Punch Design Research Articles

Polymer Shaped Punches Produces with Fused Filament Fabrication to Improve Cup Accuracy in Sheet Metal Forming

Rapid tooling has become an effective solution for reducing time and costs in tool production. In sheet metal forming, polymer tools produced via additive manufacturing offer performance comparable to traditional tools. However, a key challenge in this area is compensating for the radial expansion of polymer tools during the forming process, which leads to reduced accuracy in the produced parts and limits the achievable forming depth. To address this issue, the authors of this study proposed a novel punch design aimed at containing radial expansion, thereby enabling greater drawing depth and improved part accuracy. Different punch geometries were designed with a re-entrant angle varying between 150° and 180°. Numerical simulations were conducted to evaluate the optimal geometry, identifying the 160° angle as the best option to compensate for radial expansion and reduce punch load. Experimental tests were then performed to verify the numerical results, demonstrating the potential of this new design producing cups with higher drawing depth and best radial accuracy.

Experimental and numerical analysis of structural inhomogeneity of grooved compacts

Structural inhomogeneity developed within compacted powders using punches with grooved surfaces, is a critical issue due the cracking tendency. This study aims to provide a better understanding of the structural inhomogeneity according to the design of the punch surfaces using a finite element modelling. Two case studies are compared. In this modelling, the Drucker-Prager Cap model with density-dependent parameters is considered while the density distributions of manufactured grooved compacts are determined using X-ray tomography. The structural inhomogeneity is then analysed with the goal to determine which punch design is likely to improve the homogeneity.The contact-stress, stress and density distributions within the compact are computed. Predictions of the density distributions are validated from the measurements and show high densified regions localized essentially under the grooves and decreases drastically towards the compact center. The inhomogeneity of structure generated by each punch design is explained by the resulting contact-stress and the wall friction. A notable improvement of the homogeneity is qualitatively showed using the design of five instead of two grooves which was confirmed by X-ray tomography images and modelling thanks to the regular distribution of contact-pressure over the powder bed, even though this last is not uniform.

Possibilities of Increasing the Durability of Punches Used in the Forging Process in Closed Dies of Valve Forgings by Using Alternative Materials from Tool Steels and Sintered Carbides.

This study refers to an analysis of the durability of forging tools applied in the second operation of producing a valve forging from the chromium-nickel steel, NC3015. Due to the extreme working conditions of the tools, caused by cyclic thermo-mechanical loads, the average durability of tools made from tool steel WLV (1.2365) equals about 1500 forgings. An in-depth, complex analysis was performed on the technology, using macroscopic tests combined with a measurement of the wear/allowance on the tool working surface through 3D scanning; microstructural tests by means of light microscopy; observations of the changes taking place on the working surface with a scanning electron microscope; microhardness measurements; and multi-variant numerical simulations. It was established that the key issue is the proper selection of the process technological parameters, such as the input material and tool temperature, friction, lubrication, tribological parameters, type of tool material, or punch design, because even small changes made to them significantly affect the service life of forging punches. Therefore, to increase the durability of the forging dies, alternative materials made of W360, as well as two high speed steels, S600 and S705, were applied. However, the implemented punch materials did not bring the assumed effect of increased durability, as the highest average durability of steel W60 equaled only 1500 forgings, whereas in the case of the tool steels, this was below 900 forgings. For this reason, at the further stage, punches with sintered carbide inserts were introduced, which made it possible to significantly improve the durability up to the level of as many as 20,000 forgings, which, at the same time, points to a promising direction of further studies on the use of materials and solutions of this type.

