Process For Metal Parts Research Articles

Oblique laser shock peening effect of the FGH95 superalloy with a PCA and comprehensive index

As a metal surface strengthening technology, oblique laser shock peening uses the force effect of pulsed laser beams to significantly improve the mechanical properties of materials and prolong service life. However, the processing of metal parts still requires a high cost for testing the quality of the finished product. At present, there is no systematic and complete measurement method or evaluation system for the finished products of oblique laser shock peening technology. In this paper, a principal component analysis method and a comprehensive index method are organically combined to construct a method for evaluating the effect of oblique laser shock peening of FGH95 superalloy turbine disks. We measured 10 real data of FGH95 superalloy specimens after oblique laser shock peening by using the orthogonal test method and verified the data. Based on the evaluation results, we put forward a series of suggestions to improve the quality of oblique laser shock peening of FGH95 high-temperature turbine disks, providing a certain reference and guidance for processing FGH95 superalloy turbine disks.

Additive manufacturing of ZrB2–ZrSi2 ultra-high temperature ceramic composites using an electron beam melting process

Owing to their high melting points and ability to resist extreme thermal stresses, ultra-high temperature ceramics (UHTCs) are important materials for critical applications such as hypersonic flights, space re-entry vehicles, and rocket engines. Traditional manufacturing processes restrict the freedom to manufacture UHTCs with complex geometries due to the limitations of die and mold designs. Electron beam melting (EBM) is an established powder-bed layer-by-layer additive manufacturing (AM) process for metal parts. In this research, an effort was made to evaluate the feasibility of EBM for the AM fabrication of UHTC-based materials, and to investigate the microstructures of the fabricated materials under different processing conditions. A mathematical model was developed to simulate and optimize the processing parameters for the fabrication of ZrB2-30 vol% ZrSi2 UHTC using EBM. The simulation results were compared with experimental observations. For EBM fabrication of ZrB2-30 vol% ZrSi2 composites, the optimal processing parameters are beam power of 500 W with scanning speeds of 500, 750, and 1000 mm/s, and beam power of 1000 W with scanning speed of 1000 mm/s. This study demonstrates the potential for additive manufacturing of UHTCs with complex geometries by the EBM technique.

Analysis of Density, Roughness, and Accuracy of the Atomic Diffusion Additive Manufacturing (ADAM) Process for Metal Parts.

Atomic Diffusion Additive Manufacturing (ADAM) is a recent layer-wise process patented by Markforged for metals based on material extrusion. ADAM can be classified as an indirect additive manufacturing process in which a filament of metal powder encased in a plastic binder is used. After the fabrication of a green part, the plastic binder is removed by the post-treatments of washing and sintering (frittage). The aim of this work is to provide a preliminary characterisation of the ADAM process using Markforged Metal X, the unique system currently available on the market. Particularly, the density of printed 17-4 PH material is investigated, varying the layer thickness and the sample size. The dimensional accuracy of the ADAM process is evaluated using the ISO IT grades of a reference artefact. Due to the deposition strategy, the final density of the material results in being strongly dependent on the layer thickness and the size of the sample. The density of the material is low if compared to the material processed by powder bed AM processes. The superficial roughness is strongly dependent upon the layer thickness, but higher than that of other metal additive manufacturing processes because of the use of raw material in the filament form. The accuracy of the process achieves the IT13 grade that is comparable to that of traditional processes for the production of semi-finished metal parts.

Multi Pass Optimization of Cutting Conditions by Using the Genetic Algorithms

Production of high-quality products with lower cost and shorter time is an important challenge to face of increasing global competition. Determination of optimal cutting parameters is one of the most important elements in any planning process of metal parts. In this study we present a multi-optimization technique based on genetic algorithms and dynamic programming, to search for optimal cuttings parameters such as cutting depth, feed rate and cutting speed of multi-pass turning processes. Two conflicting objectives, the production cost and operation time are simultaneously optimize under a set of practical of machining constraints. The proposed model deals with multi-pass turning processes in which the cutting operations are divided into multi-pass rough machining and finish machining. Results obtained from Genetic algorithms method are used to define the optimum number of machining passes by dynamic programming; such technique helps us in the decision making process. An example is presented to develop the procedure of this technique.

W722 Lathe of Fault Detection and Diagnosis

Shanghai YinChaoChang a W722 lathe processing of metal parts, workpiece surface machining quality external circular no obvious problem, and the machine's vibration is small. But in the processing of main parts - rubber managers stamped drum, workpiece surface appear periodically outside round the chatter marks, general examination of hard to find the failure causes of machine tools. We adopt mechanical fault diagnosis technology to find fault location and fault machine of the machine, first nature of transmission chain of analysis and calculation, obtains each train parts, use characteristic frequency JGZY - 1C type mechanical failure diagnosis in the daily use of the lathe spindle 560 turn/points and 735 turn/cent two kinds of rotating speed sensor separately carried on the test, pick up the spindle box, respectively go knife box and slip board box to collect the vibration signal of signal filtered (stationary fault) and demodulation spectral analysis, got a lot of lathe vibration signal spectrum diagram. And the calculated value and vibration signal spectrum diagram compares analysis, find out the fault location and machine determine the fault properties. Replace the corresponding gear and bearing, fault phenomena disappear.