Pre-impression speed change shearing blanking method
Technical field
What the present invention relates to is a kind of technology of metal blanking field, specifically a kind of pre-impression speed change shearing blanking method.
Background technology
Shearing blanking technique, compared to traditional sawing and the blanking that fractures, has the feature that efficiency is high and stock utilization is high, is therefore widely applied.But the cross section quality that shearing blanking obtains exists some defects, such as section is ovality, and section is rough jagged etc.Traditional shearing blanking method is that stationary knife and moving knife are held tightly bar, then under the effect of moving knife, completes shear history.
For improving cross section quality, the new method of multiple technology for blanking is suggested, as Chinese patent literature CN1189403A and CN2322729Y all proposes combination shearing process, a kind of combined precision rod shearing machine is related in this technology, comprise combination shearing degree of depth adjustment member, clamping and cutting out section, promotion clamping and unclamp part, crank combination shearing part, be characterized in that the preshearing degree of depth is about the shearing degree of depth of 1/3 to 3/4, after preshearing terminates, slide block counter motion, thus obtain the vertical section in shearing section.But the preshearing degree of depth of 1/3 to the 3/4 shearing degree of depth, propose very high requirement to the plasticity of material, for the material that plasticity is poor, this kind of method is difficult to be suitable for.
Conventional pre-embossed V-shaped groove shearing blanking technique in production, by pre-embossed V-shaped groove, people, for causing stress concentration point, reduces shearing force, can obtain more smooth section simultaneously.Within 2010, be published in as Tang Yong etc. in the article " metal bar material precise blanking new technology and experimental study " on " China Mechanical Engineering " periodical and propose a kind of rotation and forge tired technology for blanking, this technique is divided into three steps: the first step, to get on the bus annular V shape groove processed at metal bar material, produce initial crack; Second step, determines the striking frequency of tired forging machine and hits Bit andits control curve, thus obtaining suitable load mode; 3rd step, by regulating the control of rotating speed realization to metal bar material striking frequency of frequency converter mair motor, realizing the control to hitting stroke by radial displacement governor motion and servomotor, thus reaching object metal bar material being implemented to reasonable load mode.This rotation forges tired function and carries out blanking to different-diameter different materials.But, before blanking, increase by one car annular V shape groove technique, shear efficiency reduced.
Summary of the invention
The present invention is directed to prior art above shortcomings, propose a kind of pre-impression speed change shearing blanking method, the material of various plastic properties can be sheared, while ensureing shear efficiency, promote cross section quality.
The present invention is achieved by the following technical solutions:
The present invention by by blank as axial gap, radial clearance and precompressed trace in the shearing die of adjustment, complete the shearing of preshearing amount with low speed, at a high speed to complete remaining stroke, the pre-impression speed change realizing blank is sheared.
Described blank adopts the coiled strip after bar or alignment.
Coiled strip after described bar or alignment is annealed state, and linearity is not more than 1:500.
Described shearing die, comprising: dynamic model and cover half, wherein: the relative cover half of dynamic model carries out moving up and down and realizes blank shearing, and the spacing of dynamic model and cover half is axial gap, and the gap between shearing die and blank is radial clearance.
Described axial gap, by adjustment dynamic model and the gap of cover half, make its control bar diameter 1% ?3%.
Described radial clearance, mould put into by the blank met the demands by linearity, reaches the cutting length of specifying, and then tightens up the gap between mould and blank, its monolateral gap is met: when bar diameter is greater than 20mm, monolateral gap value is less than or equal to 0.4mm; When bar diameter is less than 20mm, monolateral gap value is less than 2% of bar diameter.
Described precompressed trace, is set to the cutting stroke of 10% ~ 25%, described cutting stroke, to complete and shears the stroke that the process that is separated walks for moving knife starts action and be defined as cutting stroke to blank and bar.Before shearing, first shear one section of blank, thus determine its cutting stroke, and then according to this cutting stroke determination precompressed trace.