Optimization of cutting die life cycle and investigation of parameters affecting die life cycle

In this study, an investigation into the factors influencing the die life cycle was prompted by the substantial costs associated with punch and matrix wear in the die used for ventilation hole cutting of the disc component, featuring MW05 material. The study focused on optimizing the life cycle through a series of experiments conducted in two stages. Initially, punch life cycle studies, including geometry and PVD surface coating, were carried out. Subsequently, matrix life cycle studies encompassing hardness, manufacturing method, surface roughness, press tonnage, and alternative material were conducted. The introduction of a flat area around the cutting edge of the punches led to a significant reduction in abrasive wear, while the modification to the punch design, coupled with AlCrN surface coating, effectively decreased adhesive wear on the cutting contour, resulting in an increased punch life cycle. Notably, a transition from wire erosion to milling machining for the matrix cutting contour yielded a substantial improvement in the matrix life cycle. These advancements in die life cycle optimization will serve as vital inputs for new die designs. Quantitative results reveal a 15-fold increase in punch life cycle and a 3.33-fold increase in matrix life cycle, demonstrating the efficacy of the implemented modifications.

Pengaruh Desain Punch Terhadap Mutu Fisik dan Disolusi Tablet MUPS Metformin HCl

The compaction of multi-unit pellet system (MUPS) into tablets is a potential alternative for sustained release drugs. Tableting tools (punch and die) affect the compaction process and quality of MUPS tablets. The punch design intends to preserve the desired drug release of compacted pellets. This study aims to investigate the effect of two punch shapes, the flat face radius edge (FFRE) and concave-faced punch (concave), each at two different cup depths, on the physical properties and release profile of metformin HCl MUPS tablets. Drug release parameters, t50 values, showed that the metformin HCl released from MUPS tablets was faster than the uncompacted sustained release pellets. The similarity of the dissolution profile (f2) between MUPS tablets and uncompacted metformin HCl pellets was lower than 50 as the minimum acceptance value. The tablet tensile strength obtained was below the requirements (<1.7 MPa). Tablet disintegration time was approximately less than 2 minutes. In conclusion, drug release profile of the MUPS tablets showed damage of the pellets due to compaction process. Nevertheless, pellets compacted at low compaction pressure using FFRE with a deeper cup depth (size 0.80 mm) showed a slightly better protection compared to other punch shapes and cup depth sizes applied.

Design and analysis of punch and die combination for fabrication of tractor fender using FEM

In the current times, most of the manufacturers are focussed on technology assisted optimization of resources, pertaining to capital investment in consonance with higher production rates with lowest minimum defects in the output produced. In agreement with the same, the present research identifies the designing characteristics of punch and die arrangement; meant for securing high degree of production outcomes associated with manufacturing of tractor fender component (side part) as part of press tool exercise. Moreover, the aforementioned line of action is adopted to achieve minimum time cycle for production as well as for minimising die material used by involving two different die blocks; unlike previous approach of adopting a die plate combination. The novel approach led to significant decrement in die steel consumption and material cost as well. The CAD model of punch and die arrangement has been developed on Catia Software whereas; the structural analysis has been accomplished by Ansys software. Besides that, this scheme also develops a comprehensive picture of punching through mathematical calculation of all the die parts and detailed analysis of same by way of finite element analysis. The die was specifically designed and manufactured at the establishment of Indofarm Equipments Private Limited, Baddi (Himachal Pradesh).

Redesigning & Manufacturing the First Punch for 107 mm Warhead

This paper is devoted to show the effect of changing the design of the first punch on the wear consumption of the second punch by redesigning, simulating and manufacturing of the first punch for 107 mm warhead in order to reduce the consumption in the second punch, increase the productivity and also produce the product with high quality. SOLIDWORKS software for design and simufact forming for analysis has been used to design and manufacturing the first punch. Simufact forming has been used to study the die wear to determine the consumption rate of the second punch. The effective stress that affect the properties of the final product has been calculated by simufact. A comparison between the second punch which has been used after using the designed first punch and after using the old first punch shows that the wear in the second punch after using the new design is less than the wear in the second punch after using the old one, which means the life time of the second punch after using the new designed first punch will be longer than using it after using the old first punch. The various machining processes which is required for producing the punch are done, beside heat treatments. Final results of this work show that it is possible to improve the dies and use it in the optimal way also it prove the possibility of manufacturing dies locally instead of importing it from outside Sudan.

