A kind of wear of diamond cutter monitoring method based on cutting Force Model
Technical field
The invention belongs to Tool Wear Monitoring field, have and relate to a kind of wear of diamond cutter based on cutting Force Model
Monitoring method.
Background technology
Workpiece is during machining, and cutter can wear and tear, and the abrasion of cutter can cause the geometry of cutter
Change, thus process workpiece and will produce dimensional discrepancy, also can affect the crudy of workpiece.Inclined in order to avoid workpiece
Difference is excessive, improves crudy, needs to be monitored the wear extent of cutter, determine whether to change according to monitoring result
Cutter.
The cutting tool of diamond material is widely used in actual production.Conventional monitoring wear of diamond cutter
Method be direct monitoring method, direct monitoring method mainly by directly measurement major flank wear land mid portion average abrasion amount
Detect.Owing to direct monitoring method needs constantly to measure tool abrasion when monitoring, production process can be made to interrupt, impact
Working (machining) efficiency, occurs in that the most again indirect monitoring method.Indirect monitoring rule is by measuring the thing relevant with tool wear
Reason amount such as cutting force, acoustic emission etc., and set up the corresponding relation of these physical quantitys and tool wear, thus realize Cutter wear
Indirect monitoring.What indirect monitoring method was conventional is chooses the ratio of cutting component and the change of ratio as differentiating characteristic quantity, and one
Denier the two characteristic quantity exceedes a certain threshold value, i.e. it is believed that cutter has worn out.But when actual monitoring, owing to vibration is with random
The interference of noise, uses the method to judge that tool wear is easily made mistakes, causes erroneous judgement.And owing to the normal wear of cutter is with different
Often the boundary between abrasion has certain uncertainty, therefore predefines threshold value the most difficult, it is necessary to rule of thumb and carry out
Just can determine that after more test, and in different occasion threshold values instability.
Diamond cutter has high hardness and wearability, low-friction coefficient, high elastic modulus, highly thermally conductive, low grade fever is swollen
Swollen coefficient, and the advantage such as little with nonferrous metal affinity, may be used for hard brittle materia such as graphite, high abrasion resisting material,
Composite, silumin and the Precision Machining of other toughness nonferrous materials.But, its tool wear monitoring is the most tired
Difficult, it is impossible to the wear extent of cutter in real-time online detection and measurement machining so that its application and scope are restricted.
Summary of the invention
It is contemplated that for problems of the prior art, propose a kind of diamond cutter based on cutting Force Model
Wear monitoring method, it is by being optimized modeling to cutting force so that its can with accurate characterization wear of diamond cutter state,
By the monitoring of this cutting force being realized the monitoring to wear of diamond cutter, thus realize wear of diamond cutter
Real-time online and monitoring accurately.
For achieving the above object, the technical solution adopted in the present invention is specific as follows:
A kind of wear of diamond cutter monitoring method based on cutting Force Model, it is for the wear extent to diamond cutter
Carry out real time on-line monitoring, it is characterised in that the method includes:
(1) non-decile shear zone model is utilized to calculate the sharp diamond knife produced in working angles by being formed of chip
Cutting force under tool effect;
(2) the plough shear force caused in working angles is calculated by cutting edge roundness;
(3) the plough shear force caused according to the cutting force under the above-mentioned sharp diamond cutter effect determined and cutting edge roundness
Obtain diamond cutter cutting force;
(4) according to diamond cutter cutting force obtained above, set up wear of diamond cutter monitoring model, thus realize
Real-time monitoring to wear of diamond cutter, wherein wear of diamond cutter amount with the relation of cutting force is:
Wherein, δ is wear of diamond cutter amount, and μ is for characterizing diamond cutter and the performance-relevant constant of friction of workpiece, B
For characterizing the constant of workpiece material hardness factor, V is diamond cutter cutting speed, and D is diamond cutter bite, x, y and z
Being respectively cutting feed Rate Index, cutting force index and bite index, its span is respectively (0,1).
As present invention further optimization, cutting force under sharp diamond cutter effect and cutting edge roundness cause
The detailed process that plough shear force obtains diamond cutter cutting force is as follows:
F1=aFc+bPc
F2=cFt+dPt
Wherein, F1Cutting force in cutting speed direction in processing for orthogonal cutting, F2Vertically in processing for orthogonal cutting
The cutting force in cutting speed direction, a, b, c, d respectively represent sharp with blunt round mutual relation constant, and it meets
In various, β is the angle of friction between diamond cutter and chip, and α is diamond knife tool hook angle,For the angle of shear, t
For thickness of cutting, w is cutting width, and τ is the shear flow stress of main shear zone, FsIt is the shearing force on main shear surface, PcIt is to cut
Cut the plough shear force on velocity attitude, PtBeing perpendicular to the plough shear force on workpiece machined surface direction, λ is middle parameter, andρ0For the inclination angle of intermediate incline between chip and green surface.
As present invention further optimization, the shear flow stress τ of main shear zone is calculated by equation below:
In above formula, C is the strain rate sensitivity coefficient of material, and n is the hardenability value of material, and m is thermal softening index (coefficient),
γ is shear strain rate, and T is the fusion temperature of material, and Tr is reference temperature.
