JPH03274407A - Instrument for inspecting surface condition of molded product - Google Patents

Abstract

PURPOSE:To save labor in an inspection by irradiating laser spot light on the surface of a molded product, receiving reflected light to detect the pattern of light intensity, extracting a predetermined property quantity from the pattern and judging the surface condition of the molded product. CONSTITUTION:Laser spot light from a laser light source 12 is irradiated on an injection-molded product 11. Regular reflection light from the molded product 11 is received by a pattern detection sensor 13 and the pattern of light intensity is detected. The three values of a half value width (r), a 1/3 value width (r1) and a 2/3 value width (r2) are extracted as a property quantity in a judging device 14 for a light intensity pattern from the sensor 13. These values are compared with a threshold value set in advance according to the injection- molded product. The roughness of a surface condition is judged by the half value width (r) and the degree of the presence of a shrinkage can be judged by the 1/3 value width (r1) and the 2/3 value width (r2). Thus, an inspection can be automated and labor can be saved.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to the surface condition of molded products, particularly injection molded products.

For example, the present invention relates to an apparatus for inspecting the degree of surface roughness, the presence or absence of whiskers, etc.

(Prior Art) Improper transfer, sink marks, warpage, etc. are factors that degrade the appearance quality, that is, the surface condition, of injection molded products. Conventionally, these defective factors have been inspected visually, and individual differences in inspection results are unavoidable.

(Question 8 to be solved by the invention) By the way, this type of surface condition inspection is not only used to discover and eliminate defective products, but also to help optimize the molding conditions of an injection molding machine. is desirable. especially,
In the case of precision molding, feeding back the inspection results of surface conditions to the molding conditions seems to be important from the point of view of quality improvement. However, in order to feed-pack test results, it is necessary to quantify the test results.

An object of the present invention is to provide an apparatus for automatically inspecting surface conditions such as roughness and sink marks on the surface of a molded product.

The present invention also includes: It is an object of the present invention to provide a surface condition inspection device that is capable of quantifying and outputting inspection results of the surface condition of a molded product and is suitable for feedback controlling the molding conditions of a molding machine.

(Means for Solving the Problems) A surface condition inspection device according to the present invention includes a means for irradiating a laser spot light onto the surface of a molded product, and a light beam for detecting a pattern of light intensity by receiving reflected light of the laser spot light. intensity pattern detection means; and means for extracting predetermined feature quantities from the pattern detected by the light intensity pattern detection means and determining surface conditions such as roughness and sink marks of the surface of the molded product from the feature quantities. have

The feature amounts include the half-width of light intensity, 1/3 width, and 2
It is desirable to extract the /3 value range etc.

(Function) The surface condition inspection device according to the present invention detects characteristic quantities such as half width, 1/3 width, and 2/3 width from a light intensity pattern in the specular reflection direction obtained by irradiating a laser spot light onto the surface of a molded product. The degree of surface roughness and the presence or absence of whiskers are quantitatively determined by extracting the features and performing threshold processing or fuzzy inference from the feature values.

(Example) A preferred embodiment of the present invention will be described below.

In FIG. 1, a surface condition inspection apparatus according to the present invention includes a laser light source 12 for irradiating an injection molded product 11 with a laser spot light. A pattern detection sensor 13 that receives specularly reflected light from the injection molded product 11 and detects a pattern of light intensity. A determination device 14 that extracts feature amounts from the pattern detected by the pattern detection sensor 13 and quantitatively determines the surface condition of the molded product, and a display for displaying the light intensity pattern and determination results from this determination device 14. It includes a device 15.

The pattern detection sensor 13 is composed of a CCD array or other light-receiving element array, and since the light intensity pattern of reflected light changes depending on the degree of roughness and inclination of the molded product surface, it detects spatial frequency components from the image of the entire molded product. Compared to the case where the surface condition is extracted and inspected, the processing for determination can be made faster.

FIG. 2 shows the intensity distribution of reflected light when a laser spot light is emitted onto the surface of the injection molded product 11.

FIG. 3 shows an example of a light intensity pattern of incident light and reflected light in the state shown in FIG. The incident light is.

Since it is spot light, it has a sharp peak at the optical axis position as shown in Figure 3 (a), but when the incident light is scattered by the rough surface of the injection molded product, it becomes a gentle regular peak as shown in Figure 3 (b). As the surface roughness improves, the distribution approaches the state shown in FIG. 3(a).

From this point of view, as shown in Figure 4, the roughness of the surface of an injection molded product can be quantified by defining the half width r of the light intensity p/2 based on the maximum value p of the light intensity. I can do it. The smaller the half-width r is, the closer it becomes to a mirror surface, and as the roughness increases, the half-width r also increases. Therefore, by dividing the half-width r into certain sections, it is possible to create a poor transfer state, that is, roughness, on the surface of the molded product.

