CN101028740B - Injection-machine parameter setting method with automatically-resetting graded injection speed and position - Google Patents

Abstract

An injection moulding machine able to automatically set up the hierarchical injection speed and injection position is composed of a screwed barrel, a screw bolt is said barrel, a heating jacket, a nozzle with a radial through hole, and a sensor in said through hole, in contact with the fused substance and connected electrically to computer. A method for setting up the parameters of said injectionmachine features tha nozzle pressure-time curve in the condition of constant injection speed is measured for searching the injection position (time) at jump point, that is, finding the position (time)for changing injection speed.

Description

The injection machine parameter setting method of automatic setting multi-level injection speed and injection position

Technical field

The present invention relates to injection machine, the injection machine parameter setting method of particularly a kind of automatic setting multi-level injection speed and injection position.

Background technology

Injection mo(u)lding basic process is that the moulding material heating and melting is become flowable state (being called the plasticizing attitude), and high-pressure is injected into mould, cools off and curing molding (for thermoplastic resin), takes out required moulded products then from mould.

The factor that the related technological parameter of the injection-molded item of production high-quality produces is a lot, in general, after the serviceability that proposes a new product and other relevant requirements, at first should under the principle of economical rationality and technical feasibility, select only raw material, production technology, equipment and mold structure.After these conditions were determined, Selection of technological conditions and control were exactly the main factor of considering.

Conventional plastic die forming process proposes finite element mechanics netting analysis method according to high molecule plastic rheology theory method, with computer plastic flow in the mould is simulated product forming process, the injection parameters that this rheology method is obtained realizes the injection molding molded article by injection machine again by manually being input to injection machine by keyboard.In the prior art, it is to adopt the three-dimensional structure algorithm of CAD to realize the parameter setting that injection machine is set the injection parameters method, this multi-level injection procedure parameter is set shortcoming: because in the real-time control procedure of injection machine, can not do a large amount of mathematical operations, an injection molding chamber process general-purpose computers analog simulation, the plastics simulation is drawn parameter at the dies cavity flow process, be input to the injection machine panel, this method complex structure, the algorithm complexity, computational process assumed condition or constraints are added emulator, and the injection parameters that obtains departs from actual value.

Summary of the invention

The shortcoming that the objective of the invention is to overcome prior art is with not enough, and a kind of algorithm is simple, simple in structure, die trial efficient the is high automatic setting multi-level injection speed and the injection machine parameter setting method of injection position are provided.

Purpose of the present invention is achieved through the following technical solutions: the injection machine of automatic setting multi-level injection speed and injection position, comprise screw tube, be arranged at screw rod in the screw tube, be arranged at the outer heating jacket of screw tube, be arranged at the nozzle of described screw tube one end, it is characterized in that: described nozzle radially is provided with through hole, be provided with sensor in the described through hole, melt in described sensor and the screw tube contacts, and described sensor is connected with Computer signal.

The outer heating jacket of described screw tube is provided with sensor.

Described sensor is a pressure-temperature sensor.

The parameter setting method of the above-mentioned automatic setting multi-level injection speed and the injection machine of injection position is characterized in that may further comprise the steps:

Step 1: injection machine carries out the injection moulding mold filling to mould, records the pressure-time curve at nozzle place by the sensor at nozzle place, gets the N point on the pressure-time curve in whole mold filling stage, and N is a natural number, and whole mould-filling time is t _f, determine pressure P and time value t that described N is ordered, calculate the slope K of each point _i

Step 2: calculate each point slope variation rate K _i';

Step 3: set i=1, K _i=K ₁=0;

Step 4: if K _i'＞δ, described δ is the slope variation threshold value, claims that the i point is a separation, this point should be the classification point on the injection stroke, writes down the pressure value P of this point _kWith time value t _k, K=K+1, to step 5, otherwise i=i+1 turns back to step 4;

Step 5:, then arrive step 6, otherwise i=i+1 turns back to step 4 if all point operations are intact;

