Datum Planes Research Articles

Creation of Engineering Drawing Learning Modules Using Datum Plane Media in Improving Students' Competence in Automotive Engineering Skills at SMK Negeri 55 Jakarta

The aim of this research is to determine the feasibility and effectiveness of the engineering drawing module using datum plane media to strengthen students' knowledge about projections on objects. This research uses the 4D research method developed by S. Thiagarajan, Dorothy S. Semmel, and Melvyn I. Semmel in 1974 which consists of 4 stages, namely Define, Design, Develop and Disseminate. Data was collected through interviews, questionnaires and pre test-post test. The subjects of this research were students majoring in automotive engineering at SMKN 55 Jakarta 2023/2024 academic year class x semester 1 with a sample size of 30 students from a population of 3 classes totalling 103 students. The research began with Define, namely defining the need for difficulties in students' understanding of reading and drawing projections by observing and interviewing teachers who teach technical drawing. Furthermore, from the observation data obtained, the researchers looked for solutions to the problems faced by automotive vocational school students with modules that use datum planes, so the researchers designed the required modules and datum planes. At the Develop stage, the researcher's design is validated by material experts and media experts, their criticism and suggestions are used as input for revising the media created. Finally, the Disseminate media stage, which had been validated and revised, was used on 30 students from SMKN 55 Jakarta, carried out a pre-test-post test and obtained an average result for the entire pre-test sample of 45.33 and post-test of 68.17.

Basin-wide erosion and segmentation of the Plio-Pleistocene forearc basin in central Japan revealed by tephro- and biostratigraphy

The basement of the Tokyo metropolitan area consists of the Miocene–Pleistocene forearc basin fills that are well exposed around Tokyo Bay, especially on the Miura and Boso peninsulas. The forearc basin fills on these two peninsulas are called the Miura and Kazusa groups, and they were deposited during the late Miocene–Pliocene and Pliocene–middle Pleistocene, respectively. Because many biostratigraphic datum planes, paleomagnetic reversal events, and other chronostratigraphic tools are available for these deposits, they provide the “type stratigraphy” of other equivalent sedimentary sequences on the Japanese islands and in the northwest Pacific. However, the use of such stratigraphic markers has not been fully applied to understand the architecture of a basin-wide unconformity between the Miura and Kazusa groups called the Kurotaki unconformity. For our study, we made correlations among the Pliocene vitric tephra beds based on their stratigraphic levels, lithologic characteristics, the chemical compositions of glass shards, and calcareous nannofossil biostratigraphy. As a result, we were able to correlate tephra beds Ng-Ky25 just above the C3n.3n normal subchronozone (4.7 Ma), IkT16-An157.5 and IkT19-An158.5 near the top of the Mammoth reverse polarity subchronozone (3.21 Ma), and Ahn-Onr (2.6–2.7 Ma) across Tokyo Bay on the Miura and Boso peninsulas. We were able to recognize erosional surfaces and coeval mass-transport deposits immediately below the top of the Mammoth reverse polarity subchronozone, which suggests that submarine landslide(s) may have produced the lack of stratigraphic horizons (4.5–3.2 Ma) in the Miura and eastern Boso regions. Basal pebbly sandstone beds pervasively cover the erosional surfaces, and they show lateral variations into the thick (up to 60 m) mass-transport deposits and overlying turbidite sandstones. The lateral variations in sediment thickness of the post-failure deposits suggest that the basin-wide erosion was associated with the initial growth of a basin-bounding structural high that separates two distinct sub-basins in the forearc basin, which resulted in the subsequent onlapping deposition in the earliest stage of the Kazusa forearc basin. The basin-wide erosion marks the initiation of tectonic reconfigurations that led to segmentation of the forearc basin around the Tokyo Bay region.

