Clamping Tool Research Articles

Design of Mold Flipper in an Effort to Improve The Efficiency of Mold Maintenance Process

Molding is a production process by forming raw materials using a rigid frame or model used in the manufacturing industry to mold materials called a mold. Injection molding is a technique in the manufacturing industry for molding thermoplastic materials. Thermoplasctic materials commonly molded with Injection Molding techniques are Polystyrene, Acrylonitrile Butadiene Styrene (ABS), PMMA (Polymethyl Methacrylatic) and others. The purpose of this research is to design and build a flipper molding tool for an easier and more efficient mold maintenance process. This research uses descriptive methods. Data is taken through direct observation and through reference books both from companies and websites and journals related to the report material. The data obtained was analyzed using descriptive analysis. it is found that the material used in the work is Carbon Steel (S45C). The process of making Flipper Clamps Mold has several stages, namely the Design Making Process, Material Selection Process, Cutting Process, Milling Process, Grinding Process, Drilling Process, Welding Process, and Assembly Process. With this Flipper Clamping tool, it is hoped that it can make it easier for operators to maintain and repair molds, because the previous mechanism requires two operators to flip molds that weigh more than 200 kg, now they only need to flip by turning the lever of this tool.

Research on a kind of positioning anti-eccentric fixture for measuring thin wall gear with special big inner hole

This paper mainly studies and designs the clamping tool which is installed in the measuring of big gears with big inner holes and thin walls. This paper analyzes the disadvantages of conventional clamping of large gears with special inner holes, and presents an example of the research and development of the Assembly of the mounting and positioning device of the special large inner hole gear based on the gear measuring instrument. At present, in the field of gear measurement, the measurement of large gears is always a technical problem. The technical ability of gear testing in our country is restricted by various factors. Most gear high-precision instruments and their accessories still depend on imports, which cannot be a good solution to the measurement of special gear installation and positioning problems from the economy and timeliness. Especially, large gears with large bores and thin walls face the problem of determining the position of the measuring device and the measured gears, that is, the measuring datum is difficult to determine [1]. This paper proposes how to use the existing gear measuring instrument to develop and use small accessories, so as to help the production enterprises and measuring institutions solve the problem of reference positioning in the actual production measurement process and determine the accuracy of special gear samples.

Endo-Surgical Force Feedback System Design for Virtual Reality Applications in Medical Planning

Virtual reality (VR) applications for surgical planning and mentoring are currently becoming more widespread. Within these fields of applications, haptic systems are crucial to help the understanding of the feedback provided by the tissue during the interaction with the surgical tool. The accuracy of the VR scenario is related to many aspects, among them the ability of the haptic device to provide the force feedback and thus the adoption of proper characterization and modeling of the soft tissue behavior during deformation. This paper presents the current development concerning a VR environment to be equipped with a force feedback haptic device to simulate and experience clamping in colorectal surgery. The reaction at the clamp handle is provided starting from a FEA of the contact between the surgical tool and the tissue, coupled with the kinematic analysis of the mechanism. Connecting the virtual scenario to a microcontroller board, the reaction force is applied to the the haptic device, shaped as a clamping tool handle, so that the user may experience the tissue impedence during clamping. By simulations made through Simscape, a concept is evaluated according to some simulation paths that involve common scenarios of the virtual reality experience (such as collision, partial or total clamping operation). The novelty of the research regards the system design oriented to increase the accuracy of the soft tissue material behaviour through a preliminary off-line dedicated FEA investigation. Through Simulink simulations, the system design is verified so that the VR system set-up may be carried out. The results highlighted: (a) a good correspondence among the theoretical study of the reference kinematism that the haptic device must reproduce; (b) the implementation of a bilinear material model, derived off-line from FEA, is suitable to capture hyperelastic and geometric non-linearities of the soft tissue; (c) the feasibility of the open loop haptic control in accordance to the explored kinematism. The final goal of the research is to propose a system design approach able to tune the VR experince for teaching and mentoring through a in-house set-up easy to be tailored.

Computer-based design and development of a fully automated assembly of aircraft doors made of thermoplastic composite material

For production of aircraft doors using innovative lightweight materials, a fully automated assembly process was developed. Therefor a door structure of an overwing-exit-door is to be joined from thermoplastic composite material components. The innovative material enable the use of new joining concepts. The assembly process was virtually simulated in order to forecast production time, process sequence, provision of operating resources and investment costs. Relevant manufacturing equipment was designed and accessibilities of the clamping and joining tools as well as collision areas were determined and optimized. To quality management, process control concept was developed with which geometric deviations of the components can be automatically compensated.

