CN107053637B - A kind of film thickness monitoring system based on marking auxiliary positioning - Google Patents

Abstract

The invention discloses a kind of film thickness monitoring systems based on marking auxiliary positioning, it includes one by acquisition module, auxiliary positioning module, processing module, the monitoring control unit of the compositions such as control module, under the instruction of processing unit, dimming portion in auxiliary positioning module, focusing portion and the movement of driving portion co- controlling executing agency, marking subelement is set to mark out V-arrangement or the U-shaped breach marking on the predeterminated position of slab, based on the acquired data of acquisition module, processing module calculates the position for obtaining film thickness and each bolt of extruder die head, and the aperture of extruder revolving speed and die head is controlled by frequency converter and die head adjuster respectively.The present invention is handled by marking marking and cross-sectional data, analysis handles to obtain thickness parameter, quickly diebolt can be accurately positioned, to reach the uniform of film transverse and longitudinal thickness by lip aperture and extruded velocity adjusting, and marking amount needed for auxiliary positioning process is few.

Description

A kind of film thickness monitoring system based on marking auxiliary positioning

Technical field

The present invention relates to film fabrication techniques fields, and in particular to a kind of film thickness monitoring system based on marking auxiliary positioning System.

Background technique

BOPP film, that is, bidirectional stretching polypropylene film be as obtained by biaxial tension, it be by physics, chemistry and The plastic product that the means specially-shaped such as machinery is process.BOPP production line is a complicated nonlinear system.Its technique stream Journey specifically includes that raw material melting, extrusion, cooling and shaping, longitudinal stretching, cross directional stretch, trimming, sided corona treatment, batches.

Physical mechanical property such as tensile strength, elongation at break, turbidity, gloss as BOPP film product quality indicator Deng because depending mainly on the attribute of material itself, so all easily reaching requirement.And as the main of re-workability and service performance Con trolling index, i.e. film gauge variation and Film Average Thickness deviation, then depend mainly on the manufacturing process of film.Even if manufacture For plastics thickness control in the deviation range that standard allows, but after the winding of thousands of tunics is accumulative, thickness deviation is big in the process Position on may form the bad defects such as hoop, sudden and violent muscle or chase, the reprocessing that these defects directly influence user uses, Such as phenomena such as the dislocation of color printing chromatography or gluing irregular corrugation, it is made to reduce or lose use value.So in BOPP film production Topic is how to improve and stabilizing films thickness and precision between the quality of most critical.

For plastics thickness control based on the real-time detection to thickness, it is logical that such as application No. is 2014201577223 Chinese patents After crossing X-ray scanning acquisition film thickness, two PID regulators are respectively adopted to carry out the control of the horizontal and vertical thickness of film System, similar method is also used application No. is 2007201517097 Chinese patent, is pointed out simultaneously, in order to obtain thickness Uniform film, it is necessary to realize that thickness measurements and measurement position are accurately positioned.Application No. is 2014204575910 China Patent then carries out the alignment of basement membrane by deckle.

The online Plastics Thickness Control System of Quo of BOPP Films in China manufacturing line and thickness gauge be much it is complete from Foreign countries introduce, and the data of calibrator, which need manually to carry out the corresponding positioning of bolt in operation interface, to be provided with for control system The thickness data of effect.Currently, carrying out the corresponding common method of bolt to the thickness data of calibrator output, there are mainly two types of, It marks first is that crossing at different bolts, corresponding place is then found on calibrator scanning support, to determine the position of bolt It sets；Second is that also measuring the developed width of film web, the width referring to die head is thin to calculate while detecting section with calibrator The necking down amount of film, and then diebolt is corresponded to.Both methods is required to manually be carried out according to practical condition auxiliary Mark, measurement and judgement are helped, artificial judgment is not only inaccurate, can not also stablize.Due to lacking to the continuous accurate of film profile Positioning, the thickness control effect of film and the quality of produced product suffer from influence.For this reason, it may be necessary to solve film thickness monitoring system The problem of bolt auxiliary automatic positioning is carried out to the film profile thickness curve of calibrator output in system.

Summary of the invention

In view of this, the purpose of the present invention is to provide a kind of film thickness monitoring system, it can be in the incipient stage of control process Calibrator is assisted to carry out thickness measuring positioning to bolt, after the inscribing inscriptions on the slab predeterminated position of extrusion molding, to thickness measuring The film profile thickness curve of instrument output is acquired and analysis processing, stamp positions is obtained, thus to extruder die hook bolt It is accurately positioned, the film profile thickness value set for obtaining and being marked with diebolt position periodically is handled after positioning, and The horizontal and vertical consistency of thickness control of film is carried out based on the set.

