Blanking Tool Research Articles

A Study on the Effect of V-Ring Position on the Die Roll Height in Fine Blanking for Special Automobile Seat Recliner Gear

In this paper, the relation between die roll height and V-ring position was studied by fine blanking experiments for imaginary special automobile seat recliner gear. The three die inserts and three guide plate inserts with different V-ring positions were machined, and fine blanking tool was manufactured. Using the fine blanking tool, three experiments were conducted on the 650 ton fine blanking press. Each die roll height was measured, analyzed and we found the tendency of die roll heights on imaginary special gear to increase with increasing the distance between V-ring position and contour of gear. This result can be used to minimize the die roll height of fine blanking gear parts when designing V-ring of fine blanking tool.

An investigation of the blanking process of the quenchable boron alloyed steel 22MnB5 before and after hot stamping process

Recently, one of the most important issues in the automotive industry is lightweight construction. While maintaining safety standards, the fuel consumption can be decreased by reducing the weight of the vehicle. To manufacture lightweight vehicle components with high strength, hot stamping with quenchable boron steels is becoming more common in automotive industries. However, the high strength achieved in the press-hardened parts causes severe wear and sometimes unexpected premature failure in the blanking tools during the trimming and piercing processes. Because of high costs for repairing blanking tools, laser cutting has been used in almost all automotive industries in spite of the long process time. Thus, the aim of this work is to develop economical shearing methods for use on the press hardened ultra high strength steels which will enhance the tool life and meanwhile to achieve good product quality. As a preliminary investigation into the blanking strategies of the hardened boron steel 22MnB5, the conventional mechanical blanking process was carried out to predict the sheared edges of the parts and the wear evolution of blanking tools versus the number of blanking strokes. Subsequently, warm blanking was performed with a developed tool, while simultaneously applying hot stamping process to improve the tool life by reducing the shearing load.

A Study on Die Roll Height of Special Automobile Seat Recliner Gear According to Die Chamfer Shape in Fine Blanking Tool

In this paper, the effect of die chamfer shape on the die roll height was studied by fine blanking experiments for imaginary special automobile seat recliner gear. The three die inserts with different die chamfer shapes were machined, and fine blanking tool was manufactured. Using the fine blanking tool, three experiments were conducted on the 650 ton fine blanking press. Each die roll height was measured, analyzed and we found the tendency of die roll heights on imaginary special automobile seat recliner gear to increase with increasing die chamfer angle, with the horizontal distance of die chamfer being constant. This result can be used to minimize the die roll height of fine blanking gear parts when designing die chamfer of fine blanking tool.

A Study on the Relation between Die Roll Height and Die Chamfer Shape in Fine Blanking for Special Gear

In this paper, the relation between die roll height and die chamfer shape was studied by fine blanking experiments for imaginary special gear. The three die inserts with different die chamfer shapes were machined, and fine blanking tool was manufactured. Using the fine blanking tool, three experiments were conducted on the 650 ton fine blanking press. Each die roll height was measured, analyzed and we found the tendency of die roll heights on imaginary special gear to increase with increasing die chamfer angle, with the horizontal distance of die chamfer being constant. This result can be used to minimize the die roll height of fine blanking gear parts when designing die chamfer of fine blanking tool.

Light Metal in High-Speed Stamping Tools

The required number of punched and blanked parts in the electronic industry, such as leadframes, contact pins or plugs often reach several million pieces. According to this, the production process has been sped up to frequencies up to 2000 parts per minute. At this production rate parts of thin steel or copper sheets are produced with high-speed stamping presses and blanking tools. Because of the high gating velocities in the blanking tool there is a recurring acceleration at the moment, when the blank holder contacts the sheet metal. A second shock in the blanking tool arises, when the sheet cracks. This is also known as the impact shock during the blanking process. Trough these two impulses and through the cycle of the plunger movement a periodic oscillation arises in the tool. Horizontal vibrations can lead to an undefined position between punches and die-plate, while vertical movement leads to increased wear because of friction forces between the blanked surface and the lateral area of the punches. The goal of this project was to minimize these oscillations in cutting tools by the usage of lightweight materials in the flux of forces. An experimental cutting tool was designed with alternative top and bottom plates for the comparison of the oscillation status in the cutting process when using plates of steel, aluminium or magnesium. The centre plate of the tool remains constant. Experiments were accomplished for several velocities and tool setups with different plate materials. To determine the influence of the materials with different density and elasticity acceleration, force and acoustic emission sensors were integrated in the tool. The set of problems was investigated by analyzing the measured data and by determining the wear in practical tests.

