Summary of the invention
The present invention is theoretical based on magnetic suspension aiming at the problem that existing detection mode, proposes a kind of based on maglev zero
The detection device of part defect, the detection device overall structure is simple, uses simplicity.
Invention also provides a kind of detection methods based on maglev part defect, can be quick using this method
Detect that detection efficiency and precision are high, practical with the presence or absence of external or internal flaw in sample.
A kind of detection device based on maglev part defect, comprising:
Two magnet of vertical direction coaxial arrangement, two magnet homopolarities are oppositely arranged, and the magnetic in the magnetic pole surfaces
Induction is identical;
It is arranged between two magnet and has the detection container of setting-out mouth, is contained with paramagnetism medium in the detection container
Solution;
The detection device is the sample of center symmetrical structure for cross section, and height of specimen is not more than cross-sectional maximum dimension
3/4, and the magnetic susceptibility of sample is less than 1 × 10-5。
Height of specimen is not more than the 3/4 of cross-sectional maximum dimension, and for the sample of circular cross section, cross-sectional maximum dimension is
Diameter prevents sample to be flipped, the judgement of interference detection results.The detection container is not by having ferromagnetic material
It is made, avoids its adverse effect to testing result.
For detected sample, flawless sample should be symmetrical and even density sample, detects in a device
When, it should be at keeping the posture of certain height z and holding level in corresponding density gradient.
Preferably, the magnetic induction intensity that the magnet is oppositely arranged magnetic pole surfaces is 0.3T~0.6T.
Preferably, the vertical range between two magnet homopolarities is 40~45mm.
Preferably, the medium solution is ferric chloride in aqueous solution, manganese chloride aqueous solution or gadolinium chloride aqueous solution.
As further preferred, the medium solution is manganese chloride aqueous solution, the molar concentration of manganese chloride aqueous solution is 1~
5mol/L.At this point, its density is about 1.0~1.3g/cm3;Magnetic susceptibility is about 1.7~5.5, can meet most of plastic, rubber sample
The detection of product.
Preferably, it is circular high molecular material that sample, which is cross section,.Such as can be detected with rubber seal, it can
PMMA lenses are detected etc..
Preferably, the detection container is transparent vessel.The detection container is made by not having ferromagnetic material,
Avoid its adverse effect to testing result.Equally, detector lens can also be set in opaque detection container as needed
Deng can realize the detection to sample state by external display.It as a further improvement, can be by connecting with computer
It connects, realizes automatic identification.
The present invention also provides a kind of detection methods based on maglev part defect, using any of the above-described technical solution
The device, the specific steps are as follows:
(1) different according to sample to be tested material, suitable medium solution is configured, guarantees that sample to be tested is placed in medium solution
When middle, it can swim in medium solution, medium solution is then placed in detection container;
(2) sample to be tested is placed in the medium solution of detection container;
(3) detection container with sample to be tested is placed between described two magnet;
(4) after sample to be tested is stablized, the posture of observation sample to be tested in the solution determines defect type in sample
And defective locations.
To further increase detection accuracy, preferably, any coordinate system can be constructed before sample to be tested detection, it should
The Z-direction of coordinate system is parallel with two magnet axis directions or is overlapped, and X-axis and Y axis be on horizontal plane, according to step (2)~
(4) standard sample is detected, determines the coordinate value at standard sample center, the standard coordinate value to get standard samples, and
Horizontal plane where standard coordinate value, the horizontal plane are index plane.In the present invention, the standard sample being previously mentioned refers to internal, outer
The equal zero defect in portion is sample.
Preferably, the posture of observation sample to be tested in the solution in step (4), determines defect type in sample and lacks
Fall into position, specifically: first determine whether sample to be tested centre coordinate and across centre coordinate the plane of symmetry whether with standard coordinate
Value is corresponding with index plane: if it does correspond, then illustrating test sample zero defect;If do not corresponded to, illustrate that test sample is defective.
As further preferred, specifically the step of are as follows:
When sample to be tested centre coordinate is overlapped with standard coordinate value, but when itself run-off the straight, then the sample interior
Existing defects;Defect is typically in the side of run-off the straight;
When the plane of symmetry across centre coordinate of sample to be tested is overlapped with index plane, but centre coordinate deviates
When, then illustrate the sample exterior existing defects;Defect is typically in the side of translation direction;
When the centre coordinate of sample to be tested is identical as standard coordinate value x, y, i.e., on the axis in two magnet, and
The plane of symmetry across centre coordinate is parallel with index plane coincidence, and when not being overlapped, then illustrates that the sample interior has symmetrical lack
It falls into.
