Method for removing burrs from tiny holes

Abstract

The present invention provides a method for removing micropores and micropore burrs, comprising: step S1: preliminary cleaning of burrs at the micropore outlet of a part; step S2: grinding the surface of the micropore outlet of the part to turn the originally raised burrs inside the hole, below the surface of the micropore outlet, thereby weakening the adhesion between the burr root and the part; step S3: polishing and cleaning the ground surface; step S4: using an abrasive flow to process the part to completely remove the burrs turned inside the hole; and step S5: cleaning the abrasive flow abrasive inside the micropore of the part. The present invention combines grinding and abrasive flow processing methods to maintain the sharp edge of the hole mouth while completely removing the micropore burrs; significantly improving processing efficiency compared to the manual deburring currently used in the industry.

Description

Technical Field

[0001] The present invention relates to the field of mechanical processing, in particular to a method for removing burrs from micro-holes. Background Art

[0002] The core components of aerospace liquid engines are equipped with impact holes on their injection cores, which are generally less than 0.5mm in diameter and are classified as microscopic holes. These holes have precise aperture and inner wall finish requirements and are typically machined using extremely fine drill bits. During machining, plastic deformation of the orifice creates burrs at the inlet and outlet of the impact holes. Burrs can affect the engine's liquid spray flow and performance, so engines have very high requirements for burr removal. Furthermore, the rounded corners of the orifice can also affect the liquid spray flow. Furthermore, the orifice's sharp edges must be maintained as much as possible after the burrs are completely removed, which undoubtedly increases the difficulty of deburring.

[0003] The plasticity of the injection core material is strong, and the burrs are sticky and difficult to remove. The typical structure of the injection core is as follows: Figure 1 As shown; the burrs of the impact hole need to be seen with a magnifying glass, and most of them are oblique hole burrs with irregular shapes, mainly including large cap-shaped burrs and root burrs. The large cap-shaped burrs cover the hole mouth and are easier to remove; the root burrs are located at the root of the oblique hole outlet, and are shaped like raised irregular semicircular burrs, which are more difficult to remove. Ordinary deburring methods can easily fillet the hole mouth or turn the burrs into the hole, leaving residues. Currently, the industry mainly uses manual deburring for injection cores, which has low processing efficiency and puts a heavy burden on people's eyesight and energy. The typical structure of the impact hole and the location of the burrs are shown in the figure below. Figure 2 As shown;

[0004] Table 1 lists some common methods for deburring tiny holes in the industry. Most methods focus primarily on removing burrs, with little emphasis on rounded corners, and some even include filleting as a processing requirement. Furthermore, engine injection cores require maintaining fuel flow parameters, necessitating sharp edges at the holes. Furthermore, due to the structural characteristics of the parts, burrs are primarily found at oblique holes. This is a rare occurrence in the machinery industry, and burr removal is extremely challenging.

[0005] Table 1

[0006]

[0007] You Jianmin. Small hole processing of injector disk [J]. Aerospace Technology. 1997 and Research on thermal deburring process [J]. Aerospace Manufacturing Technology. 2002 are related studies on deburring of injection core. The two papers respectively use manual and thermal methods to remove burrs from injector disks. Manual deburring is less efficient; the thermal method requires higher equipment costs, and the surface oxide ash needs to be treated after processing. The impact of instantaneous explosion on the performance of aerospace product materials needs to be analyzed.

[0008] Song Zhengui. Theoretical analysis and experimental research on abrasive flow machining technology. Doctoral dissertation of Taiyuan University of Technology. 2010. This is a related study on the rounded corners produced by abrasive flow.

[0009] The present invention removes burrs from tiny holes by combining grinding and abrasive flow methods, thereby achieving the effect of removing burrs and maintaining sharp edges. This method has not yet been seen in related articles or patents. Summary of the Invention

[0010] In view of the defects in the prior art, the purpose of the present invention is to provide a method for removing micro holes and micro hole burrs.

[0011] A method for removing burrs from micro-holes provided by the present invention comprises:

[0012] Step S1: Preliminary cleaning of burrs at the outlet of tiny holes of parts;

[0013] Step S2: Grind the surface of the micro-hole exit of the part to turn the originally raised burr inside the hole, lower than the surface of the micro-hole exit, and weaken the adhesion between the burr root and the part;

[0014] Step S3: polishing and cleaning the grinding surface;

[0015] Step S4: using abrasive flow to process the parts and remove the burrs in the hole;

[0016] Step S5: cleaning the abrasive flow in the tiny holes of the parts.

[0017] Preferably, the step S1 is performed by using a brush to brush off the large cap-shaped burrs and large adhesions connected to the hole opening after punching.

[0018] Preferably, the step S2 adopts: plane grinding, outer / inner circle grinding or bevel grinding is selected according to different part structures.

[0019] Preferably, in step S2, the grinding sand is made of diamond micropowder or white corundum micropowder.

[0020] Preferably, the step S3 comprises: polishing the ground surface to remove the oxide layer caused by grinding, so that the surface of the part recovers the original color of the metal; and cleaning the grinding sand and excess materials in the tiny holes of the part.