Parametric Optimization of Cryogenic-Treated D-3 for Cutting Rate in Wire Electrical Discharge Machining

Cryogenic treatment (Cryo) is a supplementary process to improve the properties of metals like high carbon high chromium alloy tool steels (D-3) which are increasingly used in manufacturing high-performance cutting tools (dies and punches), blanking and punching tools, extrusion tools, parts of aerospace and automotive industries, etc. The purpose of this study is to investigate the effect of parameters like pulse width, time between two pulses, maximum feed rate, servo reference mean voltage, short pulse time, and wire mechanical tension, on cutting rate (cr) of cryogenic-treated D-3 in wire electrical discharge machining. An L27 orthogonal array has been used to conduct experiments and statistically evaluate the experimental data by analysis of variance (ANOVA). It is seen that cr decreases with increase in pulse width, time between two pulses, and servo reference mean voltage. cr first decreases and then increases with increase in wire mechanical tension. The confirmation experiments have also been conducted to validate the results obtained by Taguchi technique.

Finite element prediction of blanking tool cost caused by wear

The total cost of a blanked part is determined by a large number of factors, including the material cost, manufacturing costs. Predicting the manufacturing costs of a blanked part requires accurate estimation of tool cost caused by wear. The aim of this paper is to develop a finite element model allowing for the numerical prediction of the blanking tool life which allows for the evaluation of the cost rate of blanking tool caused by wear needed to assess the total cost of a blanked part. A wear prediction model has been implemented in the finite element code Abaqus in which the tool wear is a function of the normal pressure and some material parameters. In the present work, the tool is modeled as rigid body hypothesis, and the wear variables are computed in the contacting elements. The altered tool contact surface and contact pressure tool shapes are updated iteratively to simulate wear over a long period of time of about 100,000 cycles. A damage model is used in order to describe crack initiation and propagation into the sheet. The distribution of the tool wear on the tool profile is obtained and compared to industrial observations.

In situ punch wear measurement in a blanking tool, by means of thin layer activation

The improvement in the productivity of the leadframe blanking industry of is a key for its competitiveness. Consequently the challenge for researchers covers a wide range of scientific areas (materials, lubrication, process, etc.). Among others the improvement of the punch wear resistance is one of the most important parameters in the blanking process. Consequently punch wear understanding is the topic of this paper. Because of the strong influence of the centering of the punch-die clearance upon the burr amount, it is crucial to directly measure punch wear in the blanking press without disassembling the tool. In this paper a new method for a direct measurement of the punch wear, selective activation technique, which has never been applied in the field of blanking is described. With the help of this technique, a precise relation between the loss of activity and the worn volume on the punch has been established. In addition this method allows the influence of the blanking process parameters, like lubrication or nature of the blanked material, to be quantified in real time. The measured wear volumes by this method have been confirmed by means of measurements of the profile of the worn punch carried out after completion of a large amount of blanked parts. These geometrical results exhibit a good agreement with the selective activation technique.

FE simulation of the blanking of electrically heated engineering materials

The blanking of electrically heated engineering materials is simulated using the commercially available software, ABAQUS: the temperature distribution, the “thermal” punch force and the blanking force for different heating conditions are investigated. Electrical heating provides an advantageous temperature distribution in the shear-zone of the material, which substantially reduces the maximum punch force and enables blanking with larger aspect ratios. Electrical heating can be achieved at a sufficiently rapid heating rate, is flexible with reference to setting conditions and may be easily incorporated into a blanking tool system, thus promising scope for application in an industrial environment.

Tool life equation for blanking 18-8 stainless steel strips

Hereinafter it is presented a model for the behaviour and life of circular blanking tool used in sheet forming processes of 18-8 stainless steel (sheet thickness: 1 mm). Firstly it has analyzed the different studies that have previously delt with this problem. Secondly taking into account recently made experiments, it is proposed a simple formulation to predict tool life with enough reliability. To this purpose it has examined different parameters in the wear process, inferring from these the fundamental parameters that regulate them and about which the different equations have been configurated. Blanking tests were performed using a 20 t press at a speed of 150 strokes/min. Punch materials used in these tests were AISI A2 and AISI D2 with diameters between 1.5 and 10 mm. The blanking tests were performed at a clearance between 5 and 20 % of the work material thickness.