Конечно-элементное моделирование нарезания резьбы мет-чиком с целью прогнозирования ее приведенного среднего диаметра

The development of high-precision tapping operations involves predicting such accuracy. Very often, this requires expensive experiments. Numerical calculation methods, which have recently received wide application, make it possible to replace these experiments with computer simulations. However, this modeling is now mainly associated with determining the stresses and strength of tools, for which only the cutting tool itself and a fragment of the workpiece are modeled. This approach turns out to be unacceptable for predicting the machining accuracy, since the errors in the thread size and shape significantly depend on the actual movement of the tool, which, in turn, depends on the conditions of its fixing in the machine spindle. In this regard, the task concerns with not only the specified above technological system elements, but also an clamping tool. In addition, after calculating the thread surface of the part, it is necessary to calculate accuracy characteristics of this thread. It is these issues that are considered in this article: the results of finite element modeling of threading with a tap fixed in a tapping chuck of a floatingoscillating type are shown. The obtained graphs of axial force and torque correspond to the expected curves, both in its shape and in numerical values. The obtained thread point cloud made it possible to further calculate its virtual pith thread diameter, which turned out to be comparable with the corresponding tap diameter and the same thread size from the state standard. Thus, the above calculations show their realism and the possibility of application in the practice of designing thread-cutting operations.

Hexbox Canopy: A Segmented Timber Plate Shell with Hardwood Wedge Joints

The HexBox Canopy demonstrates a new "plug & play" system for the rapid on-site assembly and disassembly without formwork of a segmented timber shell, consisting of relatively inexpensive, prefabricated hexagon-shaped boxes made from plywood plates. With 1531 timber segments making up 201 boxes, the HexBox shell is made exclusively of plywood components without the addition of any kind of metal fasteners for the main load-bearing structure. The major novelty is the wood-only connections between the box components, which are produced from cut-off waste material resulting from the cutting of the main plates of the structure. These connectors are inspired by traditional wedge joints, which were a smart and common method in handcrafted carpentry and cabinetmaking. Rather than attempting ultra-precisely fabricated elements, the wedges allow assembling box-like segments even when there are small imprecisions. Additionally, these joints allow for pulling and forcing the boxes together, closing gaps between the elements which may occur during assembly. Another key aspect is the introduction of an innovative technique that allows for the simple and safe 1K PUR adhesive joining of thousands of miter joints with individual dihedral angles. Conventional clamping tools are indeed designed for orthogonal miter joints and could therefore not be used here.

Laser welded lip seal for UHV class fusion vessels–A methodical study

Lip seals are considered, the most promising options for the vacuum boundary joints in large size vacuum vessels (like rectangular neutral beam vessel with an opening size of ∼30 m) of fusion machines. Lip seals are designed with the corner welding of 2 mm thickness sheets of SS304L with the welding penetration requirement of 3 mm. With the first phase of development, laser welding parameter optimization and the sensitivity analysis was carried out to understand the effect of manufacturing tolerances (like air gap between the plates, laser beam misalignment and plate misalignment) on the weld quality. To ascertain the defined tolerances, a specialized clamping tool was configured, designed, manufactured and tested by integrating that with the assembly of laser welding head and robotic arm. For the prototype welding demonstration, the Lip seal welding of a rectangular configuration and an elliptical configuration of size 3 m × 1.5 m (∼1/3rd size of Diagnostic Neutral Beam (DNB) vessel lip seal); and 1 m length with 1.2 m diameter (exact size of DNB high voltage bushing lip seal) are considered. Welding qualification was done with the Non-Destructive and Destructive examinations. Further, the camera based feedback system for the seam tracking was incorporated to the system, which enables the remote detection and correction of the weld path. This development also extended to enable the repair of welding operation.

The application of metaheuristic algorithms in multi-objective optimization of engineering problems

Comparative testing of three modified metaheuristic algorithms - the cyclic algorithm of the bat family (Loop BFA), the hybrid cuckoo search and the firefly algorithm (H-CS-FA) and the modified krill herd algorithm (MKH)was performed in the paper. The authors tested these algorithms in relation to original ones and the effectiveness of the modifications was confirmed for each individual algorithm. Here, the effectiveness of all three algorithms was verified on two engineering problems in the field of metal cutting - optimization of the body of the turning knife and optimization of the eccentric of the clamping tool. In both cases, multi-objective optimization with two objective functions was performed. By comparing the obtained optimization results as well as the speed of convergence, appropriate conclusions about the efficiency of the algorithms and recommendations for their application were made.

