JPH01150517A - T-die for plastic extrusion molding - Google Patents

Abstract

PURPOSE:To improve the adjusting accuracy of fine thickness nonuniformity of a sheet width direction and also improve the product accuracy of a plastic sheet by constituting the wall thickness of a movable lip in the form of being equalized or reduced ranging from the basement end to the forward end of a T-die. CONSTITUTION:A movable lip 3 is projected out of the basement end 2 of the T-die main body 1 and a die slit gap 5 is formed between the movable lip 3 and the fixed lip 4 provided opposite to the movably lip and further the wall thickness T of the movable lip 3 is constituted in the form of being equalized straight or reduced like a slope ranging from the basement 2 to the forward end of the T-die main body 1. By this constitution, the movable lip 3 is performed so that the adjusting of lip open-degree during presetting may be possible and the adjusting of the fine thickness nonuniformity of a sheet width direction during plastic sheet molding to the push-pull motion of a die bolt 7 may also be possible.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a T-die for plastic extrusion molding.

(Prior art) T-dies for extrusion molding are used to manufacture plastic sheets or films, but in this case, the thickness unevenness in the width direction of the sheet can be adjusted by adjusting the die slit gap between the sheet and the fixed lip. A method is used in which the movable lip of the T-die is deformed by a load transmitting device such as a plurality of gouging bolts arranged at equal intervals in the width direction of the T-die to adjust the lip gap pattern.

That is, Japanese Patent Publication No. 60-50133, which the applicant previously applied for.
In the publication, as shown in FIG. 16, in a T-die a having a lip gap d between a fixed lip b and a movable lip C through which a sheet or film is extruded, the movable lip C
A constriction e is provided in order to increase the overall deformation of the movable lip C against a load, and the movable lip C is pushed and pulled by a plurality of equally spaced die bolts f.
There is a device in which the lip gap d between the fixed lip b and the fixed lip b is adjusted.

(Problem to be Solved by the Invention) In adjusting the thickness unevenness in the width direction of the sheet during such extrusion molding of plastic sheets, the movable lip of the conventional device has a mechanism for adjusting the relatively large thickness unevenness of the sheet. 1st
A constriction e as shown in Fig. 6 was provided.

However, with the recent improvements in quality and precision of plastic sheets, it has become necessary to finely adjust the thickness unevenness.

However, in the movable lip of the conventional device, since there is a constricted portion, the influence of mutual interference of lip displacement is large, and it is impossible to adjust fine thickness unevenness. The shape of the movable lip (fin) affects two important factors during sheet forming. The first factor is the absolute amount of the lip unit relative to the load, and the second factor is the lip displacement. This is a mutual interference effect.The first factor is related to the adjustment of the lip opening degree (average setting value of the initial lip gap) at the time of presetting, and the second factor is the average thickness in the width direction of the plastic sheet to be molded. It is related to the adjustment of local thickness unevenness.

Therefore, the thinner the wall thickness of the constriction of the movable lip, the more
The absolute amount of lip displacement with respect to the load becomes large, and the first factor, that is, lip opening adjustment, becomes more refined.

However, since the lip displacement curve approaches a flat surface and the mutual interference effect of lip displacement increases, it is not effective in correcting the second factor, that is, local thickness unevenness. When the mutual interference effect of lip displacement becomes large, in order to adjust the local thickness unevenness at a certain position in the sheet width direction, that is, fine thickness unevenness, the lip gap is adjusted by a load transmission device such as a die bolt corresponding to that position. Even if the lip is adjusted, it interferes with the lip displacement due to the load transmission position of the die bolt or the like at another position, and as a result, there is a problem that adjustment becomes impossible.

In view of this, the present invention eliminates the constriction in order to adjust the fine thickness unevenness of the sheet, and either makes the entire lip uniform in thickness or has a thin tip shape to reduce the mutual interference effect of lip displacement. , to provide a plastic extrusion molding square T-die which eliminates the drawbacks of the movable lip of conventional devices by making the lip displacement in the width direction of the movable lip more independent by means of load transmission devices such as individual die bolts. It was done for the purpose of

[Structure of the invention]

(Means for solving the gap) In order to achieve the above object, the present invention has a movable lip protruding from the base end of the T-die main body, and a die between the movable lip and a fixed lip provided opposite to the movable lip. A plastic extrusion molding angle T that forms a slit gap and adjusts the die slit gap while bending the movable lip by pushing and pulling a plurality of die bolts provided at equal intervals in the width direction on the movable lip side. The die is characterized in that the thickness of the movable lip is substantially the same or decreases from the proximal end to the distal end of the T-die main body.

