JPS60172513A - Control of sheet thickness for calender molding - Google Patents

Abstract

PURPOSE:To correct variations in the sheet thickness easily and accurately by periodically adjusting the rotational speed of a rol adapted to take off a sheet calender molded being wound with a pair of rolls in accordance with variations in the gap between both rolls due to the eccentricity of these rolls. CONSTITUTION:In a calender molding, when the speed Vb of a roll Rb is increased (or decreased) with the speeds Va and Vt of a roll Ra and a takeoff roll Rt fixed, a tension force (or a compression force) is generated in the sheet 2 at the point A while a compression force (or a tension force) at the point B. Depending on the tension force or the compression force in the sheet 2 generated at the point A or B, the sheet 2 is made thin or thick. Thus, the thickness of the sheet can be kept constant by adjusting the rotational speed of the rolls so as to correct variations in the gap (variations in the thickness of the sheet) due to eccentricity.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to thermoplastic materials such as rubber and plastics. The present invention relates to a sheet thickness control method when manufacturing sheets by calender molding.

[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 adjusting the gap between forming rolls or a method of adjusting the total fA of the pulling speed by a tick-off roll has been generally adopted.

The former method involves measuring the size of the gap between the forming rolls and adjusting the gap to an appropriate level by operating the rolling device of one of the rolls.

However, this method is only a gap measurement device! In addition to the control that requires high responsiveness such as roll eccentricity correction, the normal electric motor type pressure device d is insufficient and requires high responsiveness and high output. There is a problem in that it is necessary to change to a hydraulic cylinder type lowering device.

In addition, the method described later adjusts the sheet take-up speed by changing the simultaneous rotation speed of a tick-off roll (take-off roll) installed directly in front of a pair of final forming rolls. The thickness of the sheet is adjusted by stretching and pulling out the sheet that is stuck on the roll. However, in the case of this method, the line speed after the tick-off roll must be made equal to the speed of the tick-off roll, and there is a drawback that control is troublesome.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and does not require the conventional gear A adjustment method or sheet take-up speed adjustment method, but instead is capable of reducing sheet thickness changes 'atb' caused by roll gap fluctuations due to roll eccentricity. The object of the present invention is to provide a sheet thickness control method in calender molding that allows for easy and reliable thickness correction.

[Structure of the invention]

And sheet thickness Q+ in calendar molding of the present invention
In the II A111 method, when the notebook calender-formed by a pair of rolls passes through the rolls, the catfish 11
One important point is that the thickness of the sheet can be adjusted by circumferentially adjusting the rotational speed of the roll taken up from the sheet in accordance with the gap variation between the two rolls caused by the eccentricity of each roll. This is a method of controlling

[Basics of invention and Garu principle]

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

First, let's discuss the above principle with reference to FIG. f
51-, the rolls l(a and Rb of -J are rotating in the direction of the arrow at speeds Va and Vb, respectively, and the original 1Δ
The plastic material from the spinneret bank 1 is formed into a sheet 2, which sheet 2 is taken off by a tick-off wheel t rotating at a speed Vt. At this time, the sheet 2 is taken up while being wound around the roll Rb of the take-up In. In such calender molding, the speeds Va and Vt of the roll Ra and the tick-off roll t are
When the speed vb of the roll itb is increased (or decelerated) to 1 with constant 1, a tensile force (or compressive force) is applied to the sheet 2 at point A, and a compressive force (or compressive force) is applied to the sheet 2 at point B. tensile force) is generated. Sheet 2 generated at these points A and B
The tensile or compressive force applied to the sheet 2 causes the sheet 2 to become thinner or thicker.

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

That is, Go... ■A-h -K = H,, Vb, so
H-(1+11 units 9110 Vb 2 = (1+ upper), 1 series - 11001,, (1) fr 2 Therefore, when fr changes by Δfr, the thickness change rate Δ
H/H is ΔH1Δfr H=l−1−fr·□ (2). Here, 11: Sheet thickness Go: Roll gap, varnishing ratio, etc. 1・(Thus determined coefficient f r = Vb/Va: Speed ratio (iiJ[)Δfr
/fr: Rate of change in speed ratio.