[0021] Preferably, in step S4, the abrasive particles in the abrasive flow need to be smaller than 1 / 10 of the aperture.

[0022] Preferably, the step S4 adopts the following method: when the diameter difference of each circle of micro-holes of the part is greater than a preset value, one type of holes is blocked and abrasive flow is performed separately.

[0023] The present invention provides a micro-hole, which is prepared by using the above-mentioned method for removing burrs from micro-holes.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention combines grinding and abrasive flow processing methods to achieve the effect of completely removing burrs from tiny hole openings while maintaining sharp edges. The present invention can process all burrs at the same time, which greatly improves efficiency compared to the current manual deburring method of processing each hole one by one. Practical verification has shown that the efficiency is at least 3 times higher than that of traditional manual deburring.

[0026] 2. The present invention stabilizes the processing state by solidifying the grinding processing parameters (such as grinding time and grinding pressure) and the abrasive flow processing parameters (abrasive flow pressure, stroke, and number of cycles). This avoids the disadvantages of manual deburring that requires reliance on operator experience and the product's state stability, thereby improving product quality.

[0027] 3. The method provided by the present invention can be combined with other equipment, making it easy to operate. Traditional methods have a significant impact on the operator's vision and energy. The present invention can be combined with equipment such as grinders, drilling machines, and milling machines, reducing the burden on operators.

[0028] 4. The present invention is low-cost and highly safe. Compared to explosive deburring, which requires expensive equipment and carries the potential safety risk of explosion, the present invention has low-cost equipment and materials and poses little risk to the human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0030] Figure 1 Schematic diagram of the typical structure of the injection core.

[0031] Figure 2 Schematic diagram of the typical structure of the impact hole and the location of the burr.

[0032] Figure 3 Schematic diagram of grinding.

[0033] Figure 4 Schematic diagram of abrasive flow.

[0034] Figure 5 Flowchart of the deburring method. DETAILED DESCRIPTION

[0035] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0036] Example 1

[0037] This invention provides a method for removing burrs from micropores, combining grinding and abrasive flow. This method is the result of numerous attempts and failures to find a solution. Previously tried methods include turning, ceramic brush deburring, laser deburring, electrochemical deburring, single grinding deburring, and single abrasive flow deburring. None of these methods can fully remove burrs while maintaining sharp edges.

[0038] The burrs described in the present invention are located at the root of the inclined hole outlet, and are in the shape of raised irregular semicircular burrs, which are difficult to remove. Ordinary deburring methods can easily round the hole opening or turn the burrs into the hole, leaving residues. The present invention combines grinding and abrasive flow methods, and has achieved good processing results in actual verification. The role of grinding is to turn the originally raised burrs into the hole, below the surface where the tiny hole outlet is located, thereby weakening the adhesion between the burr root and the part. At the same time, the state of the burrs turning into the hole is more conducive to the abrasive flow to remove the burrs. If a single grinding method is used, the burrs will turn into the inner hole, and it cannot be guaranteed that the burrs are completely removed. The abrasive flow is to remove the burrs turned into the hole. Using a single abrasive flow method will damage the sharp edges and form rounded corners due to the high adhesion strength of the burrs, resulting in burr removal. During the experiment, the present invention overcame the difficulties in selecting relevant grinding materials, grinding abrasives, and abrasive flow abrasives, as well as the selection of relevant processing parameters: such as grinding processing parameters (such as processing time, grinding pressure), abrasive flow processing parameters (abrasive flow pressure, stroke, number of cycles).

[0039] According to a method for removing burrs from micro-holes provided by the present invention, Figures 1 to 5 Shown, including:

[0040] Step 1: Pre-processing. Pre-process the burrs at the exit of the tiny holes of the parts. Use a brush to brush off the large cap-shaped burrs and large adhesions connected to the hole after drilling to avoid affecting subsequent processing.

[0041] Step 2: Inspection: Check the appearance of the part to ensure that there are no uncovered large burrs or large adhesions at the outlet of the tiny holes in the part.

[0042] Step 3: Grind. Grind the surface where the tiny hole exits the part, turning the originally raised burr inside the hole, below the surface where the tiny hole exits, and weakening the adhesion between the burr root and the part.

[0043] Step 4: Polishing: Polish the ground surface to remove the oxide layer caused by grinding and restore the original metal color of the part surface.

[0044] Step 5: Cleaning: Clean the abrasive sand and excess materials in the tiny holes of the parts.

[0045] Step 6: Cleaning: Use an ultrasonic cleaner or other cleaning equipment to remove abrasives and excess materials from grinding and polishing.

[0046] Step 7: Abrasive flow: Use abrasive flow to process the parts and remove the burrs in the hole.

[0047] Step 8: Cleaning: Clean the abrasive flow inside the tiny holes of the parts.

[0048] Step 9: Cleaning: Use an ultrasonic cleaner or other specialized cleaning equipment to clean the parts.

