Method for testing flatness of engine base, rack and door frame of marine diesel engine

Abstract

The invention discloses a method and a device for testing flatness of a marine diesel engine base frame door frame, and belongs to the technical field of machine manufacturing detection. According to the innovative detection principle that steel panel pressing is matched with ink trace analysis, the method comprises the following steps that a steel bottom plate and a cushion block are installed, a channel steel guide rail system is arranged, standard viscosity ink is coated, a test face is pressed at a constant speed, and finally ink distribution is analyzed to evaluate the flatness. The matching device is composed of a main frame, a movable pressing assembly and a measuring system, and standard steel and adjustable design are adopted. Compared with a traditional method, 0.05 mm-level detection precision is achieved, the single-time detection time is shortened to be within 30 minutes, and the flatness deviation of the whole plane of the door frame can be quantitatively evaluated.

Description

Technical Field

[0001] The present invention relates to a method for testing the flatness of a door frame of a marine diesel engine base frame. The method is applicable to testing the flatness of door frames of marine diesel engine base frames of different sizes. The method effectively solves the problem of a single testing method in the past, and can perform a flatness test on the entire surface of the door frame, effectively ensuring the flatness requirement of the engine for the door frame of the base frame. Background Art

[0002] As the core power plant of a ship, the structural stability and sealing of a marine diesel engine are crucial to its safe operation. The door frame, a crucial component of the engine frame, not only provides structural support but also acts as a seal, preventing external dust and impurities from entering the engine and preventing fuel and vapor leakage, thereby reducing the risk of fire and explosion. Therefore, the flatness of the door frame is directly related to the sealing performance and overall stability of the diesel engine.

[0003] Traditional methods for testing door frame flatness primarily include flashlight illumination and ruler measurement. The flashlight method determines flatness by observing the amount of light passing through the door frame. While simple to use, it suffers from low accuracy and inconvenient results. The ruler measurement method checks flatness by measuring the contact between the ruler and the door frame surface. However, this method only measures a specific area, resulting in low efficiency and difficulty in fully reflecting the overall flatness of the door frame. These traditional methods suffer from significant deficiencies in accuracy, efficiency, and comprehensiveness, making them unable to meet the high standards for door frame flatness required by modern marine diesel engines. Summary of the Invention

[0004] To address the above shortcomings, the present invention aims to improve the surface integrity of the door frame by capping the surface to be tested for flatness, observing the size of the ink on the surface and whether it is flat, and then polishing or processing it. This method is simple and convenient, highly intuitive and easy to operate.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for testing the flatness of a marine diesel engine frame frame is characterized in that it comprises the following steps: Provide a test device, including two steel panels, four spacers, a box of ink, four concave channel steels and two rectangular long steel plates; Weld the pads between the steel base plate and the back of the door frame to ensure the flatness of each contact surface; Install two concave channel steels on the inside of the door frame and another two concave channel steels on the inside of the steel panel, keeping the four channel steels parallel and coplanar; A rectangular steel plate is installed through four concave channel steels to form a movable transmission structure; Apply ink evenly to the pressed surface of the steel panel; Slowly push the steel panel to press the door frame plane, keeping the force even; Observe and record the distribution of ink marks on the door frame plane; Assess door frame flatness based on ink mark continuity, uniformity, and coverage. Furthermore, the size of the steel panel is 20 mm larger than the periphery of the door frame being measured, the thickness is 8-12 mm, and the material is Q235 steel. Furthermore, the thickness of the pad is 30-50 mm, and the contact surface needs to be milled before welding, with a surface roughness Ra≤3.2 μm. Furthermore, the ink has a viscosity of 200-300 cP and is evenly coated using a scraper method with a coating thickness of 0.05-0.1 mm, ensuring that every area is evenly coated. Furthermore, the subsequent processing steps include: marking the area not stained with ink; trimming the raised area using a grinder; and repeating the test until the ink marks are evenly distributed. The present invention also provides a device for implementing the above-mentioned testing method, which is characterized in that it includes: Main frame assembly, including steel base plate and door frame fixing structure; Mobile pressing assembly, including steel panels, channel steel rails and rectangular steel strips; measurement components, including an ink applicator and a trace analysis scale; Auxiliary components, including level calibration and force measurement gauge. A door frame flatness assessment method, using the ink trace data obtained by the above method for assessment, comprises: Calculate ink coverage percentage; Measure the maximum continuous length of the unstained ink area; Determine the flatness level according to preset standards. Furthermore, when the ink coverage is ≥95% and the maximum blank area is ≤3mm, it is judged as the first-level flatness. A method for manufacturing a marine diesel engine base frame is characterized in that it includes the steps of detecting and correcting the flatness of a door frame by using the above method.

