Press Punch Research Articles

자동차용 기계부품의 홀 가공 품질 검사를 위한 비전 시스템

This paper presents a vision system for machined hole quality inspection of mechanical parts in an automobile. Automobile parts have various shapes and holes created by press punches. However, if the press punch pin is broken, a hole is not created on the mechanical parts. This problem causes serious part quality defects. To solve this problem, we proposed a vision system that could easily and cheaply inspect the quality of holes in automotive machining parts. A software development environment was created to build an economical vision inspection system. Images were gathered using the Near-real-time method to overcome the low frame-per-second of inexpensive Complementary Metal Oxide Semiconductor (CMOS) webcams. Status of the hole was determined using template matching and distance between holes as a feature. The hardware required for vision inspection was designed so that it could be directly applied to the automotive part manufacturing process. When the proposed vision inspection system was tested by installing it in an automobile parts factory for 3 months, the system showed an inspection accuracy of at least 97.9%. This demonstrates the effectiveness of the proposed method with accuracy and speed of hole defect inspection of machined parts.

New Die Design for High-Pressure Torsion

A special design of the die was developed, which allows to implement the process of severe plastic deformation by high pressure torsion to deform ring blanks, which will be the starting material for creating high-strength piston rings. A special feature of the die design is the provision of torsion of the deforming tool with constant rectilinear movement of the press punch due to the composite deforming tool, which includes both displacement and rotation blocks. Using the obtained geometry, computer simulation of this process in the Deform program was performed in order to assess the possibility of a stable process flow. AISI-316 austenitic stainless steel was chosen as the material of the billet. The resulting strain force on the first two cycles was considered. On the first cycle, the force was equal to 464 kN, on the second cycle the force value was about 1200 kN. The obtained values are quite adequate, which indicates the possibility of multi-cycle deformation.

Adaptive system for automatic control of the fine drawing process

The paper considers the technological process of deep drawing, taking into account the high degree of deformation of the metal and the small thickness (0.5 mm) of the workpiece. Given the high complexity of the process and the impossibility of its representation in an analytical form, the paper uses its representation in the form of a phase portrait in the plane of the drawing force and movement of the hydraulic press punch. Phase trajectories in the mentioned plane determine the geometric dimensions of the product, characterize stresses and deformations during the process and determines the structure of the process control algorithm. The digital positional tracking system considered in the work includes electromechanical, hydraulic, pneumoelectric and electronic links. The system provides precision positioning of the hydraulic press punch with control and control of its movement speed. The paper provides an ideal mathematical model of the extraction process. As a result of comparing the phase trajectories of the model and the real process, a possible difference is revealed due to the interference in the real process. The resulting difference makes it possible to form an additional control effect on the punch speed control circuit in the system in order to compensate for the resulting misalignment. Thus, the stabilization of the drawing force in the function of the movement of the punch is realized. The paper provides mathematical descriptions of all parts of the system, provides dynamic characteristics of the process. As disturbing effects on the drawing process, the following are considered: metal hardening, the unstable friction force that occurs when the workpiece is pressed, the change in the drawing force when the parts of the workpiece are drawn into the matrix, corrugation, metal thinning during the transition of the bottom part to the side wall of the product. The mentioned disturbances without the system in question did not fully ensure the quality of the products. As a result of the resulting marriage, significant production costs took place. The materials of the work and numerical data of the links of the technological process system were obtained by the example of manufacturing a cylinder of an OP-2(3)-ABCE powder fire extinguisher produced at the ZPO plant Itself (fire fighting equipment plant).

Конструкция штампа для реализации кручения под высоким давлением

A special design of the die was developed, which allows to implement the process of severe plastic deformation by high pressure torsion to deform ring blanks, which will be the starting material for creating high-strength piston rings. A special feature of the die design is the provision of torsion of the deforming tool with constant rectilinear movement of the press punch due to the composite deforming tool, which includes both displacement and rotation blocks. Using the obtained geometry, computer simulation of this process in the Deform program was performed in order to assess the possibility of a stable process flow. AISI-316 austenitic stainless steel was chosen as the material of the billet. The resulting strain force on the first two cycles was considered. On the first cycle, the force was equal to 464 kN, on the second cycle the force value was about 1200 kN. The obtained values are quite adequate, which indicates the possibility of multi-cycle deformation.