Step 6: if K then increases δ greater than the customer-furnished maximum progression that divides, turn back to step 4, otherwise to step 7;

Step 7: the pressure-time curve of step 1 is converted to pressure-stroke curve, pressure-stroke curve is divided into the K section, the classification point time is the t of step 4 _k, calculate t _kMulti-level injection position L on the pairing screw stroke _k, and multi-level injection position L _kCorresponding melt volume Q _k

Step 8: the orderly numeral (L that tries to achieve by step 4 and step 7 _k, P _k) determine each classification point, the straight line that each classification point is connected into segmentation is represented pressure-stroke curve;

Step 9: export injection speed, injection position and the progression of each classification point, finish.

The K of above-mentioned steps 1 _iComputational methods be

$K_i=\frac{P_{i+1}-P_i}{t_{i+1}-t_i},i=\mathrm{1,2},\mathrm{\ΛN}-1---\left(1\right)$

The each point slope variation rate K of above-mentioned steps 2 _i' computational methods be

$K_i^{\′}=\left|\frac{K_{i+1}-K_i}{T}\right|,i=\mathrm{1,2},\mathrm{\Λ},N-1$ T is sampling interval (2)

The multi-level injection position L of above-mentioned steps 7 _kComputational methods be

$L_k=t_k\·L_{\mathrm{inj}.}/\left(\frac{t_f}{T}\right)=T\×\frac{t_k{L}_{\mathrm{inj}.}}{t_f},$ L _InjTotal kilometres (3) for screw rod

Described melt volume Q _kComputational methods be:

$Q_k=\frac{{\mathrm{\&pi;<figure-callout\; id="2"\; label="D"\; filenames="H2007100275184E00011.png,H2007100275184E00022.png"\; state="\{\{state\}\}">D</figure-callout>}}^2\&CenterDot;{\mathrm{<figure-callout\; id="4"\; label="L\; k"\; filenames="H2007100275184E00011.png,H2007100275184E00033.png"\; state="\{\{state\}\}">L</figure-callout>}}_k}{4},$ D is the interior diameter (4) of described screw tube

The span of the N of above-mentioned steps 1 is between 50～100.

The span of above-mentioned T is between 20～100ms.

The maximum classification of above-mentioned steps 6 is several according to processing parameter setting, and span is between 3～10.

The present invention is based on following principle:

(1) speed of injection speed influences the quality and the die trial efficient of goods each side.In the actual injection process, injection speed generally is to decide situation " be subjected to machine control flow " according to situations such as plastics performance, process conditions, article shape, wall thickness and moulds, and the mold filling flow velocity meets following relational expression:

$g={\left(\frac{P_r}{\mathrm{xSt}+R_{T}t}\right)}^n---\left(5\right)$

Wherein: g-melt average flow velocity; P _r-put on the pressure of polymer; The mold filling length of x-any time; The flow resistance of S-unit length; R _T-polymer enters the mobile drag overall before the mould; The proal time of t-screw rod; N-rheology index.

By (5) formula as can be known, the average flow velocity v of melt not only with the pressure P that is applied thereto _rRelevant, but also with mold filling length x, flow resistance R and R _T, inject time t and many factors such as rheology index n relevant.In practical engineering application, the application of this formula is subjected to the constraint of a lot of conditions.

Clearly, unit length flow resistance R and die cavity geometry in this formula have relation, and along with the variation of injection displacement, the geometry of die cavity can show on the pressure-time curve the flow resistance that melt flows produced.The present invention determines multi-level injection speed and injection position according to the pressure-time curve of mold filling stage nozzle automatically, and these injection positions are definite values to same mould.

(2) above-mentioned slope variation threshold value δ is an important parameter of determining that the injection value parameter is set, and its selection is subjected to injection machine to allow to set the constraint of hierarchical level, and therefore, choosing generally of δ can be from small to large, until the requirement of satisfying machine.So choosing of δ value is quite important, should suitably set according to precision and quality that goods require to reach.Its value is more little, and progression is many more.

