Blanked Parts Research Articles

The effect of blanking clearances on side profiles of blanked parts in micro blanking

The effect of blanking clearances on side profiles of blanked parts in micro blanking

Research on the Method of Identifying the Collapsed Angle Surface of Fine Punching Small Gear

Aiming at the requirement of automatic assembly of automobile rear wiper for automatic identification of the collapsed corner surface of finely-punched pinion, this paper proposes a method based on the mean value of the area of multi-toothed region of finely-punched pinion as the characteristic parameter, which can better identify the collapsed corner surface. Firstly, the industrial camera is used to obtain the pinion image, and the Halcon operator is used to fit the circle in the pre-segmented region to obtain the pinion circle position parameter, and the parameter is used as the reference to accurately segment the toothed annulus ROI, and then carry out the dynamic thresholding of the region, merging the regions, shape convex package transformation, and the conditional filtering to obtain the multiple toothed regions, and then rank the toothed regions, and the maximum top three toothed regions area mean value is the feature parameter to achieve the fine blanking pinion surface automatic identification of the collapsed corner surface. The mean value of the area of the first three tooth-shaped areas is used as the characteristic parameter to achieve the identification of the collapsed angle surface of the fine blanking pinion gear. The application on the assembly line shows that the recognition accuracy of this method reaches 99.9%, with good robustness and stable operation, which meets the production requirements, and also provides a method for the recognition of collapsed corner surfaces of other fine blanking parts.

Influence of the punch with concave cutting-edge on the blanking force in micro punching process

Micro blanking machining is a promising manufacture technology to realize mass production of micro parts efficiently. In the process of blanking, the blanking force is significant to the punch, die, and sheet workpiece. In order to investigate the influence of cutting-edge shape of the punch on the micro blanking process, a self-developed micro combined EDM and blanking machine tool is applied in this paper. A punch with concave cutting-edge is capable to be fabricated online through a series of processing based on micro EDM: 3D milling, wire electrical discharge grinding and reverse EDM copy machining techniques. Then the punch and die are accurately matched online due to the preparation of them in the same coordinate system. Micro blanking parts and punching parts with the complex cross-sectional shape is obtained by using the online fabricated punch with flat cutting-edge and concave cutting-edge respectively in the workpiece of stainless steel SUS304 foil. The characteristic of blanking force varying with time indicates that the blanking force is significantly reduced in the case of concave cutting-edge, meanwhile, both blanking parts and punching parts have the high quality.

Investigation of the Micro Hardness at the Cut Surface of Fine Blanked Parts with Variation of Sheet Material and Cutting Temperature

Fine blanking is a production technology of high importance especially for the automotive industry. As a procedure of sheet metal separation, it is possible to produce complex parts in a single stroke. As a difference to conventional punching, the cutting surface of fine blanked parts can often be used as a functional surface without further process steps. However, fine blanking as a forming process changes the microstructure of the metal sheet to a higher extend than cutting or machining processes. Due to this, it is of utmost importance to investigate the cause-effect-relations between the fine blanking process parameters and the resulting properties of the fine blanked part. Especially the condition of the cut surface as an important quality criterion has to be investigated. The quality characteristics of the cut surface of fine blanked parts are often subject of investigations. In addition, it would be of importance to investigate how the material properties in the shear zone are changed by the fine blanking process. This on one hand in turn can enable conclusions to be drawn about possible punch wear. If, on the other hand, hardening of the cut surface takes place as a result of fine blanking, then this could have a positive influence on the application properties of fine blanked components. Thus, an experimental fine blanking investigation of the micro hardness of the cutting surface has been made with variation of steel material and cutting temperature. It could be demonstrated that the micro hardness increases in direction towards the burr. This is independent on material and cutting temperature.

파인 블랭킹 기술을 적용한 자동차 엔진용 VCT 플레이트 부품의 암 취출 방식

VCT plate parts for automobile engines are wear-resistant and consist of an inner plate and an outer plate. Most of the existing fine blanking parts use a method of ejecting the product by air at high pressure in the mold, resulting in product defects due to damage and scratching as the product falls. However, this study uses an arm extraction method, moving the product using the arm that guides the product outward in the mold. We conducted a study on the extraction methods of VCT outer plate parts for automobile engines by applying fine blanking technology, and developed an arm extrusion method using 2-cavity die technology for fine blanking to produce VCT outer plate parts.

Simulated analysis and experimental investigation on edge qualities of high strength steels hot blanking parts

Hot blanking of high strength steels is a new technology, which can improve edge quality, shorten cycle-time and reduce cost because punching and trimming process are completed during the period of hot stamping, before martensite formation. Numerical simulation models for hot blanking parts of B1500HS steel are established by ABAQUS to analyse the influences of different parameters on the fracture surface quality, including die clearances and original temperatures. And for verification, the computed results show good agreement with experimental results. By tests and simulations, the appropriate die clearances and other processing parameters of high strength steels hot blanking are determined.

