Acceptable Surface Quality Research Articles

Chatter Avoidance by Spindle Speed and Orientation Planning in Five-Axis Ball-End Milling of Thin-Walled Blades

Abstract Selecting suitable cutting conditions is crucial in maintaining chatter stability and achieving acceptable surface quality. However, the selection of a constant set of cutting parameters is not feasible due to the time-varying dynamics of highly flexible thin-walled blades. This paper presents an optimal selection of tool orientation and spindle speed along the tool path as the metal is removed during the ball-end milling of blades. The effects of tool orientation and speed on the mechanics and dynamics of the ball-end milling process are formulated. Test case simulations are used to demonstrate the impact of tool orientation and speed on chatter stability and forced vibrations. The proposed algorithm identifies the optimal spindle speed and tool orientation by continuously updating the workpiece dynamics as a function of time and tool position to achieve improved stability and surface quality. Stability simulations are conducted to assess the optimization approach's performance, and the results are compared with experiments by machining a series of thin-walled twisted fan blades.

Effect of magnifying loupes on tooth preparation of complete coverage crown: A quantitative assessment using a digital approach.

The purpose of this study was to evaluate the use of magnifying loupes (×2.5) on the quality of tooth preparation for complete coverage crowns; performed by predoctoral students using an objective and quantitative digital method. Forty-two predoctoral students were randomly assigned into 2 groups to perform tooth preparation for a complete coverage crown on a mandibular first molar in a manikin, with and without the use of magnifying loupes. All preparations were digitally evaluated by PrepCheck 3.0 (Dentsply Sirona). Parameters including tooth reduction, total occlusal convergence (TOC), undercut, margin quality and surface quality were assessed. Continuous data were analysed using Paired t-tests or Wilcoxon Signed Ranks tests. Ordinal data were analysed by McNemer's tests. To further detect the majority pattern ( > 50%) in each group (with and without loupes), one-sample t-test or one-sample Wilcoxon Signed Rank test was performed. The level of significance was set at p=.001 after Bonferroni adjustments for multiple testing. No significant differences in the measured outcomes were found between the groups with or without the use of magnifying loupes (p > .002). The majority (>50%) of both groups had no undercuts (99.3% and 99.4% both p < .001) and the preparation type was within tolerance (81.6% and 85.3%, both p < .001) with acceptable margin (86.4% and 86.3%, both p < .001) and acceptable surface quality (99.0% and 99.1%, both p < .001). However, the majority of both groups underprepared occlusally (96.0% and 95.4%, both p < .001) and axially (65.3% and 67%, both p < .001). Only 30.0%-42.1% of the participants achieved the TOC within 0-20°. Within the limitations of this study, the use of magnification loupes does not appear to significantly improve the quality of tooth preparation for complete coverage crown. The TOC was also found to be overprepared and occlusally underprepared.

Tool condition monitoring based on the fractal analysis of current and cutting force signals during CFRP trimming

Carbon fiber–reinforced plastic (CFRP) is becoming more popular in the aerospace industry due to its high strength-to-weight ratio and low weight. Machining CFRP to achieve the required surface quality, on the other hand, remains a challenge. High temperature in the cutting zone area affects the tool life and surface quality of the machined part. A thermally affected matrix makes an inaccurate interpretation of the surface quality. Then, the roughness parameters cannot be an appropriate indicator for surface evaluation of the CFRP. In the aerospace industry, however, ensuring the acceptable surface quality of a part is essential. Minimizing and controlling tool wear are necessary to avoid degrading the finished surface and losing the dimensional accuracy of the final part. Early detection of tool wear and appropriate surface quality in finishing operations can be achieved using online tool condition monitoring. Cutting forces and electric current signals related to the spindle during machining are very responsive to cutting conditions and can accurately represent tool condition changes. Fractal analysis, as a new approach in the online tool condition monitoring, can assess the tool condition during machining. This research investigates the fractal analysis of the spindle electric current signal and the total cutting force signal while trimming CFRP using a CVD end mill through three different tool life conditions, e.g. new tool, moderately worn tool, and severely worn tool. The empirical fractal index is also introduced to assess the tool condition and ensure the acceptable surface qualities in the finishing operations. The effectiveness of fractal analysis as a decision-making method in the tool condition monitoring was successfully proven in this study.

