KR20140083198A - Measuring method of machinability for mold steel - Google Patents

Abstract

The present invention relates to an assessment method for the cutting processability of rolled steel for a mold. The assessment method can be easily applied to an industrial site and allows to conveniently set a tool replacement cycle by directly comparing the wear of cutting tools at the same cutting condition. Provided is the assessment method for the cutting processability of rolled steel which performs a milling operation by applying the same cutting condition to different kinds of rolled steel and assesses the cutting processability of the rolled steel by measuring the wear of an insert for the same amount of processing. The assessment method comprises the following steps of (a) measuring the wear of the insert; (b) representing the wear of the insert for the amount of processing as a drawing; (c) calculating the relationship between the amount of processing and the wear of the insert as a third-order formula of the (b) step; and (d) obtaining maximum amount of processing by calculating the amount of processing up to the limiting value of the wear of a tool from the third-order formula calculated in the (c) step.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for evaluating cutting workability of a steel material for a metal mold,

More particularly, the present invention relates to a method of evaluating the machinability of a steel material for a mold, and more particularly, to a method of evaluating a cutting property of a steel material for a mold, And a processability evaluation method.

Cutting workability is one of the most important characteristics because it is an index indicating the degree of easiness of cutting among various physical properties of steel and directly related with tool life and production time in the industrial field.

However, in general, the cutting workability changes very sensitively according to the cutting method, and therefore it is not easy to define its characteristics.

ASTM E618 is used to evaluate machinability. In this method, the shape and size of the standard workpiece are given, and the cutting speed and the feed speed are adjusted under the condition that the constant surface roughness is required, and the workpiece is machined as much as possible for 8 hours, thereby exhibiting the cutting ability with the number of workpieces per hour.

Therefore, it is not used as an absolute numerical value because the evaluation method is difficult and different results are obtained when cutting conditions are changed. Particularly, since the conditions are complicated, it is difficult to apply to simple cutting processability comparison in an industrial field.

In addition, since the replacement period of the cutting tool can not be determined in the state where the steel grade is changed, it has been difficult to apply it to the automatic machining equipment.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a method and apparatus for evaluating a cutting processability of a steel material for a mold, which is easily applicable in an industrial field and is convenient for setting a replacement period of a tool by directly comparing the abrasion of a cutting tool under the same cutting condition The purpose of the method is to provide.

According to another aspect of the present invention, there is provided a method of evaluating a machinability of a steel material for a mold, comprising the steps of: performing milling by applying the same cutting conditions to different types of steel material; measuring an amount of wear of the insert with respect to the same machining amount; A method of evaluating a machinability of a steel material, comprising the steps of: (a) measuring an amount of wear of the insert; (b) graphically illustrating the wear amount of the insert with respect to the machining amount; (c) trending the relationship between the machining amount and the wear amount of the insert in a cubic form from the figure of the step (b); (d) obtaining a machining amount from the trended cubic equation of the step (c) to the wear limit value of the tool to obtain a maximum machining amount.

In the present invention, in the step (a), the wear amount of the insert is evaluated every 20 cm ³ cutting according to the cutting speed change under the milling condition.

And estimating the life of the tool by inversely calculating a tool replacement cycle using the maximum machining amount obtained in the step (d).

Further, in the step (c), when the relationship between the machining amount and the amount of wear of the insert is continuously measured and data is plotted and graphed, the graph becomes an S-shaped curve and is tentatively polynomialized by the third degree.

According to the embodiment of the present invention, cutting work is performed on various kinds of steel materials for the molds under the same cutting conditions, and the amount of insert wear is measured to obtain the maximum cutting amount, and the machinability of the different types of steel materials can be compared and evaluated .

Unlike the existing standardized processability evaluation method, it is possible to easily compare the machining characteristics by comparing the machining characteristics by simply cutting the machining conditions according to the site. In recent years, when a variety of steel grades are being replaced due to a short mold life in manufacturing plastic products such as cellular phones, it can be evaluated and applied immediately under conditions similar to the field conditions.

By comparing the characteristics of the steel material by calculating the maximum machining amount after trending in the third equation, it is very useful because it is easy to set the cutting conditions at the material change and predict the tool replacement period of the automatic equipment.

