CN-122016470-A - Intensity detection device for plastic product production

CN122016470ACN 122016470 ACN122016470 ACN 122016470ACN-122016470-A

Abstract

The invention relates to the technical field of material physical property testing and analysis, and particularly discloses a strength detection device for plastic product production, which comprises a melt filament forming assembly, a traction assembly, a measuring assembly, a motion parameter acquisition assembly and a strength detection assembly; the melt filament forming assembly outputs continuous melt filaments, the traction assembly performs traction speed scanning on the melt filaments, the measuring assembly outputs traction time sequence data, the motion parameter collecting assembly outputs traction speed and traction distance time sequence data, the strength detecting assembly performs online variable point detection to obtain a criterion for converting a stable drafting zone into an unstable drafting zone, then encrypts and samples the materials near a critical turning point, identifies the stable drafting zone on the encrypted sampled data, extracts the critical turning point, calculates transient strain rate, inverts stretching viscosity, and outputs a standardized melt strength index with confidence coefficient. The invention realizes the comparability online evaluation of the cross working condition and the cross equipment and supports the process window setting and the online control.

Inventors

LI DAOQING
ZHU BIAO
LUO GUOZHI
HUANG JINXU

Assignees

佛山市力晟塑胶制品有限公司

Dates

Publication Date: 20260512
Application Date: 20260206

Claims (10)

1. A intensity detection device for plastic goods production, characterized by, include: a melt filament forming assembly connected to a die of an extrusion apparatus for outputting a continuous melt filament (1); The traction assembly scans the traction speed of the melt filament (1); the measuring component outputs traction time sequence data; the motion parameter acquisition component outputs traction distance time sequence data; the strength detection component is used for calculating the transient strain rate, inverting the elongational viscosity and outputting a standardized melt strength index and a confidence coefficient; The strength detection assembly takes traction time sequence data, traction speed time sequence data and traction distance time sequence data as input, sequentially passes through a signal preprocessing module, an online variable point detection module, a self-adaptive scanning module and a critical inversion module, wherein the critical inversion module takes encrypted sampling data as input and calculates transient strain rate based on critical turning points, the method comprises the steps of reading a first data segment formed by the encrypted sampling data, taking a distinguishing signal as an index, extracting candidate critical points, intercepting local candidate data segments formed by a preset fixed length window which is continuous before and after the sampling points, carrying out consistency check on sliding window statistical features of the traction time sequence data and local slopes which are changed along with the traction speed time sequence data in the local candidate data segments to form a critical point feature packet, taking the critical point feature packet as an anchor point, extracting a second data segment which covers the fixed time length before and after the candidate critical points from the first data segment, generating a transient strain rate sequence aligned with the candidate critical points, and outputting a transient strain rate scalar at the candidate critical points.
2. The strength detection device for plastic product production according to claim 1, wherein the generation of the transient strain rate sequence aligned with the candidate critical point comprises taking a timestamp corresponding to the candidate critical turning point as an alignment reference, intercepting a traction speed sequence with a preset fixed length and a synchronous traction distance thereof before and after the candidate critical point from the first data segment, carrying out differential calculation on the speed change rate and sliding window smoothing on the traction speed sequence to restrain noise, and then carrying out point-by-point pairing conversion on the smoothed speed change rate and the corresponding effective traction distance to obtain a unit-length traction rate, and forming a sequence according to the timestamp sequence to obtain the transient strain rate sequence aligned with the candidate critical point.
3. The strength detection device for plastic product production according to claim 2 is characterized in that traction time sequence data and transient strain rate sequences in the second data segment are taken as input, a front neighborhood window and a rear neighborhood window with fixed length are set with a candidate critical point sampling time as a center, a traction speed non-increment segment, a traction distance abnormal jump point and a traction peak outlier are put forward in the neighborhood window, a traction fluctuation level and a strain rate fluctuation level are calculated according to a sliding window, a continuous sampling point segment with the fluctuation level lower than a preset threshold value and continuously meeting stability requirements is reserved, the continuous sampling point segment is defined as an inversion window, a start-stop time stamp and a sample index set of the continuous sampling point segment are output, in the inversion window, the traction time sequence data are taken as axial load input, real-time cross section alignment of a melt filament (1) is used for normalization, tensile stress at corresponding time is taken as a tensile response time sequence, and tensile viscosity inversion is completed by combining the tensile response time sequence with the transient strain rate, so that a candidate critical point tensile viscosity result and a tensile viscosity sequence in the inversion window are obtained.
4. The strength detection device for plastic product production according to claim 3, wherein the stretching response is combined with transient strain rate to complete stretching viscosity inversion, and a candidate critical point stretching viscosity result and a stretching viscosity sequence in an inversion window are obtained, wherein the method comprises the steps of carrying out point-by-point time alignment on a stretching corresponding time sequence and the transient strain rate sequence according to a unified sampling clock, then screening the transient strain rate sequence in the inversion window, eliminating invalid sampling points, carrying out inversion on a reserved sampling point combination of the stretching response and the transient strain rate to obtain a stretching viscosity value, generating the stretching viscosity sequence in the inversion window point by point, taking the sampling point corresponding to a critical turning point as an index, and reading the stretching viscosity value of the sampling point in the stretching viscosity sequence as the candidate critical point stretching viscosity.
5. The strength detecting device for plastic product production according to claim 4, wherein the candidate critical point extensional viscosity is used as a main characteristic quantity, and parameters in a critical point characteristic package are used as supplementary inputs, and a preset standardized mapping rule is called to generate a standardized melt strength index.
6. The strength detection device for plastic product production according to claim 5, wherein the standardized mapping rule takes critical point extensional viscosity as a main input, reads traction force value, traction speed value and traction distance value of a critical point feature packet, performs traction distance benchmark processing on the candidate critical point extensional viscosity, performs consistency check and amplitude normalization on the candidate critical point extensional viscosity after benchmark processing in combination with critical point traction force and traction speed, and finally generates a standardized melt strength index according to a preset fixed output caliber.
7. The strength detecting device for plastic product production according to claim 1, wherein the interior of the melt filament forming assembly comprises a temperature-resistant honeycomb duct and a sizing die in sequence.
8. The strength detecting device for plastic product production according to claim 1, characterized in that the traction assembly comprises a variable speed drive mechanism (4) and a traction clamping mechanism, the variable speed drive mechanism (4) is composed of a servo motor and a driver thereof or a variable frequency motor and a frequency converter thereof, and the traction clamping mechanism provides clamping force for one of a counter-rotating traction wheel, a track traction belt or a compression roller traction structure through a compression mechanism.
9. The apparatus of claim 8, wherein the motion parameter acquisition assembly includes a distance sensor that cooperates with a traction distance adjustment mechanism to determine an effective traction distance between the measurement assembly and the traction clamping mechanism and to output traction distance timing data after traction distance adjustment or locking.
10. The intensity detection device for plastic product production according to claim 1, wherein the signal preprocessing module performs denoising and smoothing processing on the traction time sequence data by adopting kalman filtering smoothing, and performs time stamp alignment and outlier rejection on the traction speed time sequence data and the traction distance time sequence data.