The establishing method of the injection machine of automatic setting multi-level injection speed of the present invention and injection position does not need to carry out the complicated rheology analysis and the calculating of die cavity geometry, only need under constant injection speed, to measure the pressure-time curve of nozzle, find the injection position of slope variation point, can learn the melt injection position that flow velocity changes during mold filling, also just obtain the position that injection speed should change.

Melt falls computing formula at oval pipe, rectangle and pressure in the different runners such as fan-shaped can obtain the flow resistance of unit length to the length variable differentiate, as (6) formula

$\frac{d\left({\mathrm{\&Delta;P}}_L\right)}{\mathrm{dl}}=\frac{2K}{R}{\left[\frac{(3n+1)}{{\mathrm{n\&pi;R}}^3}\right]}^n\left(g_1^n\right)---\left(6a\right)$

$\frac{d\left(\mathrm{\&Delta;}{P}_R\right)}{\mathrm{dl}}=\frac{K}{H}{\left[\frac{(2n+1)}{{2\mathrm{nWH}}^2}\right]}^n\left(g_2^n\right)---\left(6b\right)$

$\frac{d\left(\mathrm{\&Delta;}{P}_S\right)}{\mathrm{<figure-callout\; id="0"\; label="d\; r"\; filenames="H2007100275184E00022.png,H2007100275184E00024.png"\; state="\{\{state\}\}">d</figure-callout>}{r}_{}{}_0}=\frac{K}{H}{\left[\frac{(2n+1)}{{2\mathrm{n\&theta;H}}^2}\right]}^n\left(g_3^n{r}_o^{-n}\right)---\left(6c\right)$

By formula (6) as seen, the pressure-time curve of nozzle concerns one to one to the derivative and the melt volume flow velocity g of length.Can be write as the form of (7) formula,

$\frac{d\left({\mathrm{\&Delta;P}}_L\right)}{\mathrm{dl}}=C_1{g}_1^n---\left(7a\right)$

$\frac{d\left(\mathrm{\&Delta;}{P}_R\right)}{\mathrm{dl}}=C_2{g}_2^n---\left(7b\right)$

$\frac{d\left({\mathrm{\&Delta;P}}_S\right)}{{\mathrm{<figure-callout\; id="0"\; label="dr"\; filenames="H2007100275184E00022.png,H2007100275184E00024.png"\; state="\{\{state\}\}">dr</figure-callout>}}_0}=C_3{g}_3^n---\left(7c\right)$

Wherein,

$C_1=\frac{2K}{R}{\left[\frac{(3n+1)}{{\mathrm{n\&pi;R}}^3}\right]}^n,$ $C_2=\frac{K}{H}{\left[\frac{(2n+1)}{2n{\mathrm{WH}}^2}\right]}^n,$ $C_3=\frac{K}{H}{\left[\frac{(2n+1)}{2n{\mathrm{\&theta;H}}^2}\right]}^n{r}_o^{-n}---\left(8\right)$

The reason that causes the nozzle exit pressure curve segmentation is many-sided, and in emulation and experimentation, die trial speed is a steady state value, i.e. g in (6) formula ₁=g ₂=g ₃, obviously, causing nozzle exit pressure to go up the different reason of rate of change along its length is C ₁, C ₂, C ₃Difference, and by the visible C of (8) formula ₁, C ₂, C ₃Be the definite value relevant with the die cavity geometry.When mould design finish material selected after, C ₁, C ₂, C ₃It is exactly a definite value relevant with temperature.In order in die cavity, to obtain constant melt flow, even also the nozzle exit pressure of the moving mold filling length direction of each part charge longshore current equates the variation of length of flow, under the situation that die cavity geometry and each technological parameter are determined, (7) in the formula, have only melt flow g be can more convenient modification parameter, i.e. speed parameter classification.Succinct for what say something, suppose that mould is respectively oval pipe and rectangle for adjacent two sections, necessary