FIG. 1 is a photograph sequentially showing that insert wear according to the present invention is changed according to the number of milling operations.
2 is a graph of wear amount evaluation results in machining condition # 1 in Tables 1 and 2.
3 is a graph of wear amount evaluation results in processing conditions # 2 in Tables 1 and 2.
4 is a graph of wear amount evaluation results in machining condition # 3 of Tables 1 and 2.
5 is a bar graph showing the maximum amount of processing according to the processing conditions for each steel material.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The method for evaluating the machinability of a steel material for a mold according to the present invention is a method for evaluating the machinability of a steel material by measuring the amount of wear of the insert with respect to the same machining amount and performing the milling process by applying the same cutting conditions to different types of steel material Method.

More specifically, in the method of evaluating the machinability of a steel material for a mold according to the present invention, the abrasion amount of the above insert is first measured (step 110)

In order to comparatively evaluate the machinability of different types of steel, the milling is carried out under the same conditions, and the amount of wear of the insert is evaluated. The fine wear difference is measured using an optical microscope.

And the amount of wear of the insert of step 110 is evaluated at every 20cm ³ cutting the milling conditions in accordance with the cutting speed change.

Next, the abrasion amount of the insert with respect to the above-mentioned machining amount is shown by a graph (for example, a graph) (step 120). That is, the abrasion difference measurement result is graphically shown according to the machining amount.

From the above figure, the relationship between the machining amount and the amount of wear of the insert is tentatively expressed as a cubic equation (step 130). That is, the above graph is shown as a third order polynomial.

More specifically, in the graphs shown in Figs. 2 to 4, which will be described later, the wear amount of the insert is continuously measured according to the amount of machining, data is formed, and the result is shown in a graph.

Then, as will be described later, the curves of the above graphs tend to be S-shaped curves. That is, the curves of the graph are not constant and are distorted at least once.

Thus the above S-shaped curve 3 linear equation: may represent the trend (for example, ^{y = 0.0003x 3 -0.077x 2 + 5.6532x} ).

(Step 140). Namely, the target wear amount is set according to the wear limit of each tool, and the maximum cutting amount of each steel corresponding thereto .

In addition, the life cycle of the tool is predicted by inversely calculating the replacement period of the tool using the maximum processing amount obtained in step 140 (step 150)

A method for evaluating the machinability of a steel material for a mold according to the present invention as described above will be further described.

The method for evaluating the machinability of a steel material for a mold according to the present invention is a method for evaluating the machinability of a mold for evaluation in a comparative evaluation of the machinability which can be easily applied in an industrial field, It is possible to easily compare the cutting processability of the steel material for a mold.

Particularly, it can be used for substitution and setting of cutting conditions in a brief comparison in a general frequent situation such as a substitution from a used material to a new material.

In addition, since the replacement period of the cutting tool can not be measured in the state where the steel type has been changed, there has been a problem that it is difficult to apply to the automatic processing equipment.

Accordingly, the method for evaluating the machinability of the steel material for a mold according to the present invention is convenient for directly comparing the abrasion of the cutting tool under the same cutting condition and setting the replacement period of the tool.

More specifically, the method for evaluating machinability of a steel material for a mold according to the present invention provides an index for setting a machining condition and predicting the tool life at the time of steel material replacement by comparing and evaluating the machinability of the steel material for a mold.

The machinability is affected by various conditions such as the machining tool, the machining speed, and the depth of cut, so that the relative comparison is not easy. Therefore, there is a need for a method capable of easily comparing the machinability at each site.

Since the cutting processability of the steel material shows a large difference in cutting or milling, in the method of evaluating the machinability of the steel material for a mold according to the present invention, a milling method capable of comparing different types of steels under relatively constant conditions is adopted as a workability evaluation method.

Milling is performed under conditions suitable for each site, and the amount of wear of the insert is measured at a constant cutting amount. Using this, the amount of work and the amount of wear can be represented by a graphical representation of the cubic equation.

Generally, the milling insert replacement period is set at the machining site, and the maximum machining amount can be calculated in the third trend equation based on the corresponding amount of insert wear. This maximum machining amount can be used as a value representative of the machinability of different steels under the cutting conditions of each site.