The technical solution of the invention is as follows, provides a kind of film thickness monitoring system based on marking auxiliary positioning with flowering structure System comprising it squeezes out unit, be cooled and shaped unit, draw unit, thickness measuring unit, monitoring control unit and rolling unit, it is described Squeezing out unit includes extruder and die head, and the draw unit includes vertical drawing-die block and horizontal drawing-die block, the thickness measuring unit include First calibrator and the second calibrator, film raw material melt are cooled and shaped unit after extruder extrusion and are cured as slab, cast Piece drawn unit is stretched as after wide volume film by rolling unit harvesting being parent roll, first calibrator and the second calibrator point Not Wei Yu draw unit both ends thickness monitor is carried out to slab and wide volume film, it is characterised in that:

The monitoring control unit includes acquisition module, processing module, auxiliary positioning module, control module, die head adjusting Device and frequency converter, the auxiliary positioning module include dimming portion, focusing portion, driving portion and executing agency, the execution again Contain a marking subelement in mechanism；The acquisition module transmits after acquiring film profile thickness curve data from thickness measuring unit To processing module, processing module instructs dimming portion, focusing portion and the movement of driving portion co- controlling executing agency, makes the quarter V-arrangement or the U-shaped breach marking are marked out on the predeterminated position for the slab that mark unit is cooled and shaped after being squeezed out by extruder；It is based on Acquired data, processing module calculates the position for obtaining film thickness and each bolt of extruder die head, and passes through frequency converter respectively With the aperture of die head adjuster control extruder revolving speed and die head.

Preferably, the film raw material melt that the marking subelement is arranged in for will squeeze out from extruder is attached to Quench The front of main air knife on roller, the marking marked are made of the different rectangle cutting of multiple depth.

Preferably, system further includes a synchronous submodule, the synchronous submodule provides marking for driving portion and starts Temporal information so that all rectangle cuttings can be detected by calibrator.

Preferably, the film profile thickness curve data are expressed with film profile image format, wrapped in described image Include a film thickness curve, reference axis and the auxiliary line parallel with reference axis indicated in different colors respectively.

Preferably, the control module includes controller one and controller two, the controller two is adjusted by die head Device controls the on-off of diebolt solid-state relay in a manner of duty ratio, to adjust this by the temperature for controlling bolt The aperture of die head section where bolt, to realize that the thickness of film section corresponding to the bolt is adjusted；The controller one is to adjust The mode of frequency converter controls the revolving speed of extruder, to realize the tune of film ensemble average thickness by control extrusion output Section.

Preferably, the marking subelement include two its imprint heads respectively with extruder die head both ends bolt location The marking module being mutually fixedly connected, the marking module use laser beam marking module.

Preferably, the marking subelement includes a guide rail parallel with extruder die head lip and a marking Module, the marking module includes the imprint head that can be moved along the guide rail, has multiple and diebolt on the guide rail There is the anchor point of fixed positional relationship, the marking module uses laser beam marking module.

Preferably, it is described marking subelement marking marking depth capacity by marking slab thickness 0.05 to 0.1 Times.

Using the solution of the present invention, compared with prior art, have the advantage that the present invention is applied to BOPP production Film thickness On-line Control obtains the thickness value of each point on film horizontal section thickness curve by analytical calculation, in slab Deep trouth marking is carried out on the two or more and relatively-stationary predeterminated position of die head bolts at two ends, thus bent in film profile thickness All bolt locations are oriented on line, realize the bolt auxiliary positioning to measured film thickness, effectively prevent artificially judging The influence of mistake is realized the transverse gage uniformity and longitudinal thickness consistency of BOPP film by feedback control, improved Film product quality.

Detailed description of the invention

Fig. 1 is that the present invention is based on the structural schematic diagrams of the film thickness monitoring system of marking auxiliary positioning；

Fig. 2 is the structural schematic diagram of auxiliary positioning module in the present invention；

Fig. 3 is marking subelement and extruder die head partial structural diagram；

Fig. 4 is marking subelement imprint head and periphery partial structural diagram figure；

Fig. 5 is calibrator display interface figure in BOPP production；

Fig. 6 is the extraction aim curve data flowchart of processing module；

Fig. 7 is inscribing inscriptions schematic diagram；

Fig. 8 is cutting group structure schematic diagram；

Fig. 9 is rectangle groove structure schematic diagram；

Figure 10 is marking work flow diagram；

Figure 11 is BOPP film thickness control flow diagram.