The above-mentioned part lossless detection method based on magnetic levitation system of the present invention, the principle is as follows: two pieces of homopolarities are opposite, table
The identical strong magnet of face magnetic induction intensity, Surface field intensity are all B0On the line (we are referred to as " axis ") of magnetic blow out centre
It can generate from-B0To B0Linear magnetic induction intensity gradient.Magnetic field on upper and lower two magnet centerlines lineIt is distributed as
Wherein, B0For magnet surface magnetic induction intensity, Bx、By、BzRespectively point of the magnetic induction intensity in x, y, z axis direction
Amount, d distance between two magnet.Paramagnetic compounds solution (medium solution) if it exists between two blocks of magnet, then magnetic field can be to solution
In the very low substance of diamagnetic substance or magnetic susceptibility generate the power along magnetic induction line direction, expression formula is as follows:
In formula:It is the power that magnetic field generates, χsIt is the magnetic susceptibility of tested sample, χmIt is the magnetic susceptibility of medium solution,
μ0For space permeability, V is sample volume,For gradient operator.According to magnetic suspension theory, in any position in magnetic field
Sample suffered by magnetic field force x, y-axis direction component resultant force be directed toward two magnet centerlines, for no defect quilt
Object is surveyed, final balance position will be in two magnet centerlines.Equilibrium equation are as follows:
ρ in formulasFor sample rate, ρmFor solution density,For acceleration of gravity.Normally, measured matter is diamagnetism
Substance or magnetic susceptibility are very low, and magnetic susceptibility can be ignored.
The imperfect defect of sample appearance destroys the symmetrical shape of sample, but unequal to the density of sample entirety
Even property and local density's uniformity have an impact.In most cases, defect mostly occurs in sample edge position, when defect sample
When being in normal specimens (standard sample) equilbrium position, defect part can not balance its symmetrical region in XOY because of material deficiency
Suffered magnetic field force, sample can be pushed to the imperfect direction of shape in plane, and when being finally reached new equilbrium position, show as
There is deviation in sample original center and magnetic field center line.
Sample internal flaw causes the density uniformity in region to change.The density uniformity of defect area becomes
Change, leads to region χsWith ρsVariation.When defect sample is in the equilbrium position of normal specimens, compared with normal specimens, defect
The variation that buoyancy suffered by part and gravity resultant force are generated due to density uniformity.This variation leads to magnetic field force and gravity in region
The torque not rebalancing that buoyancy resultant force generates, deflects so as to cause sample.Under normal conditions, defect generates position, ρsBecome
It is small, therefore the region will appear the phenomenon that upward deflecting.Under extreme case, the internal flaw of sample is about sample center pair
Claim, shows as water product posture in the solution, but due to internal existing defects, sample ensemble average density changes, defect
The balance height z ' of sample is higher than zero defect Sample equilibration height z.
The detection of detection device and detection method of the invention particularly suitable for circular cross-section plastic part defect, it is actually detected
In the process, the density of product should be estimated according to product material before detection, while configures corresponding medium solution.Such as need essence
Solution magnetization rate is really calculated, solution magnetization rate can be measured with Gu Aifa.By adjusting density size, realize close to medium solution
The adjustment of degree and magnetic susceptibility.
In the present invention, medium solution can generate corresponding power to the diamagnetic substance being placed in solution under magnetic fields,
The size of power is related to magnetic induction intensity and solution magnetization rate.The magnetic induction of linear change can be generated between the opposite magnet of magnetic pole
Intensity gradient, the power generated in the solution also show as linear gradient.Inside and outside this method detection circular cross-section plastic part
Portion's defect, advantage are the convenience and low cost of non-destructive testing and the detection to circular cross-section plastic part.
Compared with prior art, the beneficial effects of the present invention are: test method of the present invention is easy to operate, operator is required
Not harsh and of the invention detection device overall structure is simple, low in cost, and test result is easy to observe, and detection sensitivity is high,
It is easy to automate.
Specific embodiment
To be more clearly understood the present invention, below according to specific example and attached drawing of the invention, the present invention is carried out
Further instruction.
It as depicted in figs. 1 and 2, is magnetic levitation system schematic diagram of the invention, including magnet 1, magnet 4, medium solution 2,
Sample 3, detection container 5.It is coaxially disposed on magnet 1,4 vertical direction of magnet, and homopolarity is oppositely arranged, in Fig. 1, two magnet
The pole N is oppositely arranged, towards detection container.
Detection container 5 is the transparent vessel of upper opening, and glass, the materials such as plastics generally can be used.
Magnet 1, magnet 4 are identical in the magnetic induction intensity of N pole surface, generally 0.3T~0.6T, in the present embodiment, magnet
1, magnet 4 is 0.5T in the magnetic induction intensity of N pole surface.The distance between magnet 1, magnet 4N pole surface are d, and d is generally 40
~45mm, in the present embodiment, d value is 45mm, be magnetic induction intensity at two magnetic blow out centre line height d/2 is 0T.
