JPH05309757A - Cutting method for weld reinforcement of plastic plate - Google Patents

Abstract

PURPOSE:To improve not only the outer appearance of a welded section but also the mechanical strength of the same by sliding a bottom plate of a cutting tool on a plastic plate while a notch section is passed through a weld reinforcement section and bringing a rotating roll blade with thick sections at its cutting edge into contact with the weld reinforcement section. CONSTITUTION:A rotating roll blade 2 with thick sections of slow curvature on its body supported in a casing 1 along a cutting edge 12 is installed, and a notch section 3 formed on a bottom plate 11 is released over a weld reinforcement section to slidingly move the casing 1 on a plastic plate. The bottom plate 11 is brought into contact with the plane of the plastic plate, and the rotating roll blade 2 is rotated by an electric motor 23, and a cutting tool is moved while the bottom plate 11 is retained to be in contact with the plane of the plastic plate by means of a handle 26. In that case, the reference level of cutting is set by a lower face 111 of the bottom plate 11 being in contact with the plane of the plastic plate P, and cutting is carried out by a thick section DELTAt of the rotating roll blade 2 coming out of the cutting edge 12. The curvature of a recessed curved face, therefore, is small and the concentration of stress can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surplus cutting method for a plastic plate welded portion which is used for cutting a weld surplus portion generated during welding of a plastic plate and increasing the mechanical strength of the welded portion. ..

[0002]

2. Description of the Related Art When welding a plastic plate, a plastic welding rod is pushed along a groove of a plastic plate, which is a base material, at a predetermined angle and with a predetermined pressing force, and the two are contacted immediately before they come into contact with each other. Only the outermost surface is melted by a hot jet gun or the like, and both are welded by the above pressing force.

Therefore, unlike the case of welding a metal plate,
Since the welding rod is not in a molten fluid state and filled between the base metal grooves, it is welded between the base metal grooves while maintaining a rod-like shape to some extent. It is easy for protrusions and excesses to occur.

Conventionally, for the appearance of a welded portion of a plastic plate, the welded portion may be cut after welding for appearance reasons. The cutting tools are disc grinders, files, and chamfering knives. Etc. are used.

[0005]

In welding of the above plastic plates, if the pressing force of the plastic welding rod is excessive, the welding rod considerably exceeds the upper end of the base material groove and reaches the base metal plane edge portion. Spreading phenomenon (overlap) occurs,
Also, if the pressing force of the plastic welding rod is too weak,
A phenomenon (undercut) occurs in which the welding rod does not reach the upper end of the base metal groove and a valley is formed inside the upper end of the groove.

In the undercut, however, stress concentration is mechanically caused by the notch effect, and the mechanical strength of the welded portion is impaired. Also, in the case of an overlap, if the surface change at the overlap portion is abrupt, a considerable stress concentration occurs and there is a mechanical problem.

However, in the cutting of the welding extra portion using the conventional disk grinder, file, chamfering knife, etc., the above undercut and overlap are deleted in a state where stress concentration can be eliminated. It is difficult and, on the contrary, often leads to further mechanical weakening.

It is an object of the present invention to provide a method for cutting a weld surplus portion, which is capable of eliminating stress concentration due to undercut or overlap of the weld portion, rather than simply cutting the weld surplus from the viewpoint of appearance. Especially.

[0009]

SUMMARY OF THE INVENTION A surplus cutting method for a plastic plate welded portion of the present invention is a method for cutting a weld surplus portion of a welded plastic plane plate, which comprises a medium-weight rotary roll blade. , A bottom plate having a blade opening for the roll blade, and a cutting tool having a notch for passing through the welding extra portion in the bottom plate, the bottom plate on a plastic plate,
It is characterized in that the notch portion is slid while passing through the extra weld portion, and the rotary roll blade is brought into contact with the extra weld portion at the blade opening.

[0010]

[Operation] The cut surface after cutting the extra welded portion is a concave curved surface with a gentle curvature due to the moderate curvature body portion of the center-thickness rotating roll blade, and stress concentration is well avoided. it can. Therefore, even if the cutting amount is increased to the extent that the undercut or overlap of the welded portion can be removed, the mechanical strength of the welded portion can be sufficiently ensured.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 (a) is a plan view of a cutting tool used in the present invention, and FIG. 1 (b) and FIG. 1 (c) are cross-sectional views and cross-sections in FIG. 1 (a). It is a figure.

In FIG. 1A to FIG. 1C,
Reference numeral 1 is a casing, and the bottom plate 11 is a plastic plate having a low friction coefficient, for example, an ultra high molecular weight polyethylene plate. Reference numeral 12 is a blade provided on the bottom plate 11. Reference numeral 2 denotes a medium-thickness rotary roll blade having a body portion having a sufficiently loose curvature, which is supported in the casing 1 so as to face the blade opening 12, and is a casing.
The vertical support shafts 21 and 21 are attached to the upper plate 13 of the sing 1 so as to be able to move up and down by adjusting screws 22 and 22, and the rotary roll blades 2 are pivotally supported at the lower ends of the vertical support shafts 21 and 21. ..