Specific embodiment

The preferred embodiment of the present invention is described in detail below in conjunction with attached drawing, but the present invention is not restricted to these Embodiment.The present invention covers any substitution made in the spirit and scope of the present invention, modification, equivalent method and scheme.

In order to make the public have thorough understanding to the present invention, it is described in detail in the following preferred embodiment of the present invention specific Details, and the present invention can also be understood completely in description without these details for a person skilled in the art.

The present invention is more specifically described by way of example referring to attached drawing in the following passage.It should be noted that attached drawing is adopted With more simplified form and using non-accurate ratio, only to facilitate, lucidly aid in illustrating the embodiment of the present invention Purpose.

As illustrated in fig. 1 and 2, film thickness control system of the present invention includes: to squeeze out unit 1, be cooled and shaped unit 2, draw unit 3, thickness measuring unit 4, monitoring control unit 5 and rolling unit 6 have wherein squeezing out unit 1 includes extruder 7 in extruder front end Die head 8, draw unit 3 include vertical drawing-die block 9 and horizontal drawing-die block 10, and thickness measuring unit 4 then includes that the first calibrator 401 and second is surveyed Thick instrument 402, monitoring control unit 5 include acquisition module 11, processing module 12, auxiliary positioning module 13, control module 14, die head Adjuster 15 and frequency converter 16.

Film raw material squeezes out for melt from die head 8 from melting after the feeding port of extruder 7 investment, then through being cooled and shaped unit 2 are cured as slab, and slab drawn unit 3 is stretched as after wide volume film by the harvesting of rolling unit 6 being parent roll, subsequent to press order It is required that being cut and being packed to parent roll.Since thickness plays a crucial role product quality, in BOPP film Thickness real-time monitoring often is carried out to slab and wide volume film respectively with two calibrators in production, two calibrators can be external The thickness data collection of section is exported, while they are also connected with display to show the profile image of slab or wide volume film.Two Front uses that of slab thickness measuring in pull-out at the beginning of film in platform calibrator, after the investment of the second calibrator below just Pause uses.

As shown in Fig. 2, the auxiliary positioning module 13 in film thickness control system of the present invention comprising dimming portion 133 is adjusted Burnt portion 134, driving portion 132, executing agency 135.Preferably, auxiliary positioning module 13 further includes synchronous submodule 131, pass through The synchronizing only to scan in timeslice to scribe position in calibrator of the submodule is just marked, to subtract significantly Print amount after a little while.

In conjunction with shown in Fig. 2 and Fig. 3, auxiliary positioning module 13 further includes the bracket 138 for being fixed on rack 17, the execution Mechanism 135 includes a marking subelement 136.The die head 8 of extruder 7 includes upper and lower two lips 81, forms lip between lips Mouth 83, lip opening size is adjusted by transversely arranged heat bolts 82.The marking subelement 136 uses laser beam marking Module marks out V-arrangement or the U-shaped breach marking on the predeterminated position for the slab being cooled and shaped after being squeezed out by extruder.

Preferably, the marking subelement 136 is set as two, their imprint head respectively with die head both ends bolt position It sets and mutually fixes, can such as make the bolt centerline edge of imprint head pedestal or its base position and first or second, both ends Lip vertical line is aligned and strictly fixes, and shift its pedestal or its base position cannot in a lateral direction.

Preferably, a marking subelement 136 can also only be arranged, but one and die head lip are set on bracket 138 The imprint head of the parallel guide rail 137 of mouth, marking subelement 136 can be along this guide rail transverse shifting, and has multiple and mould on the guide rail Hook bolt has the anchor point of fixed positional relationship, so as to form a V-arrangement or U on multiple default lateral positions of slab The v notch v marking.

Fig. 4 is marking subelement imprint head and periphery partial structural diagram figure, wherein (4a) is side view, (4b) For front view.In conjunction with shown in Fig. 2 to Fig. 4, in BOPP film production line, has after extruder 7 and be cooled and shaped unit 2, wherein wrapping The modules such as sharp cooling roll 21, main air knife 22 are included, after the melt of extrusion leaves the lips of extruder die head 8, in the outer of main air knife 22 etc. Under power effect, it is attached to rapidly on the sharp cooling roll 21 of low temperature, best bright finish, melt, which is cooled rapidly and forms solid sheet, to be cast The front of main air knife 22 is arranged in melt direction of advance in piece, marking subelement 136.