High-accuracy servo press system for the clinching joint process

This paper focuses on the quality improvements on clinching joints using a servo press with a Radial basis function neural network and a sliding mode (RBFS) control strategy. Bottom thickness, which is affected by the press punch position, is usually used to monitor clinching joint quality. Traditional clinching presses are driven by pneumatic pistons or motors that provide feedback on punch force or motor position. However, this feedback is indirectly related to the joint bottom thickness. Clinching workers who set the control parameters on these presses depend on tests and statistics. Thus, this paper presents a servo press system that utilizes punch position feedback to directly control the joint bottom thickness. Transmission errors are considered for the movement accuracy of the servo press. A mathematical model of the servo press is established for analyzing. An algorithm, which combines RBF neural network and sliding mode, is proposed and applied for press position tracking. This algorithm adopts an RBF neural network to approximate the nominal model of the press system. The update law of the algorithm is based on the Lyapunov function used to prove the stability of a closed-loop system. The sliding mode controller compensates for the neural network error and disturbance. Finally, experiments are executed on the servo press with an RBFS controller. To evaluate the performance of the proposed method, a fuzzy PID controller is also applied to the press for comparison. The results indicate that the servo clinching press system with RBFS efficiently and accurately control the clinching jointing process.

A bi-objective guillotine cutting problem of stamping strips of equal circles

Some factories use the cutting and stamping processes to divide stock plates into circles to make products. A guillotine machine cuts the plate into strips in the cutting process and then a stamping press punches out circles from the strips in the stamping process. The circles in a strip have the same size. The number of rows of circles in each strip is limited. Under these constraints, this paper addresses the following primary objective: to cut a plate by a guillotine method so that the maximal number of circles is obtained. Then the secondary objective should be optimized: the cutting layout should use a minimal number of strips. The problem is formulated as a bi-objective optimization problem and a recursive algorithm is presented for it. The computational results indicate that the algorithm can efficiently simplify the cutting process.

Hot forging of MAX compounds SHS-produced in the Ti-Al-C system

Investigated was the forgeability (extent of compression) of still hot SHS products (MAX phases) formed in the Ti-Al-C system at relatively low applied pressures (1.5–15.0 MPa in a press punch) in conditions of free SHS compression. The extent of compression was measured as a function of time delay (between the end of reaction and compression) and applied pressure. Characterized were the microstructure and phase composition of thus obtained MAX compounds.

Strips minimization in two-dimensional cutting stock of circular items

Circular items are often produced from stock plates using the cutting and stamping process that consists of two stages. A guillotine machine divides the plate into strips at the cutting stage, and then a press punches out the items from the strips at the stamping stage. The cutting cost at the first stage often increases with the number of strips in the cutting plan. An approach is presented for the two-dimensional cutting stock problem of the strips at the cutting stage. The objective is to minimize the sum of the material and the cutting costs. The approach formulates the problem as an integer linear programming, and uses a column generation method for generating the cutting patterns. The cutting patterns have the feature that each cut on the plate produces just one strip. The computational results indicate that the approach can greatly reduce the number of strips in the cutting plan.

An algorithm for the two-dimensional cutting problem of punched strips with blade length constraint

This paper presents an algorithm for generating optimal T-shaped cutting patterns of punched strips. A strip contains only items of the same type. The stock plate is divided into items in two stages. First a guillotine machine cuts the plate into strips, then a stamping press punches out the items from the strips. The blade length of the guillotine machine may be shorter than the plate length. The algorithm divides the plate into two segments. Each segment contains strips of the same direction. The strip directions of the two segments are perpendicular to each other. The algorithm uses dynamic programming techniques to determine the optimal strip layouts on segments of different lengths not longer than the blade length, considers all possible combinations of two segments, and selects the best pair as the optimal solution. The computational results indicate that the new algorithm is much more efficient than the existing algorithm.

Applying parallelogrammic strips for cutting circles from stainless steel rolls

Stainless steel rolls are often cut into circular items to make such common commodities as water jugs, buckets, pails, pots, cups and basins. The items are often cut with the shearing and punching process that consists of three stages. A guillotine shear cuts the roll into sheets at the first stage, and cuts the sheets into strips at the second stage. A stamping press punches out the items from the strips at the third stage. The sheets and the strips may be either rectangles or parallelograms. The height of the sheets is the same as the roll width. A strip contains one or more rows of items, and is parallel to a side of the sheet. This paper presents an algorithm to generate optimal cutting patterns for the three-stage cutting process mentioned above. The algorithm uses a knapsack procedure to generate optimal cutting patterns on the sheets, and uses a linear programming approach to determine the number of sheets cut according to each pattern. The computational results indicate that the algorithm is efficient in both computation time and material utilization.

Recursive Algorithm for Generating Two-Staged Cutting Patterns of Punched Strips

The manufacture of parts made of metal sheet often includes two successive processes: the cutting process at which a guillotine shear cuts the sheet into strips, and the punching process at which a stamping press punches out the blanks from the strips. This paper presents an algorithm for generating optimal two-staged cutting patterns of strips for the cutting process. At the first stage the sheet is divided into segments with parallel cuts. Each segment contains strips with the same length and direction. The segments are cut into strips at the second stage. The algorithm calls a recursion function to determine the optimal strip layouts on segments of various lengths, and calls another recursion function to optimally arrange the segments in the sheet, so that the value of the pattern reaches maximum. The computational results indicate that the algorithm is efficient both in computation time and in material usage.

