JPS60198214A - Controlling method of sheet thickness in calendering - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field] The present invention is a method for producing sheets by calender-molding thermoplastic materials such as rubber and plastics! BI! The present invention relates to a method for controlling the sheet thickness of Hiroosu's pancreas.

[Prior art and its problems]

In calender molding, controlling the thickness of the product is important. Conventionally, as a method for controlling the thickness of a sheet as a product, a method of increasing the gap between forming rolls or a method of adjusting the take-up speed of a Tikuoff roll has generally been adopted.

The former method involves measuring the gap between the forming rolls and adjusting the gap to a proper gap by operating the rolling device of one of the rolls.

However, this method requires a roll gap measuring device, and when performing control that requires high responsiveness, such as roll eccentricity correction, a normal electric motor type down device is insufficient, and the responsiveness is insufficient. There is a problem in that the pressure is high and it is necessary to change to a hydraulic cylinder type lowering device with a large output.

In addition, in the latter method, the rotational speed of a tick-off roll (take-off reroll) installed immediately after a pair of n final forming rolls is changed to adjust the sheet take-up speed, and thereby one of the final rolls is The thickness of the sheet is adjusted by stretching and pulling the sheet wrapped around the roll. However, although this method poses no problem when simply adjusting the average thickness, when performing roll eccentricity correction control, control of each roll speed after the tick-off roll becomes very complicated and is virtually impossible.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and is capable of stabilizing sheet thickness fluctuations caused by periodic roll gap fluctuations due to roll eccentricity, without using conventional gear adjustment methods or sheet take-up speed adjustment methods. It is an object of the present invention to provide a method for controlling sheet thickness in calender forming, which can be easily and reliably corrected in a controlled operation.

[Principle underlying the invention]

The present invention is based on the principle that the thickness can be adjusted by changing the relative speed of the final stage forming rolls.

First, the principle described above will be briefly explained with reference to FIG. is formed into sheet 2,
The sheet 2 is taken up by a tick-off roll Rt rotating at a speed Vt. At this time, the sheet 2 is taken up while being wound around the roll Rh on the taking-up side. In such calender forming, when the speed Va of the roll Ra is increased (or decelerated) while the speed Vb of the roll Rh is kept constant, a compressive force (or tensile force) is generated in the sheet 2 at point A. do. Also, the speed Va of the roll Ra and tick-off roll Rt.

When the speed vb of the roll Rb is increased (or decelerated) while keeping Vt constant, a tensile force (
Conversely, at point B, a compressive force (or tensile force) is generated in the sheet 2. The thickness of the sheet 2 is made thinner or thicker due to the tensile force or compressive force on the sheet 2 generated at points A and B.

As for the amount of change in the thickness of the sheet 2 at point A, the following relationship is first derived from the equation of continuity.

That is, the thickness change rate Δ when fr changes by Δfr
H/)l is as follows. Here, H: sheet thickness G,: coefficient fr=Vb/Va determined by the roll gap, varnishing ratio, etc.: speed ratio (variable) afr/fr: rate of change in speed ratio.

Since the rate of change is equal to the rate of change in speed, Δvb Change in speed of two rolls Rb b=Average speed of roll Rb Next, the effect of the eccentricity of these rolls Ra and Rb on the sheet thickness will be explained.

Generally, the above-mentioned forming rolls have some degree of eccentricity due to various factors including dimensional errors during manufacturing. For example, among a pair of forming rolls, let the eccentricity of one roll with respect to the rotation angle θ be a, sin θ1, and the eccentricity of the other roll with respect to the rotation angle 1 be a, s
jn#.

Then, the gap variation between both rolls is a, sinθ
, + a, sin θ2. Since the rotation angles θ8 and θ of the rolls change in a patent manner, and the rotation speed ratio of these rolls takes a small value of 1.0 to 1.5, this composite function has an amplitude that is approximately 1) A curve 13 occurs, and the gap variation caused by this curve results in a variation in the thickness of the sheet.

In the thickness control method described above, the thickness of the sheet can be controlled simply by adjusting the rotational speed of the roll, and even delicate adjustments can be made with extremely good responsiveness. Therefore,
By adjusting the rotational speed of the roll so as to correct the gap variation (sheet thickness variation) caused by the beat caused by the eccentricity, the sheet thickness can be kept constant.

By the way, when controlled using the method described above, the composite function of roll gap fluctuations produces a beat whose amplitude increases and decreases in a certain period due to the difference in eccentricity between each roll and the rotational speed ratio. During large periods, the rotational speed of the rolls will change significantly, resulting in uneven kneading of the thermoplastic material in the bank due to the difference in speed ratio.

In order to deal with this problem, basically, the roll gap fluctuation can be made as small as possible and then the rotational speed of the rolls can be adjusted.

