DE2939739A1 - METHOD, DEVICE AND DEVICE FOR MEASURING THE THICKNESS CHANGES OF PLASTIC FILMS - Google Patents

Description

W 117

October 1, 1979

WINZLN INTKKNAT H) NAL, JNC.
Ή) 36, Grand Avenue South
Minneapolis, MN 5 54 2O
United States

VI) M ¹ AIIIvKN, '.'I) KkICHTIiNt; UNI) KI NRJ CIITUNi; ZUR MKSSUNG DI) RI) JCKI) N- / M) NlJl) RUiJGKN FROM KUNSTSTUr ¹ FOLJ KN.

Du · Ki t ι mi Li ti · j relates to a method, a device and a I :) i in i c.-ii t uiu) to use and control machines that do this best iiiuiit s ι ml foI i en made of dielectric material, such as plastic, to be coated or poured, these machines adjusting Use transfer, press and casting matrices to produce elongated structures of uniform thickness or cross-section ei 1 (in.

Prior art of the present invention includes U.S. Patent J764899, 2562575, "3523246 and 2782367.

In e Ktfinduno includes an improved method and apparatus for Pt ot Mizing the thickness of a plastic sheet or the like which ensures that the measuring device is continuous is recalibrated to the context in operation during consecutive Maintaining operating cycles and therefore includes

030016/0798

we it οι en an improved capacitive filling 1 ei e 1 an I.: ui determination the thickness of a dielect. ι i see foil from only one rope looking and to reduce or eliminate the effects of the changes the ambient temperature as usual in connection with the Bet ι i el) of supplies for the production of plastic films did not.

The invention will now be explained with reference to the drawings at 1ieqenden for example described. In the drawings are:

Figure 1 is a side view of a capacitive sensor according to Invention;

Figure 2 is a plan view of the device of Figure 1;

FIG. J shows a chord I datste I 1unq along the line i- i of FIG. 2;

FIG. 4 shows a line 4-4 in the line I · 'i q u ι 1;

I 'ι q 11 ι S e ι in ■ sein π μ t i seile b, ι ι: i I e I I in iq ιίικί t yp i s> .: Lt ίι Au S f ill ι r ui iq s-I ι> ι in des Ve ι t ah ι ens, the Vf > ι ι i ■ tLI u nq 11 n> I K i η ι i ch t unq nai'h dei I: ι Ι ι iiduiKi;

l'iqur 6 a further embodiment of the device according to the He foundunq and

Fiqut 6Λ a 'l'e ι iguana cut t representation along the line 6A-6A of FIG. 6.

In Figures 1-4 of the drawings is a capacitive measuring sensor lü represents with an upper part 11 from a suitable metallic substance such as aluminum and having a cavity L2 and an upwardly open slot 13 in a flat top surface 21. The slot 13 has parallel side walls 14 and L5 and multiple passages 16, 17, 18 and 19 are available as downwardly open openings are formed along the lower surface of the upper part 11. Recognizes from Figures 2 and 4 it can be read further that the capacitive sensor 10 is in

030016/0798

ORIGINAL INSPECTED

Longitudinal direction only ι iM / kenden M ι t: t eaebera. · 2o has .. I) ι υ Device is symmetrical about this Mi tteneburu. Uer capacitive Probe 10 also has a bottom part 23 made of a suitable one metal 1 is a material such as aluminum and this is. with two openings 24 and 25 provided. An elongated electrode 29 from a rod-shaped element, preferably from a material with low odet zero thermal Ausdelmunqskoeffiζ ιenten, like Invar, with its long axis in the middle plane 2 () iieqend shown and arranged at the same distance from the side walls 14 and 15 of the slot 13 in the upper part 11. the Electrode 29 is supported by two rod-shaped support elements 3O and 31 carried, which in turn at their lower ends in the openings 24 and 25 by means of masses of suitable insulation material 26 and 27 and further comprise clamps 33 and 34 which extend downwardly from the bottom part 23. The electrode 29 is suitably fastened to the upper ends of the support rods 3 and 3L and is preferably arranged so that the upper surface in or slightly above the plane of surface 21 the top of the upper part 11 is located.