(Function) With this configuration, the movable lip can adjust the lip opening degree during presetting and adjust minute thickness unevenness in the sheet width direction during plastic sheet molding with respect to push and pull of the die bolt.

(Embodiments) The present invention will be described below with reference to embodiments shown in FIGS. 1 to 15.

The square T-die for plastic extrusion molding according to the present invention has a movable lip 3 protruding from the base end 2 of the T-die body 1, and a die slit gap between the movable lip 3 and a fixed lip 4 provided opposite to the movable lip 3. 5 and the thickness T of the movable lip 3
(Fig.
It is constructed as shown in FIG. 1(a) and FIG. 1(b).

Figure 2 shows the influence of the wall thickness t of the conventional constricted portion of a movable lip and the wall thickness T of the present invention without constricted portion on lip displacement at each position in the width direction of the movable lip in response to load. This was analyzed using the finite element method.If the wall thickness T is increased so that the movable lip does not have a constriction as in the present invention, the absolute amount of lip displacement in response to a load will become smaller, but the difference between die bolt contact points will decrease. The result was that the deformation of was reduced.

Note that the displacement in the figure indicates the displacement of the bottom tip of the movable lip.
The bolt numbers shown on the horizontal axis are numbers assigned to the die bolts in order from the end of the T-die, and represent the position in the width direction of the lower end of the movable lip corresponding to each die bolt.
The analysis results shown in the figure show the case where a load was applied to the movable lip only by the No. 11 die bolt.

FIG. 3 shows the movable lip according to the present invention when the maximum load is applied to each position in the width direction of the movable lip by a load transmission device such as an individual die bolt with respect to a target pattern in the lip width direction; The difference in the convergence state of the movable lip displacement of the conventional device is shown. As an example of the calculation method, the optimum load for both was calculated using the method described in Japanese Patent No. 1323627.

According to this, in the case of Fig. 3(a), the lip displacement converges to the target pattern in both cases, but in Fig. 3(b)
), (c), (d), and (e), the lip displacement of the movable lip of the conventional device does not converge to the target pattern due to the mutual interference effect.

The lip displacement of the movable lip according to the present invention converges in (b), (c), and (e) with respect to the target pattern, and converges in (d) as well.

These results show that when the movable lip according to the present invention is used in plastic sheet molding, it is possible to flatten a sheet with thickness unevenness similar to the target pattern shown in Figure 3. is understood.

4 to 16 show other embodiments of the present invention, and parts common to those in FIGS. 1(a) and 1(b) are given the same reference numerals and will be described.

FIGS. 4(a), (b), and (C) show the contact state between the load transmitting device such as the die bolt 7 and the movable lip 3 in the T-die for extrusion molding, taking into consideration the equipment around 174 of the sheet molding line. Fig. 4(a) shows an inclined groove 8 on the upper surface of the movable lip 3.
4(b) and 4(c) show the movable lip 3.
Although the top surface of the tip is thickened, it is intended for the inclined arrangement of a load transmitting device such as the die bolt 7, and is substantially the same as that shown in FIG. It is included in

In FIG. 5(a), the wall thickness of the movable lip 3 is the same from the base end 2 of the T-die body 1, and grooves 9 of a predetermined width and depth are provided at equal intervals only in the width direction. (b) shows a fifth wall in the width direction of the thick movable lip 3 that is inclined from the straight side in (a).
As in Figure (a), grooves 9 of a predetermined width and depth are provided at equal intervals. Therefore, the depth of the grooves 9 can be arbitrarily selected to be shallower or deeper depending on the sheet or film to be molded.

The grooves 10 in FIGS. 6(a) and 6(b) are formed by extremely reducing the width of the grooves 9 of the movable lip 3 in FIGS. 5(a) and 5(b), respectively.

The grooves 11 in FIGS. 7(a) and (b) are narrower at the base end 2, wider and deeper at the distal end 6 than the grooves 9 in the movable lips 3, 3 in FIGS. 5(a) and (b). The same is true.

