CN105674925B - Fluid assists product parameter ultrasound On-line Measuring Method in co-injection molding - Google Patents
Fluid assists product parameter ultrasound On-line Measuring Method in co-injection molding Download PDFInfo
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- CN105674925B CN105674925B CN201610156583.6A CN201610156583A CN105674925B CN 105674925 B CN105674925 B CN 105674925B CN 201610156583 A CN201610156583 A CN 201610156583A CN 105674925 B CN105674925 B CN 105674925B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
- G01B17/02—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations for measuring thickness
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
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- Injection Moulding Of Plastics Or The Like (AREA)
- Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
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Abstract
The invention discloses a kind of fluids to assist product parameter ultrasound On-line Measuring Method in co-injection molding, including：(1) on plastic melt flow direction, the product into forming process emits ultrasonic wave, acquires the same outer boundary reflection echo and inner boundary reflection echo of ultrasonic wave outer boundary in i-th layer：(2) time interval received between outer boundary reflection echo LB and inner boundary reflection echo is calculated；(3) plastic products middle layer, voided layer length are obtained according to 1~i layers of wall thickness numerical value.Plastic products surface layer of the present invention or other each layer wall thickness and middle layer, voided layer measurement of length need not destroy product, has the advantages that nondestructive measurement, surface layer or other each layer wall thickness and voided layer length are obtained by ultrasonic signal, it need not wait products that rear off-line operation is made, it can carry out the nondestructive measurement of real-time online, easy to operate, precision is high.
Description
Technical field
The present invention relates to plastic forming technology fields, and in particular to product parameter ultrasound in a kind of fluid auxiliary co-injection molding
On-line Measuring Method.
Background technology
It is a kind of new work to grow up on the basis of co-injection molding and fluid assistant formation that fluid, which assists co-injection molding,
Skill.For opposite co-injection molding technique, an injection that fluid has assisted co-injection molding technique mostly assists the process of fluid.Relative to
For fluid assistant formation technique, it is that a variety of plastic materials established sequentially or simultaneously inject mould that fluid, which assists the injection phase of co-injection molding,
Chamber forms the process of multilayered structure.Therefore, fluid auxiliary co-injection molding is actually the knot of co-injection molding and fluid assistant formation
It closes.
The advantages of fluid auxiliary co-injection molding had both remained co-injection molding, also remains the excellent of fluid assistant formation technique
Point may be implemented to utilize technics of reclaim of plastic waste using fluid auxiliary co-injection molding, can be using waste plastic as inner plastic
Material use.The higher plastic products of cost performance can be obtained using fluid auxiliary co-injection molding.Meanwhile it being assisted altogether using fluid
Injection forming can realize that the diversification of plastic products requires.Moreover, great surface quality can be obtained using fluid auxiliary co-injection molding
The part with complicated structure that differs greatly of wall thickness dimension, while equipment investment can be reduced.
Fluid assist co-injection molding technique in, article topsheet, middle layer wall thickness precision affect the quality of product.Surface layer
Wall thickness refers to the wall thickness for the plastics that hollow product is located at surface layer, and middle layer wall thickness is the wall thickness of the plastic layer other than skim-coat.In
It can also be multilayer that interbed, which can be one layer,.Article topsheet wall thickness, middle layer wall thickness are the passes of fluid auxiliary co-injection molding technology
One of key index, effectively control surface layer wall thickness, middle layer wall thickness are the major criterions of fluid auxiliary co-injection molding maturation.Currently,
Lot of domestic and foreign scholar has been directed to the formation mechenism and wall thickness of fluid auxiliary co-injection molding article topsheet wall thickness, middle layer wall thickness
Control largely research and analyse, research shows that the different materials fluid auxiliary surface layer wall thickness of co-injection molding, middle layer
Wall thickness is mainly related with various plastic melt preform injection amounts, delay time and the auxiliary technological parameters such as Fluid pressure.