Also, it can be applied as the insert replacement period setting value according to the steel material change.

The method for evaluating the machinability of a steel material for a mold according to the present invention using the same provides an easy machinability evaluation method that can be practically applied in each industrial field.

Example

In the present invention, the machinability of various steel steels was evaluated. The amount of insert wear was evaluated every 20 cm3 with milling conditions as shown in [Table 1] according to the cutting speed change.

Cutting conditions #One #2 # 3 Cutting tool TE90AP332W32 (Φ32) TE90AP332W32 (Φ32) TE90AP332W32 (Φ32) Cutting speed (mm / min) 250 180 100 Feed (mm) 0.1 0.1 0.1 Axial depth (mm) 2 2 2

As shown in Table 2 below, it can be seen that the maximum machining amount increases as the cutting speed decreases regardless of the type of steel.

Trends on wear results by cutting conditions Cutting conditions Steel Trend formula Max. Throughput (cm3)
#One

One 0.0013x ³ -0.034x ² + 4.7613x 56.9 2 0.0012x ³ -0.1334x ² + 11.176x 53.5 3 0.0012x ³ -0.1334x ² + 11.176x 63.4 4 0.0015x ³ -0.1711x ² + 8.7728x 82.4
#2

One 0.0017x ³ -0.197x ² + 8.7091x 88.1 2 0.0017x ³ -0.1936x ² + 8.7525x 85.8 3 0.0008x ³ -0.1255x ² + 9.3112x 89.2 4 0.0013x ³ -0.1693x ² + 7.8214x 100.8
# 3

One 0.0003x ³ -0.077x ² + 5.6352x 195.5 2 0.0008x ³ -0.1269x ² + 6.7537x 123.0 3 0.0008x ³ -0.134x ² + 7.9466x 119.4 4 0.0002x ³ -0.0639x ² + 5.9861x 226.3

1 (a) to 1 (d) show the abrasion of the insert after the milling by the number of machining. Each steel was subjected to milling and the amount of wear of the insert shown in Fig. 1 was measured.

Figs. 2 to 4 are graphs showing the amount of wear under the respective cutting conditions, with reference to the cutting amount. Particularly as shown in Figs. 2 to 4, as an S-shaped curve. The respective trend equations are expressed by a cubic equation, and these are shown in Table 2 above.

In this embodiment, the maximum machining limit is set to 400 μm insert wear, which can be set according to the situation of each site.

As shown in Fig. 2, the machining amount is calculated and shown in Table 2 with respect to the maximum machining limit. In case of cutting condition 3, it is calculated by using the trend formula.

Figure 5 also shows the maximum throughput.

As shown in Fig. 5, it can be seen that the steel material 4 exhibits the greatest maximum machining amount under all conditions, that is, it exhibits the best machinability. In the case of the steel material 1, the cutting workability is remarkably improved when the cutting speed is slow. However, when the cutting speed is increased, the cutting workability is greatly lowered. In particular, compared with the steel material 3, .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. . Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (4)

1. A method of evaluating a cutting property of a steel material by performing milling by applying the same cutting conditions to different types of steel material for a mold and measuring the amount of wear of the insert with respect to the same machining amount,
(a) measuring an amount of wear of the insert;
(b) graphically illustrating the wear amount of the insert with respect to the machining amount;
(c) trending the relationship between the machining amount and the wear amount of the insert in a cubic form from the figure of the step (b);
(d) obtaining a maximum machining amount by obtaining a machining amount from the trended cubic equation of the step (c) to a wear limit value of the tool, and evaluating the machinability of the steel material for a mold The method according to claim 1,
In the step (a), the amount of abrasion of the insert is evaluated every 20 cm ³ cutting according to the cutting speed change according to milling conditions. The method according to claim 1,
Further comprising the step of estimating the life of the tool by inversion of the tool replacement cycle using the maximum machining amount obtained in the step (d). The method according to claim 1,
In the step (c)
Wherein the relationship between the machining amount and the amount of wear of the insert is continuously measured and data is plotted and graphed so that the graph becomes an S-shaped curve and trended to a third order polynomial.

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