Post-machining allowance optimization of directed energy deposited impeller blades using point cloud registration

Complex free-form parts manufactured by directed energy deposition (DED) have problems of uneven allowance distributions and severe stair-case effects. In order to optimize allowance for post-machining in a hybrid additive and subtractive machine centre, a point cloud registration method is proposed for allowance optimization to match the on-machine measured point cloud of the deposited part with the point cloud of the theoretical model. Firstly, the deposition path is used to construct the inspection path and obtain the maximum and minimum envelops of the deposited part. Secondly, the allowance distribution for the uniform and positive criterion is solved using the pattern search algorithm, after the datum planes are overlapped. Finally, a free-form blade of a centrifugal impeller is selected as a case study for allowance optimization. The proposed method is also compared with an allowance optimization method using genetic algorithm. The results show that the proposed method is more accurate and efficient for rapid allowance optimization for DED complex parts.

Grinding characteristics and removal mechanisms of unidirectional carbon fibre reinforced silicon carbide ceramic matrix composites

The grinding performance of unidirectional carbon fibre reinforced silicon carbide ceramic matrix composites (Cf/SiC) was investigated in this paper. The effects of the fibre orientation and grinding depth on the surface integrity and grinding forces and an understanding of the grinding mechanisms are the primary concerns of this article. This problem is relatively unexplored; therefore, the main value of this research is to improve the processing quality and reduce the production cost. In the Cf/SiC grinding procedure, cracks, fibre wear, interfacial debonding, fibre pull-out and outcrop can be detected on the ground surface. The grinding depth and deflection angle have been shown to have a notable influence on the surface quality in different datum planes. A suitable grinding depth and deflection angle should be carefully chosen to achieve good surface quality in different machined surfaces. Specifically, the surface quality decreases and the grinding forces increase with increasing grinding depth. In addition, greater grinding surface quality is observed at β = 90°, i.e., γ = 0°, but poorer machined surfaces are obtained at α = 0°, i.e., γ = 90°. The surface topography, roughness and grinding forces of unidirectional Cf/SiC could be forecasted according to the analysis conclusions. This research is expected to offer guidelines for increasing the machining quality of Cf/SiC.

Facies and Sequence Stratigraphy Analyses of Klasaman Formation in the “X Well”, Northern Salawati Basin, Papua, Indonesia

The “X Well” is located in the Salawati Basin which is part of Western Papua. The interval of study is the Klasaman Formation that is characterized by thick sediment intercalated sandstones and shales. The movement of Sorong Fault strongly controlled the sedimentation of this formation. This study is very important to give a contribution for developing exploration prospect by predicting reservoir distribution since localized facies change may mark the distribution of sandstones. The current study aims: 1) to define the age of Klasaman Formation; 2) to define the vertical facies; 3) to define the sequence stratigraphy; and 4) to predict the lateral change of facies. Five nannofossil datum planes are found throughout the interval and cover the age Late Miocene to Early Pliocene. LO Sphenolithus abies points the age 3.65 Ma, LO Reticulofenestra pseudoumbilicus points the age 3.79 Ma, FO Pseudoemiliania lacunosa points the age 4 Ma, LO Discoaster quinqueramus and LO Discoaster berrgrenii point the age 5.59 Ma and Top of small Reticulofenestra Interval points the age 7.167 Ma. They define the NN11 up to NN16 Martini’s zonation. The age of Klasaman Formation is known as the uppermost Late Miocene to the Early Pliocene. Four facies can be identified, namely Upper Shoreface, Lower Shoreface, Offshore Transition and Offshore. The upper shoreface facies is characterized by thick and clean sandstones, about 2.41 - 20.64 meters thick, while the lower shoreface facies consists of predominantly very fine to fine-grained sandstones intercalated by siltstones and claystones. The offshore transition facies is marked by thick claystones and siltstones intercalated with thin sandstones, whilst the offshore facies is marked by thick laminated claystones. Nine Parasequences 4th order can be identified within study interval, namely Progradational Parasequence-1 to 2, Retrogradational Parasequence-3, Progradational Parasequence-4 to 6, Retrogradational Parasequence-7 to 9. They are bounded by Sequence Boundary-1 to 8. The upper shoreface sandstones of Parasequence-4 to 9 can be potential reservoir rocks in the Klasaman Formation since the sandstones are very thick and clean. The sediments of Klasaman Formation have been sourced from elevated highland in the northeast area, so the upper shoreface sandstones have changed become the offshore claystones from northeast to southwest. High sedimentation rate and rapid subsidence of the basin mark the deposition of Klasaman Formation especially during the deposition of Parasequence-6 to 9 as a result of Sorong Fault tectonics.

