JP3152124U - Oscillation mechanism and infeed mechanism in an oscillating band saw - Google Patents

Abstract

Provided is a mechanism and structure in which rocking and cutting feed are integrated, which enables uniform cutting at each part of a workpiece by simple control. A saw blade head and its slide guide mechanism swing together around a swing fulcrum provided at a lower portion. The swing amount is given by a cam mechanism provided at the top. The cam shape determines the swing amount and swing speed at each part of the workpiece. The cam is connected to the servo motor of the cutting feed mechanism, and the cutting and swinging are controlled simultaneously. The cutting feed is given a precise cutting amount using a ball screw. [Selection] Figure 4

Description

  The present invention relates to a band saw cutting method using an endless band saw blade as a tool.

Band saw machines are widely used for cutting steel, especially large-diameter steel, with no alternative. A band saw blade as a tool is a hoop-shaped band steel provided with a large number of blades endlessly. A band saw blade is composed of a cutting edge and a body part, and the body part has low lateral rigidity due to the characteristics of the band steel. If the cutting resistance at the time of cutting, particularly the back component force, becomes excessive, the saw blade body will bend, which will bend and lead to defective product dimensions. In order not to exceed the limit back component force, there are two adjustment methods of shortening the cutting length or reducing the cutting depth. Since the current cutting control is completely passive with respect to the cutting length, the cutting amount is unavoidably reduced to prevent excessive back force. However, adjusting the depth of cut too shallow is contrary to the rule of thumb of cutting and has many harmful effects. According to the tool life equation, the selection of cutting conditions is in principle to make the cut as large as possible and to make the cutting speed low. However, in the current band saw machine, the cutting efficiency is increased by setting the cutting speed higher because of the cutting limitation. High-speed cutting reduces the tool life by adding heat diffusion wear to the cutting edge in addition to general sliding wear. This is especially harmful for difficult-to-cut materials with work-hardening properties such as stainless steel.

During cutting, the cutting length changes from moment to moment according to the cross-sectional shape of the work material, and the depth of cut also increases or decreases accordingly. Therefore, the depth of cut cannot be used as a cutting condition index, and the cutting rate is used as an index. The cutting rate is a value obtained by dividing the cutting area by the cutting time and corresponds to the average cutting speed. This is a general index for a multi-blade tool, but it is difficult to set it in the machine in advance for the following reasons, and it must be dependent on the experience and intuition of the operator.
1) The cutting rate is a value obtained after cutting and cannot be set in advance.
2) Even if the average cutting rate is good, the cutting rate of each part is too large or too small.
3) When the blade edge of the saw blade is worn, it becomes an excessive index.

The cutting method for controlling the cutting length so as not to exceed the limit back component force is called a rocking method, a seesaw method or an oscillation method. In this method, cutting feed is given while the saw blade is swung in the cutting length direction, and various devices have been proposed in the past (see, for example, Patent Documents 1 and 2). However, the cutting feed and the swinging motion are combined operations, and it is difficult to appropriately apply the cutting length and the cutting amount, and a satisfactory performance has not yet been obtained.
JP 56-107825 A (name: oscillating band saw) JP 2006-26872 A (name: work cutting method with band saw and band saw)

The problem to be solved is that a complicated cutting control is required to give a uniform cutting at each part of the workpiece in the structure in which the swinging motion and the cutting feed are separately given to the saw blade.

The main feature of the present invention is that not only the so-called band saw head composed of the band saw blade and its driving device is swung, but also the guide mechanism for feeding the band saw head in the cutting direction is swung integrally.

According to the present invention, the cutting feed is given while maintaining an appropriate cutting length regardless of the cross-sectional shape of the workpiece. Therefore, the cutting process can be performed by directly setting the cutting amount as the cutting condition. As a result, numerical control of the cutting feed becomes possible, and a band saw machine with good operability, high cutting efficiency, and a long saw blade life can be realized.

It is a saw blade locus | trajectory figure of the conventional cutting method and a rocking | fluctuation cutting method. It is a conceptual diagram of the cutting method of the present invention. It is explanatory drawing of the cam mechanism which determines the speed change of a rocking | fluctuation. It is explanatory drawing (a front view, a top view, a side view) of embodiment of this invention.

  FIG. 1 is a simplified representation of a saw blade locus of a weighted cutting method (back component force limiting method) and a swing cutting method (cutting length limiting method). In the conventional back force limiting method, the cut becomes extremely shallow at a long cutting length, and an inappropriate state occurs in cutting conditions. On the other hand, in the swing cutting method, a uniform and appropriate cutting feed is maintained regardless of the cutting part of the workpiece. FIG. 2 is a conceptual explanatory diagram of the swing cutting method according to the present invention. The cutting feed is a screw mechanism and the swing mechanism is a cam mechanism that operates simultaneously with one drive. The swing fulcrum is a fixed point at the bottom for simplifying the structure. In order to minimize the influence of the cutting force, the cam position is the uppermost part farthest from the rocking fulcrum. Each function is organically arranged to realize a rocking cut structure with a simple structure. FIG. 3 shows a cam mechanism for swinging motion. The cam shape determines the swing speed change. It is desirable that the speed is constant at all positions, and since it is necessary to change direction instantly at the turning point, it becomes a heart shape.

4, 5 and 6 are a front view, a plan view and a side view of the embodiment of the present invention.
The workpiece (W) is placed on the bed (1) and held by the vice (2). The slide guide (4) of the band saw head (3) is supported by a portal frame (5) and a fulcrum shaft (6) fixed to the bed. A drive wheel (9) rotated by a saw blade motor (8) and a driven wheel (10) positioned on the opposite side to the workpiece are attached to the housing (7) constituting the band saw head. The saw blade (11) is circulated while being belted on both wheels. The saw blade is twisted by the insert guide (12) at the cutting action portion, and the blade tip faces downward. Then, the cutting edge is applied to the workpiece and gradually pushed to produce a cutting action, and cutting is performed.

In the present invention, the band saw head (3) and the guide frame (13) swing around the fulcrum shaft (6). The amount of swing is given by the cam (14) and the fixed cam follower (15). The cam is connected to a servo motor (16) that is driven by a cutting feed, and the cutting and swinging are controlled simultaneously. The cam position is provided at a position away from the cutting point to minimize the influence of the cutting reaction force. For the cutting feed, a ball screw (17) is used to give an accurate cutting amount. Since the band saw head is heavy and requires a large force when it is raised, a balancer cylinder (18) is provided to reduce the load on the servo motor and the ball screw.

  Shape steel, especially H-shaped steel, may cause a narrowing phenomenon during cutting, and the saw blade may be caught. To avoid this, use a special saw blade with a large cutting allowance. In oscillating cutting, the stenosis portion is cut again at the time of oscillating, so no special measures for stenosis are required. Therefore, it is also effective for cutting shape steel.

W Workpiece (Workpiece)
1 bed 2 vise 3 band saw head 4 slide guide 5 portal frame 6 fulcrum shaft 7 housing 8 saw blade motor 9 drive wheel 10 driven wheel 11 saw blade 12 insert guide 13 guide frame 14 cam 15 cam follower 16 servo motor 17 ball screw 18 balancer cylinder

Claims (2)

  A rocking mechanism in which a rocking fulcrum is provided at the lower part of the band saw machine bed, and the band saw head and its feed slide guide mechanism are rocked integrally with respect to the rocking fulcrum. A notch mechanism in which a cam mechanism for giving a swing amount is provided at the farthest part of the swing fulcrum, and the swing speed and the notch speed are controlled simultaneously by connecting the cam mechanism and a notch feed driving servo motor or through a speed change mechanism.

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