JPH05105456A - Method for blow-molding carved seamless tumbler - Google Patents

Abstract

PURPOSE:To automatically mold a tumbler having no seam lines on the outer surface except the carved part by press-forming a parison having a carved pattern with a specified thickness difference on the outer surface and spin blow-molding the parison in a blow mold. CONSTITUTION:A gob is press-formed in a rough mold 4 by a plunger 5 to obtain a parison 6, and a large carved pattern 2 is formed around the parison. The maximum difference (b-a) between the maximum-thickness part (a) and the maximum-thickness part (b) is controlled to >=2mm in the pattern 2, and hence the pattern 2 is not erased even in spin blow molding. The parison is brought out, placed in a blow mold and spun in a horizontal plane, and compressed air is blown in to spin blow-mold the parison 6 into the final shape. A seamless tumbler having a carved pattern on its outer surface is formed in this way by an automatic molding machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow molding method of a seamless tumbler having an engraved pattern on the outer surface and having no seam line on the outer surface other than the engraved portion.

[0002]

2. Description of the Related Art In order to blow-mold a glass tumbler having an engraved pattern on the outer surface with an automatic molding machine, a method of blow-molding a parison in a blow mold having an uneven pattern corresponding to the inner surface is blow-molded. Has been taken. However, in this case, as shown in FIG. 6, a seam line 3 which is a seam of the mold was inserted in a portion other than the engraved pattern 2 on the surface of the tumbler 1 to deteriorate the quality of the product.

Also, in order to eliminate such seam lines, a method of spinning a parison in a blow mold and blow molding has been known for a long time. However, in the case of a tumbler having an engraved pattern 2, this method cannot be used because the engraved pattern 2 portion is deformed when the parison is rotated with respect to the blow mold. It was used to form a tumbler without pattern 2.

[0004]

The present invention solves the above-mentioned problems of the prior art and provides a novel molding method capable of blow molding a glass seamless tumbler having an engraved pattern on the outer surface. It was completed for the purpose.

[0005]

Means for Solving the Problem The present inventor has tried and errored in order to solve the contradiction that a parison must be rotated and blown in order to form a seamless tumbler, and the engraved pattern cannot be formed by rotating and blowing the parison. As a result of repeating the above, it was found that if a deep engraving was previously formed on the parison, the engraving pattern would not disappear even if the parison was blown, and the desired seamless tumbler with engraving could be obtained.

The present invention has been completed based on the above findings, and a parison having an engraving pattern with a maximum thickness difference of 2 mm or more on the outer surface is press-molded, and this is rotated in a blow mold and blow-molded. The subject is a blow molding method of a seamless tumbler with engraving, which is characterized in that

[0007]

The present invention will be described in more detail with reference to the embodiments shown in the drawings. First, as shown in FIG. 1, a gob is press-molded by a plunger 5 inside a rough mold 4 to form a parison 6. A large engraved pattern 2 is formed on the outer surface of the parison 6 as shown in FIG. In the present invention, this engraving pattern 2 is formed such that the value of the maximum thickness difference b-a, which is the difference between the minimum thickness portion a and the maximum thickness portion b, is 2 mm or more. If the thickness difference is 2 mm or more in this way, the engraving pattern 2 will not disappear even if the resin is next blown. However, patterns less than this do not appear clearly in the final product. It goes without saying that the engraving pattern 2 should have an appropriate draft.

The parison 6 thus formed is held by the neck ring 7 and put in the blow mold 8 as shown in FIG. The neck ring 7 rotates in a horizontal plane, causing the parison 6 to rotate about its longitudinal axis. In this state, the blow head 9 is brought into contact with the upper surface of the neck ring 7, compressed air is blown therein, and the parison 6 is blown into the final shape in the blow mold 8. The blow mold 8 is a paste mold in which the porous layer 10 is formed on the contact surface with the parison 6. Further, by using the Hartford 28 machine well known in the art and rotating and blowing the porous layer 10 with water, the surface of the parison can be sufficiently cooled and the engraved pattern is hard to disappear.

In this way, the maximum thickness difference on the outer surface is 2 m.
When the parison 6 having the engraved pattern 2 of m or more is rotated and blow-molded, a part of the engraved pattern 2 of the parison 6 becomes thin due to contact with the porous layer 10, but most of it remains without disappearing. Further, the portion other than the engraving pattern 2 is blow-molded in the same manner as the conventional one, and a glass tumbler having no seam line can be obtained. The blow mold 8 may be of a split type or a pot type.

[0010]

As described above, according to the present invention, a seamless tumbler having an engraved pattern on its outer surface can be molded by an automatic molding machine. In addition, the engraved seamless tumbler formed by this method can be formed only by the artificial blowing method in the past, and has the same high quality image as the artificial blown product. Further, the molding method of the present invention can be easily carried out by using a glass molding machine such as the conventional 28 machine simply by changing the mold, and the range of moldable designs can be greatly expanded. it can. Therefore, the present invention has a great contribution to the industry as a blow molding method for a seamless tumbler with engraving which solves the conventional problems.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a parison molding step in the present invention.

FIG. 2 is a sectional view of the parison taken along the line AA of FIG.

FIG. 3 is a partial cross-sectional view showing a state in which a parison is transferred into a blow mold.

FIG. 4 is a cross-sectional view showing a blowing process.

FIG. 5 is a front view of a molded seamless tumbler with engraving.

FIG. 6 is a perspective view of an engraved tumbler formed by a conventional method.

[Explanation of symbols]

 2 Carved pattern 6 Parison 8 Blow mold

Claims (1)

[Claims] 1. A blow molding method for a seamless tumbler with engraving, which comprises press-molding a parison having an engraving pattern having a maximum wall thickness difference of 2 mm or more on the outer surface, and rotating and blowing the parison in a blow mold.