$C_1{g}_1^n=C_2{g}_2^n---\left(9\right)$

And then obtain

g ₂＝Cg ₁ (10)

Wherein,

Other various adjacent two sections situations all can be determined approximation relation therebetween as stated above.(6)～(10) calculated approximation relation between adjacent two sections simple geometry unit injection speeds by rheology knowledge.This analysis for simple mould is easily, but when die cavity was complicated, this analysis became and can't carry out.The present invention is considered as a "black box" with the die cavity geometry, obtains geometric properties from pressure-time curve, between the shape of the pressure-time curve of nozzle and the die cavity geometry corresponding relation is arranged.

By (6)～(8) as seen,

The size that reflects volume flow rate g, relation is approximately linear relationship therebetween, therefore, and can be by adjusting the shape that g change the nozzle exit pressure curve, pressure during the mold filling is changed approach desirable mold filling curve.Algorithm is as follows:

Step 1: according to the pressure-time curve of mold filling nozzle, by mould-filling time t _fAcquisition is full of die cavity pressure P constantly _f, corresponding screw stroke L _f

Step 2: calculating pressure is to the equivalent slope K of length _f=P _f/ L _f, the implication of equivalence is that pressure is to the rate of change of length when being full of the simple die cavity of same volume melt;

Step 3: the P that obtains by above-mentioned establishing method _k, T _k, L _k, calculate each section P _kThe amount that changes, for each multi-level injection position of k, variable quantity is calculated as follows

$\mathrm{\&delta;}\left(\frac{d\left({\mathrm{\&Delta;P}}_k\right)}{\mathrm{dL}}\right)=\frac{{\mathrm{dP}}_k}{\mathrm{dL}}-K_f---\left(11\right)$

Step 4: the hierarchical speed value of k section is calculated by (12) formula

$V_k=V_0-\mathrm{\&delta;}\left(\frac{d\left({\mathrm{\&Delta;P}}_k\right)}{\mathrm{dL}}\right)---\left(12\right)$

Step 5: the melt volume flow velocity of each section $g_k=\frac{1}{4}{\mathrm{\&pi;D}}^2{V}_k$ Be subjected to the restriction of shear rate and shear stress, calculate by (13)～(15) formula

The cylinder of 1. long L, radius R

${\mathrm{\&tau;}}_w=K{\left[\frac{(3n+1)g}{{\mathrm{n\&pi;R}}^3}\right]}^n---\left(13a\right)$

${\stackrel{\&CenterDot;}{\mathrm{\&gamma;}}}_{\mathrm{rep}}=\frac{4g}{{\mathrm{\&pi;R}}^3}---\left(13b\right)$

2. the rectangular tab of long L, wide W, thickness 2H

${\mathrm{\&tau;}}_w=K{\left[\frac{(2n+1)\mathrm{<figure-callout\; id="2"\; label="g"\; filenames="H2007100275184E00011.png,H2007100275184E00022.png"\; state="\{\{state\}\}">g</figure-callout>}}{{2\mathrm{nWH}}^2}\right]}^n---\left(14a\right)$

${\stackrel{\&CenterDot;}{\mathrm{\&gamma;}}}_{\mathrm{rep}}=\frac{3\mathrm{<figure-callout\; id="2"\; label="g"\; filenames="H2007100275184E00011.png,H2007100275184E00022.png"\; state="\{\{state\}\}">g</figure-callout>}}{{2\mathrm{WH}}^2}---\left(14b\right)$

(3) internal diameter R _i, external diameter R _o, angle θ fan-shaped flake

${\mathrm{\&tau;}}_w=K{\left[\frac{(2n+1)\mathrm{<figure-callout\; id="2"\; label="g"\; filenames="H2007100275184E00011.png,H2007100275184E00022.png"\; state="\{\{state\}\}">g</figure-callout>}}{{2\mathrm{n\&theta;R}}_i{H}^2}\right]}^n---\left(15a\right)$