Effect of technological parameters on microstructure and accuracy of B1500HS steel parts in the hot blanking

Hot blanking process could be used for producing diverse fine blanking parts with comprehensive mechanical properties and to solve the problems in the piercing and trimming of press-hardened parts. To explore the optimal hot blanking process and evaluate the effects of some technological parameters on the phase transformation, fracture quality, and dimensional accuracy of the parts, several different blanking temperatures (450–800 °C) and die clearances (8–25%) were used in the hot blanking of B1500HS steel. The experimental results show that as the blanking temperature increases at a certain die clearance, the dimensional accuracy shows a trend of “negative growth–positive growth–negative growth,” and a higher dimensional accuracy of blanked parts can be attained at blanking temperatures 450–500, 600–650, or 750–800 °C. Besides, the burnish zone width increases, and the burnish and rollover zone widths account for ~ 80% of the steel sheet thickness at 800 °C. At blanking temperatures 650–800 °C, the microstructure of blanked parts is completely martensite, the microhardness of parts is ~ 550 HV, and the perpendicularity of fracture increases as the blanking temperature increases. Parts with a high-dimensional accuracy, better fracture perpendicularity, wide burnish zone, better mechanical properties, and wear resistance can be obtained at blanking temperatures 750–800 °C.

Analysis of phase transformation and blanking accuracy of B1500HS steel during hot blanking

Abstract Hot blanking process not only produces a variety of fine blanking parts have comprehensive mechanical properties, but also solve the difficulties in the piercing and trimming of press-hardened parts. To explore the optimal hot blanking process and investigate the effects of some technological parameters on the phase-transformation and dimensional accuracy of the parts, several different blanking temperatures (450 °C, 500 °C, 550 °C, 600 °C, 650 °C, 700 °C, 750 °C, and 800 °C) and die clearances (25%, 20%, 18%, 16%, 14%, 12%, 10%, and 8%) were used in the hot blanking of B1500HS steel. The results show that the diameters of blanked parts increase with the decrease of die clearance at the same blanking temperature. When the die clearance is constant, the dimensional deviation of diameter for the blanked parts shows the trend of “positive growth‒negative growth‒positive growth” with the decrease of blanking temperature. The higher dimensional accuracy of blanked parts can be attained at the blanking temperatures 450–500 °C, 600–650 °C, or 750–800 °C. The microstructure of blanked parts is complete martensite at the blanking temperatures 650–800 °C, the microhardnesses of parts are approximately 550 HV.

Numerical Heat Treatment Modelling of Fine Blanked Sheet Metal and Experimental Validation

Heat treatment is one of the major sources of dimensional inaccuracy in the manufacturing of fine blanked parts. Tools and equipment often need to be iteratively corrected in order to achieve the desired quality. Numerical simulation of the heat treatment process can substantially reduce these efforts. The simulation accuracy on the other hand is strongly dependent on the accurate characterization of the thermo-mechanical boundary conditions as well as material properties. The present contribution aims to propose a novel approach in the calibration of numerical models by using a modified Jominy test as well as heat treatment experiments with parts having residual stresses from a bending process. The results are validated by comparing numerical phase content and hardness values with the corresponding experiments.

Research on parameters optimization of bilateral ring gear blank-holder in thick-plate fine blanking

To compensate for the poor quality of thick-plate blanking parts in cross-section, this paper suggests using the optimizing bilateral ring gear holder parameters to increase burnish zone and improve cutting precision. With the bilateral gear ring, the hydrostatic pressure of shear deformation zone will increase, plasticity of the material will be lifted to maximum and quality of the cross section will be raised. This paper establishes 8mm AISI-1020 fine blanking model by DEFORM2D, analysis different ring gear parameters and clearance that are influenced the stress-strain and cross section quality to predict forming defects. By using the bilateral gear ring blank holder, the poor quality of thick-plate blanking section is successfully enhanced. Therefore, the bilateral gear ring blank holder is vital to improve the quality of blanking parts and provide the reliable theory basis for the practical engineering application.

Burr Formation in Metal Cutting Operations and some Deburring Methods

Remained burrs on edges of the parts after metal cutting operations may cause many problems in the production process and in the quality of products, therefore the burrs must be completely removed. In the paper, the authors give an outline of the elements and the technical and economical influences of the burr formation, and the characteristics of the burrs and the burr formation mechanisms. The authors present some special processes that are suitable for deburring of small pieces (e.g. Magnetic Abrasive Deburring), and a frequently applied mechanical process: power brushing. The authors have carried out many investigations regarding the magnetic abrasive deburring of small, blanked sheet metal parts, furthermore the machine deburring of large-sized metal workpieces by carbide-reinforced cylindrical brushes. The detailed conditions, data, results and conclusions of these deburring experiments are treated in the paper too.