Then, at point 2 and 13, the rate of change in the thickness of the sheet 2 is equal to the amount of change in the speed σ), so Δvb ΔH=H-7 from Δ)IΔ■1-H=Vb. Here, b Δ■b Speed change of two rolls vh: Average speed of roll b Next, the influence of the eccentricity of these rolls Ra, R, and b 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, the eccentricity of one roll with respect to the rotation angle θ1 is expressed as a 1 sin θ
1 and the eccentricity with respect to the rotation angle θ2 of the other roll is a2slnθ2, then the gap fluctuation between both rolls is expressed as axsinθt+azslnθ2. The rotation angles θ1 and θ2 of the rolls change over time, and these rolls! The rotational speed ratio of / takes a value of 1.0 to 1.5 as mentioned above (d), and this composite function generates a beat that increases and decreases in a certain period, and the gap fluctuation caused by this beat results in the sheet This will result in thickness variations.

By the way, as described above, the thickness of the sheet can be controlled by a simple method of adjusting the rotational speed of the rolls, and even subtle 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 thickness and thickness of the sheet can be kept constant.

[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.

FIGS. 2 and 3 show an example of calender molding using calender rolls arranged in a 1 ml inverted to 1 ml arrangement. In FIG. 2, the thermoplastic material of bank 1 is sequentially formed into a sheet 21c by rolls 1Lt, Rz, R3, and 4, and this sheet 2 is taken up from the final roll it4 by a tick-off roll Rt.

Here, as shown in FIG. 3, a roll R3 and a roll R4 forming a pair of rolls in the final stage are eccentric by amounts indicated by e3 and e4, respectively.

Therefore, as mentioned above, the gap G between the roll 'i'L3 and the roll R4 varies due to these eccentricities 1e3 and e4, and the variation ΔG is ΔG=e3cos(ωat+aa)−1−e4 tuft(ω
It is expressed as 4t-4-a4)・-C3). Here ω3
: angular velocity of roll R4: angular velocity of roll R4.

Therefore, from the above equations (1) and (3), the variation amount Δ■( of the thickness I() of the sheet 2 is, ΔH,=K, Kamihongyō・ΔG fr 1 +fr =K ・−,,, , -(es cts ((113t+
aa) 10e4 possible (ω4t+α4))...(4)
It is expressed as

Therefore, in order to correct and control this variation amount ΔI, only the rotational speed v4 of the roll 4 is changed while keeping the rotation G and 4 degrees of the rolls H and a and the tick-off roll Rt constant. A tensile force or a compressive force is applied at each point indicated by center and B in FIG. The points indicate the points at which the sheet 2 is pulled by the tick-off rolls H, t and peeled off from the roll Rt -fl, respectively.

Therefore, when the speed v4 of the roll 1L4 is changed by Δv4, the thickness changes at point A and three points ) of the sheet 2 are as follows.

(a) If the thickness change of the sheet 2 at point A is mixed with ΔHr, then this ΔHmA is: 1-1- f r Δ1 (711A = (Ti, , (K ・2 t ,
・G)) It is expressed as XΔv4. Here, Hm: average thickness of the sheet 2 fr = v4/va: speed ratio in the horizontal direction.

(b) Change in thickness of sheet 2 at point B by ΔHrr+n
Then, this Δ)(m T3 is ΔI(mu == (Hm −-) ) XΔv4
4 1J+r+ = (-;-1) x Δv4 (6) ■4.

In the above (・0, (b), both 38m people and ΔHma6-1 shown in equations (5) and (6), respectively, are vector mice. Therefore, hereinafter, these Δ) 1m people and ΔHmB are ΔHmA and ΔHma, respectively. It is expressed as Then, ΔHrn obtained by combining these ΔHrnA and ΔHmB is the roll l (velocity of 4 v4
It shows the change in thickness given to the sheet 2 and its direction when changing the thickness by Δv4.