Calcareous nannofossil assemblages of the upper Miocene to Pliocene Shimajiri Group on Okinawa-jima, Ryukyu Islands, southwestern Japan

We investigated the calcareous nannofossil biostratigraphy and paleoceanography of the Shimajiri Group in two exploratory wells (depths, 1243 and 1800m) drilled on southern Okinawa-jima, Ryukyu Islands, southwestern Japan. Three late Miocene to Pliocene datum planes were identified: the first occurrence of Amaurolithus spp. (7.42Ma), the last occurrence of Discoaster quinqueramus (5.59Ma), and the first occurrence of Ceratolithus rugosus (5.12Ma). These datum planes were also identified in two other deep wells on southern Okinawa-jima. Nutrient levels (reconstructed from the relative abundances of small Reticulofenestra spp., and the relative abundances of Discoaster spp. plus Sphenolithus abies) suggest that deposition of the Shimajiri Group (<8.29–3.50Ma) occurred under conditions of increasing eutrophication. The eutrophication was likely caused by shallowing of the sedimentary basin, but a stepwise shift was associated with an abrupt eutrophication event that occurred in the northwestern Pacific Ocean at 5Ma.

Tolerance Analysis Considering form Errors in Planar Datum Features

The paper investigates the role of planar datum features in tolerance analysis problems. Mating relations between datum planes are shown to involve translational and rotational errors, which are related to form tolerances and are usually neglected in tolerance analysis. To evaluate these errors, the contact between datum planes was simulated by a stochastic model, where two surface profiles are randomly generated and then registered to reproduce a mating condition. Concepts of fractal geometry were exploited to make the generation consistent with the autocorrelation properties of actual surfaces resulting from manufacturing processes. A simulation plan allowed to predict the amount of contact errors as a function of size, tolerance and process-related assumptions on the two features. An example of 3D tolerance chain is presented to demonstrate the relevance of form errors in the variation of assembly requirements.

Theory and Algorithm for Planar Datum Establishment Using Constrained Total Least-squares

First, we present an efficient algorithm for establishing planar datums that is based on a constrained minimization search based on the L2 norm after forming a convex surface from sampled points. Visualized by Gauss maps, we prove that the problem reduces to a minimization search where the global minimum is localized about the minimizing facet. Second, we highlight advantages of this planar datum, including the major advantage that the datum planes have full mechanical contact with the datum features in stable cases yet are automatically balanced for rocking conditions. These advantages make this definition appealing for standardization.

Datum Planes Based on a Constrained L1 Norm

This paper has two major goals. First, we present an algorithm for establishing planar datums suitable for a default in tolerancing standards. The algorithm is based on a constrained minimization search based on the L1 (L1) norm after forming a convex surface from the original surface or sampled points. We prove that the problem reduces to a simple minimization search between the convex surface and its centroid. The data points in the discrete case do not need to have any corresponding weights provided with them, as appropriate weighting is part of the algorithm itself, thereby making the algorithm largely insensitive to nonuniformly sampled data points. Terse mathematica code is included for the reader. The code is sufficient for primary and secondary planar datum fitting as well as a 3-2-1 datum reference frame generation. The second goal of this paper is to compare this new method with several other possible means for establishing datum planes, ultimately showing several appealing characteristics of the proposed algorithm. Since both the International Organization for Standardization (ISO) and American Society of Mechanical Engineers (ASME) standardization efforts are actively working to establish datum plane definitions, the timing of such a study is opportune.

A Digital Application for Geometrical Tolerancing Concepts Understanding

The general concept and main capabilities of the application Geometrical Tolerancing that has been consequently developed by the authors for a couple of years to effectively present and disseminate the ISO GPS system rules in industry and technical universities are presented. The application structure is shortly shown and discussed through a few screen shoots. The paper is focused on the approach used to present differences between requirements defined by the position tolerance of the two hole pattern without and with maximum material requirement with respect to the datum system created by three datum planes. The other cases of the two hole pattern tolerancing covered by the application are also briefly discussed. It should be noticed that visualizations of deviation measurements by usage of the various measuring methods starting from classical techniques employing indicators and measuring plate or hard gauges up the modern ones like FMM or CMM are just implemented in the application for selected tolerances.