In conjunction with shown in Fig. 1, Fig. 2 and Fig. 4, wide volume film is formed after the traction of slab drawn, it is during which right by thickness measuring unit 4 It carries out Thickness sensitivity；Acquisition module 11 obtains film profile thickness curve data from calibrator, is carried out by processing module 12 After reason to dimming portion 133, focusing portion 134 and by synchronization module 131 to driving portion 132 issue command information, by described Dimming portion 133, focusing portion 134 and driving portion 132 control executing agency 135 and act, and marking subelement 136 is based on executing The movement of mechanism 135 is marked in the slab of fast cooling shaping.

The collected film profile thickness curve data of acquisition module institute, can be the numerical string arranged by certain format, It is also likely to be to be presented with film profile image format, the calibrator as is to be conveyed to display with VGA image.Such as Fig. 5 It is shown, in the film profile data acquired with image format i.e. film profile image, there are two width sectional thickness curve graphs respectively With some character informations；Wherein, a-quadrant indicates the corresponding thickness a reference value 35.5um of film thickness profile axis of abscissas and curve The longitudinal coordinate scale value 5% of coordinate system in picture；The region C is the target thickness curve for stating current film profile, coordinate Axis is set by the description of a-quadrant, and the auxiliary line parallel with reference axis is also contained in coordinate system；AVG=in B area 35.51um refers to the thickness average value of current film profile shown by C region curve, and R=2.83% is then curve wave up and down The very poor value of dynamic statistics.

In conjunction with shown in Fig. 5 to Fig. 6, during thickness control, processing module wants output token to have the thin of diebolt position Film sectional thickness value set, film profile image has above-mentioned Block Characteristic as based on it, processing of the invention Module inside sets curve segmentation sub-block, and a continuous whole and achiasmate film thickness is extracted from reading in system or from image Curve, and according to the reference value read offline from systemic presupposition value, to point each on the curve, by its pixel in the picture Coordinate is transformed to corresponding thickness value.

As shown in fig. 6, curve segmentation sub-block for the region C in Fig. 5, carries out gray processing and filtering to target image first Processing obtains discontinuous film thickness curve image g1 and auxiliary dot matrix image g2 further according to color component and translation specifications；Secondly, Gradient threshold segmentation is carried out, i.e., to two images g1 and g2, obtains two after carrying out Otsu Threshold segmentation and Double Thresholding Segmentation respectively Value image g1 ' and g2 '；Then, g1 ' is mutually merged with g2 ' the two and generates a continuous whole and achiasmate film thickness curve Image g；Finally, according to the acquired root thickness value, coordinate scale value, thickness average value, to generated film thickness curve Its pixel coordinate conversion in the picture is corresponding thickness value by upper each point.

After obtaining film profile each point thickness value, needing to carry out film thickness curve bolt location mark just be can be carried out effectively Film thickness monitoring, but traditional bolt location mark need it is artificial position, this will introduce deviation.For this purpose, the present invention passes through It carries out marking on the specific position of slab and the marking detect to sentence knowledge.

In conjunction with shown in Fig. 1, Fig. 7 to 9, the lateral sampling density of the sectional thickness curve of calibrator output is sufficiently high, works as quarter Mark unit is when forming V-arrangement or the parabolical U-shaped breach marking in slab, due to the fixed bit of imprint head pedestal and bolt Relationship is set as being aligned the central point of the marking along lip vertical line with bolt centerline when marking, acquired module 11 acquires thickness Curve, processing unit 12 is by extreme value point search to the curve and judgement, and by obtaining, diebolt is accurate on curve Positioning.This positioning is minimum to need two, it is assumed that the cross of U1 and the corresponding two positioning endpoints of two bolts of U2 in thickness curve Axial coordinate is respectively X1 and X2, then can obtain the positioning of other bolts.To the Uk bolt, corresponding horizontal axis coordinate Xk Are as follows:

Wherein, Round () is round function.The bolt horizontal axis coordinate exported in formula (1) is integer value.

Preferably, can also be several to indicating using following (Xk ', h ' (k)), in which:

H ' (k)=h (Xk ')+(h (Xk2 ')-h (Xk ')) (Rk-Xk ') (3)

Wherein, fix () is round numbers partial function, and Xk2 ' is Xk '+1.

As shown in fig. 7, marking overall depth Lz is set as the 0.05 of marked slab thickness by taking the V-notch marking as an example To 0.1 times.