[Specific configuration of the invention]

Based on the above principle, a sheet thickness control method for correcting periodic sheet thickness fluctuations due to roll eccentricity will be specifically described below.

FIG. 2 shows an example of calender forming using so-called inverted calender rolls. In FIG. 2, the thermoplastic material of bank l is sequentially rolled into rolls R1, R1,
Ro and R4 are used to form a sheet 2, and this sheet 2 is taken off from the final roll R4 by a tick-off roll Rt. Roll R forming a pair of rolls in the final stage.

and roll R4 are eccentric by amounts indicated by C1 and C4, respectively, as shown.

In the present invention, as shown in FIG.
The average rotational speed of each roll R1 and R4 in one rotation is electrically controlled to be equal, and the average eccentric phase of each roll R1 and R4 is controlled to be in the same phase, and further one roll R, (or roll R4) is a constant rotational speed, and the other roll R,
(or roll R,) is controlled in speed in relation to fluctuations in the roll gap G. In other words, in the present invention, by performing average equal rotation control and same phase control, the gap fluctuation between both rolls can be kept within the minimum range, and the difference in eccentricity between both rolls (
In order to eliminate the uneven thickness of the sheet as shown in FIG. 4 due to
When the rotational speed of roll R4 is 14, the rotation of rolls R0 and R4 is determined to have the following relationship, and the speed of the roll on the speed adjustment side is periodically varied in relation to the fluctuation of the roll gap G with respect to the rolls. This keeps the thickness of the sheet constant (see Figure 5).

To explain in more detail the case of controlling under the condition (b),
These eccentric amounts C, , C4 in rolls R1 and R4
The gap G between roll R1 and roll R4 varies, and the amount of variation ΔG is ΔG-e3coSω3t-e4cOSω4t...
・Represented by (3). Here ω. : Angular velocity of roll R, [constant surface] ω, : Angular velocity of roll R4 (however, the average value for one period of ω: “,=ω.

It is.

Therefore, from equations (1) and (3) above, the amount of variation ΔH in the thickness H of the sheet 2 is expressed as , cosω4t) """ (represented by 41).

Therefore, in order to correct and control this fluctuation amount ΔH, the roll R
0 and the rotational speed of the tick-off roll Rt are kept constant, and only the rotational speed v4 of the roll R4 is changed. Then, tensile forces or compression horns are applied to the sheet 2 at each point indicated by center and B in FIG. Here, above A
The point indicates the point where the sheet 2 is sandwiched between the rolls R and R4, and the point B indicates the point where the sheet 2 is pulled by the tick-off roll Rt and peeled off from the roll R4.

Therefore, when the speed v4 of the roll R4 is changed by Δv4, the changes in the thickness of the sheet 2 at points A and B are as follows.

[B] The thickness change of sheet 2 at point A is Δ) IITI
When A, this ΔHIIIA is expressed as follows. Here, Hm: average thickness fr of sheet 2 =
v, /v, is the average speed ratio.

(b) If the thickness change of the sheet 2 at point B is ΔHmB, this ΔHIIIB is.

It is expressed as ΔHm B-(8-(Hm,?))XΔv4.

In the above [B] and extension], equation (5) and (
Both ΔHmA and ΔHmB shown in equation 6) are vector quantities. Therefore, below, these ΔHmA and ΔHn
+n is represented by 2 and 2, respectively.

The 1 yield obtained by combining these 5 and 1 Te indicates the change in thickness given to the sheet 2 and its direction when the speed v4 of the roll R4 is changed by Δ■4. .

Therefore, the above equation can be expressed as follows from equations (5) and (6) above: Here, since the amount of change in fr during one rotation is small, there is no practical problem even if fr''=fr'' in the above equation. Therefore, for the above 7, where θ is the angle between ge and ``) (see Figure 6),
Moreover, this phase 6 is expressed as follows. Therefore, the above [T'iii'fr
<In order to correct the above-mentioned thickness variation amount ΔH of the sheet 2, it is sufficient if ΔH−17×1=0. Therefore, the above (4
), (7) and (8), 1+fr K ・−, −, −(e3cos@3t, −φ) −e, Q
Q & (ω, t-φ month) If this is expressed in terms of ΔV, it is expressed as follows.

That is, the eccentricity C8, c of roll R0 and roll R4
Correction of the thickness variation of the sheet 2 according to 4 can be performed by adding a periodic variation represented by Δ■4 in the above a@ formula to the rotational speed V of the roll R4.

The various coefficients for obtaining the above-mentioned Δv4 can be easily obtained from the eccentricity C1, the amount of eccentricity C1, which is individually measured for each roll in advance, and the commonly used fr value. Further, by analyzing several variations in sheet thickness obtained by rotating roll R0 and roll R4 at a constant speed in advance, various coefficients for obtaining a more accurate ΔV can be calculated.