The capacitive measuring probe 10 consists of a hollow metal housing, which can be grounded in a suitable manner and one capacitance-forming electrode, soft in a slot in the upper surface for contact with a stationary or moving plastic film is arranged.

FIG. 5 of the drawings shows a device for carrying out the method in the operating position in a typical plastic film production machine 41, which produces a continuous plastic film 40 by pressing out liquid plastic through a film molding die 42 with an adjustable slot 43. In a typical arrangement, the plastic film I _{n is} pressed out to the right in the drawing in the direction indicated by an arrow and is wound up there on a roll (not shown) after it has run over a roll 56. In the space between the film forming device 41 and the roller 56, the film can be drawn to a point in which it is stabilized. and so measure

Thickness can be used to determine that the correct / has been achieved

0300 1 6/0798

ORIGINAL INSPECTED

Ln the l'iqui 5 LüL a capacitive one! The measuring sensor 10 is shown with its slot parallel to the direction of movement of the plastic lines 4O and is fastened in a suitable manner on the upper part of a mounting device 55 to the dei llandbedi enungsmitte L for setting the sensor IO upwards or downwards and on the aucli mot orgel, rubbed devices for lowering the measuring sensor 10 to prevent contact with the moving plastic film 40 during parts of a cycle of the sensor IO in the direction perpendicular to the direction of movement; to lift the plastic film 4O. The mounting device 50 is fixed to one end of a piston rod 45 which is reciprocated by means of a double-acting hydraulic cylinder 44 which in turn is controlled by a hydraulic source 46 which is connected to the cylinder 44 via lines 47 and 48 and also from signals derived from the adjustable limit switches 51 and 53, which switches are connected via lines 52 and 54 to the respective input terminals 49 and 50 in order to achieve a continuous back and forth movement of the mounting device 55 and the measuring sensor when the storage Solution is carried out by a suitable power source (not provided). Partial representations of the sensor 10 are shown by the references 1ΟΛ and 10B, the position of the sensor IO selecting an operating cycle in (performance of a plastic ie4O daizust.e 1 len.

A signal processing circuit 60, consisting of the same or elements similar to those in US Pat. No. 37648D9 is used to generate a reference signal with a frequency im Provide range of IO Hertz and is as an oscillating circuit 7O shown and another resonant circuit, which the capacitive Measuring sensor 10 is marked with the reference number 61. The frequencies of the oscillators are compared and any difference appears at the output of a discriminator 80. The signal appearing at the output of the discriminator 80 can a digital display 106 and / or a strip chart recorder 111 are fed.

The oscillating circuits 71 should have a predetermined constant relationship have to each other with regard to their oscillation frequencies. The swinging

030016/0798

k ι (. · ι .s Vo can with the help of the> ■ i ns I <. · II ba ι en Kimdiüisaloicn Vj u nci 76, which between f1jü: ii 'iiiiii der 1 ·: ι! K) .uui :; k J emme 73 with the help of (ioi Keiler 7Ί and 79 anqesch I essen y iiul, with regard to its frequency cH'sl iHiL'i (. The adjustable capacitor Ti can be connected to Jem Sk, ι J enknopf 7 ¹ J and is connected by hand.Andeiei since s the first 1J ba ιe condensate 76 is connected via suitable anti iebsmittei 103 with a servomotor iod, which has 1 ·: i nqancjskJ eiimien 101 and J O2. The IJ i ngaimsk 1 emmen 101 and 1Ο2 are connected to the output terminals H '> and 86 on the Di ski iinjnator HO by means of lines 1Ο4 and LO ¹ J and a switch 96. The switch 96 is used to di / u die-I ¹ J ι ngangsk J emnien of the servo motor 100 to the output terminals of the I) i sk ι im i nat ors 80 at the end of each operating cycle 1 us <i (-s Messtühluis C and is to be connected via corresponding lines Iu4 and 1Ο5 with connected to the limit switches 51 and 53, so that the switch 96 is in operation to connect the output of the Di skr j ini nut ors to the servomotor 100 during those times when the measuring sensor 10 is not in contact with the plastic film 40, be it that he has a position on a side edge of the film 4O he reaches or that the sensor by Absonkon with