Fracture mechanism of AISI 1025 rod shearing in automatic multi-stage cold forging and critical shearing speed

Experimental and numerical studies on shearing processes that focused on automatic multi-stage cold forging (AMSCF) are conducted to reveal the mechanisms of the fracture phenomena that occur in the cold rod shearing process in AMSCF. First, AISI 1025 (treated for AMSCF, specifically called SWCH25F) coil-rod of radius 17.5 mm was straightened and cut by an AMSCF machine at operating speeds of 20–90 rpm to elucidate the effects of speed on the surface quality of the sheared billet. Second, a universal testing machine was used in combination with a special shearing apparatus for experimental cold rod shearing to measure the shearing load-time (or stroke) curve and examine fracture mechanisms at sufficiently low speeds. Fractographical observations showed that speed clearly affects the cold shearing of a straightened coil-rod. The surfaces of billets sheared at low speeds showed clear evidence of ductile fracture, whereas those sheared at normal speeds did not. The experimental results were used in thermoviscoplastic finite element (FE) analysis together with the flow behaviors of the material in the cold-forging temperature range to explain the brittle fracture of the ductile material during cold coil-rod shearing in AMSCF. The concept of a critical coil-rod shearing speed for acceptable surface quality is presented.

A force-insensitive impedance compensation method for giant magnetostriction ultrasonic cutting system of Nomex honeycomb composites

The high-quality machining of Nomex honeycomb composites is challenging due to its intrinsic brittleness. The rotary ultrasonic cutting performed on Giant magnetostriction ultrasonic system (GMUS) has been recognized as a superior method for the high-quality machining of Nomex honeycomb, owing to its capability to generate large-amplitude ultrasonic tool vibration. The stability of ultrasonic tool vibration plays a critical role in guaranteeing the acceptable surface quality of Nomex workpiece. However, the unique inhomogeneity of honeycomb induces time-varying cutting force, which can violate the stability of ultrasonic tool vibration using conventional compensation methods. In this study, a force-insensitive impedance compensation (FIC) method was proposed to improve the vibration stability of GMUS for honeycomb machining. A theoretical model which describes the vibration characteristics of GMUS was developed to calculate the optimum compensation impedance to adapt the time-varying cutting force. Experimental tests were conducted on Nomex honeycomb composite to evaluate the performance of proposed FIC method by inspecting the surface quality of machined workpiece. The experimental results demonstrated that the compensated ultrasonic cutting system showed an enhanced vibration stability during the machining of Nomex honeycomb composite. Compared with conventional compensation method, the honeycomb processed by GMUS with the FIC method showed much fewer cell collapses.

Numerical Analysis Nucleation and Growth Conditions of Single-Crystallinity Control during Laser Surface Modification of Ni-Based Single-Crystal Superalloy Part I: Thermal and Chemical Determinants

Nucleation and growth conditions of single-crystallinity control are convincingly elaborated by multi-scale mathematical modeling of heat and mass transport to totally abate undesirable weld defects, e.g. disoriented crystal and hot cracking inside molten pool of nonequilibrium crystallization, in order to illustrate the usefulness of predictive capability through theory and experiment procedures. Crystal growth is complicated by crystallinity-dependent thermal and chemical driving forces in front of dendrite tip during viable laser surface modification of Ni-based single-crystal superalloy. These two thermal metallurgical determinants play crucial role in crack-insusceptible columnar crystal growth, which is favorably oriented throughout weld depth. There is particular challenge in complete elimination of disoriented crystal, i.e. stray grain formation, for acceptable surface quality. Conservative (001)/[100] crystalline orientation is desired to diminish Al concentration and supersaturation, and morphologically satisfy epitaxial growth kinetics to successfully lessen central cracking with satisfactory variability of laser power and welding speed. Comparatively, (001)/[110] crystalline orientation is disadvantageous to asymmetrically augment Al concentration and supersaturation and aggressively increase interface instability, microstructure heterogeneity and hot cracking vulnerability along disoriented crystal boundaries. Disoriented crystal is increasingly withstood if the Al concentration and supersaturation in front of dendrite tip are low enough and crack-unsusceptible part is relatively large enough in case of attractive (001)/[100] crystalline orientation with optimal range of heat input to ameliorate microstructure homogeneity. Crystalline orientation region varies with diverse welding configurations, and epitaxy across solid/liquid interface is also sensitive to heat input of laser processing, which necessitate high efficient welding conditions optimization. Considerable effort is made to distinguish diffusion-driven crystal growth between a series of combinations of multiple welding conditions, such as critical welding configuration and heat input. Metallographically, the morphologies of crystal growth and hot cracking are experimentally observed to consistently support kinetics calculation result and well explain correlation between solidification behavior and crystal growth.

