JPS61117434A - Method for penetration flaw detection and inspection in machining process - Google Patents

Abstract

PURPOSE:To perform the surface flaw inspection of a machined component which is mass-produced without providing any special inspecting process by adding a high-brightness fluorescent material to cutting fluid, and irradiating it with ultraviolet rays after cleaning and making an observation. CONSTITUTION:A component to be machine is cut in a machining process S1 while applied with the cutting fluid. Then, the fluorescent material which fluoresces when irradiated with ultraviolet rays is added to the cutting fluid, and then if the component has a surface flaw, the cutting fluid containing the fluorescent material penetrates the flaw and also sticks on the surface. Further, the cutting fluid sticking on the surface is removed in the cleaning process S2 after the machining, but the cutting fluid in the flaw remains unless a special cleaning process is performed. The fluid is irradiated with ultraviolet rays in an inspecting process S3, and then the cutting fluid remaining in the flaw fluoresces, so the surface flaw is easily inspected. Further, no special processing is required for the inspection, so this is suitable to the quality control over machined components, such as bolts and pipe joint, which are mass-produced.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to nondestructive testing of metals or non-metals, and in particular penetrant testing in machining processes suitable for surface flaw inspection of machined parts for mass production. It concerns inspection.

[Background of the invention]

Conventionally, surface flaw inspection of mass-produced machined parts is carried out after machining is completed, followed by a cleaning operation to remove cutting oil (liquid), followed by visual inspection or penetrant inspection methods such as non-destructive testing technology series, penetrant test AC1976. 2009) was conducted using the technology shown in Chapter 2 Penetrant Testing Methods published by the Japan Nondestructive Testing Association, but the former has a high risk of overlooking flaws, and the latter requires penetrating work and surplus penetrant liquid. Not only does the manufacturing cost become high because the number of beads required for removal work, but also the machine.

Since the cutting oil penetrates into the surface flaws during machining, there is a drawback that it is almost impossible to penetrate even if a penetrating fluid is applied afterwards.

[Purpose of the invention]

An object of the present invention is to provide an inspection method that allows surface flaw inspection of metal or non-metal machined parts that are particularly mass-produced with high precision and without the need for special inspection steps.

[Summary of the invention]

Generally, cutting oil is used when machining gold or non-metals, but these cutting oils are removed by a cleaning process after machining is completed, so these processes are used in penetrant testing for surface flaw inspection. If it can be used as an inspection process, a new inspection process will be unnecessary. In other words, oils and fats such as cutting oil generally have good permeability, so if there are surface flaws such as cracks on the machined surface, the cutting oil will penetrate into them, and in the subsequent cleaning process, the cutting oil will only penetrate to healthy surfaces. Although it is removed, cutting oil will remain in the flawed area.

Cutting oils are generally mineral oils, and those with a low degree of refinement have a high sulfur content, which causes them to fluoresce under ultraviolet light. However, the fluorescence emitted by these cutting oils and the like is white, and although it is possible to detect surface flaws using this colored fluorescence, depending on the color tone, it may not catch the eye and may be easily overlooked. Therefore, when a high-intensity fluorescent substance is added to cutting oil, the fluorescent color under ultraviolet light becomes noticeable, making it easier to detect surface flaws. Further, in the case of a highly refined cutting oil that does not contain sulfur or fluorescent substances, the cutting oil itself does not produce any luminescent phenomenon, so the brightness of the added fluorescent substance is not impaired, which is preferable.

As these oils, spindle oil-based oils refined to have a sulfur content of less than iooppm are suitable because they have little white fluorescence and good permeability.

The present invention involves adding high-intensity fluorescent substances to refined spindle oil-based cutting oil, and these substances that naturally penetrate into surface flaws during the machining process are removed during the next cleaning process. After the cleaning process, ultraviolet rays are irradiated and observed, and only the surface flaws emit fluorescence, making it possible to easily select defective products.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a flowchart of a penetrant inspection method in the machining process of machined parts. .

The parts are cut while being sprayed with cutting oil in the machining step s1, and it is preferable to add a fluorescent substance that emits fluorescence when irradiated with ultraviolet rays to this cutting oil. In that case, if a part has a surface flaw, the cutting oil containing the fluorescent substance will penetrate into the flaw and also adhere to the surface. After machining is completed, the cutting oil adhering to the surface is removed in the cleaning step S, but the cutting oil that has penetrated into the flaws remains unless a special cleaning treatment is applied, and if UV rays are irradiated in the inspection step S. Cutting oil remaining in the flaws emits fluorescence, making it easy to inspect surface flaws, and machining parts such as bolts and pipe joints that can be manufactured in large quantities because no special process is required for inspection. suitable for quality control. Figure 2 shows a flowchart using the conventional method.
After the 1% cleaning step S, a penetrating solution containing a fluorescent substance or a penetrating solution containing a red pigment is applied (s4).
, as well as a washing step S for removing excess penetrating liquid, which required nine man-hours and a special step for inspection, which was a problem. In addition, in the case of this method, the cutting oil used in the machining process penetrates into the surface flaws and is not removed even in the subsequent cleaning process S, so even if the penetrating liquid is applied, it hardly penetrates into the flaws. Since the liquid does not penetrate, there are problems such as low flaw detection accuracy, and the mainstream is quality control based on visual inspection without using general I'll penetrating liquid.

[Effects of the Invention] According to the present invention, parts to be machined can be subjected to penetrant inspection without changing the original work process, the production process can be shortened, and the detection accuracy of surface flaws can be completely improved. .

[Brief explanation of the drawing]

FIG. 1 is a flowchart of a penetrant inspection method in a machining process according to an embodiment of the present invention, and FIG. 2 is a flowchart when a penetrant inspection process is newly provided. SI...machining process, 8t...cleaning process, S...
...Inspection process, S4... Penetration work process.

Claims (1)

[Claims] 1. A penetrant inspection method in a machining process, which is characterized by cutting metal or non-metal using a cutting agent containing a fluorescent agent, and detecting surface flaws by irradiating them with ultraviolet rays after cleaning.