${\stackrel{\&CenterDot;}{\mathrm{\&gamma;}}}_{\mathrm{rep}}=\frac{3\mathrm{<figure-callout\; id="2"\; label="g"\; filenames="H2007100275184E00011.png,H2007100275184E00022.png"\; state="\{\{state\}\}">g</figure-callout>}}{{2\mathrm{\&theta;<figure-callout\; id="2"\; label="R\; i\; H"\; filenames="H2007100275184E00011.png,H2007100275184E00022.png"\; state="\{\{state\}\}">R</figure-callout>}}_i{H}^{}{}^2}$

Step 6: finish.

The present invention has following advantage and effect with respect to prior art:

Nozzle is one of parts of connecting screw rod tube and die cavity, and the suffered pressure of melt is an important parameters herein.The present invention is by the measurement to nozzle place pressure in the mold filling process, owing to have intrinsic internal relation between nozzle exit pressure and the die cavity geometry, therefore mold cavity can be considered as a "black box", under constant injection speed, measure nozzle exit pressure-time graph, find the injection position (time) of trip point, can learn the melt injection position (time) that flow velocity changes during mold filling, also just obtain the injection position (time) that injection speed should change.The method avoids measuring melt flow and to the calculating of complex geometric shapes, for the automatic setting of injection speed value parameter provides a simple practical approach.

The present invention has tangible advantage than the three-dimensional structure algorithm of CAD: one, can once find out all possible injection classification point; Its two, the data that concrete quantification is arranged are foundation, its three, reduce the die trial number of times, improve die trial efficient, economical with materials cuts down the consumption of energy.

Description of drawings

Fig. 1 is the structural representation of a kind of injection machine of the present invention.

Fig. 2 is a kind of vertical view of plastic products.

Fig. 3 is the front view of Fig. 2.

Fig. 4-1～Fig. 4-the 4th, the nozzle exit pressure-time graph of a kind of plastic products under different condition of injection moulding Fig. 2.

Fig. 5 is the vertical view of another kind of plastic products.

Fig. 6 is the front view of Fig. 5.

Fig. 7-1～Fig. 7-the 4th, the nozzle exit pressure-time graph of another kind of plastic products under different condition of injection moulding Fig. 5.

Fig. 8 is desirable nozzle exit pressure-time graph during the mold filling.

Fig. 9 is the algorithm flow of automatic setting multi-level injection speed and injection position.

Figure 10 and Figure 11 are the schematic diagrames of finding the solution of value parameter.

The specific embodiment

The present invention is described in further detail below in conjunction with embodiment and accompanying drawing, but embodiments of the present invention are not limited thereto.

Experiment injection machine: the TTI-120C type precise injection machine that big industrial equipment (Hong Kong) Co., Ltd (WELLTECINDUSTRIAL EQUIPMENT LTD.) of China produces;

For the used WELLTEC TTI-120C of the present invention type precise injection machine, injection divides progression to be not more than 10 grades.

Sensor: the pressure-temperature sensor that KISTLER LTD. produces, 4085A or 4090B respectively on nozzle place and screw tube five places install additional, as shown in Figure 1, two kinds of sensors of this of KISTLER can directly measure the pressure and temperature of melt.

Among Fig. 1,1 is die cavity, and 2 is cast gate, and 3 is runner, and 4 is sprue, and 5 is hopper, and 6 is mould, and 7 is the sprue gate, and 8 is nozzle, and 9 is pressure-temperature sensor, and 10 is heating jacket, and 11 is screw rod, and 12 is screw tube.

Mold shape: shown in Fig. 2,3,5,6, the plastic products of Fig. 5 are to open a cuboid window in the centre of the plastic products of Fig. 2, make to change to some extent along the cross-sectional area of mold filling direction.

Experiment uses the plastic products of material: Fig. 2 and Fig. 5 all to adopt PP (polypropylene-polypropylene).