But current surface layer wall thickness and middle layer wall thickness are measured by offline mode, and product is cut to obtain cross section
Carry out mechanical measurement.The shortcomings that this method is：(1) this method needs to destroy product, has destructive；(2) it needs to carry out
The trial-production experiment of a large amount of numbers carrys out adjusting process parameter, to obtain relatively accurate remaining wall thickness, this method time and effort consuming；(3)
Once change mold or injected plastics material change, then need to come adjusting process parameter, this method again through a large number of experiments
Flexibility is poor.Therefore, a kind of cost-effective detection means of urgent need comes real-time online measuring surface layer wall thickness and sandwich layer wall thickness, so as to
Real-time adjusting process parameter is to optimize the molding effect of product.
In addition its machinery and mechanical property of the effect length of voided layer of moulding in fluid assists coforming, however
Voided layer is usually covered by opaque skin-material, therefore can not optically be measured, unless moulding is blocked survey
Otherwise it is very difficult to measure voided layer length for amount.There is presently no very feasible methods.
In plastic products, each layer wall thickness and voided layer measurement of length are all very important.Currently, some developed countries
Experts and scholars all finding a kind of cost-effective wall thickness measurement method, under this competitive landscape, the present invention provides one
Kind utilizes the real-time online measuring method of ultrasonic reflections phenomenon.
Invention content
Co-injection molding, surface layer wall thickness, middle layer wall thickness and middle layer length, voided layer are assisted as described previously for fluid
Measurement of length is of great significance.In view of the deficiencies of the prior art, the purpose of the present invention is to provide it is a kind of it is of low cost, make
Article topsheet wall thickness, middle layer wall thickness and middle layer in co-injection molding are assisted with the fluid that is used for that convenient, precision is easy to control, lossless
The method of length, core layer length real-time online measuring.
Product parameter ultrasound On-line Measuring Method in a kind of fluid auxiliary co-injection molding, corresponding product is from surface layer to most interior
Layer is defined as 1~n-layer successively, and wherein n is the positive integer more than or equal to 2, and the corresponding plastic melt of 1~n-layer is 1~n
Layer plastic melt, is detected i-th layer of wall thickness, and wherein i is the positive integer of 1~n, is included the following steps：
(1) on plastic melt flow direction, the product into forming process emits ultrasonic wave, acquires the ultrasound
A same outer boundary reflection echo and inner boundary reflection echo for wave outer boundary in i-th layer：
Wherein：
Outer boundary reflection echo is the reflection echo that the ultrasonic wave occurs in i-th layer of outer boundary, as i=1, described i-th
Layer outer boundary is the interface of the 1st layer of plastic melt (surface layer plastic melt) and mould inner wall；When i is more than 1, described i-th layer outer
Interface is the interface of (i-1)-th layer of plastic melt and i-th layer of plastic melt；
Inner boundary reflection echo is the reflection echo that occurs in i-th layer of inner boundary of the ultrasonic wave, when i is less than n, described the
I layers of inner boundary are the interface of i-th layer of plastic melt and i+1 layer plastic melt, and when i is equal to n, i-th layer of inner boundary is
The interface of n-th layer plastic melt (innermost layer melt) and auxiliary fluid；
(2) the time interval △ t received between outer boundary reflection echo and inner boundary reflection echo are calculated, plastics system is obtained
I-th layer of wall thickness h of product：
H=1/2 × V × △ t；
Wherein, V is spread speed of the ultrasonic wave in i-th layer of plastic melt；
The detection to one or more layer wall thickness is realized according to step (1) and step (2)；
It is selectable to enter step (3)；
(3) plastic products middle layer and voided layer length are obtained according to 1~i layers of wall thickness numerical value.
Preferably, the n is 2 or 3.Two layers or three-layer fluid auxiliary co-injection molding be at present it is the most widely used
Two kinds of co-injection molding techniques, the method that the present invention can be used realize on-line checking.