Next, whiskers often occur on the surface of injection molded products at the boundaries between thick and thin parts, and when there are whiskers, the light intensity pattern of the reflected light is as shown in FIG. 5(b). However, the pattern shown in Figure 5(b) has a half-width of 5
It cannot be distinguished from the pattern without whiskers as shown in Figure (a).

Therefore, as shown in Figure 6, the 1/3 value width ``1 (w width) defined by the light intensity p/3, and the 2/3 value width r2 (n width) defined by the light intensity 2p/3. Define a new one.

If the molded product surface has roughness without sinkage, r, > r2
Or, if sinking occurs, there is almost no difference between 1 and r2.

From this point of view, in the first determination device 14, the half width r,
By extracting the three values of 1/3 value width r and 2/3 value width r2 as feature quantities, and comparing these values with thresholds set in advance according to the extruded molded product, The roughness of the surface condition is determined by the half-value width r, ]/3-value width r,,
The presence or absence of a sink mark can be determined based on the 2/3 value range r2.

A specific example of the determination algorithm of the determination device 14 based on the threshold value as described above will be described below.

Note that the description will be made assuming that 1 is the roughness threshold value -a and the sinkage threshold value is 1.

■Roughness judgment a) If 0≦r≦a, the roughness is small b) If r>a, the roughness is large Note that the roughness degree g, (, > 0) is g, −(ra)/a.

■ Sink judgment a) If r2/r+≦b, there is no sink b) If 1≧r2/rl>b, there is sink, but the sink level is g
h is gh ``' under the condition 1≧gh >Q
It is expressed as (r2/r+-b)/(1-b), and the closer it gets to 1, the higher the degree of whiskers.

■Comprehensive judgment a) When 0≦r≦a or r 2 / r r ≦b Good product b) When other than a) Defective product (roughness gel, sinkage gh) The above explanation is based on the half width r, 1/ 3 value width r, 2/3
This is a case where the determination is made deterministically from the value range r2 and the corresponding threshold value, but the determination may also be made using fuzzy inference. In other words, comprehensive inspection of injection molded products can be considered to include the inspector's intuitive judgment, or by using fuzzy inference techniques, it is possible to make judgments that are close to the inspector's intuitive judgment. In this case, the member part function is set depending on the type of injection molded product.

The algorithm for this determination will be explained below.

However, the roughness is r T −r / 4 a. Here r
When z4a is r-4a, 0≦“,≦1.

Also, Hike r7 is rh=1 3 (1rz / r+ ) /4 (1b
). However, 0≦rh≦1.

■The pass/fail judgment rule is as follows.

Below, the membership functions of the margin ■Roughness rl and lineage rh are as shown in Figure 7.

■The output membership function is as shown in Figure 8.

■ Comprehensive Judgment ■ 1 An evaluation value g standardized to 0 to 1 can be obtained by performing fuzzy inference based on the judgment rules and membership functions such as (1) and (2). the result.

0≦g≦0.25 Good product If g>0.25, the product is considered defective.

The determination device 14 determines the quality of the surface condition of the injection molded product based on the above-described determination rule, and also determines the roughness degree g1.
．． Quantified data such as the degree of shrinkage gb is output to the display device 15 for display, or other equipment.

For example, it is fed back to a molding condition setting device of an injection molding machine to perform feedback control.

Although the embodiments of the present invention have been described based on two types of decision rules, the present invention is not limited to these decision rules.

(Effects of the Invention) According to the present invention, by automating the inspection of the surface condition of injection molded products, significant labor savings can be achieved, and quantified inspection result data can be obtained. Common standards can be set with users.

[Brief explanation of drawings]

Fig. 1 is a block diagram for explaining the schematic configuration of an embodiment of the present invention. Fig. 2 is a diagram showing the intensity distribution of reflected light when laser spot light is emitted from the surface of an injection molded product. , Fig. 3 shows an example of the light intensity pattern of the incident light 1 reflected light in the state shown in Fig. 2. Fig. 4 shows the light intensity pattern of the light intensity pattern to explain the operation of determining the surface roughness of an injection molded product. Figures 5 and 6 are diagrams showing examples of light intensity patterns to explain the operation of determining whiskers on injection molded products. Figures 7 and 8 are diagrams showing the surface of injection molded products. The figure which showed the example of the membership function when a state is determined by fuzzy inference. In the figure, Ni: injection molded product, 12: laser light source. 13... pattern detection sensor, 14... determination device,
15...Display device.

Claims (1)

[Claims] 1) means for irradiating the surface of the molded product with laser spot light;
a light intensity pattern detection means for detecting a light intensity pattern by receiving the reflected light of the laser spot light; and a light intensity pattern detection means for extracting a predetermined feature quantity from the pattern detected by the light intensity pattern detection means; A surface condition inspection device for a molded article, comprising means for determining surface conditions such as roughness and sink marks on the surface of the molded article. 2) As the feature quantity, the half-width of light intensity, the 1/3-width,
2. The surface condition inspection apparatus according to claim 1, wherein a 2/3 value width or the like is extracted.