Controlled depth micro-abrasive waterjet milling of aluminum oxide to fabricate micro-molds containing intersecting free-standing structures

Traditionally, photolithography and soft-lithography methods have been used to fabricate micro-molds for casting polymeric microfluidic chips. Because of the time and cost involved, there has been motivation to fabricate microfluidic micro-molds using other techniques. A previous study utilized stainless steel masks cut using abrasive waterjet micro-machining (AWJM) together with abrasive slurry jet micro-machining (ASJM) to mill micro-molds in Al6061 which would allow casting of polymeric microfluidic chips with intersecting micro-channels. However, the deflected slurry jet from the mask edge struck the substrate at oblique incidence and led to two undesirable effects: a trench along the edges of the raised structures representing the channels, and an undercut of the mask. Both effects were linked to the propensity for ductile materials to erode more rapidly at oblique incidence than perpendicular. The present paper demonstrates that these effects can be greatly reduced by using AWJM to create molds in more brittle materials which erode in the opposite fashion, i.e., more rapidly at perpendicular than oblique incidence. To demonstrate this, AWJM was used to machine masks from aluminum oxide and subsequently mill micro-molds with raised intersecting free-standing structures into aluminum oxide substrates. It was found that for molds of identical depth, the undercut and the undesirable erosion in aluminum oxide molds could be reduced by five and four times, respectively, when compared to molds machined in Al6061 using the previous AWJM/ASJM hybrid technique. It was also found that much deeper molds containing intersecting raised free-standing structures of up to 435 μm in height could be made in aluminum oxide, while still maintaining an acceptable surface quality (1.51 μm Ra and 2.47 μm Wa), undercut (25 μm), and undesirable erosion (3%). Finally, since the technique involved only AWJM, it was much more convenient than the previously utilized hybrid AWJM/ASJM.

Friction drilling of AA7075-T6 and AZ31B alloys under dry and oil containing ceramic particulates

This study investigates the friction drilling behaviors of AA7075-T6 aluminum and AZ31B magnesium alloys containing ceramic powders of B4C, SiC, and Al2O3 under dry and minimum quantity lubrication (MQL). The aim is to create a composite structure while applying the pressure of a drilling tool on the hole surface when adding ceramic powders into the cutting oil during frictional drilling. Friction drilling tests are performed at a constant spindle speed and feed speed, and the effects of dry and cutting oil mixtures containing ceramic particulates on the thrust force, temperature, hole surface quality, bushing profile, and thread stripping strength of the specimens are investigated. The results revealed that ceramic particles penetrated through the hole and created a composite structure on the surface. The dry friction drilling of AA7075-T6 and AZ31B yielded acceptable surface quality. However, the surface quality worsened considerably during the friction drilling of AA7075-T6 using the oil mixture, whereas the surface roughness and hole bushing of AZ31B magnesium alloys are not negatively affected by the ceramic containing oil mixtures. Petal formation and cracks appeared in the hole profiles of the AA7075-T6 aluminum alloy. Thread stripping tests indicate that the ceramic-particle- containing oil mixtures enhanced the thread shear strength of AA7075-T6 by 19.2 %, and the highest shear strength of 56.78 kN is achieved using the Al2O3 containing an oil mixture. The oil mixture-containing B4C ceramic particles improved the thread shear strength of AZ31B by 7.7 %.

Material characterization of workability and process imaging for robotic concrete finishing

In this paper, we discuss a robotic-assisted concrete finishing method for fabricating architectural panels. Concrete finishing is an important process for producing architectural elements with acceptable surface quality. It is also a challenging process conventionally relying on skillful laborers. We describe a hybrid framework incorporating both human skill and robotics in the concrete finishing process and a multi-phase sensing strategy to assist in part touch-up and to validate final surface quality. The paper discusses a general approach to finishing from three perspectives: (1) Material characterization of concrete’s workability throughout its setting process, (2) A modular system-architecture for collaborative human-robot concrete finishing, and (3) Assessment feedback of surface quality using process images.