Activation model for various punching shear reinforcement types in flat slabs and column bases optimized for design

Various types of punching shear reinforcement have been developed during the past decades to increase the punching capacity and ductility of slab-column connections. Due to diverse geometries and thus varying anchorage conditions, the effectiveness of these elements contributing to total punching resistance can differ significantly. Generally, the degree of activation of shear reinforcement can be described by contributions of anchorage and of bond. Yet, most of current punching design provisions follow a simplified, empirical approach. Despite its mechanical background, the punching design according to the next generation of Eurocode 2 still does not consider the effect of better anchorage of, for example, double headed studs compared to simple stirrups.In this paper, an extended activation formula for flat slabs as well as column bases is proposed as refinement for the next generation of Eurocode 2. This unifying approach considers different anchorage categories and thus enables more progressive design results. After discussing the background of possible activation scenarios, the effects of bond and anchorage in cracked concrete and the kinematic deformation behavior of slabs subjected to punching are identified as governing constraints. The major focus is on the transformation process from mechanical considerations to a simplified design formula to ensure practical applicability.

3D Finite element modeling of wear effects in the punching process

Sheet metal forming operations are widely used in the industry because of their ability to produce complex shapes at higher production rates. These operations utilize high stresses to plastically deform workpiece in the desired geometry. For reliable performance, punch design and operating parameters can play significant role. To investigate the tool wear finite element (FE) based numerical methodology was developed in this study. Tool wear is one of the main causes of tool failure and process deviation in the punching operation. Research in the past has covered process parameters and effects of wear on the die plate. However, little research focused on the effects of wear on the punch itself. In this paper a full analysis of the punching process was performed, giving an understating of the effects of tool rounding due to wear on various punching parameters, while focusing on the evolution of wear on the punch in all cases. It was found that wear accelerates as the punch's bluntness is increased. It was also identified that most of the wear is expected on the radius on the punch as opposed to its face, and the full punch diameter will be affected by the abrasive wear between the sheet metal and the punch as opposed to only the striking edge. However, it was also seen that in cases of highly worn-out punches, the wear on the side can be decreased due to the increased deformation of the sheet metal which occurs due to the blunt punch.

AISI D2 punch head damage: Fatigue and wear mechanism

The purpose of this work is to analyze the damage of AISI D2 punch head whose main part is used halting production. The punch head failure could be categorized into three major types namely the swollen, the mated and the cracked punch. Furthermore, this study underlines the punch damage causes using the optical microscope and SEM so as to check and characterize the microstructure of cracks. In this respect, EDS was used to inspect corrosion, then XRD and micro hardness were utilized to identify the chromium carbides. The obtained results showed that back up plate wear and fatigue, low toughness of AISI D2 steel, poor heat treatment as well as non-optimized punch-gun drill clearance are the main causes for tool premature damage.For the sake of analyzing its microstructure, AISI D2 Punch head damage was extensively investigated in this work using various methods such as SEM. Additionally, EDS micrography, Xray diffraction and micro hardness were exploited to make comparison between the damaged tools. To this effect, we were able to distinguish between three types of damaged punches namely the swollen, the mated and the cracked one. Concerning the mechanical fatigue, low wear resistance as well as weak toughness proved to be behind the short tool life. Poor heat treatment and non-optimized punch-gun drill clearance can also lead to tool premature damage. Therefore, a suitable head punch design, an optimized clearance and a new punch guiding solution are indispensable to improve the punching conditions.

A squircle-shaped punch design for efficient contact performance of elastic materials

A new curvature, called the squircle, is proposed as a punch profile to provide superior contact performance for bulk elastic materials. Plane contact problems of a rigid squircle-shaped punch pressed onto an elastic half-plane are treated via an integral equation (IE) approach which is evidently substantiated by a finite element (FE) approach. Compared to the piecewise-defined curvatures, the continuous surface gradient of the squircle profile enables the IE formulations more tractable. In the presence of sliding friction, the consistency condition in the IE approach is implemented through a new iteration procedure. Subsurface stresses are demonstrated via the FE approach. The squircle punch profile is shown to induce a low-magnitude and smoother pressure distribution on an elastic surface, promising to cause less wear under the action of tangential oscillations.