Preferably, spread speed V of the ultrasonic wave in i-th layer of plastic melt is determined with the following method：
(I) emit ultrasonic wave on plastic melt flow direction in advance, acquire the ultrasonic wave inside and outside i-th layer
A same outer boundary reflection echo and inner boundary reflection echo at interface：
Wherein：
Outer boundary reflection echo is that in i-th layer of outer boundary reflection echo, as i=1, described i-th layer occur for the ultrasonic wave
Outer boundary is the interface of the 1st layer of plastic melt and mould inner wall；When i is more than 1, i-th layer of outer boundary is (i-1)-th layer of plastics
The interface of melt and i-th layer of plastic melt；
Inner boundary reflection echo is the reflection echo that the ultrasonic wave occurs in i-th layer of inner boundary, as i=n, described i-th
Layer inner boundary is the interface of i-th layer of plastic melt and auxiliary fluid；When i is less than n, i-th layer of inner boundary is i-th layer of plastics
The interface of melt and i+1 layer plastic melt；
(II) the time interval Δ t received between outer boundary reflection echo and inner boundary reflection echo is calculated；
(III) plastic products obtained are blocked in ultrasonic wave corresponding position, obtains i-th layer of wall thickness h of plastics, and then calculate
Obtain spread speed V, V=2h/ △ t of the ultrasonic wave in i-th layer of plastic melt.
For a certain layer, ultrasonic wave first time outer boundary reflection echo and inner boundary reflection echo may be by noise signal shadows
It rings, generates fluctuation, so, under the premise of intensity is met the requirements, to obtain stable ultrasonic reflection echo, preferably, step
Suddenly in (1), the back wave numerical value of acquisition ultrasonic wave the 2nd~3 time.
Preferably, in step (3), the method for calculating voided layer length is as follows：
(3-1) acquires multigroup corresponding voided layer length data and voided layer thickness data in advance；
(3-2) carries out linear fit or fitting of a polynomial, obtains the letter of voided layer length data and voided layer thickness data
Number equation；
(3-3) detects or calculates the hollow layer thickness of the product during molding, the hollow layer thickness that detection is obtained
Data substitute into above-mentioned functional equation and obtain voided layer length.
Alternatively, in step (3), the method for calculating middle layer length is as follows：
(3-11) acquires multigroup corresponding middle layer length data and intermediate layer thickness data in advance；
(3-22) carries out linear fit or fitting of a polynomial, obtains the letter of middle layer length data and intermediate layer thickness data
Number equation；
(3-33) detects or calculates the intermediate layer thickness of the product during molding, the intermediate layer thickness that detection is obtained
Data substitute into above-mentioned functional equation and obtain middle layer length.
Step (3-1), (3-11) and step (3-2), (3-22) are usually to be determined before technique is gone into operation, in co-injection molding mistake
Cheng Zhong can detect to obtain voided layer or middle layer length in real time.
Preferably, the voided layer thickness h for the plastic products being calculated as in step (3-3) during typeiThe method of data
It is as follows：
hi=D-2 ∑s h；
Wherein D is the outer diameter of plastic products；∑ h is the sum of 1~n-layer wall thickness.
To ensure the higher degree of correlation, preferably, in step (3-2), (3-22), using second order polynomial fit or three
Rank multinomial is fitted.
As further preferred, in step (3-2), (3-22), using second order polynomial fit.It is quasi- using second order polynomial
It closes, had not only ensured the degree of correlation but also reduced calculation amount, the degree of correlation is 0.98 or more.
Preferably, in step (I), repeatedly emit ultrasonic wave, acquires multigroup outer boundary reflection echo and inner boundary reflection
Echo；Spread speed of the final ultrasonic wave in i-th layer of plastic melt is that every group of outer boundary reflection echo and inner boundary are reflected back
The average value for the spread speed that wave obtains.Meanwhile also can multiple ultrasonic probes be set in plastic products different location as needed.
In step (III), vernier caliper measurement surface layer wall thickness h can be used.