Description

Intensity detection device for plastic product production Technical Field The invention relates to the technical field of material physical property testing and analysis, in particular to a strength detection device for plastic product production. Background In the extrusion molding process of plastic products, the drafting stability of the melt after the outlet of the die directly influences the quality problems of broken filaments, necking, thickness fluctuation, surface defects and the like, so that the drafting capacity and the strength characteristics of the melt need to be tested on line. In 2023, liu Shuang was applied to polymer characterization by rheology technology published in journal of high molecular theory, namely, tensile rheology test, introducing a common traction type melt strength evaluation method in engineering, wherein the traction speed increment or traction ratio increment is implemented on extruded melt filaments, a force-traction ratio curve is formed by recording traction force along with the change of traction speed or traction ratio, and strength indexes are output at breaking points or characteristic points of the curve. As shown in FIG. 2, the Rheotens draw test is a typical draw down evaluation framework that characterizes melt draw down behavior and melt strength by drawing down a melt filament and measuring the draw down force. On the other hand, in 2013, xiaoyong, published in journal of mechanical engineering in China, has proposed that in film or strip production lines, as shown in fig. 3, tension measurement and tension control systems have been used for closed loop tension control in the pulling section, but the goal of such systems is usually to maintain tension at a set value, and the problems of melt draft curve feature extraction and cross-condition comparability test are not directly solved. The existing traction type melt strength online application still faces three types of defects, namely firstly, non-isothermal cooling and hardening effects exist in the traction of a melt filament in air, traction force is amplified by environment heat exchange conditions, so that test results lack unified comparable standards under different environments and different traction distances, secondly, the melt strength is highly sensitive to traction distances and extrusion rates, a transition boundary from a stable traction area to an unstable traction area cannot be covered stably by traction speed scanning with a fixed step length or a fixed acceleration rate under different working conditions, so that repeatability is insufficient when only a breaking point or a single-point traction force is used as an index, thirdly, the support online control needs to stably output movable characteristic parameters, particularly the boundary of the stable traction area, a critical turning point and corresponding transient stretching viscosity or equivalent strength, but a fixed scanning strategy is sparse in sampling vicinity of the inflection point, sensitive to noise, and difficult to stably extract the characteristic quantity. Therefore, there is a need for an extrusion line-oriented strength detection device, in which the traction speed scanning stage is updated to an adaptive closed-loop scanning based on online variable point detection, so that physical property data such as traction force is updated to the characteristic inversion in a data flow manner of progressive layer by layer, and a comparable and reusable melt strength test result is obtained. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a strength detection device for plastic product production, which is used for carrying out online test and analysis based on physical data such as traction force, traction speed, traction distance and the like in melt filament drafting detection, realizing self-adaptive closed loop control in a traction speed scanning stage, acquiring a boundary and a critical turning point of a stable drafting zone, and further inverting an extensional viscosity output standardized melt strength index and confidence level so as to solve the problems in the background art. In order to achieve the above purpose, the present invention provides the following technical solutions: a intensity detection device for plastic goods production includes: and the melt filament forming assembly is connected with a die of the extrusion equipment and outputs continuous melt filaments. And the traction assembly scans the traction speed of the melt filament. And the measuring component outputs the traction time sequence data. And the motion parameter acquisition component outputs traction distance time sequence data. And the strength detection component is used for calculating the transient strain rate, inverting the elongational viscosity and outputting a standardized melt strength index and a confidence coefficient. As a further aspect of the invention, a melt filament f