An Experimental Study on the Effect of Die Chamfer Shape and V-Ring Position on Die Roll Height in the Fine Blanking of a Special Part with Various Corner Shapes

In this paper, a change of die roll height according to the die chamfer shape and V-ring distance of a fine blanking tool was studied by experiments on a special part with various corner shapes. Three guide plate inserts with different V-ring positions and three die inserts with different die chamfers were machined, and then a fine blanking tool was manufactured for the fine blanking experiments. Nine experiments were conducted on a 650-ton fine blanking press. Each die roll height was measured and analyzed. It would be noticed that the die roll heights on the corner shapes of the fine blanked parts increased with increasing V-ring distance and die chamfer angle, but it decreased with increasing corner radius and angle. The results in this study can be used to minimize the die roll height of fine blanked parts with corner shapes when designing the V-ring and die chamfer of a fine blanking tool.

An Experimental Study on the Die Roll Height According to the V-Ring Distance of the Fine Blanking Tool for the Seat Recliner Holder with Various Corner Shapes

In this paper, the relation between die roll height and V-ring distance of a fine blanking tool was studied by experimenting on a special designed seat recliner holder with various corner shapes. Three guide plate inserts with different V-ring distances and a die insert with constant die chamfer were machined, and a fine blanking tool was manufactured for the experiments. Three experiments were conducted on a 650-ton fine blanking press. Each die roll height on the sample from the experiments was measured and analyzed. It should be noticed that the die roll heights on the corner shapes of fine blanked parts increase with increasing the distance between the V-ring distance, and decrease with increasing corner radius and angle. These results can be used to minimize the die roll height of fine blanking parts with corner shapes when designing the V-ring of a fine blanking tool.

An Experimental Study of V-Ring Position on the Die Roll Height in the Fine Blanking of Special Part with Corner Shapes

In this paper, the relation between die roll height and V-ring position of a fine blanking tool was studied by experimenting on a special part with various corner shapes. Three guide plate inserts with different V-ring positions and a die insert with constant die chamfer were machined, and a fine blanking tool was manufactured for the fine blanking experiments. Three experiments were conducted on a 650-ton fine blanking press. Each die roll height was measured and analyzed. We found the tendency of the die roll heights on the corner shapes of fine blanked parts to increase with increasing the distance between the V-ring position and the contour of the special part, and to decrease with increasing corner radius and angle. These results can be used to minimize the die roll height of fine blanking parts with corner shapes when designing the V-ring of a fine blanking tool.

Residual Stress and Corrosion Resistance Experimental Analysis of Closed Extruding Fine Blanking Parts Surface

In order to research the residual stress distribution and corrosion resistance of closed extruding fine blanking parts, surface and deep layer residual stress is tested and electrochemical corrosion behavior is also researched through polarization curve test in the 3.5%NaCl solution. The results show that: the surface’s residual stress is compressive stress, compressive stress value increases with the deformation degree, and the maximum value is 150 Mpa or so; Along with increase of depth from surface, residual stress first increases, then decreases, it is on the inferior surface reaches to maximum value, and the influence depth is 200μm; In the polarization curve test, closed extruding fine blanking parts' initial corrosion resistance is better than turning parts and blank, but with the test proceeding, the corrosion resistance drops, and closed extruding fine blanking parts’ final passivation phenomenon delays.

Parameter Design for the Counter-Blanking Process Using the Finite Element Method and the Taguchi Approach

There is an increasing demand for high quality metal stamped parts. In general, burr formation is the main defect found subsequent to the blanking process. This defect must be strictly removed specifically for consumer products in order to prevent any kind of injury to the operators. Such a removal process results in an increase of the production cost. The unique merit of the counter-blanking process focuses on fabricating the burr-free blanked parts. However, it is difficult to control the numerous process parameters involved in this process in order to achieve the burr-free blanked parts. Thus, this study aims at investigating the process parameter design for the counter-blanking process by means of combining the finite element method (FEM) and statistical analysis techniques, including the Taguchi method and the analysis of variance (ANOVA) techniques. The results indicate that the process parameter of blanking clearance has a major influence on the die-roll formation features of the burr-free blanked part, respectively followed by the punch penetration depth and the same level of influence of the two process parameters of punch and die diameters in the second step. To conclude, this technique could be applied as a tool to achieve good quality of the burr-free blanked parts by optimizing the value of the process parameters and their favorable combinations.

Study of residual stresses in tailor rolled blanked Al5J32-T4 sheets

Several automotive parts such as door panels have been manufactured by using load-adapted blanks for crash optimization and weight minimization. Recently, Tailor Rolled Blanks (TRB) has been introduced to remove the disadvantages of a welding process which was used in joining panel components. TRB offers better structural design capabilities due to the seamless transitions on the panels with different thicknesses. In spite of the advantages of the process, TRB leaves internal stresses in the panel. This residual stresses lower the formability of Tailor Rolled Blanked (TRBed) parts and cause cracks near severe curvature during subsequent forming processes. In this research, the residual stresses of TRBed Al5J32-T4 sheets were studied by X-ray stress analysis, and also microstructure was observed along the rolling direction. In addition, heat treatment was done after TRB process in order to compare the residual stresses to that of the TRBed sheets before the heat treatment.