Preview long hair follicular unit excision: An up-and-coming technique.

Follicular unit excision (FUE) is a popular hair transplant technique, but requires shaving the donor area. This is a deterrent for some patients wishing to keep their hair transplant discreet. The new long hair FUE technique avoids shaving the donor area, which appeals to a wider patient population; however, it has a reputation of being technically challenging and slow. We review the tools and techniques developed for long hair FUE and present our experience using the Trivellini Long Hair System and Long Hair punch. With the new advances in tools and techniques for long hair FUE, this method is gaining momentum and has the potential to be the next trend in the hair transplant industry. There are a few different punch designs marketed specifically for long hair FUE (window/slotted, Trivellini Long Hair, and bi-pronged). Although this technique is slower to perform than shaven FUE, graft survival and final outcome are comparable. Innovations in technology have made the long hair FUE technique more accessible to hair transplant surgeons. It is important for hair restoration surgeons to keep knowledgeable about this technique in order to maintain a competitive business.

Optimal design and experiment of multi-row rolling-style planting-hole punch for rapeseed plant seedlings

Optimal design and experiment of multi-row rolling-style planting-hole punch for rapeseed plant seedlings

Follicular Unit Excision Punches and Devices.

Follicular unit excision (FUE) is used to harvest follicular units for hair transplantation using trephine punches. The characteristics of FUE punches can impact the success of this technique; thus, many innovative punch designs and devices have been developed. With many options available, it can be difficult for the hair restoration surgeon to know which punch best suits the needs of their patients. To provide a comprehensive review of punch shapes and devices available. Search of PubMed, reference mining of relevant publications, and hand searching trade publications. We examined FUE punches and devices and consolidated descriptive information for each to create textual and visual guides. No single punch shape or device may suit all cases; thus, it is important to know the best uses and limitations of each. The surgeon should have a comprehensive knowledge base of available punch shapes and devices and understand the advantages and disadvantages of each. It is also beneficial to have an in-depth knowledge of skin properties and follicular unit structure. Ultimately, understanding the dynamics behind punch excision will enhance the FUE technique.

Innovations hair restoration surgeons have made to adapt to the challenges of follicular unit excision.

Early use of follicular unit excision (FUE) as a method of hair transplantation was limited by high rates of hair follicle transection. This hurdle has been overcome by innovative methods, punch shapes, and devices. With the vast array of tools available, it can be difficult for hair transplant surgeons to choose the best option for their practices. To provide an in-depth review and comparison of currently available FUE methods, punch designs, and motorized devices, and discuss how these tools fit the unique skin and hair characteristics of patients. A review of the literature and available information on FUE methods, punches, and devices, as well as the authors' experience in this area, is provided. Innovative FUE methods, punch shapes, and motorized devices have successfully minimized the rate of hair follicle transection. Methods include the use of sharp punches with depth control, and blunt rotating punches. Punch shapes such as flared, hybrid, and edge out have successfully reduced transections by keeping the cutting edge away from the follicles under the skin. The development of motorized devices using features including rotation, roto-oscillation, oscillation, vibration, suction, and hydration has also aided in achieving more successful graft excision. Follicular unit excision is a widely used technique by hair restoration surgeons. Therefore, it is important for physicians to be aware of the array of punches and devices available and understand how these tools can be used to adapt to the unique skin and hair characteristics of individual patients to optimize successful graft harvesting.