FRAMEWORK FOR COUPLED DIGITAL TWINS IN DIGITAL MACHINING

This paper presents a further elaboration of the use of the digital twin concept in digital machining. The main goal of the research is an attempt to combine digital representations of different objects involved in the machining process in a holistic manner. Digital twins of the in-process workpiece, cutting tool, clamping, and machine tool along with the process twin are connected in a framework in which all these elements can influence each other. The framework shows different levels of integration of different digital twins and practical recommendation on the implementation. Besides, the framework supports a simulation layer that provides data for the intensity of the interaction. Such interactions can result in, for instance, cascading calculations of cutter workpiece engagement, cutting forces, tool wear, tool deflection, chatter, and so on. Eventually, a design for a software mockup was elaborated to present the developed framework. The entire workflow to simulate part machining in such a digital representation can be used as an ultimate tool for CAM simulation and NC verification within the Zero Defect Manufacturing paradigm.

Simulation of vise production process using Flexsim Software

In the industrial the process of clamping on an object is an important process carried out to facilitate the work when the process of cutting, sculpting, welding and etc. A vise is a clamping tool to clamp a workpiece milled. Using the vise, the workpiece clamped tightly to facilitate the work and the results of a process is maximum. The components contained in a vise have their own functions. This research is about simulating vise production process. The purpose of this study is to model the vise production process using Flexsim software and compare the simulation results data with the vise production target data to find out whether the simulation describes the actual condition of the vise production process. The results obtained in the manufacture of vise production lines using Flexsim software produce an output of 22 units for 1 shift / day or 7 working hours. The vise production line simulation model produces 25 vise production target data, 22 simulation results data and 12% deviation occurs, so the simulation describes the actual condition of the vise production process.

Aluminum-steel dissimilar robotic arc spot welding with auxiliary insert

The authors have developed the novel process for joining dissimilar metals, which uses gas metal arc welding and an auxiliary insert or element. In this process, the element or the flanged steel rivet that has a hollow center is inserted into the pre-hole prepared in an aluminum alloy sheet for the first step. Second, the hollow center is filled with steel weld metal by arc spot welding to join the element and a steel sheet at the fixing point, and thereby the element and the steel sheet are welded strongly enough to fasten the aluminum alloy sheet between the flange of the element and the steel sheet. This new joining process is called element arc spot welding (EASW). EASW has such advantages that it can easily be applied to a dissimilar metal joint with ultra-high-strength steel; it does not need to pinch the joining metals from the upper and lower sides of the joint with a clamping tool; and the resultant shear and peel strengths of the joint are equal to or greater than those by other dissimilar metal joining processes. The prototype robot system for automating the EASW process has also been developed. In this robot system, the position of the pre-hole in the aluminum alloy sheet is detected by an image sensor, and then the tool at the tip of the robot arm moves to the detected pre-hole position to insert the element correctly into the hole; in the next step, low-spatter arc welding is carried out to fasten the aluminum alloy sheet between the element and the steel sheet.

The development of technology of Be/CuCrZr joining using induction brazing

The article describes the method of vacuum induction brazing of beryllium tiles covering the surface of the first wall of ITER. To prevent the formation of brittle intermetallic and preservation of the mechanical properties of the CuCrZr alloy, it leads to the need to minimize the brazing temperature and time of the brazing cycle. Designed according to the results of calculations and optimized in experiments, the inductor allows heating locally the beryllium tile/CuCrZr alloy region with required heating rate. With the aim to minimize brazing temperature this paper presents the result of selection of the optimal eutectic of STEMET 1101 brazing alloy thereby reducing the temperature of the brazing to 680 °C. To fix each of the beryllium tiles during the brazing cycle, a unique clamping tool was developed and applied. As a confirmation of the reliability of this method, along with the results of ultrasonic testing of brazed joints, the paper presents the successful results of high heat flux testing of the mock-ups throughout the full life-time of the ITER first wall panels (15,000 heat cycles).