Table (1), table (2) are respectively main procedure parameter and machine parameter, in the experimentation, change the bigger Several Parameters of mold filling influence: injection speed, keep-up pressure and the dwell time.

The pressure record of nozzle place melt in the mold filling process is got off.Under the various process parameter condition, during the mold filling nozzle place pressure to the curve of time shown in Fig. 4-1～4-4, Fig. 7-1～7-4.Among the figure, the magnitude of voltage that longitudinal axis unit records for the KISTLER sensor, the corresponding conversion pressure of KISTLER4085A and 4090B sensor is as table (3); Transverse axis is the time, the T of a unit correspondence 50 (ms), i.e. data of 50 milliseconds of samplings.

The main procedure parameter of table (1)

Mold temperature (℃)	Melt temperature (℃)	Mould-filling time (s)	(bar) keep-ups pressure	Dwell time (s)	Cool time (s)
						34.5	200	1.6	Change	3.5	15.8

The main machine parameter of table (2)

Coolant temperature (℃)	Nozzle temperature (℃)	The screw tube temperature (℃)	Injection speed (mm/s)	Screw speed (rpm)
					35	200	195/190/ 185/180	Change	?150

(bar) keep-ups pressure	Dwell time (s)	Cool time (s)	Back pressure (bar)
					Change	Change	15.8	10

Table (3) 4085A and 4090B pressure-temperature sensor performance indications

Sensor	Signal type	Measurement category	Sensitivity	The linearity
					4085A5A2	Pressure	0-3000bar	3.33mV/bar	＜± 1%, full scale
4090B20A25A2	Pressure	0-2000bar	5mV/bar	＜± 0.8%, full scale

A kind of plastic products of injection moulding Fig. 2, the pressure-time curve of the nozzle during mold filling is shown in Fig. 4-1～4-4, when mold filling begins, do not have material in the mould, the pressure at nozzle place mainly reflects the entry-end effect of sprue gate (Sprue), under the thrust of injection cylinder, pressure increases sharply, in the process of filling runner, pressure increases slowly (this increase with length of flow is relevant), and is comparatively steady; Afterwards, melt is by ingate (Gate), and the ingate of the mould of Fig. 2 plastic products is the chip cast gate, and this kind cast gate is fit to the large tracts of land flat articles, reduces distortion, reduce internal stress, but it is more to take the cast gate material.Ingate makes and because screw rod is injected with constant injection speed, causes the pressure at nozzle place to increase sharply once more along the cross-sectional area flip-flop (diminishing) on the mold filling direction, finishes until mold filling process, enters packing stage.By nozzle exit pressure-time graph of Fig. 4-1～4-4 two tangible steps as can be seen.

Fig. 4-1～4-4 as seen, the shape of its curve is identical, promptly all has a flex point and a maximum, the difference between them is injection position and the size that flex point and maximum occur, and this point depends on the Shooting Technique parameter.For example, injection speed is fast, and the morning that flex point occurs, maximum is big; It is big to keep-up pressure, and maximum is big etc.

In like manner, the nozzle exit pressure-time graph for the another kind of plastic products of injection moulding Fig. 5 as Fig. 7-1～7-4, also has identical shape between them, promptly have the flex point and the maximum of same number, and difference also is the difference of its injection position and numerical values recited.Analyzing its origin cause of formation, is owing to the change along mold filling geometry of direction shape causes equally.

The plastic products shape of Fig. 2 and Fig. 5 is fairly simple, can use the origin cause of formation that rheology knowledge is analyzed its mobility status and nozzle exit pressure-time graph shape from the process of melt through cast gate, runner (Runner), interior sprue gate, die cavity etc.If complex-shaped goods, then analytic process is incited somebody to action very difficult even can't be carried out.