of
Hilltyiei mounting device 55 associated drive notοι κ of the slide 4O has been removed, which motor, for example, dui.-h ei ι e Cndscha I Lei 5 1 and 53 can be operated to the "]> ■:,:,! Üh I The end edges of the plastic are enough to lower them.Although there are many ways to perform this function, it would be possible to use pneumatic motors and mechanical, linearly controlled valves or the limit switches jI and 53. The oscillating circuit 61 has two input terminals 62 and 63, which are each connected to an electrode terminal 3 3 or via a K (Mt (M 64, a terminal 65 and a conductor 66) The output terminal 68 of the oscillating circuit 61 is connected to the input terminal 83 of the discriminator 80 via a line 69 and the input terminal 84 of the discriminator is connected to the output terminal 71 of the oscillating circuit 70 via a line 7 2 connected. The discriminator 80 also has a terminal 81 which is connected to ground via a line 82. The output terminals of the discriminator 8O are connected to the input terminals of an amplitude calibration potentiometer 90 by means of

033016/0798

ORIGINAL INSPECTED

Ie i I inside ') ·! mill 'J ¹ J anqesch I os.seii. The hachputontuiU'ü l 'K) has tin by hand uinsl.el lhaie scale ¹ Jl Lind a Paat Ausqanqsk I emmet) 97 and 98. The Ausqanqsk 1 eiiimen') / and 98 are to the D 11 | ι talanze i> | u KX) (which may contain a suitable Ana I oqd iqita 1 wall 1) via iiit, 'l, eit unqen 109 and NO connected to the Einyanyakleimien \ (> H and 107. The output terminals 97 and 9H are also connected to a pen -sLel lmotoi II ':> of the Stro i fenschre ibers 111 via corresponding lines Luntjen 113 and J 19 to the terminals 116 and 117.

The SLfO 11 ensclu eber IJi has a moving SLi ei fen suitable regi sLrieroapieres, which responds more to a typical pen, which is moved by means of a motor 115 in accordance with the supplied signals in order to determine the changes and position of the To record permanently with the pen. The strip 112 has: a plurality of parallel lines that cross in the longitudinal direction, which can be provided with suitable scales, depending on the application, and, under operating conditions, in a large number of successive profiles of plastic films. It is fine if the probe is moved successively from one side to another. At the Beq ι nn and at the end of each Z / klusses ili'i 1 ¹ Ui; i Ijewequnq a notch is indicated in the profile with the help of NuJ lon II ί for the purposes described below.

In all FIGS. 6 and 6A, a film manufacturing device with a rotating die 120 is shown, which has a rotating circular slot 121 through which the liquid plastic cone MiUi (Ji J ich hot is pressed out and pulled off when the die 120 is threatened [/.υ. a plastic bubble 122 wild through the Vl ιwendung a suitable air pressure inside the device / utückbeha1ten and because the film rotates continuously, a swept profile can be derived by the sensing ei IO in the illustrated manner, in 6, in a position as shown in FIG used to compress the bladder into a two-ply folio which is placed over a roller 125 to the right

030016/0798

ORIGINAL INSPECTED

? 93973ä

TO UNIT "quuitjiu; teii Auf: w i disgust directed by direction: wild.