For assisting co-injection molding, under normal circumstances, surface layer plastics, middle layer (if there is), inner plastic material are different,
Property is also different, when middle layer plastic melt, sandwich layer plastic melt are injected into the plastic melt of surface layer, for a certain layer, ultrasound
Wave generates reflection echo in this layer of plastic melt outer boundary, and reflection echo occurs in this layer of plastic melt inner boundary, anti-by two
It is emitted back towards wave and can measure propagation time of the ultrasonic wave between two interfaces, i.e. propagation time of the ultrasonic wave in the plastics.Another party
Face is blocked Manufactured plastic products under the conditions of same process by offline mode, with length gage measuring ultrasonic probe
The surface layer of corresponding points plastic products, middle layer wall thickness can calculate the spread speed of ultrasonic wave in plastic products.With above-mentioned side
Method measures the propagation time of ultrasonic wave in plastic products in real time again, you can calculates surface layer or the middle layer wall of plastic products
It is thick.
The present invention co-injection molding ultrasound on-line measurement system include：Supersonic detection device, at least one ultrasonic probe, mould
Tool, fluid auxiliary device and the injector that two or more plastic injections can be carried out.Wherein ultrasonic probe is jointly mounted to mold table
Face.Supersonic detection device can be digital ultrasound card, can also be the reflectoscope of integral type.Digital ultrasound card is used for
Control ultrasonic probe sends out pulse ultrasonic wave, is additionally operable to receive and acquire specific reflected ultrasonic wave.Ultrasound of the PC machine to acquisition
Signal is handled, and surface layer, middle layer wall thickness and middle layer, voided layer length are calculated.
Compared with prior art, the present invention has the following advantages：Plastic products surface layer or other each layer wall thickness and middle layer,
Voided layer measurement of length need not destroy product, have the advantages that nondestructive measurement, by ultrasonic signal obtain surface layer or its
His each layer wall thickness and length, need not wait products that rear off-line operation is made, and can carry out the nondestructive measurement of real-time online, operation letter
Single, precision is high.
Description of the drawings
Fig. 1 is that fluid assists co-injection molding ultrasound real-time measurement system and transonic schematic diagram.
Fig. 2 is the reflected ultrasonic wave signal graph before plastic products will be detached with mold cavity surfaces.
Fig. 3 is voided layer length and thickness relationship linear fit result figure.
Fig. 4 is voided layer length and thickness relationship fitting of a polynomial result figure：Wherein (a) is binomial fitting as a result, (b)
For trinomial fitting result.
Fig. 5 is middle layer length and thickness relationship linear fit result figure.
Fig. 6 is middle layer length and thickness relationship fitting of a polynomial result figure：Wherein (a) is binomial fitting as a result, (b)
For trinomial fitting result.
Specific implementation mode
In order to make the purpose , technical scheme and advantage of the present invention be clearer, below in conjunction with attached drawing and exemplary reality
Example is applied, the present invention will be described in further detail.It should be appreciated that exemplary embodiment described herein is only explaining this
Invention, the scope of application being not intended to limit the present invention.
The present invention is illustrated with carrying out two layers of co-injection by two kinds of plastics by taking gas is auxiliary fluid as an example.
Specifically, as shown in Figure 1, for auxiliary co-injection molding injector ultrasound real-time measurement system schematic diagram.Measure system
System includes：Supersonic detection device, by supersonic detection device control a ultrasonic probe, injection molding mold, can carry out two kinds with
The injector and gas auxiliary device of upper plastic injection.
In the present embodiment, supersonic detection device is made of digital ultrasound card and PC machine, and ultrasound card is for controlling ultrasound
Probe sends out pulse ultrasonic wave, is additionally operable to receive and acquires reflected ultrasonic wave, and the reflected ultrasonic wave of acquisition is sent to PC machine.
PC machine handles the ultrasonic signal of acquisition, calculates surface layer, middle layer wall thickness and middle layer, voided layer length.
In the present embodiment, ultrasonic probe is longitudinal wave probe, and pulse ultrasonic wave is perpendicular to plastic melt flow direction.
In this example, surface layer plastics are HDPE (high density polyethylene (HDPE)), and internal layer is PP (polypropylene), without middle layer.This
In example, the auxiliary device gas injection pressure of gas is 3MPa, and gas injection postpones 3s, flow rate 7.41cm3/ s, 210 DEG C of material temperature.