Therefore, the above ΔHm can be expressed as ΔHm=ΔHm*+Δ4mB from the above equations (5) and (6). Here, since the change in fr during one qm is small, there is no practical problem even if "f = fr" in the L equation.Therefore, the above Δmount n is lan-rich and H
m, ΔV4T and T word 1. +c old θa+sln"θ-,-
(7) ■4 , and its phase φ4 is given by . Therefore, in order to correct J: 311 m for the above-mentioned thickness and vertical movement ΔH of the sheet 2, ΔH−
It is sufficient if 1Δ rudder l = Q. Therefore, the above (4)
From equations, (7) and (8), K −”−”−'
−(e3ay, (ω3=1φa−1−aa)+e4(ω4t−φa−4−x4))fr If this is expressed for Δv4, it is expressed as follows. Here, φ3=1·φ4.

fr i.e. (JLlea of roll JMo3 and roll R4)
Correction of the thickness variation of the sheet 2 by e4 is performed by adding the circumference I shown by Δv4 in the above equation (9) to the rotational speed v4 of the roll box 4.
This can be done by adding JI-like fluctuations.

The various coefficients for obtaining the above Δv4 can be easily obtained from the number 1+& of each eccentricity tea, e4, and positions υα3, α4, etc., which have been calculated separately for each roll in advance, and the commonly used frO value. be able to. Further, by numerically analyzing the sheet thickness variation obtained by rotating the one-goal box 4 at a constant speed in advance, it is possible to determine various coefficients for obtaining a more accurate Δv4. Then, the various first series obtained from these are applied to an analog or digital beat generator that is synchronized with the rotation of the two rolls, and the above (
Generate the same waveform as in equation 9) and manually add it to the speed control circuit for the rotational speed v4 of the roll R4. This results in
The rotational speed Kiv4 of the roll R4 can be varied by Δv4, and the jIf-value IWIJ of /-t2 can be changed by ;'it i,E.

〔Effect of the invention〕

As explained above, the method for controlling the sheet thickness in calender forming of the present invention involves using a calender device f that folds the sheet formed between a pair of rolls four times and then takes the sheet while winding it around one of the rolls. Karen
During no-forming, the thickness of the sheet can be adjusted by periodically adjusting the rotational speed of the rolls on which the sheet is tiled in response to the gap fluctuation between the two rolls caused by the eccentricity of each roll. Since this method controls the sheet thickness by 1llJ, it is possible to extremely easily and reliably correct the sheet thickness caused by the center of the roll, which requires high responsiveness and minute correction.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the present invention in detail, and FIGS. 2 and 3 are diagrams for explaining one embodiment of the present invention. R3, R4... Roll 2... Sheet e
3, e4...Eccentricity H...Sheet thickness G
...Gap Comparable Person Ishikawajima Harima Heavy Industries Co., Ltd. Figure 1 I Rb Figure 2 Figure 3 Procedural Amendment (6 Button Display of Case No. 1988 Patent Application No. 29907 Name of Invention Calendar Molding Pressure Sheet Patent applicant for thickness control method correction (θ09) Ishikawajima-Harima Heavy Industries Co., Ltd. Agent 2) Drawing. (1) In the 9th line of Specification 4TVM2, ``This method uses the gap 1 (φ + JIU child device?)'' is corrected to ``This method uses the roll gap l1III constant device.'' (2)・・tll '?G 7JG 7 Tei・πDelete "as in 1iiJ" in the 1st line. (3) Plan to "make it bigger or smaller with υJ" in the 2nd item on page 7 of the specification rli'i1 (4) Ming 4.] Correct Mf in the first line of the first line of the 110th member. (51 specification, δ small / second line of page I and the correction In the formula on the third line, ``474m A + ΔHmBJ'' is (6)
l1fl tumor, page 12, line S from the bottom, "is roll I (
4" is corrected to "10-Rs and Roll R4J. (7) Figures 1 to 3 of the drawings are corrected as shown in the attached sheet. Figure 1 Figure 2 Q+ Figure 3

Claims (1)

[Claims] After passing the formed sheet between a pair of rolls,
When performing calender forming using a calendar device that takes the sheet while winding it around one of the rolls, the rotational speed of the roll around which the sheet is wound is controlled by the amount of eccentricity between the two rolls caused by the eccentricity of the roll in the troughs. A sheet thickness control method in calender molding, characterized in that the thickness of the sheet is controlled by periodically adjusting it in response to gap fluctuations.