles and cracks.

[0069] 3.1 During the hydroforming process of rubber bladders, proper edge trimming, edge setting, and the use of a polishing machine can effectively eliminate wrinkles and cracks in the parts.

[0070] 3.2 During the hot pressing process, adjusting the blank holder force, changing the lubrication, changing the punch-die clearance, changing the depth of the reinforcing ribs, changing the blank size, and changing the die fillet radius can all effectively improve the quality defects of the parts during the hot pressing process.

Claims

1. An apparatus suitable for forming titanium alloy sheet metal parts, characterized in that, The device comprises: a preforming tool for preheating and primary forming of the part, improving the forming quality of the part and increasing the processing qualification rate of the part; a hot pressing forming tool for avoiding wrinkles in the hot pressing process of the part; the preforming tool comprises: a workbench; a rigid female die arranged on the workbench; a rubber block arranged in the rigid female die; wherein a sheet metal is arranged on the rigid female die and above the rubber block; a device rubber which, under the pressure of a rubber bladder, extrudes the sheet metal until the part is fully die-bonded; the hot pressing forming tool is a draw depth tool structure, which comprises: a hot pressing female die; a hot pressing male die which presses the hot pressing female die at a preset pressing rate until the hot pressing female die is die-bonded with the hot pressing male die, and the temperature and pressure are kept stable after die-bonding until the forming time is reached.

2. The apparatus of claim 1, wherein, the preforming tool further comprises: a rolling machine for light drawing of the part to prevent wrinkles of the part.

3. The apparatus of claim 2, wherein, the draw depth tool structure further comprises: a blank holder device which, by adjusting the blank holder force, controls the material flow of the part in the forming process, thereby avoiding wrinkles of the part in the forming process.

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