JPH071547A - Metal mold for extrusion molding of synthetic resin sheet - Google Patents

Abstract

PURPOSE:To provide a metal mold for extrusion molding of a synthetic resin sheet wherein change of a clearance of a resin passage parallel part (a land) in changing a product sheet thickness can be easily carried out in sufficiently short time, and the clearance can be set with hight precision. CONSTITUTION:A metal mold is divided into an upper part and a lower part. A spacer 2 setting a clearance of a parallel part (a) is put between mated faces of the metal molds 11, 12 having a resin passage consisting of a resin inflow port 13, a manifold 4, and the parallel part (a), between the upper and lower parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold used for extrusion molding of synthetic resin sheet.

[0002]

2. Description of the Related Art When a synthetic resin sheet is extrusion-molded, a sheet molding die is connected to the extruder and the resin sent from the extruder is made into a product sheet width within the die. It is necessary to spread it up to the end and extrude it in a sheet shape from the tip of the mold.

Conventionally, as this sheet molding die, FIG.
(A) and T-type manifold shown in (b) of FIG.
Ludodai is known. In this T-type manifold die, an upper lip 152 'and a lower lip 151' are formed on the inner surfaces of the tips of the upper mold body 12 'and the lower mold body 11' having a resin inflow hole 13 'and a manifold 14'. Are attached respectively, and these upper and lower lips are used to connect the parallel part a ′ of the resin flow path.
(Land) is formed. When the resin from the extruder reaches the manifold 14 'through the resin inflow hole 13', the resin is spread in the width direction, and this width-direction expanding resin is a resin flow path parallel portion a between the upper and lower lips 151 ', 152'. 'In the product shape (see
(Shaped), while being extruded from the tip of the mold.

In this T-type manifold die, the factor for setting the product sheet thickness is the clearance of the resin flow path parallel portion a ', that is, the clearance between the upper and lower lips 151', 152 '.

Therefore, in order to change the thickness of the product sheet,
Replacing the upper lip or lower lip is usually required,
The thickness of the product sheet is changed according to the following work procedure.
Ie. First, suspend the operation of the production line, stop the extruder, remove the mold from the extruder, move it to a predetermined mold disassembly location, disassemble and disassemble the mold body up and down,
Cleans by removing the attached resin, releasing the bolt fastening between each lip and each die body, removing the lip from the die body, and temporarily fastening each lip to each die body with bolts Then, tighten the upper and lower mold bodies with bolts, adjust the clearance between the upper and lower lips,
After setting the clearance to the set value, each lip is finally fastened to each mold body, the mold is connected to the extruder, and preparations for restarting production are made. It is carried out according to the work procedure such as restarting.

[0006]

The number of bolts to be fastened to the die body of the above-mentioned lip (one of these bolts is indicated by 4'in FIG. 3A) reaches several tens. , The lip bolt hole is slightly larger than the bolt in order to allow a slight positional deviation in processing of the lip bolt hole. Therefore, after each lip is temporarily fastened to each mold body with bolts and these upper and lower mold bodies are fastened with bolts, as shown above, each lip is finely adjusted up and down and the clearance between the lips is set to a predetermined clearance. It is necessary to finally fasten each lip to each mold body with a set value of.

However, bolting each lip to each mold body while maintaining the clearance between the upper and lower lips at a predetermined value is not easy and requires skill, and the width of the lip is wide. Since the number of bolts to be fastened reaches several tens (usually about 70), it takes a long time and the productivity is inevitably reduced.

It is an object of the present invention to easily change the clearance of the resin flow path parallel portion (land) when changing the thickness of the product sheet in a sufficiently short time, and moreover, to make the clearance highly accurate. An object is to provide a mold for synthetic resin sheet extrusion molding which can be set.

[0009]

The synthetic resin sheet extrusion molding die of the present invention is divided into upper and lower parts, and has a resin flow path consisting of a resin inflow hole, a manifold and a parallel portion between the upper and lower parts. A spacer for setting the clearance of the parallel portion is held between the mating surfaces of the molds.

[0010]

The clearance of the parallel portion of the resin flow path to be set is set with the accuracy of the thickness of the spacer. in this case,
Since the spacer is clamped at the same time when the mold is fastened using the upper and lower fastening bolts, unlike the conventional method of setting the clearance in the resin flow path parallel part by mounting the lip, It does not require bolting to attach to the body. Further, even if the spacer is misaligned when the spacer is held, the misalignment does not have any effect on the space between the upper and lower molds, and the above clearance is ensured to ensure the thickness of the spacer. It can be set with accuracy.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A shows the main members used in the present invention, and FIG. 1B is a sectional view taken along the line RO in FIG.

In FIGS. 1A and 1B, 11
Is a lower mold and 12 is an upper mold. A resin inflow hole 13 and a manifold 14 are formed on the inner surface of the main body so that the resin flow path shown in FIG. A lip portion 15 is connected to the main body portion 10. 1
6 are bolt holes with a bottom formed in the lower mold, and 17 are bolt holes formed in the upper mold 12. Reference numeral 2 denotes a spacer, which has an outer shape equal to the mating surfaces of the upper and lower dies and has bolt insertion holes 21, corresponding to the bolt holes 16 ,.
... is provided.

FIG. 2 shows an embodiment of the mold of the present invention, in which the spacer 2 is sandwiched between the upper and lower molds 11 and 12, and these are bolts 3.
Are fastened together and assembled into a mold. In addition,
Similar to the conventional die, side pieces are attached to both ends of the width of the upper and lower dies by bolt fastening, and both ends of the parallel portion of the resin flow path are closed, but the side pieces are not shown. .