USING NON-DESTRUCTIVE TESTS FOR EVALUATING FLYOVER FOOTBRIDGE: CASE STUDY

The concrete structures deterioration in the last few decades required effective methods for evaluating and maintaining the structure condition. Currently, assessing the performance and safety of reinforced concrete (RC) structures relies on routine-based visual inspection (VI). However, there are another non-destructive test (NDT) technique that can provide a more accurate assessment of the structures. Thus, in this study, a footbridge located in Liverpool, UK is chosen as a case study and has NDT techniques used for assessment. The main objective of this research is to determine the condition of structural bridge components and investigate its level of defect and deterioration using non-destructive tests. The methodologies involved are visual inspection, and NDT techniques include the rebound hammer, cover meter, Moisture Content &amp; Depth of Carbonation Testing, Chloride Testing and Half Cell Test. The framework, when implemented with the best selection of NDT techniques, helps in determining the level of defect and deterioration of the structural bridge components and next recommendation regarding the condition of the bridge. The involved bridge structural components include column, deck, wall and staircase. Findings from the visual inspection show that there were many defects and deteriorations found at the structural bridge components, which includes crack, spalling, and delamination and rusting. Further, NDT techniques that were carried out at the selected bridge structural part shows that some of the components exhibited a moderate risk of corrosion and acceptable concrete surface quality. In general, further maintenance is needed specifically to some critical structural components of the bridge.

Characterization of machinability of sintered steel foams having different porosities during drilling operations

Steel foams are a new class of engineering materials with exceptional structure and properties. Foams produced by powder metallurgy generally have a near-net shape, however, sometimes machining operations may be required. The presence of porosity in steel foams significantly affects the cutting process and causes poor machinability. This study deals with the evaluation of the machinability of Cu-Ni-Mo-based steel foams having different porosity produced by powder metallurgy. High speed steel and carbide-tipped drills were used for the drilling. All tests were performed in dry condition with drill diameter of 3 mm. The drilling characteristics were evaluated in terms of the surface roughness, chip formation, drilling force, tool wear, microstructure and hardness change after drilling. The machinability was also evaluated by measuring average width of breakout and skewness values of the hole drilled. The results indicated that the increase of porosity negatively affected the drilling quality of high porous steels. Both drills broke the chips in powder form and produced discontinuous chips. High porous parts exhibited higher hardness change as compared to lower ones. The carbide drill showed acceptable drilling forces and surface quality. HSS drill is not suitable for drilling due to poor hole quality and high drill wear. Highlights Steel foams exhibit poor machinability due to highly porous structure. Porosity and tool type significantly affect the surface integrity of steel foams. Surface roughness and drill wear increased with increasing porosity; however, feed force decreased. Intense presence of pores decreases the tool life remarkably. The skewness values of hole are positive in all porosities. Carbide-tipped drill produced the finest hole quality. The larger damage was observed at the exit of the drilled holes with HSS drill.

An experimental study on fabricating microstructured surface by using LS-WEDM-prepared ball micro end mills

In recent years, there is an increasing demand for fabricating microstructures such as micro grooves, micro holes, micro dimples, and micro channels on various materials. Micro machining is an alternative method to manufacture microstructures due to its high efficiency and flexibility, and the micro end mill preparation is an essential step. In this study, the low-speed wire electrical discharge machining (LS-WEDM) is used to fabricate ball micro end mills with four cutting edges and radius of less than 200 μm, and the optimized parameters and multiple cutting strategies are adopted to improve machining surface quality and edge sharpness of ball micro end mills. Then, the micro dimples on soft and hard materials are formed by the designed and prepared ball micro end mills made of cemented carbide, respectively. The micro machining performance of ball micro end mills was evaluated by investigating the surface quality and microstructure of micro dimples, cutting force, and tool wear, and the influence of micro machining parameters on micro dimples is discussed in detail. Experimental results indicated that tool wear patterns mainly are adhesion friction and cutting edge damage, and the LS-WEDM-fabricated ball micro end mills with four cutting edges are potential to manufacture microstructures on hard and soft materials with acceptable surface quality and tool wear.