The grooves 12 in FIGS. 8(a) and 8(b) have the same width as the grooves 9 in the movable lips 3, 3 in FIGS. It is made deeper and has a slope.

The groove 13 in FIGS. 9(a) and 9(b) is the same as the groove 9 of the movable lips 3, 3 in FIGS. , the groove 14 in FIGS. 10(a) and (b) is the same as the groove 13 in FIGS. 9(a) and (b).
It is made shorter than the length of , with only 6 parts at the tip.

The grooves 15 in FIGS. 11(a) and 11(b) are similar to those in FIG. 9(a).
And holes 15.15 are formed at equal intervals in the width direction between the proximal end 2 and the distal end 6 as a substitute for the groove so that the distal end 6 side of the groove 13.13 in (b) is filled. It was established in

The grooves 16 in FIGS. 12(a) and 12(b) are similar to those in FIG. 1(a).
A thin U-shaped groove 16 is provided at an appropriate depth at the tip 6 in the width direction of the movable lip 3 in (b) so as to face the tip 6.

FIGS. 13(a) and 13(b) show a hole 17 of an appropriate thickness and depth provided horizontally from the end surface 6a on the distal end 6 side toward the base end 2 directions instead of the grooves as described above. It is.

In FIG. 14, the proximal end 2 side of the groove 9 in FIG. 5(a) is formed into an R shape, and the end surface of the groove 9 is further chamfered 9a.

Although several embodiments have been listed above, it goes without saying that the present invention is not limited to these embodiments, and any similar embodiments are included in the present invention.

Regarding the arrangement of the die bolt 7, FIG. 15 shows an example where the die bolt 7 is provided at a high place between the grooves 9 of the movable lip 3,
Figure 6 shows an example where the die slit gap 5 is provided in the groove 9.
You are free to select and use them as appropriate.

〔Effect of the invention〕

As explained above, according to the present invention, the adjustment precision of fine thickness unevenness in the sheet width direction during plastic sheet (film) molding is improved, the product precision of the plastic sheet (film) is improved, and the movable lip Processing is easy as there is no need for a constriction like in the past.
Effects such as reduced machining time and improved strength of the movable lip can be obtained.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the T-die for plastic extrusion molding according to the present invention, (a) is a straight type, (a) is a straight type, (a) is a straight type;
b) is a side view of the slope type, Fig. 2 is a graph showing the experimental results of the influence of wall thickness in the present invention and conventional wall thickness on lip displacement under load, Fig. 3 (a), (b)
,(c). (d) and (e) are graphs showing a comparison between the movable lip of the present invention and the movable lip of the conventional device in a convergence state of lip displacement with respect to the target pattern, and FIG. 4(a). (b) and (C) are perspective views of an embodiment of the inclined arrangement of a load transmitting device such as a die bolt with respect to the movable lip according to the present invention, and Figs. 15 and 16 are perspective views showing another embodiment in which a load transmitting device such as a die bolt is arranged for the movable lip of the present invention, and FIG. 17 is a perspective view showing a conventional extrusion molding device. It is a perspective view of a T-die. DESCRIPTION OF SYMBOLS 1...Die body, 2...Base end, 3...Movable lip, 4...Fixed lip, 5...Die slit gap, 6
...Tip, 7...Die bolt, T...Thickness (movable lip). Applicant's representative Mr. Sato Figure 1 Figure 2 Movable Litz of conventional device. Fig. 3 (b) (LQ 〇 I Cbas x) TI (C) Fig. 4 (a) (b) Fig. 5 (a) (b) Fig. 6 (a) 1st (b) 9 Figure (b) Figure 0 (a) (b)
Figure 11 Figure 12 Figure 15 Figure 16 Figure 14 Figure 17

Claims (1)

[Claims] 1. A movable lip is protruded from the base end of the T-die main body, and a die slit gap is formed between the movable lip and a fixed lip provided opposite to the movable lip, and the width of the movable lip side is In a T-die for plastic extrusion molding in which the die slit gap is adjusted by bending a movable lip by pushing and pulling a plurality of die bolts provided at approximately equal intervals in the direction, the wall thickness of the movable lip is A T-die for plastic extrusion molding, characterized in that the main body is substantially the same or decreases from the base end to the distal end. 2. The T-die for plastic extrusion molding according to claim 1, wherein the movable lip has a plurality of grooves arranged in a width direction extending from the proximal end side to the distal end side.