The Influence of Fracture Toughness on the Fine Blanking Tools Life

One of the most important operations in the manufacturing of fine blanking tools from HSS AISI M2, is vacuum heat treatment with uniform high-pressure gas quenching. The importance of optimal heat treatment is the possibility of making the optimum combination of the basic characteristics of fine blanking tools made from HSS for the given working part/fine blanking tool combination. Four different austenitization temperatures and four different tempering temperatures were chosen to produce the correct hardness balance, toughness, cutting properties and wear resistance in the finished tool. The result of the present investigation is important for the optimization of vacuum heat treatments of different tools made from HSS which are under tensile impact stress during exploitation. For them the optimal combination of hardness and fracture toughness are decisive.

Optimization of sheet metal forming processes by determination of the force vector and the position of its application

It is possible to minimize the tilting and horizontal displacement of the press ram with a 3-component piezo-electric transducer system. This could be demonstrated by experiments with a blanking tool. The force vector and its application point were measured and the tool position in the press was changed.

The condition monitoring of power press blanking tools using surface acoustic waves (SAWs) and acoustic emission (AE) : Impact of Non-Destructive Testing, Proceedings of the 28th Annual British Conference on Non-Destructive Testing, Sheffield (United Kingdom), 18–21 Sep. 1989. pp. 179–184. Edited by C. Brook and P.D. Hanstead. Pergamon Press, (1990)

The condition monitoring of power press blanking tools using surface acoustic waves (SAWs) and acoustic emission (AE) : Impact of Non-Destructive Testing, Proceedings of the 28th Annual British Conference on Non-Destructive Testing, Sheffield (United Kingdom), 18–21 Sep. 1989. pp. 179–184. Edited by C. Brook and P.D. Hanstead. Pergamon Press, (1990)

On high speed precision blanking of IC lead-frames using a progressive die

The factors affecting the dimensional accuracy of blanked IC lead-frames are discussed. Attention is focussed on the elimination of the residual stress in the material caused by roll-slitting. Improvement in the designing and manufacturing of the blanking tool is explained and the mechanism of vibration of the stripper in high-speed blanking is analyzed. A high speed precision press that has been developed in Japan is introduced. The effects of blanking conditions such as tool clearance, strip-holding force, lead-shape, and order of blanking are explained, using a newly proposed mechanical model.

Wear on Shearing Tools : (Wear on Cutting Edges of Blanking Tool for Square Parts)

In blanking, many factors influence tool wear. In this report, the authors investigated how the wear on cutting edges of blanking tool increased with the number of parts blanked, and discussed how the wear influenced the blanking force, energy, dimensional accuracy, burr height, etc. (1) On the face of punch and die, crater wear occurred and changed gradually into crater-slope wear with the increasing number of parts blanked, but punch flank wear and die opening wear were slope wear and increased uniformly. (2) Die face wear was greater than punch face wear, but at the sharp corners punch face wear and punch flank wear were remarkable. (3) The blanking force scarcely increased with the number of parts blanked, but the blanking energy increased considerably. (4) Dimensions, burr height and dishing increased and the sheared surface became worse with the number of parts blanked.

剪断加工工具の寿命試験(その二)

In this research the 12 × 7.2 mm and 8 × 5 mm rectangular blanking tools are used. With the former which is made from high carbon high chromium tool steel No.1, 400, 000 brass blanks of 0.6 mm thickness are cut out and with the latter made from special tool steel No.2, 40, 000 blanks of high class finished mild steel of which thickness is 0.5mm are cut out. The results obtained are as follows:1. In the sectional shape of blanks, burrs, depth of distortion of blank surface, width of sheared surface and angle of fractured surface increase gradually in proportion to wear of cutting edge, while angle of sheared surface decreases. These phenomena can be seen in both brass and steel blanks.2. In proportion to wear of cutting edges, the roughness on the side of die and punch edge, the upper surface of die edge and sheared surface of blanks increase gradually in both brass and steel blanks.3. The outermost dimension of blanks, in proportion to wear of cutting edges, becoms gradually larger than the original one in both brass and steel blanks.4. And others

K.M. Alloy Blanking and Press Bend Tools

Percival Aircraft Ltd. have recently adopted a most interesting sytem for the economical manufacture of small part press tools. The material used is the K.M. Alloy low melting‐point alloy and by its use the tool room work on punches and dies has been drastically cut. The method is not entirely original, but it is still comparatively little used.