When operating the present HeisLei! Device 41, the various pneumatic olectionic elements in the FIG. 5 is fed by qeeiqneten Eneiq i etjuel len (not shown). The sensor IO is made out of contact with. the slide 40 brought. A sample of the plastic film of the desired thickness is placed on the surface 21 and so touches the top of the electrode 29. The frequency of the oscillator 70 is adjusted with the aid of the button 77 so that the pen 115A of the Motor 115 is in a suitable position across the desired scale on strip 112 (note that the Size of the movement of the pen 115A with the aid of a Anipli tudens control 90 can be set in a suitable manner). It should also be noted that during the initial calibration of the Servo motor 100 not energized or from the output of the discriminator remains switched off. The pattern then wildly removed and the engine 1L5 will return the pen 1 i 5A to its rest position. to At this point in time, no output signal 1 should be sent to the output signal 85 and 86 of the Di skrimi naLois appear. Should the frequency of the oscillating circuit 7O change for any reason, that will Connecting the servo motor 100 to the output terminals of the Diski iminators a setting of the adjustable capacitor 76 cause to deliver the desired frequency.

After the resonant circuit 7O submitted to the desired frequency has been, the remainder of the system is energized and the hydraulic cylinder 44 is controlled to operate the sensor 10 continuously to move back and forth between its end positions of its path, as well as it is determined by the limit switches 51 and 52. The upper surface 21 of the measuring sensor 10 is set so that while the plastic film 40 is being painted over, a continuous contact with the lower surface of the film 40 is achieved; this can cause a slight upward deformation of the plastic film 40, but this is not so great that a permanent deformation or change in the thickness of the film occurs.

During the cyclical operation of the transverse movement of the measuring sensor IO, the mode of operation of the entire device is such that then

030016/0798

~ Ii ~

if the Messfühlei IO his ext ι 'a Met r ι ebsgi enzi.-n iul ι ι »jeiideinei side his)" Ouerbewegunvj en e ii.-lit, the Hndsclia 1 t ei 51 and' j4 WIi ksain graze to either ilen Measuring fill I im] <> j _n (.Hi ei ι leihtung aussei contact in i L det KunststoJ lol ie to bend or they can be used in the manner indicated above to retract the measuring probe IO downwards into the Montagevori ichtung 55; in both cases the measuring sensor IO is without contact with the plastic and the servo motor 100 is connected to the output of the discriminator ^ ⁸⁰ with the help of the switch 96 in order, if necessary / to readjust the frequency of the oscillator to in fact, to continuously re-calibrate the resonant circuit 70 to maintain the desired mode of operation.

The recording made on the recording strip 112 can be a reproduction of the exact thickness of the plastic film 40 or can serve to indicate changes in the plastic film with respect to successive, transversely separated parts of the same. It has been found Feiter that the hollow interior of the probe 10 with appropriate LuftdurchJäsen, and it is indicated in the figures 1 to 4 may be provided _/ a free Strömunq of air in and out of the hollow ι jum or to allow under to connect the ilium to a vacuum source under certain conditions in order to obtain a downwardly directed force acting on the plastic film 40 in order to keep the film in close contact with the upper surface 21 and the electrode 29 of the probe.

It has been stated above that the electrode and its Mounting means made of a suitable material, such as Invar, with low thermal expansion coefficient can exist; Under certain conditions it may be desirable to have the hollow, conductive body of the probe 10 from the same or a similar material.

From a consideration of the above description of the elements and operation of the thickness profiling system and measuring device It should now be clear that the method and apparatus for performing the method are unique and not Obvious concept for determining the thickness of a film

030016/0798

odel «..MIIUS KÖl |) .: l :, π, 1 I c 1 c I, I ι!: .. ■!:. ■ !!! MaIc-I UlJ 1 lcl.-l I <| CIIi, ".:,: I

(UiMi aUU'lll.iluJt'l Γ., Ι icn.h · "ii <Uiietasuiiqeli Mein, ι« ¹ Ii I Wei del. Um del Dickt 'des Malet i.il :; ρ ι 11 | χ> ι I i οίκι I e SiqnaJe zn Jiefein ijnri /.ii qeqebencn wi ci lc ι h <> J ending times of the due ι niesszyklusses win! cine I'est J equnq made to s ι ehe · ι to :; I e J 1 en that the measurements zusaiiiineiihänqeiii au ί an a / i (n. n Hezuqswet L l> are asiert Ks may further tesiqesLellL be that the Kiriwi ikunq ii ^ r Aeiulerunqen the IJiuqebunqs tempera (u ι dmcli the · Vei weiidunq of egg wz i qa r L i qen MessfühJeis riiininiaJ i: j I as well as dm cli the use of the Pi incipia of the Vei ialu ens and the "Otricht υπ") / AW lju ι eh lead ι uiKj of the age, as it is mentioned above Where ι deIi is ..