[0049] Step 10: Inspection. Check the part's appearance and ensure the machined surface is the natural metal color and free of rust. Use a microscope to inspect the hole to ensure there are no burrs, rounded edges, or excess material inside the hole.

[0050] The step 3 comprises:

[0051] 1) Abrasive sand uses common abrasive materials such as diamond micropowder and white corundum micropowder.

[0052] 2) The degree of grinding is such that the original raised burr is lower than the surface of the part, and the hole burr is slightly adhered to the tiny hole.

[0053] 3) Grinding can be done by hand or with a grinder.

[0054] 4) The type of grinding can be selected according to the different structures of the parts, such as: plane grinding, external / internal grinding, bevel grinding, etc.

[0055] The step 7 comprises:

[0056] 1) The abrasive particles of the abrasive flow must be smaller than 1 / 10 of the pore size.

[0057] 2) The number of abrasive flow machining should not be too many. The machining pressure and cycle times should be based on the actual machining status of the parts until the remaining burrs on the tiny hole are cleaned and the hole is not rounded.

[0058] 3) If the diameters of the micro-holes in each circle of the part differ too much, tooling can be designed to block one type of hole and perform abrasive flow separately.

[0059] Example 2

[0060] Example 2 is a preferred example of Example 1

[0061] Taking a certain injection core part as an example, the number of small holes is 150 and the hole diameter is 0.47.

[0062] Step 1: Pre-treat the burrs on the outlet of the tiny holes of the injection core, and use a brush to remove the large cap-shaped burrs and large adhesions connected to the hole after punching.

[0063] Step 2: Check the parts to ensure that there are no uncovered large burrs or large adhesions at the outlet of the tiny holes in the injection core.

[0064] Step 3: Use a grinder to grind the surface where the micro-holes of the injection core are located. The grinding materials and parameters are as follows:

[0065] 1) The grinding tool is made of cast iron, and the size of the grinding end corresponds to the annular surface of the part.

[0066] 2) The grinding sand is made of diamond powder.

[0067] 3) The grinding time is 15 minutes. After grinding, all the burrs of the impact holes are lower than the surface of the part, and the burrs at the hole mouth are slightly adhered to the bottom of the elliptical hole.

[0068] Step 4: Polish the ground surface with sandpaper to remove the oxide layer caused by grinding and restore the original metal color of the part surface.

[0069] Step 5: Use high-pressure gas to blow out the abrasive and excess material in the hole where the part hits.

[0070] Step 6: Cleaning: Use a cleaning machine to remove the abrasive sand and excess materials on the parts.

[0071] Step 7: Abrasive flow: Use abrasive flow on the part to remove the remaining burrs.

[0072] 1) The abrasive particles of the abrasive flow are approximately 1 / 15 of the aperture size.

[0073] 2) The number of abrasive flow machining cycles was 2 and the pressure was 8.5 MPa.

[0074] Step 8: Use high-pressure gas to blow the abrasive out of the part's impact hole.

[0075] Step 9: Cleaning: Use a cleaning machine to clean the parts.

[0076] Step 10: Inspection.

[0077] 1) Check the appearance of the parts and make sure the machined surface has the original color of the metal and is free of rust spots.

[0078] 2) Use a magnifying glass to check the hole mouth. There should be no burrs left on the hole mouth, no rounded edges on the hole mouth wall, and no excess residue inside the hole wall.

[0079] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A method for removing burrs from micro-holes, characterized in that: include: Step S1: Preliminary cleaning of burrs at the outlet of tiny holes of parts; Step S2: Grind the surface of the micro-hole exit of the part to turn the originally raised burr inside the hole, lower than the surface of the micro-hole exit, and weaken the adhesion between the burr root and the part; Step S3: polishing and cleaning the grinding surface; Step S4: using abrasive flow to process the parts and remove the burrs in the hole; Step S5: cleaning the abrasive flow in the tiny holes of the parts.

2. The method for removing burrs from micro-holes according to claim 1, characterized in that: The step S1 comprises: using a brush to brush off the large cap-shaped burrs and large adhesions connected to the hole opening after punching.

3. The method for removing burrs from micro-holes according to claim 1, characterized in that: The step S2 adopts: selecting plane grinding, outer / inner circle grinding or bevel grinding according to different part structures.

4. The method for removing burrs from micro-holes according to claim 1, characterized in that: In step S2, the grinding sand is made of diamond micropowder or white corundum micropowder.

5. The method for removing burrs from micro-holes according to claim 1, characterized in that: The step S3 comprises: polishing the ground surface to remove the oxide layer caused by grinding, so that the surface of the part recovers the original color of the metal; and cleaning the grinding sand and excess materials in the tiny holes of the part.

6. The method for removing burrs from micro-holes according to claim 1, characterized in that: The step S4 adopts the following principle: the abrasive particles of the abrasive flow must be smaller than 1 / 10 of the aperture.

7. The method for removing burrs from micro-holes according to claim 1, characterized in that: The step S4 adopts the following method: when the diameter difference of each circle of micro-holes of the part is greater than a preset value, one type of holes is blocked and abrasive flow is performed separately.

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