Reference numeral 23 is an electric motor for driving the rotary roll blade 2, and the electric shaft of the motor 23 is connected to the rotary shaft of the rotary roll blade 2 by a transmission belt 24. .. 25
Is a cover for housing the electric motor 2, and 26 and 26 are handles.

Reference numeral 3 denotes a notch provided in the bottom plate 11, which allows the casing 1 to be slidably moved along the welding line on the plastic plate by escaping the welding extra portion. Using the above cutting tool, the bottom plate 1 of the cutting tool is used to cut the welding extra portion of the plastic plate according to the present invention.
The welding extra portion is released in the notch 3 of No. 1, the bottom plate 11 is brought into contact with the flat surface of the plastic plate, the electric motor 23 is driven to rotate the rotary roll blade 2, and the handle 26 is operated. While maintaining the contact between the bottom plate 11 and the flat surface of the plastic plate, the cutting tool is moved in the extending direction of the welded portion to rotate the rotary tool.
Cut the extra weld area with the blade 3.

In this case, in the final cutting stage, as shown in FIG. 2, the reference level of cutting is the plastic plate P.
Of the bottom plate 11, which is kept in contact with the plane P of the bottom plate 11, and is cut by the thickness portion Δt of the rotary roll blade 2 exposed from the blade opening 12 of the bottom plate 11. Be seen. Therefore, as shown in FIG. 2, the cutting surface a of the welded portion W becomes a concave curved surface having the same curvature as the body of the rotary roll blade 2 having a sufficiently gentle curvature, and the curvature of the concave curved surface is extremely small. Therefore, the stress concentration can be sufficiently eliminated, and when there are undercuts or overwraps in the weld surplus portion, the cutting amount should be increased to a certain extent so that these undercuts or overwraps can be deleted. However, the mechanical strength of the welded portion can be sufficiently ensured.

In the above, as an intermediate cutting stage,
As shown in FIG. 3, the support level of the rotary roll blade 2 is set so that the lowermost level n of the rotary roll blade 2 is set to an intermediate level between the upper end b of the welding extra portion and the plane level c of the plastic plate. Adjust the height and perform cutting with this intermediate level rotary roll blade,
Then, the final cutting step shown in FIG. 2 may be performed. In particular, when the thickness of the plastic plate is large and the height of the welding extra portion is high, this intermediate cutting step should be provided. Is preferred.

In the above, when the welded portion is straight, as shown in FIG. 4, the guide bar 4 is arranged in parallel with the welding line L, and both ends 41, 41 of the welded portion L are clamped to the plastic plate P by the clamps 42, 42. Alternatively, the side wall 10 of the casing 1 of the cutting tool may be fixed and brought into contact with the guide bar-4, and the cutting tool may be moved along the guide bar-4. In this case, the side wall 10 of the cutting tool, the guide bar 4, or both can be molded of a plastic having a low friction coefficient, for example, ultra high molecular weight polyethylene.

In the above, it is also possible to perform buffing after cutting the extra welded portion, and it is particularly desirable to perform buffing in a transparent plastic plate used for optical applications.

[0019]

As described above, in the method of cutting the excess of the plastic plate welded portion of the present invention, the flat and thick surface of the plastic plate is cut by using the medium-thickness rotary roll blade having the body portion having the gentle curvature. As a reference level, the weld roll can be cut with the exposed thickness of the rotary roll blade from the blade opening of the tool bottom plate, and even if there is an undercut or overlap in the weld roll, the rotary roll can be rotated. By properly setting the exposed thickness of the blade, it is possible to delete the undercut or overwrap, and even under such deletion, the cutting surface can be rotated with a thicker rotary roll.
Since the body portion of the blade can be formed into a concave curved surface with a gentle curvature and stress concentration can be avoided well, not only the appearance of the welded portion can be improved but also the mechanical strength can be increased by cutting the extra welded portion.

[Brief description of drawings]

1A is a plan view of a cutting tool used in the present invention, and FIGS. 1B and 1C are FIG. 1A.
FIG. 3 is a cross-sectional view and a cross-sectional view taken along the line of FIG.

FIG. 2 is an explanatory diagram showing an example of the present invention.

FIG. 3 is an explanatory view showing a cutting state at an intermediate stage used in the embodiment of the present invention.

FIG. 4 is a plan view showing another embodiment of the present invention.

[Explanation of symbols]

 11 Bottom plate 12 Blade opening 2 Rotating roll blade 3 Notch

Claims (1)

[Claims] 1. A method for cutting a welded extra portion of a welded plastic flat plate, comprising a rotary roll blade having a middle weight, the bottom plate having a blade opening for the roll blade, and A cutting tool having a cutout portion for passing through the welding extra portion is slid while the bottom plate is placed on a plastic plate while the notch portion is passing through the welding extra portion, and the rotary roll blade is provided at the above-mentioned blade opening. A method for cutting a surplus of a welded part of a plastic plate, which comprises contacting the surplus weld with a welded part.