As present invention further optimization, shearing force F on main shear surfacesIt is calculated by equation below:
In general, technical scheme is classified as under sharp state and blunt according to diamond cutter cutting characteristic
Two kinds of situations under circle effect, and set up corresponding cutting force respectively, form the cutting Force Model under virtual condition accordingly, then
Obtain wear of diamond cutter relational expression according to cutting Force Model, thus the reality of wear of diamond cutter can be realized the most online
Time monitoring, it is simple that the method calculates process, and result accurately and can present by real-time online.
Detailed description of the invention
Below in conjunction with embodiment, the present invention is described in further detail, but the present embodiment is not limited to the present invention,
The similarity method of every employing present invention and similar change, all should list protection scope of the present invention in.
During the model of cutting force is set up, calculate first with non-decile shear zone model and produced by being formed of chip
Sharp diamond cutter effect under cutting force, next calculates the plough shear force caused by cutting edge roundness, will the two is comprehensive
Superposition considers i.e. to obtain considering cutting force during cutting edge roundness.
In the forming process of chip, the power required for shearing slip is by diamond cutter rake face and by chip
Transmission, owing to chip is flowed out along rake face friction with certain speed, therefore the effect of cutting force is it suffices that rake face
Friction condition, so, owing to the power required for the power required for the friction of rake face and shear surface deformation must balance, so two
Person is equal in magnitude, in opposite direction, and acts on the same line
Non-decile shear zone model is computation model ripe in the industry, and this programme directly applies this model to carry out cutting force.
Under sharp diamond cutter effect, cutting force F is that chip contacts rubbing of being subject to diamond cutter rake face
Making a concerted effort of wiping power and normal force, the cutting force F in cutting speed direction can be resolved intocCentripetal force with vertical cut velocity attitude
Ft, wherein
Wherein, β is the angle of friction between diamond cutter and chip, and α is diamond knife tool hook angle,For the angle of shear, t is
Thickness of cutting, w is cutting width.
FsIt is the shearing force on main shear surface,
τ is the shear flow stress of main shear zone,
In above formula, C is the strain rate sensitivity coefficient of material, and n is the hardenability value of material, and m is thermal softening index, and γ is for cutting
Shear strain rate;T is the fusion temperature of material, and Tr is reference temperature, is room temperature under normal circumstances.The shear flow of main shear zone should
Power the present embodiment preferably calculates acquisition by Johnson-Cook material constitutive model, this Johnson-Cook material constitutive
Model belongs to the scheme of the shear flow stress calculating main shear zone ripe in the industry.
Because diamond cutter is not the sharpest, always there is a blunt round radius at cutting edge, therefore in reality
In the cutting process on border, cutting force is to have dimerous, and a part is in the sharpest situation of diamond cutter
Under calculated cutting force, another part is the plough shear force produced by cutting edge roundness, and two parts superposition just constitutes reality
The cutting force state that diamond cutter is formed.
The plough shear force acted on workpiece machining surface by cutting edge roundness can be calculated by following formula:
Wherein, PcIt is the plough shear force on cutting speed direction, PtIt is perpendicular to workpiece machined surface direction (direction of feed)
On plough shear force, τ is the shear flow stress of main shear zone,For the angle of shear, w is cutting width, and λ is middle parameter,
ρ0For the inclination angle of intermediate incline between chip and green surface.
Cutting force in orthogonal cutting processing and the cutting force under sharp diamond cutter effect and cutting edge roundness effect
The plough shear force produced meets following relation:
F1=aFc+bPc (8)
F2=cFt+dPt (9)
Wherein, F1Cutting force in cutting speed direction in processing for orthogonal cutting, F2Vertically in processing for orthogonal cutting
The cutting force in cutting speed direction.
A, b, c, d respectively represent sharp and blunt round mutual relation constant, and usually it meetsA and c, and the span of b with d can be the same or different.
Final cutting force size is:
Based on the cutting Force Model set up, utilize diamond cutter and the coefficient of friction of workpiece and cutting speed,
Set up the relation of wear of diamond cutter amount and cutting force:
Wherein, δ is wear of diamond cutter amount, and μ is diamond cutter and the performance-relevant constant of friction of workpiece, its value
Value is preferably 2 < μ < 4, and the material with specific reference to diamond cutter with workpiece selects to determine, B is relevant to workpiece material hardness
Constant, value is relevant to workpiece material, such as, be preferably [0.8-1.75], and V is diamond cutter cutting speed, and D is Buddha's warrior attendant
Stone cutter bite (cutting depth), x, y and z be respectively cutting feed Rate Index, cutting force index and bite index,
Its span is respectively (0,1).
In one embodiment, x, y and z value respectively is 0.1,0.3 and 0.1;In another embodiment, x, y and z are respectively
Value is 0.1,0.3 and 0.1, but in the present invention, x, y and z value is not limited to this, can take in (0,1) according to practical situation
Value.
It should be noted that the foregoing is only presently preferred embodiments of the present invention, not in order to limit the present invention, all
Any amendment, equivalent and the improvement etc. made within the spirit and principles in the present invention, should be included in the guarantor of the present invention
Within the scope of protecting.