Nozzle exit pressure-time graph of Fig. 7 that we measure experiment-1～7-4 is idealized as Fig. 8.Simple clear and definite for what analyze, suppose the pressure-time curve saltus step of for once rising progressively, that is be similar to the situation of Fig. 4-1～4-4.We adopt during experiment be constant injection speed and other injection parameters without any change, as seen from Figure 8, at OA section, A ' B section and B ' afterwards, die cavity is constant (but resistance vary in size) to the flow resistance of melt; ' and from B to B ' produces the saltus step of nozzle exit pressure from A to A, illustrate that die cavity has saltus step to the resistance of melt flows, along with the increase flow resistance of length of flow will constantly rise, but can not produce saltus step, what is the reason of saltus step? can only be relevant with the geometry of die cavity.

Because the difference of mould, Fig. 4-1～4-4 is obviously different with the pressure curve shape that Fig. 7-1～7-4 shows, this also is one of Main Conclusions of the present invention, i.e. the shape of die cavity geometry decision nozzle exit pressure-time graph.The injection position of flex point (time), be exactly during the mold filling die cavity also be the injection position of die cavity geometry flip-flop to the injection position (time) of melt flows resistance flip-flop.At these points, the resistance saltus step to some extent that die cavity flows to the melt mold filling, thus causing the flip-flop of melt flow, the flip-flop of this melt flow will cause the generation of product defect.If the injection position at these trip points adopts different injection speeds to adapt to its different resistance, we will obtain constant melt flow.

This method does not need to carry out the complicated rheology analysis and the calculating of die cavity geometry, only need under constant injection speed, to measure nozzle exit pressure-time graph, find the injection position (time) of trip point, can learn the melt injection position (time) that flow velocity changes during mold filling, also just obtain the injection position (time) that injection speed should change.

Fig. 9 is the algorithm flow of automatic setting multi-level injection speed and injection position:

1, with 50% injection speed value of 50% force value of specified injection pressure and specified injection speed by screw tube toward goods of cavity injection, recording nozzles pressure-time curve.Get the N point on the pressure-time curve in whole mold filling stage, N is a natural number, and whole mould-filling time is t _f, determine pressure P and time value t that described N is ordered;

2, calculate the slope K of each point _i, calculate each point slope variation rate K _i';

3, set i=1, K _i=K ₁=0.If K _i'＞δ, described δ is the slope variation threshold value, claims that the i point is a separation, this point should be the classification point on the injection stroke, writes down the pressure value P of this point _kWith time value t _k, K=K+1, to step 4, otherwise i=i+1 turns back to step 3;

If 4 all point operations are intact, then arrive step 5, otherwise i=i+1 turns back to step 3;

If 5 K greater than 10, then increase δ, turn back to step 3, otherwise to step 6;

6, output result.

Figure 10 and Figure 11 are the schematic diagrames of finding the solution of value parameter.

The pressure-time curve that Fig. 9 is obtained converts pressure-stroke curve to, and pressure-stroke curve is divided into the K section, and K=3 among the figure is divided into 3 sections, and the classification point time is the t of Fig. 9 step 3 _k, calculate t _kMulti-level injection position L on the pairing screw stroke _k, and multi-level injection position L _kCorresponding melt volume Q _kBy orderly numeral (L _k, P _k) determine each classification point (P _kTry to achieve by Fig. 9 step 3), the straight line that each classification point is connected into segmentation is represented pressure-stroke curve, as shown in figure 10.Energy according to the injection merit equates principle, with P ₀L ₀, P ₁L ₁, P ₂L ₂... P _fL _InjBroken line obtains the nozzle exit pressure curve (shown in Figure 10 dotted line) of a linear straight line when goods of die cavity injection moulding.

The foregoing description is a preferred implementation of the present invention; but embodiments of the present invention are not restricted to the described embodiments; other any do not deviate from change, the modification done under spiritual essence of the present invention and the principle, substitutes, combination, simplify; all should be the substitute mode of equivalence, be included within protection scope of the present invention.