On the forming mechanisms of frictionally engaged linear processes under consideration of incremental swivel bending (ISB)

Kinematic bending processes offer chances for flexible production by adapting their process parameters to variant part geometries or materials. As such a technique, Incremental Swivel Bending (ISB) is characterized as frictionally engaged in-plane bending process for strips or open profiles. At the present state of technology, the kinematic process parameters for ISB can only be derived from FE simulations. Due to frictional engagement, the strain distribution of an incrementally bent arc depends on the applied clamping force. In this study, an analytic model for frictionally engaged forming is derived for uniaxial tensile stretching as first approach towards in-plane bending. The central hypothesis bases on equilibria of i) force caused by the materials’ strain hardening in the tensile stretched cross section, ii) force at the location of yield criterion propagated over the initial cross section and iii) friction forces at the clamping tools’ surfaces. Material is assumed to lose contact to the clamping tools as soon as yield criterion is locally reached. Strain is calculated by the ratio of tool travel to material pull-out of the fixation. Numerical simulations on solid finite elements are compared to this approach by means of resulting forces at the forming tools indicating sufficient prediction of material being drawn out of the fixation in dependency of process parameters, mechanical material properties and cross section.

Modelling the dynamics of a large damped boring bar in a lathe

Boring bars with tuned mass dampers have a passive damper tuned with respect to the frequency of the first bending mode of the tool. When the tool is clamped into the machine tool there is a stiffness loss that lowers the natural frequency of the bar compared to ideal clamping conditions. For large tools the difference can be more than 35%, depending on clamping structure, tool size and overhang. In this paper we investigate a simple two-degree-of-freedom model for the tool-machine interaction consisting of a bending mode coupled with a rotational stiff mode. The model gives good insight into the system behavior and fits well with measurements.

Development of hydraulic clamping tools for the machining of complex shape mechanical components

All markets revolve around quality and, regarding a big portion of the industry, factors such as productivity and profitability are crucial to the growth and sustainability of companies'. Processes need to be well thought to ensure process repeatability and stability, particularly in machining through chipping. In order to allow this, it is necessary to perfectly define the process, machining sequence and to create physical and organizational tools that are less prone to error. Machine setup can encompass several machining errors which, sometimes, are difficult to detect using traditional control tools such as dimensional inspection. There are some cases in which the final product is faulty and it is difficult to trace the real root-causes. To avoid those errors, it is important to create easily tuneable tools which require minimal instruction to use and to create mechanisms which allow for flaw detection during production and not only during final inspection. This work will bring a chance to improve the machining processes of complex shaped mechanical components that present strong failure risks during the machine setup, through the development of a clamping tool, giving way to easier setup operations.

Laser transmission welding of automotive headlamps without a clamping tool

A car’s front headlamps represent an important design element in the automotive industry. In order to protect them from external influences, the complex lighting technology is inserted into a stable plastic housing, which is then sealed with a transparent plastic lens. The combination of the transparent lens and the black housing is eminently suitable for laser transmission welding (LTW); the numerous advantages of this technique can be exploited here, especially with regard to design. Due to tolerance compensation, it is state of the art to join automotive headlamps by adhesive bonding. In the investigations of the KTP, a prototype with a special geometry of the joining area was evolved and analyzed. Because of segmental snap-fits, which apply the necessary joining pressure, gaps can be eliminated during the welding process as a result of the setting of the lens. With this special geometry of the joining area, a clamping tool is not necessary anymore. The two parts are welded quasi-simultaneously by a laser scan system with a fast z-axis. Also, the typical material combinations (PBT+ASA GF20, PC) of automotive headlamps were analyzed by using rectangular overlap specimens and American Welding Society specimens.

Role of the Excitability Brake Potassium Current IKD in Cold Allodynia Induced by Chronic Peripheral Nerve Injury.