Analysis of the Wall Geometry with Different Strategies for High Deposition Wire Arc Additive Manufacturing of Mild Steel

Additive manufacturing has gained relevance in recent decades as an alternative to the manufacture of metal parts. Among the additive technologies, those that are classified as Directed Energy Deposition (DED) are characterized by their high deposition rate, noticeably, Wire Arc Additive Manufacturing (WAAM). However, having the inability to produce parts with acceptable final surface quality and high geometric precision is to be considered an important disadvantage in this process. In this paper, different torch trajectory strategies (oscillatory motion and overlap) in the fabrication of low carbon steel walls will be compared using Gas Metal Arc Welding (GMAW)-based WAAM technology. The comparison is done with a study of the mechanical and microstructural characteristics of the produced walls and finally, addressing the productivity obtained utilizing each strategy. The oscillation strategy shows better results, regarding the utilization rate of deposited material and the flatness of the upper surface, this being advantageous for subsequent machining steps.

Milling Microchannels in Monel 400 Alloy by Wire EDM: An Experimental Analysis

This paper presents the results of an investigation on the capacity of wire electrical discharge machining (WEDM) to produce microchannels in the Nickel-based alloy, Monel 400. The main objective of the current study is to produce microchannels with desired/target geometry and acceptable surface quality. Square cross-sectional microchannels with dimensions of 500 × 500 µm were investigated. Experiments were conducted based on the one-factor-at-a-time approach for the key input WEDM process parameters, namely pulse-on time (TON), pulse-off time (TOFF), average gap voltage (VGAP), wire feed (WF), and dielectric flow rate (FR). Dimensional accuracy, machining speed, surface roughness, surface morphology, microhardness, and microstructure were analyzed to evaluate the microchannels. The minimum errors of 6% and 3% were observed in the width and depth of the microchannels, respectively. Furthermore, microchannels with enhanced surface integrity could be produced exhibiting smooth surface morphology and shallow recast layer (~0–2.55 µm).

A thermo-mechanical model of drill margin-borehole surface interface contact conditions in dry drilling of thick CFRP laminates

Dry drilling of thick carbon fiber reinforced polymer (CFRP) laminates requires careful selection of process parameters in order to obtain acceptable borehole surface quality. Complex contact conditions between the drill margin and the borehole surface determine the integrity of the borehole surface depending on the process parameters and temperature-dependent viscoelastic material properties. Temperature rise during dry drilling reduces the elastic modulus of the CFRP and causes thermal expansion of the drill, resulting in considerable contact length at the drill margin and borehole surface interface. Manufacturers need a better understanding of the interaction among contact pressure, sliding velocity, temperature at the interface, and temperature-dependent material properties to develop predictive models for drilling CFRPs. To examine this complex interaction, this study develops a novel, hybrid model that combines a time-based analytical modeling of drilling process with a finite element-based modeling of temperature rise. Drilling experiments were performed in which thrust force, torque, and temperature were measured as a function of feed, and these measurements were used to identify unknown hybrid model parameters. The results revealed that a significant change in friction conditions occurs when increased temperatures at the margin and borehole surface interface approach and exceed the glass transition temperature of the CFRP laminate at a large feed rate. These findings show the benefit of increasing feed during dry drilling, which is nonetheless limited by the temperature-dependent material properties of the work material.

Experimental Continuous Casting of Nitinol

Commercially available nitinol is currently manufactured using classic casting methods that produce blocks, the processing of which is difficult and time consuming. By continuous casting, wherein molten metal solidifies directly into a semi-finished product, the casting and processing of ingots can be avoided, which saves time and expense. However, no reports on continuous casting of nitinol could be found in the literature. In this work, Φ 12 mm nitinol strands were continuously cast. Using a graphite crucible, smelting of pure Ni and Ti in a medium frequency induction furnace is difficult, because it is hard to prevent a stormy reaction between Ni and Ti and to reach a homogeneous melt without a prolonged long holding time. Using a clay-graphite crucible, the stormy reaction is easily controlled, while effective stirring assures a homogeneous melt within minutes. Strands of nearly equiatomic chemical compositions were obtained with acceptable surface quality. The microstructure of strands containing over 50 at. % Ni, consisted of Ti2Ni and cubic NiTi, whereas the microstructure of strands containing less than 50 at. % Ni consisted of TiNi3 and cubic NiTi. This is consonant with the results of some other authors, and indicates that the eutectoid decomposition NiTi → Ti2Ni + TiNi3 does not take place.