In Fig. 2, LB indicates that ultrasonic wave molds the first reflection echo at interface on mould inner wall and surface layer, and LS indicates ultrasound
For wave in the first reflection echo at surface layer plastics Yu inner plastic interface, LG is the first time of inner plastic and auxiliary fluid boundary
Reflection echo.
1. the specific implementation step of surface layer wall thickness, internal layer wall thickness measuring is as follows：
(1) in the flowing direction, being normally at for inner plastic melt assists in front of fluid, is not having sandwich layer plastic melt
Plastic melt part, without LG generate；And in auxiliary fluid front ends, inner plastic melt inner wall is generally arc knot
Structure, inner plastic melt thickness is variation, when using first reflection echo LS and LS at this time, the internal layer modeling that is calculated
Expect that melt thickness error is larger, institute is to avoid using first reflection echo LG and LS calculating plastic melt thickness at this time；Table
There is also similar problems between layer plastic melt and inner plastic melt.When practical operation, it can believe in first reflection echo
(i.e. when the amplitude fluctuations at former and later two moment are little, illustrate the plastic melt of detection shape after number LB, LG and LS amplitude stability
At stable wall thickness) acquisition reflection signal LB and LG and LG and LS between time interval Δ t, be ultrasonic wave in plastics system
Propagation time in product.Then surface layer wall thickness, internal layer wall thickness can be calculated by formula (1)：
H=1/2 × V × △ t (1).
In formula, h is that either internal layer wall thickness V is ultrasonic wave in surface layer plastic melt or internal layer to plastic products surface layer wall thickness
Spread speed in plastics.Ultrasonic reflection echo-signal is as shown in Fig. 2, this example △ t1=1451.6404ns, △ t2=
1136.0664ns。
Under normal circumstances, there is higher sensitivity to molding interface conditions due to high order echo, the case where meeting intensity
Under, second-time-around echo LB and LG, LS can be selected as the basis calculated；
(2) measurement process of spread speed V is as follows in step (1)：
(2-1) measures ultrasonic wave in reflection echo signal LB, LS and the LG at three interfaces by step (1), can measure ultrasound
Propagation time △ t1 and △ t2 of the wave in two kinds of plastic Hs DPE and PP.△ t1=1467.4191ns in this example, △ t2=
1120.2877ns。
(2-2) will be measured △ t made molding plastic products probe UT at block, obtain its cross section, use
Vernier caliper distinguishes measurement remnant wall thickness h.H1=1.8mm in this example, h2=1.42mm.
(2-3) substitutes into formula (1) and calculates ultrasonic propagation velocity V1=2453.29m/s, V2=2535.06m/s.
(2-4) can also further repeat step (2-1) to (2-3), repeatedly measure, average to obtain ultrasonic propagation
Speed V1 and V2.
(3) by spread speed V1=2453.29m/s and V2=2535.06m/s, propagation time △ t1=1451.6404ns
It is respectively h1=1.78mm and h2=to substitute into formula (1) to calculate the remaining wall thickness of HDPE and PP with △ t2=1136.0664ns
1.44mm。
By verification, which measures after being blocked at probe UT through electronic digital indicator, the thickness of two layers of HDPE and PP
Respectively H1=1.8mm and H2=1.42, error is 1% or so.
2. voided layer linear measure longimetry
In assisting co-injection molding, the principal element for influencing voided layer length has：Plastic melt material performance itself, material
Percent by volume assists the pressure and flow of fluid, the geometry and mold temperature of mold.When other process conditions are constant
When, only change material volume percentage, is found through experiments that between the length of voided layer and hollow layer thickness that there are correlations.Needle
To the same process systems, the data of 9 groups of voided layer length and hollow layer thickness that experiment obtains are subjected to linear fit respectively
It is fitted with two, three rank multinomials, Fig. 3 show linear fit, degree of correlation R2It is 0.9333, precision is higher.In Fig. 4 (a)
(b) shown in be respectively second order polynomial and three rank multinomials fitting as a result, degree of correlation R2Respectively 0.9859 and 0.9862,
Precision higher.Not only to ensure the degree of correlation but also reducing calculation amount, thus it is ideal using second order polynomial fit.Second order polynomial
The equation of fitting is：
Y=-219.42x2+870.76x-707.07 (2)
Wherein, x indicates that hollow layer thickness, y indicate voided layer length.To according to the equation, can by hollow layer thickness Lai
Calculate voided layer length.