The various coefficients obtained from these are then applied to an analog or digital cos signal generator synchronized with the rotation of the roll to generate the same waveform as in equation (a) above, which is then applied to the rotational speed v4 of the roll R4. Addition input to speed control circuit. Thereby, the rotational speed v4 of the roll R4 can be varied by Δv4, and the thickness variation of the sheet 2 can be corrected.

〔Effect of the invention〕

As explained in detail above, according to the present invention, (i)
The sheet thickness can be controlled by simply adjusting the rotational speed of one of a pair of forming rolls, eliminating the need for conventional methods such as gap adjustment and sheet take-up speed adjustment. There is no need to install a dimension measuring device, and there is no need for troublesome control such as adjusting the speed of the take-off line below the pick-off roll one by one to make it consistent.Q) Also, it is possible to compensate for gap fluctuations caused by roll eccentricity By periodically adjusting the rotational speed of the rolls, the sheet thickness can be kept constant and product thickness can be more strictly controlled.
■ The rotational speed of the rolls is always adjusted in the region where the roll gap fluctuation is the smallest by controlling the average rotational speed of both rolls in one rotation to be equal and the eccentric phases to be equal on average. Therefore, the rate of speed fluctuation applied to the rolls is small, and therefore the excellent effect that the kneading of the thermoplastic material does not become uneven can be achieved.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the present invention in detail, FIG. 2 is a diagram for explaining the invention in detail, FIG. 3 is a diagram showing the eccentric phase of two rolls in the present invention, and FIG. FIG. 5 is a diagram showing the relationship between the sheet thickness irregularity and the roll rotation speed, and FIG. 6 is a diagram showing the operation of the present invention. 1 is a collection of raw materials, 2 is a sheet, Ra, Rh, R. ~R4 represents the roll, and C, , C9 represent the amount of eccentricity. Patent issued by Ishikawajima Harima Heavy Industries Co., Ltd. Patent applicant's agent Hikaru Sakamoto #IP sand W field Figure 1 Figure 2 Figure 3 Procedures Amendment (self-motivated) April 18, 1980 Year Patent Application No. 54846 2 Title of Invention Method for controlling sheet thickness in calender molding 3 Person making the amendment Patent applicant 2-2-1 Otemachi, Chiyoda-ku, Tokyo (009) Ishikawajima Harima Heavy Industries Co., Ltd. 4゜Agent 3-5-3 Uchikanda, Chiyoda-ku, Tokyo, Detailed description of the invention column of the specification subject to amendment, Drawing (1), page 3, line 7, ``Notogi'' has been changed to ``. "Toki," he corrected. (2) Correct ra, sin e, +a, sin e * J in page 6, line 15 to "l'a, sin 8 + -a, sin θ,". e] In page 7, line 17, amend "of the thermoplastic material in the bank" to "in the molded sheet." (4) [For example, roll R, j in the 6th line to the 7th line of the 9th page is corrected to [roll R, J. (6) In lines 5 to 8 of page 10, [ω, angular velocity of roll R4 (however, the average value for one period of ω): ω4 “ω.” is defined as [ω,: the angular velocity period of roll R4 Average value of minutes: i,.i4=ω,)" is corrected. (7) [ ΔH on page 12, lines 13 to 14
m=ΔHIIIA+ΔHn+n1ΔHml=IΔHmA
+ΔHmBI J is “ΔHm= ΔHmA −ΔH+nn1ΔHml=l
ΔHmA −ΔHIIIB1”. ■Correct "(石ブ)" in the third line of page 13 to the lower r (7) J. (9) Correct “small phase” in line 4 of page 13 to “phase advance angle 6”. Q@Page 13, line 9, "From equations (7) and (8)," is corrected to "From equations (7) and (8), considering a phase advance angle of 6." (11) Correct the following on the last line of page 13. (Correct “r cos signal generator” in line 16 of page 14 of 1 to “r sin signal generator”. (Correct “gap” [sheet thickness” in line 13 of page 15 of 1 to “sheet thickness”.) II) Amendment of drawings Figures 2 and 6 are revised as shown in the attached drawings. 7. List of attached documents (1) 1 copy of drawings

Claims (1)

[Claims] 1) When performing calender forming using a calender device that passes a sheet to be formed between a pair of rolls and then takes the sheet while winding it around one of the rolls,
The average rotational speed of each roll in one rotation is made equal, and the eccentricity phases of each roll are controlled so that they are in the same phase on average, and the rotational speed of one of the rolls is controlled to By periodically adjusting in relation to the gap variation between the two rolls caused by the
A method for controlling sheet thickness in calender molding, the method comprising controlling the thickness of the sheet.