Claims (7)

1. the parameter setting method of the injection machine of automatic setting multi-level injection speed and injection position, the injection machine of described automatic setting multi-level injection speed and injection position, comprise screw tube, be arranged at screw rod in the screw tube, be arranged at the outer heating jacket of screw tube, be arranged at the nozzle of described screw tube one end, it is characterized in that: described nozzle radially is provided with through hole, be provided with pressure-temperature sensor in the described through hole, melt in described pressure-temperature sensor and the screw tube contacts, and described pressure-temperature sensor is connected with Computer signal; The outer heating jacket of described screw tube is provided with pressure-temperature sensor; It is characterized in that may further comprise the steps:

Step 1: injection machine carries out the injection moulding mold filling to mould, records the pressure-time curve at nozzle place by the pressure-temperature sensor at nozzle place, gets the N point on the pressure-time curve in whole mold filling stage, and N is a natural number, and whole mould-filling time is t _f, determine pressure P and time value t that described N is ordered, calculate the slope K of each point _i

Step 2: calculate each point slope variation rate K _i';

Step 3: set i=1, K _i=K ₁=0;

Step 4: if K _i'＞δ, described δ is the slope variation threshold value, claims that the i point is a separation, this point should be the classification point on the injection stroke, writes down the pressure value P of this point _kWith time value t _k, K=K+1, to step 5, otherwise i=i+1 turns back to step 4;

Step 5:, then arrive step 6, otherwise i=i+1 turns back to step 4 if all point operations are intact;

Step 6: if K then increases δ greater than the customer-furnished maximum progression that divides, turn back to step 4, otherwise to step 7;

Step 7: the pressure-time curve of step 1 is converted to pressure-stroke curve, pressure-stroke curve is divided into the K section, the classification point time is the t of step 4 _k, calculate t _kMulti-level injection position L on the pairing screw stroke _k, and multi-level injection position L _kCorresponding melt volume Q _k

Step 8: the orderly numeral (L that tries to achieve by step 4 and step 7 _k, P _k) determine each classification point, the straight line that each classification point is connected into segmentation is not represented pressure-stroke curve;

Step 9: export injection speed, injection position and the progression of each classification point, finish.

2. the parameter setting method of the injection machine of automatic setting multi-level injection speed according to claim 1 and injection position is characterized in that: the K of described step 1 _iComputational methods be

$K_i=\frac{P_{i+1}-P_i}{t_{i+1}-t_i},i=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;N-1---\left(1\right)$

3. the parameter setting method of the injection machine of automatic setting multi-level injection speed according to claim 1 and injection position is characterized in that: the each point slope variation rate K of described step 2 _i' computational methods be

$K_i^{\&prime;}=\left|\frac{K_{i+1}-K_i}{T}\right|,i=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,N-1$ T is sampling interval (2)

4. the parameter setting method of the injection machine of automatic setting multi-level injection speed according to claim 1 and injection position is characterized in that: the multi-level injection position L of described step 7 _kComputational methods be

$L_k=t_k\&CenterDot;L_{\mathrm{inj}.}/\left(\frac{t_f}{T}\right)=T\&times;\frac{t_k{L}_{\mathrm{inj}.}}{t_f},$ L _InjTotal kilometres (3) for screw rod

Described melt volume Q _kComputational methods be:

$Q_k=\frac{\mathrm{\&pi;}{D}^2\&CenterDot;L_k}{4},$ D is the interior diameter (4) of described screw tube

5. the parameter setting method of the injection machine of automatic setting multi-level injection speed according to claim 1 and injection position is characterized in that: the span of the N of described step 1 is between 50～100.

6. the parameter setting method of the injection machine of automatic setting multi-level injection speed according to claim 3 and injection position is characterized in that: the span of described T is between 20～100ms.

7. the parameter setting method of the injection machine of automatic setting multi-level injection speed according to claim 1 and injection position is characterized in that: the maximum classification of described step 6 is several according to processing parameter setting, and span is between 3～10.

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