Cold allodynia is a common symptom of neuropathic and inflammatory pain following peripheral nerve injury. The mechanisms underlying this disabling sensory alteration are not entirely understood. In primary somatosensory neurons, cold sensitivity is mainly determined by a functional counterbalance between cold-activated TRPM8 channels and Shaker-like Kv1.1-1.2 channels underlying the excitability brake current IKD Here we studied the role of IKD in damage-triggered painful hypersensitivity to innocuous cold. We found that cold allodynia induced by chronic constriction injury (CCI) of the sciatic nerve in mice, was related to both an increase in the proportion of cold-sensitive neurons (CSNs) in DRGs contributing to the sciatic nerve, and a decrease in their cold temperature threshold. IKD density was reduced in high-threshold CSNs from CCI mice compared with sham animals, with no differences in cold-induced TRPM8-dependent current density. The electrophysiological properties and neurochemical profile of CSNs revealed an increase of nociceptive-like phenotype among neurons from CCI animals compared with sham mice. These results were validated using a mathematical model of CSNs, including IKD and TRPM8, showing that a reduction in IKD current density shifts the thermal threshold to higher temperatures and that the reduction of this current induces cold sensitivity in former cold-insensitive neurons expressing low levels of TRPM8-like current. Together, our results suggest that cold allodynia is largely due to a functional downregulation of IKD in both high-threshold CSNs and in a subpopulation of polymodal nociceptors expressing TRPM8, providing a general molecular and neural mechanism for this sensory alteration.SIGNIFICANCE STATEMENT This paper unveils the critical role of the brake potassium current IKD in damage-triggered cold allodynia. Using a well-known form of nerve injury and combining behavioral analysis, calcium imaging, patch clamping, and pharmacological tools, validated by mathematical modeling, we determined that the functional expression of IKD is reduced in sensory neurons in response to peripheral nerve damage. This downregulation not only enhances cold sensitivity of high-threshold cold thermoreceptors signaling cold discomfort, but it also transforms a subpopulation of polymodal nociceptors signaling pain into neurons activated by mild temperature drops. Our results suggest that cold allodynia is linked to a reduction of IKD in both high-threshold cold thermoreceptors and nociceptors expressing TRPM8, providing a general model for this form of cold-induced pain.

An analysis of grasp quality measures for the application of sheet metal parts grasping

Acquiring a qualitative force-closure grasp requires the determination of feasible contact points on the object based on a defined criterion. The determination must be fast in order to implement feasible synthesis algorithms. Moreover, grasping of sheet metal parts has further requirements derived from its geometry and clamping tools. This paper presents a grasp quality analysis for the application of sheet metal parts. Moreover, a novel grasp quality measure approach is proposed based on standard deviation computation of the contact's coordinates. The proposed measure is frame invariant, simple to implement, and has low computational complexity. A comparative analysis over other measures is presented. Further, a stress analysis was performed to show that the proposed criterion yields low stress on the sheet metal part compared to other criteria. Simulations show advantage to grasp synthesis with the proposed quality measure.

Reliability improvement of induction heat treatment with design of experiments

Nowadays, some industrial systems are developing an alternative process of martensitic through hardening by induction heating combined with a quenching unit on the rings with a thin section in order to replace the current process (furnace heating and oil quenching). The main motivation for this change is to reduce geometrical distortions caused by the currently used hardening process, thus in order to optimize the grinding parameters. In the earlier phase of this project, the heating parameters were definitely fixed in order to obtain a microstructure and hardness value inside the current product specifications at that time, the produced rings showed lower geometrical distortions compared to the standard process. However a spring back effect appeared during the grinding and honing operations and also unstable growth variation was noticed. The work presented in this report aims at proposing new design of quenching clamping tools with new methods for the setup optimization. The goal of optimizing the setup is to improve the control of characteristics (microstructure, hardness, retained austenite, growth, ovality, conicity, residual stresses) by combining different parameters. The problem-solving method based on design of experiments generates lessons learned that provide valuable conclusions (the tools analysis and the quenching way analysis) and knowledgeable recommendations (increase clamping pressure and decrease quenching intensity). The demonstration-application principle aims to decrease the stresses in order to avoid the spring back effect after grinding and honing.

Prediction of Wall Thickness Distribution in Simple Thermoforming Moulds

Thermoforming is widely used in manufacturing industries to produce large and labour-intensive products. Compared to other manufacturing techniques, thermoforming is a very efficient process that is suitable for high-efficiency mass production. In this paper, experimental thermoforming operations were carried out using a lab-scale, sheet-fed thermoformer. Carbon fibre reinforced PP and unreinforced PS thermoplastic sheets were used in the experimental thermoforming operations. The processing parameters were determined for each thermoformed material. Moreover, a simulation of the thermoforming process was performed using LS-DynaTM software. The thickness distributions obtained from the experiments were compared with the simulation results. The results show that the parameter that affects the wall thickness distribution the most is the geometry of clamping ring. To produce thermoformed products that have a more uniform thickness distribution, the clamping tool geometry must be selected according to the geometry of the product being thermoformed.