03jÜ16 / 0798

ORIGINAL INSPECTED

Claims (1)

PATtr! T'- NW * LT £ MGES & stake Erhardtstrasse 12. D-ΘΟΟΟ Munich 5 Patent Attorneys Menges & Prahl. Erhardts.r. 12. D-8000 Munich 5 Telephone (089) 26 3847
Telex 529581 BIPATd
Telegram BIPAT Munich u 1 17th YourSign / Yourref. 1.1 0.1979 Our mark / Ourref. Date WINZEN INTERNATIONAL, INC. Minneapolis, MN 55420, V.St.A. PATENT CLAIMS <1 j Method for measuring the thickness of a dielectric body, characterized in that a capacitive sensor is guided over a body made of dielectric material in contact with the same, that the capacitive sensor is used as a frequency-determining MLtLeI in an oscillating circuit, that the frequency of the resonant circuit is compared to a reference frequency to generate a signal proportional to the thickness of the dielectric material, that the signal is displayed on a recording device with a reference mark, that the probe is periodically removed from the body of dielectric material and that the displayed signal is displayed with the reference mark is compared. 2. Capacitive sensor for determining the thickness of a plastic film from one or the other side of the same, characterized by an elongated, hollow, conductive housing with a main surface which is created for contact with a surface of the plastic film and is more uniform with an elongated opening Width to define parallel sides which extend along the elongated major surface to provide an opening to the hollow interior of the conductive housing, 020016/0798 A guiding clue that is shaped to make you feel ij Io ic.hförniigen distance from the sides and endextr em i ι al en dt. ι elongated Oeffnuiuj in the hollow conductive housing Delivers, a ! Rapid device for securing the conductive electrode in the elongated opening with the conductive device extending through another surface of the hollow conductive housing and means for isolating the conductive device from the housing and connected to the hollow housing by a first Clamp and a second clamp connected to the conductive device outside the hollow housing. J. Capacitive sensor according to claim 1, characterized in that the main surface is flat. 4. Capacitive sensor according to claim 2 or J, characterized in that the upper part of the conductive electrode and the main surface of the hollow electrode lie in the same plane. '}. Device according to one of claims 2 to 4, characterized in that the conductive electrode consists of a material with a very low coefficient of thermal expansion. 6. Device for the continuous determination of the thickness of a moving dielectric, characterized by a capacitive Measuring sensor, means for fixing the same, whereby tile Means comprising means to cyclically transverse the probe reciprocate to the direction of movement of the dielectric and around the probe in contact with a surface of the dielectric to bring or take off from the same, a resonant circuit connected to the sensor, so that the frequency of the Resonant circuit is determined by the capacitance of the sensor, a second adjustable resonant circuit, a device for comparing the frequencies of the first and second resonant circuit, Means in connection with the second resonant circuit for setting the Frequency of the same to the frequency of the first resonant circuit when the sensor is not in contact with the moving dielectric Touch represents, and one connected to the second resonant circuit Control device with means for comparing the output signals of the first oscillating circuit if the sensor does not match the im 030016/0798 COPY yicli moving D ie I ok (, ι kirn »i η ik; rühruii. | -i.'lil uii..l MMi ₁ -I, .urn KinsleJlen der! '. ee | uenz, Iuh two Lon Mesa'TiIi u -ry, wimhi _t | _{1 (} . ,,, _c . des zwoi Lon Messfühl οι s an ΙΊ eduenzändernq 01 falls 1. 050016/0798 ORIGINAL INSPECTED Copy