Specifically, the method for calculating voided layer length is as follows：
(3-1) acquires multigroup voided layer length data and voided layer thickness data；
(3-2) uses the above method, carries out binomial fitting, obtains voided layer length data and voided layer thickness data
Functional equation, as shown in formula (2)；
(3-3) calculates the core layer thickness data of the product during molding, and the voided layer thickness data acquired is substituted into
It states and obtains voided layer length in functional equation.
Voided layer length is obtained with thickness by the way that product is splitted progress mechanical measurement along shaft section in step (3-1).
The voided layer thickness h of the product during type is calculated as in step (3-3)iThe method of data is as follows：
hi=D-2h1-2h2；
Wherein D is the outer diameter of product.
H1, h2 are respectively the surface layer being calculated in 1 and middle layer wall thickness value.
Middle layer 3. (PP) linear measure longimetry
In assisting co-injection molding, the principal element for influencing middle layer and voided layer length has：Plastic melt material itself
Performance, material volume percentage assist the pressure and flow of fluid, the geometry and mold temperature of mold.When other techniques
When condition is constant, only changes material volume percentage, be found through experiments that between the length of middle layer and intermediate layer thickness and exist
Correlation.For the same process systems, the data of 9 groups of middle layer length and intermediate layer thickness that experiment obtains are carried out respectively
Linear fit and the fitting of two, three rank multinomials, Fig. 5 show linear fit, degree of correlation R2It is 0.9589, precision is higher.
It is respectively second order polynomial and the fitting of three rank multinomials shown in (a) and (b) in Fig. 6 as a result, degree of correlation R2Respectively 0.9829
With 0.9839, precision higher.Not only to ensure the degree of correlation but also reducing calculation amount, thus it is ideal using second order polynomial fit.
The equation of second order polynomial fit is：
Y=-158.01x2+558.42x-332.5 (2)
Wherein, x indicates that intermediate layer thickness, y indicate middle layer length.To according to the equation, can by intermediate layer thickness Lai
Calculate middle layer length.
Specifically, the method for calculating middle layer length is as follows：
(3-1) acquires multigroup middle layer length data and intermediate layer thickness data；
(3-2) uses the above method, carries out binomial fitting, obtains middle layer length data and intermediate layer thickness data
Functional equation, as shown in formula (2)；
The intermediate layer thickness data h2 acquired in 1 is substituted into above-mentioned functional equation and is obtained middle layer length by (3-3).
Voided layer length is obtained with thickness by the way that product is splitted progress mechanical measurement along shaft section in step (3-1).
The foregoing is merely the preferred embodiment of the present invention, protection scope of the present invention is not limited in above-mentioned embodiment party
Formula, every technical solution for belonging to the principle of the invention all belong to the scope of protection of the present invention.It moulds on the surface layer of embodiment of the present invention
Material melt is HDPE (high density polyethylene (HDPE)), and inner plastic melt is PP (polypropylene), but the method for the invention can also be used for
The thickness value real-time online measuring of other kinds of double-layer product or multi-layer product, therefore also belong to the protection model of the present invention
It encloses.For a person skilled in the art, several improvements and modifications carried out without departing from the principles of the present invention,
These improvements and modifications also should be regarded as protection scope of the present invention.