In order to mark out the marking, disposable formation, or the forming method with multiple stacking can choose.If with one Secondary property forms method, needs the marking module of relatively high power, and if may continuously make in the marking of same lateral position to slab itself At some influences.For this purpose, the cutting group formation method that selection is as shown in Figure 8, it is assumed that film is moved down with Vy speed, in cutting group The cutting marking be moved back and forth with Vx speed, cutting group is formed as the right half part of the V-arrangement marking as illustrated in the drawing, I.e. cutting group contains N=2k rectangle cutting in total.

In conjunction with shown in Fig. 7 to 9, width Lx is set as a value, on the sectional thickness curve for making it possible to obtain from calibrator Enough points are obtained, such as within the scope of Lx, NS=2N point can be sampled out.Preferably, can set Lx as with Lz in phase With on the order of magnitude.The width dx and depth increments dz of each rectangle cutting are respectively the 1/k of marking overall width Lx and depth Lz； And its length dy then can choose are as follows:

So that adjacent rectangle cutting is adjacent in the longitudinal direction or partially overlaps, so that synchronizing rear calibrator can continuously detect To rectangle cutting.

As shown in Figure 10 to mark work flow diagram in the present invention, the entire cutting group period is Tq, and calibrator one way is from one While the time for being moved to another side is equal to the integral multiple of Tq.After system initialization, V-arrangement cutting group is marked since the t0 moment, often The imprinting period of a rectangle cutting is Tr, and Tr=Tq/k.One rectangle cutting of every marking will judge whether to carve k Slot marking finishes, if it is, waiting the arrival in next cutting group period, otherwise, to prepare to mark next time: imprint head resets Prepare, the precise motion module in driving portion control executing agency carries out station preparation, dimming portion cooperation carries out marking function The adjustment of rate, focusing portion change the height of focus point, until current rectangle cutting is marked after next imprinting period Tr arrives.It carves When print, the motion module of executing agency mobile to film will carry out longitudinal velocity compensation.The marking in slab is marked with slab It is detected after being drawn by calibrator, and is synchronized by synchronous submodule.

Since the marking of marking subelement marking is made of the different rectangle cutting of multiple depth, in order to enable all these Cutting can be detected by calibrator, provide the alignment of marking start time by synchronous submodule for driving portion.After synchronizing, In In the one single pass scan time of calibrator, it is only necessary to mark a cutting group, that is, from front after the N number of cutting superposition marked It sees to form a V-arrangement or the U-shaped breach marking, can be achieved with auxiliary positioning.

In conjunction with shown in Fig. 1 and Figure 11, the BOPP film thickness control process of film thickness control system of the present invention are as follows:

(L1) after melt extrusion, marking subelement forms V-arrangement or U-shaped breach print on the default lateral position of slab Note, slab before the stretching after Thickness sensitivity carried out by calibrator, generate film profile image；

(L2) acquisition module monitored in control unit acquires film profile image, is carried out by processing module to the image Reason analysis, obtains and is marked with the film profile thickness value set of diebolt position, wherein diebolt position by marking and Detection calculates acquisition；

(L3) to each element of the thickness value set, k-th of data is taken, its thickness value is preset with product thickness Value is compared acquisition point deviation, which send the controller two of control module, carries out PID control, output control by controller two Amount processed adjusts the duty ratio of this bolt heating waveform by die head adjuster, to adjust the aperture of this section of die lips；

(L4) to the thickness value set obtained in L2, calculate film profile thickness average value in this period, by its with Product thickness preset value, which is compared, obtains this period integral thickness deviation, which send the controller one of control module, by controlling Device one processed carries out PID control, and output control amount adjusts frequency converter, changes extruder revolving speed, thus when adjusting die head entirety unit Interior extrusion flow, that is, extruded velocity；

(L5) it waits next period to be timed to come, returns to step L2.

In the above control process, thickness deviation is converted to temperature compensation value by controller two, by die head adjuster with The mode of duty ratio controls the on-off of solid-state relay on computer heating control channel, to control the temperature of current diebolt. Due to the expansion and contraction property of metal, when heater conducting, the gap compression of slab lip, the film of such slab lip are thick Degree can be gradually reduced, on the contrary then increase.

Controller one is periodically averaged laterally upper film thickness data, converts as unit time extrusion output, with The corresponding extrusion output of product thickness setting value compares, and obtains extrusion output deviation, then is transformed into motor speed compensation rate, by changing Become the input quantity of frequency converter to control the revolving speed of main extruder.When motor speed increases, the melt flow of extruder die head lip Amount increases, and pressure increases, and the film integral thickness after corresponding slab and stretching can gradually increase.