Simplest optimal guillotine cutting patterns for strips of identical circles

The manufacturing industry often uses the cutting and stamping process to divide stock plates into circles. A guillotine machine cuts the plate into strips for stamping at the cutting stage, and then a stamping press punches out the circles from the strips at the stamping stage. The problem discussed is to cut a plate into strips of identical circles such that the number of circles is maximized. A dynamic programming algorithm is presented for generating the simplest optimal cutting patterns of the strips. The computational results indicate that the algorithm is much efficient in simplifying the cutting process.

Dynamic programming algorithms for the cutting problem of equal circles

The current paper presents an approach for generating cutting patterns of equal circular blanks processed with the shearing and punching process, which includes two stages. A guillotine machine divides the sheet into strips at the first stage. A stamping press punches out the blanks from the strips at the second stage. Normal patterns consisting of orthogonal strips are proposed and four dynamic programming algorithms for generating them are presented. The first two algorithms deal with the unconstrained problem in which there is no constraint on the number of blanks included in a pattern, and the last two deal with the constrained problem in which the blank demand must be met exactly. The computational results indicate that the algorithms are efficient in both computation time and material utilization.

Exact algorithm for generating two-segment cutting patterns of punched strips

Metal plates are often divided into items in two stages. First a guillotine shear cuts the plate into strips at the shearing stage, and then a stamping press punches out the items from the strips at the punching stage. This paper presents an algorithm for generating optimal two-segment cutting patterns of strips at the shearing stage. An orthogonal cut divides the plate into two segments, each of which contains strips of the same direction and length. The algorithm uses dynamic programming techniques to determine the optimal strip layouts on segments of various lengths, and selects two segments to appear in the optimal pattern. The segments are considered in increasing order of their lengths, so that dominant properties can be used to shorten the computation time. The computational results indicate that the algorithm is efficient in both material utilization and computation time.

Recursive algorithm for the two‐dimensional cutting problem of punched strips

PurposeTo provide an algorithm for the two‐dimensional guillotine‐cutting problem of punched strips.Design/methodology/approachIt is assumed that the stock sheet is cut into blanks in two stages. First a guillotine shear cuts the sheet into strips, and then a stamping press punches out the blanks from the strips. To generate good strip layout, the sheet is divided into two segments with an orthogonal cut. Each segment consists of strips in the same direction. The strip directions of the two segments are perpendicular to each other. A recursion function is established to determine the optimal strip layouts on segments of different lengths. All possible segment lengths are considered either explicitly or implicitly. Two segments of different strip directions are selected optimally to compose the final cutting pattern.FindingsA strip can be taken as consisting of rectangular pieces, where the length of the first piece may be longer than that of the others. Normal lengths and widths can be defined according to the properties of punched strips. Considering only normal segment lengths and using lower bound in the recursion function can reduce the computation time drastically.Practical implicationsBased on the algorithm, practitioners may develop applications to solve real world two‐dimensional cutting problem of punched strips.Originality/valueThe two‐segment cutting patterns for punched strips are proposed. They are simple to cut and may be welcomed in practice.

Resolution of the material and machine contributions to the area to height ratio obtained from force-time powder compression data. I: Instrumented laboratory press

The area to height ratio (AH ratio) was developed as a data analysis technique for the treatment of tablet press punch force-time data (Chilamkurti et al., 1982). This technique has been applied to force-time data collected with an instrumented laboratory press and the uncorrected AH ratio has been resolved into the machine and material components. The machine component was determined via analysis of blank compressions and subtraction of the machine AH ratio from the uncorrected AH ratio, determined via compression studies on a material of interest, yielded the material specific corrected AH ratio (MSC AH ratio). In the case of the tableting conditions employed in this study the MSC AH ratio was, 0.22, 0.22, 0.15 and 0.03 s for microcrystalline cellulose, anhydrous dicalcium phosphate, lactose and polyethylene, respectively. Relationships between the MSC AH ratio and other compression and compaction properties (mechanical energy and tensile strength) were investigated.

Objective measurement of texture variables in raw and processed French fried potatoes

The five most important variables encountered in french fry production and texture measurement are: specific gravity, raw potato storage, raw potato firmness, freezing of fried product, and cooling of hot french fry slices. Shear force curves are presented to illustrate the effects of these variables. A double maximum cruts shear peak is exhibited by properly processed french fried potatoes when they are hot. Bursting of the crust is less evident with less desirable fries and with frozen and reheated samples. Shear press punch tests proved to be best for analyzing raw potato firmness. In order to determine and study the texture variations within a potato, Durometer3 tests were conducted on concentric zones and sections from bud to stem end of most firm and least firm raw tubers. Higher resistance to penetration was encountered in the most firm potatoes. Durometer values vary directly with solids within a tuber which can be explained by certain morphological conditions. Because of turgidity, however, solids and Durometer values vary inversely between firm and non-firm tubers. A table is presented which lists the texture inferences derivable from changes which occur in the french fried potato shear force curves.