Claims (7)
1. product parameter ultrasound On-line Measuring Method in a kind of fluid auxiliary co-injection molding, corresponding product is from surface layer, middle layer
It is defined as 1~n-layer successively to innermost layer, wherein n is the positive integer more than or equal to 2, and the corresponding plastic melt of 1~n-layer is
1~n-layer plastic melt, which is characterized in that i-th layer of wall thickness is detected, wherein i is the positive integer of 1~n, including as follows
Step：
(1) on plastic melt flow direction, the product into forming process emits ultrasonic wave, acquires the ultrasonic wave and exists
A same outer boundary reflection echo and inner boundary reflection echo for outer boundary in i-th layer：
(2) the time interval Δ t received between outer boundary reflection echo and inner boundary reflection echo is calculated, plastic products are obtained
I-th layer of wall thickness h：
H=1/2 × V × △ t；
Wherein, V is spread speed of the ultrasonic wave in i-th layer of plastic melt；
The detection to one or more layer wall thickness is realized according to step (1) and step (2)；
Further include step (3)；
(3) plastic products middle layer and voided layer length are obtained according to 1~i layers of wall thickness numerical value；
In step (3), the method for calculating voided layer length is as follows：
(3-1) acquires multigroup corresponding voided layer length data and voided layer thickness data in advance；
(3-2) carries out linear fit or fitting of a polynomial, obtains the function side of voided layer length data and voided layer thickness data
Journey；
(3-3) detects or calculates the hollow layer thickness of the product during molding, the voided layer thickness data that detection is obtained
It substitutes into above-mentioned functional equation and obtains voided layer length；
The method for calculating middle layer length is as follows：
(3-11) acquires multigroup corresponding middle layer length data and intermediate layer thickness data in advance；
(3-22) carries out linear fit or fitting of a polynomial, obtains the function side of middle layer length data and intermediate layer thickness data
Journey；
(3-33) detects or calculates the intermediate layer thickness of the product during molding, the intermediate layer thickness data that detection is obtained
It substitutes into above-mentioned functional equation and obtains middle layer length.
2. product parameter ultrasound On-line Measuring Method in fluid auxiliary co-injection molding according to claim 1, feature exist
In the n is 2 or 3.
3. product parameter ultrasound On-line Measuring Method in fluid auxiliary co-injection molding according to claim 1, feature exist
In spread speed V of the ultrasonic wave in i-th layer of plastic melt is determined with the following method：
(I) emit ultrasonic wave on plastic melt flow direction in advance, acquire ultrasonic wave outer boundary in i-th layer
A same outer boundary reflection echo and inner boundary reflection echo：
(II) the time interval Δ t received between outer boundary reflection echo and inner boundary reflection echo is calculated；
(III) plastic products obtained are blocked in ultrasonic wave corresponding position, obtains i-th layer of wall thickness h of plastics, and then be calculated
Spread speed V, V=2h/ △ t of the ultrasonic wave in i-th layer of plastic melt.
4. product parameter ultrasound On-line Measuring Method in fluid auxiliary co-injection molding according to claim 1, feature exist
In, in step (1), the back wave numerical value of acquisition ultrasonic wave the 2nd~3 time.
5. product parameter ultrasound On-line Measuring Method in fluid auxiliary co-injection molding according to claim 1, feature exist
In being calculated as the voided layer thickness h of the plastic products during type in step (3-3)iThe method of data is as follows：
hi=D-2 ∑s h；
Wherein D is the outer diameter of plastic products；∑ h is the sum of 1~n-layer wall thickness.
6. product parameter ultrasound On-line Measuring Method in fluid auxiliary co-injection molding according to claim 1, feature exist
In in step (3-2) or step (3-22), using second order polynomial fit or the fitting of three rank multinomials.
7. product parameter ultrasound On-line Measuring Method in fluid auxiliary co-injection molding according to claim 3, feature exist
In in step (1), repeatedly emitting ultrasonic wave, acquire multigroup outer boundary reflection echo and inner boundary reflection echo；Final ultrasonic wave
Spread speed in i-th layer of plastic melt is the spread speed that every group of outer boundary reflection echo and inner boundary reflection echo obtain
Average value.
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| CN105674925A (en) | 2016-06-15 |
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