In the die assembly of the present invention, even if the position of the bolt insertion hole 21 of the spacer 2 is slightly deviated from the position of the bolt hole 16 (17) of each mold 11 (12) in processing, The bolt insertion hole 21 of the spacer 2 is slightly larger than the diameter of the bolt 3 so as to absorb the deviation.
Even under such circumstances, it is possible to assemble the mold so as not to hinder the resin flow in the resin flow path, and the front end face 221 of the spacer 2 is connected to the manifold by a normal mold processing technique.
Align the part of the field 14 without any steps and
It is possible to align the lateral end surface [222 of FIG. 1 (A)] of the resin 2 with the part of the resin inflow hole [13 of FIG. 1 (A)] without any step.

The front end surface 221 of the spacer 2 serves as a resin flow path surface and is located near the resin flow path parallel portion where the sheet product is shaped. Is preferably finished.

In the mold of the present invention, as shown in FIG. 2, the resin flow path parallel portion a (a in FIG. 2) is formed according to the thickness of the spacer 2.
Even if the spacer 2 is displaced when the spacer 2 is held between the upper and lower dies 11 and 12,
The deviation is in the horizontal direction and has no effect on the interval between the upper and lower molds 11 and 12, and hence the clearance of the resin flow path parallel portion a, and the spacer 2 can be parallel to the resin flow path with the thickness accuracy of the spacer 2. The clearance of the part a can be set.

In the present invention, the spacer 2 has a sufficient thickness and heat resistance even under the tightening pressure by bolt fastening, and preferably has no affinity for the molten resin. Materials are used, and in addition to metals such as steel, ceramics and engineering plastics can also be used.

The mold of the present invention is a synthetic resin sheet (hard vinyl chloride resin, soft vinyl chloride resin, chlorinated vinyl chloride resin, polyethylene, polypropylene, polycarbonate).
It is used for extrusion molding of sheet, acrylic resin, polystyrene, etc., and the thickness of the sheet can be easily changed.

The thickness of the sheet is changed in the following work procedure. That is, first, the operation of the production line is interrupted, the extruder is stopped, the mold is removed from the extruder and moved to a predetermined mold dismantling place, the mold is disassembled into upper and lower molds, and the existing space is used. -The mold is removed by removing the spacer, removing the resin adhered to each mold and cleaning it, then sandwiching a new spacer having a predetermined thickness between these upper and lower molds and fastening them with bolts. Is connected to an extruder to prepare for restarting production, the extruder is re-driven, and production is restarted.

As compared with the conventional case where the sheet thickness is changed by changing the lip, it is not necessary to attach and detach a large number of bolts (usually about 70) for replacing D.
Further, it is not necessary to adjust the clearance of the parallel portion of the resin flow path and to set the clearance to a predetermined value, and a spacer having a predetermined thickness is sandwiched between the upper die and the lower die, and the upper and lower bolts are clamped. Since only fastening is required, the sheet thickness of the product can be changed in an extremely short time.

Moreover, if the clearance of the parallel portion is completely fastened even by fastening the bolts, the clearance of the parallel portion can be reliably set to a predetermined value with the thickness accuracy of the spacer, and the reproducibility is also good.

In the mold of the present invention, synthetic resin sheets of various thicknesses can be manufactured by preparing spacers of various thicknesses according to the sheet thickness of the product. For example, in the case of a mold having only the upper mold and the lower mold having a clearance of 4.5 mm in the resin flow path parallel portion, a sheet having a thickness of 3 to 4 mm is adjusted by adjusting the roll gap outside the mold and adjusting the take-up speed. However, according to the present invention, a spacer having a thickness of 2.0 mm can be manufactured.
If the spacer is held between the upper and lower dies, a sheet having a thickness of 4 to 7 mm can be manufactured. If the spacer having a thickness of 6.0 mm is held between the upper and lower dies, the sheet having a thickness of 7 to 10 mm can be produced. Can be manufactured.

Needless to say, in the mold of the present invention, the lip portion can be detachably attached so as to be replaceable against wear or the like.

[0024]

EFFECT OF THE INVENTION The synthetic resin sheet extrusion molding die of the present invention is constructed as described above, and the clearance change depending on the product sheet thickness of the resin flow path parallel portion (land) can be changed. -It can be done only by unscrewing the fastening bolts between the upper and lower molds that sandwich the tool, and it is not necessary to replace the lip with the conventional mold, and the number of unscrewed bolts can be changed when changing the thickness of the product sheet. It is possible to remarkably reduce the clearance, and it is not necessary to adjust the clearance when setting the clearance to a predetermined value, so that the working time required for changing the thickness of the product sheet and the number of steps can be reduced.

In addition, if the upper and lower fastening bolts are completely tightened, the clearance can be set to a predetermined size with the thickness accuracy of the spacer, and the reproducibility is excellent.
The stability of product dimensions can be secured.

Further, since the spacer is flat, the processing cost is lower than that of the lip, which is advantageous in terms of cost.

[Brief description of drawings]

1 (a) is a perspective view showing main members constituting a mold of the present invention, FIG. 1 (b) is a cross-sectional view taken along the line of FIG. 1 (a). (C) is an explanatory view showing a resin flow path constituted by the member of (A) of FIG. 1.

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

3 (A) is an explanatory view showing a conventional example, and FIG. 3 (B) is a cross-sectional view taken along line (A) of FIG.

[Explanation of symbols]

 11 Lower mold 12 Upper mold 13 Resin inflow hole 14 Manifold a Parallel part 2 Spacer

Claims (1)

[Claims] 1. A spacer for setting a clearance of the parallel portion on a mating surface of a mold which is divided into upper and lower parts and has a resin flow path composed of a resin inflow hole, a manifold and a parallel portion between the upper and lower portions. A synthetic resin sheet extrusion molding die which is held.