Described low speed refers to: 10 ~ 50mm/s; Described high speed refers to: more than 1m/s.
Technique effect
Compared with prior art, the technology of the present invention effect comprises:
1, shear the section obtained more smooth, improve cross section quality;
2, compared to traditional high speed shear baiting method, the method for pre-impression speed change shearing blanking can save energy to a certain extent.
Accompanying drawing explanation
Fig. 1 is process chart of the present invention.
Fig. 2 is moving knife trip map.
Fig. 3 is shearing die schematic diagram;
In figure: dynamic model 1, cover half 2, blank 3.
Schematic diagram is sheared in Fig. 4 precompressed.
Fig. 5 is the contrast schematic diagram of common shearing area figure and precompressed shearing area figure.Can find out that section euphotic belt is divided into euphotic belt and the euphotic belt in high speed shear stage in preshearing stage, and precompressed shear band section is more smooth than common shearing area figure.
Detailed description of the invention
Elaborate to embodiments of the invention below, the present embodiment is implemented under premised on technical solution of the present invention, give detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment.
Embodiment 1
As shown in Figure 3, the shearing die that the present embodiment adopts comprises: dynamic model 1 and cover half 2, after during blank 3 is as cover half 1 and dynamic model 2, after the initial level spacing that arranges cover half 2 and dynamic model 1 and vertical interval, drive dynamic model 1 and cover half 2 to produce relative motion by hydraulic means, thus realize shearing.
The present embodiment comprises the following steps:
1, select diameter to be the 20cr bar of 15mm, condition of heat treatment is annealed state, and meets linearity and be not more than 1:500;
2, adjust the position relationship of fixed half and moving half, make mould axial gap be 0.3mm, namely bar diameter 2%;
3, bar is put into mould, regulating radial clearance, makes radial clearance be 0.3mm, namely bar diameter 2%;
4, first shear one section of blank, obtaining cutting stroke is 3mm, and determine that the preshearing degree of depth is 0.7mm, the preshearing degree of depth is about 23% of cutting stroke;
5, the shear rate of preshearing stage moving knife is 20mm/s, and remaining stroke stage shear rate is 1m/s;
6, shearing blanking is carried out according to above-mentioned moving knife stroke.
Embodiment 2
The present embodiment comprises the following steps:
1, select diameter to be No. 10 steel disk material of 20mm, condition of heat treatment is annealed state, carries out uncoiling alignment, after alignment linearity be not more than 1:500;
2, adjust the position relationship of fixed half and moving half, make mould axial gap be 0.3mm, namely bar diameter 1.5%;
3, bar is put into mould, regulating radial clearance, makes radial clearance be 0.3mm, namely bar diameter 1.5%;
4, first shear one section of blank, obtaining cutting stroke is 4mm, and determine that the preshearing degree of depth is 1mm, the preshearing degree of depth is about 25% of cutting stroke;
5, the shear rate of preshearing stage moving knife is 10mm/s, and remaining stroke stage shear rate is 1.1m/s;
6, shearing blanking is carried out according to above-mentioned moving knife stroke.
Embodiment 3
The present embodiment comprises the following steps:
1, select diameter to be No. 10 steel disk material of 20mm, condition of heat treatment is annealed state, carries out uncoiling alignment, after alignment linearity be not more than 1:500;
2, adjust the position relationship of fixed half and moving half, make mould axial gap be 0.3mm, namely bar diameter 1.5%;
3, bar is put into mould, regulating radial clearance, makes radial clearance be 0.3mm, namely bar diameter 1.5%;
4, first shear one section of blank, obtaining cutting stroke is 4mm, and determine that the preshearing degree of depth is 1mm, the preshearing degree of depth is about 25% of cutting stroke;
5, the shear rate of preshearing stage moving knife is 10mm/s, and remaining stroke stage shear rate is 1.2m/s;
6, shearing blanking is carried out according to above-mentioned moving knife stroke.