[0007] Compared with the existing testing methods, the present invention has the following benefits:

[0008] Through steel panel pressing and ink trace analysis, the system can visually display surface flatness deviations as small as 0.05mm. A grid scale is used for quantitative assessment, identifying localized unevenness as small as 0.5mm, meeting the industry standard requirement of ≤1mm / m for the sealing surface of marine diesel engine door frames. Through the innovative contact print detection principle and modular device design, the present invention significantly improves the efficiency, safety and economy of marine diesel engine door frame flatness detection while ensuring detection accuracy, providing a reliable solution for the quality control of key components of marine power equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Left schematic diagram of flatness test

[0010] Figure 2 Schematic diagram of the equal side of the flatness test DETAILED DESCRIPTION

[0011] The present invention will be further described below with reference to the accompanying drawings:

[0012] like Figure 1 As shown, the step 1 is to install the steel base plate (8) and the pad (7): before installation, the surface roughness of the pad and the flatness of the back of the steel base plate and the door frame (5) in contact with the pad should be ensured. Before installation, the steel base plate and the pad area on the back of the door frame should be polished flat so as not to affect the surface flatness test of the front of the door frame.

[0013] like Figure 2 As shown, the step 2 is to install the channel steel (4): 2 concave channel steels are installed on the inner side of the door frame. During installation, the installation position should not affect the pressing of the steel panel (3). The other 2 concave channel steels are installed on the inner side of the steel panel. During installation, keep the four concave channel steels in a parallel state and in the same plane.

[0014] like Figure 1 As shown, the third step is to install the rectangular steel plate (6): the rectangular steel plate is installed in the channel steel through four concave channel steels to form a device similar to a transmission belt. The steel panel (3) can move back and forth through the channel steel and the rectangular steel plate. When installing, keep the rectangular steel plate and the channel steel at zero clearance to prevent the steel panel from swaying when pressing the door frame plane.

[0015] like Figure 1 As shown, in step four, ink is applied to the steel panel pressing surface, and the door frame surface is pressed by slowly pushing the steel panel on the rectangular long steel plate manually. Mechanical weight should be avoided in this process, as excessive weight may cause deformation of the door frame.

[0016] like Figure 1 and Figure 2As shown, the step five, test is completed: the flatness of the door frame is tested based on the size and presence of ink marks.

Claims

1. A method for testing the flatness of a marine diesel engine frame, characterized by: The steps include: Provide a test device, including two steel panels, four spacers, a box of ink, four concave channel steels and two rectangular long steel plates; Weld the pads between the steel base plate and the back of the door frame to ensure the flatness of each contact surface; Install two concave channel steels on the inside of the door frame and another two concave channel steels on the inside of the steel panel, keeping the four channel steels parallel and coplanar; A rectangular steel plate is installed through four concave channel steels to form a movable transmission structure; Apply ink evenly to the pressed surface of the steel panel; Slowly push the steel panel to press the door frame plane, keeping the force even; Observe and record the distribution of ink marks on the door frame plane; Assess door frame flatness based on ink mark continuity, uniformity, and coverage.

2. The method for testing the flatness of a marine diesel engine frame frame according to claim 1, characterized in that: The steel panel is 20 mm larger than the periphery of the door frame being tested, has a thickness of 8-12 mm, and is made of Q235 steel.

3. The method for testing the flatness of a marine diesel engine frame frame according to claim 1, characterized in that: The thickness of the pad is 30-50 mm, and the contact surface needs to be milled before welding, with a surface roughness of Ra≤3.2 μm.

4. The method for testing the flatness of a marine diesel engine frame according to claim 1, wherein: The viscosity of the ink is 200-300 cP, and it is evenly applied using a scraper method with a coating thickness of 0.05-0.1 mm to ensure even application everywhere.

5. The method for testing the flatness of a marine diesel engine frame frame according to claim 1 further comprises the following steps: marking the unstained area; trimming the raised area using a grinder; and repeating the test until the ink marks are evenly distributed.

6. A device for implementing the test method according to claims 1-5, characterized in that: include: Main frame assembly, including steel base plate and door frame fixing structure; Mobile pressing assembly, including steel panels, channel steel rails and rectangular steel strips; measurement components, including an ink applicator and a trace analysis scale; Auxiliary components, including level calibration and force measurement gauge.

7. A door frame flatness assessment method, characterized in that Evaluating the ink trace data obtained by the method according to any one of claims 1 to 5, comprising: Calculate ink coverage percentage; Measure the maximum continuous length of the unstained ink area; Determine the flatness level according to preset standards.

8. The evaluation method according to claim 7, wherein: When the ink coverage is ≥95% and the maximum blank area is ≤3mm, it is judged as first-level flatness.

9. A method for manufacturing a marine diesel engine frame, characterized in that The method comprises the steps of detecting and correcting the flatness of the door frame by using the method described in any one of claims 1 to 5.

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