Experimental study on the meso-scale milling of tungsten carbide WC-17.5Co with PCD end mills

Tungsten carbide is a material that is very difficult to cut, mainly owing to its extreme wear resistance. Its high value of yield strength, accompanied by extreme brittleness, renders its machinability extremely poor, with most tools failing. Even when cutting with tool materials of the highest quality, its mode of cutting is mainly brittle and marred by material cracking. The ductile mode of cutting is possible only at micro levels of depth of cut and feed rate. This study aims to investigate the possibility of milling the carbide material at a meso-scale using polycrystalline diamond (PCD) end mills. A series of end milling experiments were performed to study the effects of cutting speed, feed per tooth, and axial depth of cut on performance measures such as cutting forces, surface roughness, and tool wear. To characterize the wear of PCD tools, a new approach to measuring the level of damage sustained by the faces of the cutter’s teeth is presented. Analyses of the experimental data show that the effects of all the cutting parameters on the three performance measures are significant. The major damage mode of the PCD end mills is found to be the intermittent micro-chipping. The progress of tool damage saw a long, stable, and steady period sandwiched between two short, abrupt, and intermittent periods. Cutting forces and surface roughness are found to rise with increments in the three cutting parameters, although the latter shows signs of reduction during the initial increase in cutting speed only. The results of this study find that an acceptable surface quality (average roughness $$R_{\text{a}} 600\,{\text{mm}}$$) can be obtained under the conditions of the given cutting parameters. It indicates that milling with PCD tools at a meso-scale is a suitable machining method for tungsten carbides.

Investigation of machining and wear performance of various diamond micro-grinding tools

The wear of micro-grinding tools less than 1 mm in diameter is crucial for achieving acceptable surface quality and accurate dimension of the workpiece. To control wear behavior of the micro-grinding tools, an investigation through experiments was conducted on the machining and wear performance of various (D-shaped PCD, CVD, electroless plated, and electroplated) diamond micro-grinding tools on monocrystalline silicon workpiece in this study. The experiments showed that a CVD diamond micro-grinding tool had excellent machining performance, but its relatively large diameter limited its application range. An electroplated diamond micro-grinding tool had a good machining performance but displayed severe wear. To comprehensively understand its wear mechanism, a series of grinding experiments were further done. Its mechanism was analyzed through investigating the tool and machining process parameters. In order to accurately evaluate tool wear, the ratio of tool radius loss to average grain diameter (δ) and the ratio of the lost grain number to the total grain number (η) were proposed. The δ-ratio and η-ratio related to the wear limit of 600 mesh size micro-grinding tools having a diameter of 0.5 mm were 0.16–0.18 and 11.50–13.88%, respectively.

1 Published By: Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP) © Copyright: All rights reserved. Retrieval Number: F13830986S319/2019©BEIESP DOI:10.35940/ijeat.F1383.0986S319 Journal Website: www.ijeat.org Examination of Surface Finish in Burnishing of Brass and Copper

Fine machining process of cylindrical surfaces exposed to the high exploitation loadings has to ensure acceptable surface quality and it’s longer functionality. Quality of surface is an important factor to decide the performance of a manufactured product. The main aim of this research work is to analyse the impact of roller burnishing operation on the cylindrical work material, directed to achieving smaller roughness of test specimens. Roller burnishing is a fine machining process that is used to improve certain physical and mechanical properties. The common parameters in this work selected for burnishing process is to determine and analyse surface roughness. The process parameters considered for roller burnishing process are tool material, force applied and the number of tool passes. The Roller burnishing tool is made of high carbon steel, the burnishing operation is done on copper and brass specimens with different burnishing forces which are varying from 1 to 6 burnishing tool passes. The surface roughness of the specimens was measured before and after burnishing by using surface roughness tester. It has been observed from the surface roughness Ra.

Cryogenic Forming of Al‐Mg Alloy Sheet for Car Outer Body Applications

During deep‐drawing of Al‐Mg sheet at room temperature, stretcher‐strain marks can appear on the material's surface. Such parts are not suitable for car outer body applications because the visually unappealing marks are still visible after painting. In this paper, the occurrence of surface marks on a miniaturized engine hood is significantly reduced by deep‐drawing at approximately −180 °C. Yield strength, ultimate tensile strength, and tensile elongation are significantly higher at cryogenic temperature and the Portevin–Le Chatelier effect disappears. Scanning electron microscopy of fracture surfaces reveals that the ductile fracture mechanism is similar at cryogenic temperature and room temperature. However, the localized ductility is reduced at cryogenic temperatures, resulting in a finer structure of the fracture surface. In summary, cryogenic forming permits the use of Al‐Mg alloys for producing outer body car parts with acceptable surface quality.