Control module further include control vertical drawing, the speed of each roller and the submodule of temperature in horizontal drawing and rolling unit, It is adjusted according to production film thickness according to preset technological parameter.

The present invention is based on the film thickness monitoring systems of marking auxiliary positioning by marking and detection, can carry out to diebolt quasi- It determines position, obtains the film profile thickness value number for being marked with all diebolt positions to set, send controller progress to Plastics thickness control adjusts die lips aperture and extruded velocity, so that the horizontal and vertical thickness of film is kept in production It is consistent and stable.

In addition to this, although embodiment is separately illustrated and is illustrated above, it is related to the common technology in part, in this field Those of ordinary skill apparently, can be replaced and integrate between the embodiments, be related to one of embodiment and record is not known Content, then can refer to another embodiment on the books.

Embodiments described above does not constitute the restriction to the technical solution protection scope.It is any in above-mentioned implementation Made modifications, equivalent substitutions and improvements etc., should be included in the protection model of the technical solution within the spirit and principle of mode Within enclosing.

Claims (4)

1. a kind of film thickness monitoring system based on marking auxiliary positioning comprising squeeze out unit, be cooled and shaped unit, stretch list Member, thickness measuring unit, monitoring control unit and rolling unit, the extrusion unit include extruder and die head, the draw unit Including vertical drawing-die block and horizontal drawing-die block, the thickness measuring unit includes the first calibrator and the second calibrator, film raw material melt from Extruder is cooled and shaped unit and is cured as slab after squeezing out, slab drawn unit is stretched as after wide volume film by rolling unit Harvesting is parent roll, and first calibrator and the second calibrator are located at draw unit both ends and carry out to slab and wide volume film Thickness monitor, it is characterised in that:

The monitoring control unit include acquisition module, processing module, auxiliary positioning module, control module, die head adjuster and Frequency converter, the auxiliary positioning module include dimming portion, focusing portion, driving portion and executing agency, the executing agency again In contain a marking subelement；From the acquisition module is sent to after acquiring film profile thickness curve data from thickness measuring unit Module is managed, processing module instructs dimming portion, focusing portion and the movement of driving portion co- controlling executing agency, makes marking V-arrangement or the U-shaped breach marking are marked out on the predeterminated position for the slab that unit is cooled and shaped after being squeezed out by extruder；Based on being adopted Collect data, processing module scans for and judges to the extreme point of the curve, calculates and obtains film thickness and extruder die head The position of each bolt, and the aperture of extruder revolving speed and die head is controlled by frequency converter and die head adjuster respectively；

The main air knife that the film raw material melt for will squeeze out from extruder is attached on sharp cooling roll is arranged in the marking subelement Front, the marking marked is made of the different rectangle cutting of multiple depth, after the multiple cutting superposition in terms of front Form a V-arrangement or the U-shaped breach marking；

The marking subelement includes that two its imprint heads are mutually fixedly connected with extruder die head both ends bolt location respectively Module is marked, the marking module uses laser beam marking module；Also, the film thickness monitoring system further includes a synchronous submodule Block, the synchronous submodule provide the temporal information that marking starts for driving portion, and the calibrator one way is moved from one side The time moved to another side is the integral multiple of the rectangle cutting imprinting period and all rectangle cuttings can be by thickness measuring Instrument detects.

2. a kind of film thickness monitoring system based on marking auxiliary positioning according to claim 1, which is characterized in that described thin Film sectional thickness curve data is expressed with film profile image format, includes one indicated in different colors respectively in described image Film thickness curve, reference axis and the auxiliary line parallel with reference axis.

3. a kind of film thickness monitoring system based on marking auxiliary positioning according to claim 1, which is characterized in that the control Molding block includes controller one and controller two, and the controller two controls mould in a manner of duty ratio die head adjuster The on-off of hook bolt solid-state relay, thus the aperture of die head section where adjusting the bolt by the temperature for controlling bolt, with Realize that the thickness of film section corresponding to the bolt is adjusted；The controller one controls extruder in a manner of adjusting frequency converter Revolving speed, to realize the adjusting of film ensemble average thickness by control extrusion output.

4. a kind of film thickness monitoring system based on marking auxiliary positioning according to claim 1, which is characterized in that the quarter The marking depth capacity of mark unit marking by 0.05 to 0.1 times of marking slab thickness.