Medium solution 2 selects molar concentration for the ferric chloride in aqueous solution, manganese chloride aqueous solution or gadolinium chloride of 1~5mol/L
Aqueous solution.In the present embodiment, the medium solution 2 that selects for 2.5M MnCl2Solution, the relationship of concentration and density and magnetic susceptibility
It is as shown in table 1:
Table 1 is various concentration MnCl2Density corresponding to solution and magnetic susceptibility.
Concentration (mol/L) |
Density (g/cm3) |
Magnetic susceptibility |
1 |
1.099 |
1.774×10-4 |
1.5 |
1.148 |
2.771×10-4 |
2 |
1.196 |
3.724×10-4 |
2.5 |
1.244 |
4.650×10-4 |
3 |
1.292 |
5.438×10-4 |
It is found that it can be by adjusting MnCl by table 12The concentration of solution realizes the adjustment to its density and magnetic susceptibility.
Detection device is the sample of center symmetrical structure for cross section, and height of specimen is not more than the 3/ of section maximum gauge
4, sample run-off the straight is prevented, the magnetic susceptibility of sample is less than 1 × 10-5.PMMA lens are detected using method of the invention,
The sample 3 is 10 × 3.0 biconvex lens of Φ, is diamagnetic substance.
In the present embodiment, the magnetic suspension detection method of circular arc interface plastic part, comprising:
(1) sample density is estimated according to sample material.
The medium solution of suitable concentration is configured, molar concentration 2.5M guarantees that sample can float in the solution.It configures
After medium solution, it is poured into detection container.
Before testing can be right, it can configure the medium solution that concentration is every liter of integer mole, carry out density and magnetic susceptibility
Calibration, according to the sample rate of estimation, can immediately arrive at the concentration of the medium solution needed to configure.
Under normal circumstances, in suitable range, solution density is slightly less than sample density.
(2) sample to be tested is placed in medium solution.
(3) medium solution is placed among two in magnetic suspension detection device magnet.
(4) observation tested sample position in the solution and posture.
Any coordinate system can be constructed before sample to be tested detection, Z-direction is parallel with two magnet axis directions or again
It closes, standard sample is detected according to step (2)~(4), the coordinate value at standard sample center is determined, gets standard samples
Horizontal plane where standard coordinate value and standard coordinate value, the horizontal plane are index plane.In standard sample herein refers to
Portion, external zero defect are acceptable lens.Acceptable lens are placed in device, and center should be located on magnetic field center line,
Posture should keep horizontal with horizontal plane, and the central horizontal plane of symmetry is located on index plane.Levitation height is mark to sample in the solution
Quasi- height Z.
The posture of observation sample to be tested in the solution, determines defect type and defective locations in sample in step (4), has
Body are as follows: first determine whether sample to be tested centre coordinate and across centre coordinate the plane of symmetry whether with standard coordinate value and index plane
It is corresponding: if it does correspond, then illustrating test sample zero defect;If do not corresponded to, illustrate that test sample is defective.
Specifically the step of are as follows:
When sample to be tested centre coordinate is overlapped with standard coordinate value, but when itself run-off the straight, then the sample interior
Existing defects;Defect is typically in the side of run-off the straight;
When the plane of symmetry across centre coordinate of sample to be tested is overlapped with index plane, but centre coordinate deviates
When, then illustrate the sample exterior existing defects;Defect is typically in the side of translation direction;
When the centre coordinate of sample to be tested is identical as standard coordinate value x, y, i.e., on the axis in two magnet, and
The plane of symmetry across centre coordinate is parallel with index plane coincidence, and when not being overlapped, then illustrates that the sample interior has symmetrical lack
It falls into.
Fig. 3 and Fig. 4 is that lens specimen detects the imperfect defect schematic diagram of appearance, and wherein defective locations are A.Outside lens
It sees imperfect defect and shows as two magnetic blow out centre lines of lens centre deviation in a device, offset direction is that defect generates direction,
Deviation distance size depends on defect size.
Fig. 5 and Fig. 6 is that lens specimen detects internal flaw schematic diagram, and wherein defective locations are B.The internal flaw of lens is drawn
It is uneven to play lens interior Density Distribution, shows as lens and deflects in a device, upward deflecting direction is defect generation side
To deflection angle size depends on defect size.
The foregoing is merely an application example of the invention, the not restrictions to sample range is applicable in.It can apply
The part that the present invention measures, there is no need and unable to exhaustive one by one, it is all within spirit of that invention and principle, done any repair
Change, equivalent replacement, improve etc., it should be included within the scope of the present invention.