Punching shear design of RC flat slabs supported on wall corners

AbstractReinforced concrete buildings are typically braced with shear walls positioned around lift shafts and stairs. Vertical transfer of load from slab to walls leads to a concentration of shear stress in the slab at wall ends and corners, which needs to be considered in punching shear design. This issue is not addressed in EN 1992 (2004) and only partially addressed in fib Model Code 2010 leaving engineers to resort to their own judgment. Consequently, consideration of punching shear at wall corners can be overlooked entirely or not properly addressed through lack of knowledge. The paper addresses this issue by proposing a method for calculating the design shear stress at wall corners for use in conjunction with the Critical Shear Crack Theory. The method is initially validated against test results for slabs supported on elongated columns as well as numerical simulations. Subsequently, the method is extended to the punching design of a slab supported by a wall corner. The proposed analysis of the slab‐wall corner junction is validated against the predictions of nonlinear finite element analysis (NLFEA) employing 3‐D solid elements as well as the joint‐shell punching model (JSPM) previously developed by the authors.

Novel warping-included punching parameters for interior rectangular columns in flat slabs

In this paper, a new term is proposed – through a novel technique – to the ACI equation for checking punching in order to account for the effects of warping. New punching parameters γvw and Jw are hence presented and evaluated/calibrated to include the effects of warping on punching and moment transfer analysis. The method is based on elastic analysis of the entire slab using principles of the theory of elasticity via the boundary element method (BEM) and the shear deformable plates. For verification purposes, the adopted model is first used to compute the classic punching design parameters γv and γf due to unit moment. Curves for the aforementioned punching parameters due to warping, namely, γvw and Jw, are hence generated for rectangular columns to be conveniently and efficiently used for design purposes. Then, through applying the proposed method to some real-world examples, it has been shown that punching checks shall be carried out considering warping effects in order to avoid un-conservative results from a design perspective, i.e., to avoid underestimation of the actual (maximum) punching-shear stress demand.

Design and Analysis of Stage Progressive Die for a Sheet Metal Component

Stamping die industries had been a significant impact on research and development of new technology for bigger and advance. To sustain the stamping die industry under the current global situation, cost and time are most important factors that need to be focus. In this case study, the main problem of design and analysis of progressive die is cost spent for die fabrication is high, the number of station or stages is high that will affect the production time and lifespan of tool is short. This paper focused at the stages or station that will be redesign to reduce the cost for the die, station optimization to reduce time taken for stamping process and simulate the design of tools to calculate the life cycle of punch. The study is conducted through AutoCAD and Solidwork to redesign the die and strip layout optimization. Subsequently, the ABAQUS/CAE and e-fatigue are used to completed the analysis and life cycle results for punch with various design of punch edge. Theoretical analysis indicates that design of punch plays a vital role in life cycle analysis.

Design and Analysis of Punch and Die of a Micro Blanking Tool

Stamping dies one of the essential industries in engineering. The sheet metal blanking procedure is a shearing operations. In the blanking procedure the sheet metal is detached from the bulky portion of stock through the application of shearing force on the sheet. Nowadays, the increase of gadgets and smart phone is because of the 4th industrial revolution. This situation leads the demand for micro parts that will include in electronic devices. The main problem occurred in sheet metal stamping is damage to the punch after running thousands of stamping process. This paper focuses on designing a micro blanking dieset that meet the industrial demand. The study is conducted using solidworks to design the micro blanking dieset and perform analysis using FEM. The result of FEA will be calculated using e-fatigue to get the lifecycle for the punch.

Optimal Design and Experiment of Multi-row Rolling-style Planting-hole Punch for Rapeseed Plant Seedlings

In order to realise high-efficiency hole-forming and pursue optimal forming hole parameters which satisfied agricultural requirements for awl-shaped punch transplanter, a optimally designed indigenously-developed pure rolling planting hole-forming machine's hole forming mechanism parts is proposed. The CAD software graphing method was used to study the effect of forming planting hole by structural parameters, with the numerical simulation method by MATLAB 7.0 software and CATIA software were used to verify the rationality of the hole-forming key parameters optimisation design. Subsequently, prototype trial-production was carried out, followed by field testing. The results showed that forming planting hole opening lengthwise shrank from originally 88.8 mm to 72.6 mm, lateral width was 41.2 mm, the effective depth reduced from 58.9 mm to 48.5 mm, qualified radio of forming planting hole reached to 95.1%, which 1.93% higher than the original prototype, which was significant for the provision of technical support for the design of new transplanter.