Assembly Tolerance Analysis Method Based on the Real Machine Model with Three Datum Planes Location

An assembly tolerance analysis method based on the real machine model is proposed, aiming to investigate the effect of the geometric errors of datum feature on the result of tolerance chain. The real parts are simulated by the variation of the geometric features, which are represented by the control point variation model and generated by the Monte Carlo simulation. The investigated objective is the assembly success rate of pin-hole assembly at the location with the three datum planes, the assembly clearance or interference is calculated according to the assembly requirements and assembly process. The part coordinate system in assembly is constructed firstly by the datum embodiment principles, then the position of the junction planes are determined according to the assembly requirements, and finally, the position of the parts relative to machine are determined by the coordinate transformation. The assembly success rate is represented by the probability distribution of clearance or interference between pin and hole, and the influences of the datum errors on the assembly result are discussed by the example assembly.

Assembly tolerance analysis method based on the real machine model

The position errors of an objective feature of a machine is affected comprehensively by the geometric errors and assembly errors of the parts on the assembly chain. In order to investigate the effect of assembly datum errors on the transformation and propagation of the geometric errors in an assembly chain, a modeling and analysis method of assembly error accumulation based on the real machine model is proposed. In this approach, the calculation process of the real position of geometric feature is consist of four steps. Firstly, the deviation geometric feature are represented by the control point variation model , and the deviations of geometric feature from its normal position are simulated by the Monte Carlo method. Secondly, the normal position of the deviation geometric feature in the datum reference frame (DRF) is determined by theoretical dimension. The third step, the DRF establishment method is proposed, and the measure DRF of the objective feature is established with the datum geometry example. The fourth step, the assembly contact model is proposed, the relationship between the measure datum reference frame and assembly datums is calculated according to the assembly sequence and the deviation geometry example of assembly datum surface. The real position of all related parts on the assembly chain in machine coordinate system are calculated by above procedures, and the transformation and propagation of the geometric errors of assembly datum in an assembly chain are obtained. The procedure to simulate the real machine assembly is decomposed into four modular processes, which is useful in realizing the automation of assembly error analysis. A assembly error accumulation example of pin-hole assembly with the three orthogonal datum planes is investigated, and the proposed approach is verified.

The Study on Accuracy Control System with the Three Datum Planes in Fixture Design

The fixture accuracy is controlled on the three datum planes with fixture or compound body used as design object, with structure of parts and the machine accuracy used as the target required, with cutting tool and the machine datum plane mounted fixture used as viewed body. The assistance datum plane is towards the machine locating planes mounted fixture, and it is parallel to the cutting speed of tools; the assistance datum plane (or line) is perpendicular to the assistance datum plane, and it is passing through center line of tool (or fixture);the assistance datum plane is through the single point of fixture , perpendicular to both two.

Application and Research on Fixture Accuracy Control with the Three Datum Planes

The application accuracy control system with the three datum planes in machining fixture accuracy design can be used to be integrity for the item, index sign reasonable, to be easily for the criterion design and be advantageous to the computer assistance fixture design.

Development of a novel high-speed dynamic length measurement system for mobile and large-scale cylinder workpiece

A high-speed length measuring system for mobile and large-scale cylinder workpiece was designed and constructed. This measuring system is characterized by two stationary laser scanning systems placed on two sides of workpiece responsible for the acquisition of points of key parts. Meanwhile, for making the measuring process faster and more flexible, the virtual measurement datum planes play an important role, and are step-by-step generated according to various features of measured surface in an online virtual inspection environment. Moreover, modeling and identification of end point of workpiece are established based on height variations in its nearest neighborhood. The three-dimensional dynamic length measurement data are then obtained by calculating the displacement between end point and corresponding datum plane. The prototypal system has been tested on different real cases with several typical cylinder workpieces (length 1000 ± 20 mm, diameter 50 ± 25 mm). Compared with the measurement results of coordinate measuring machine, the root-mean-square errors of the measurement data are smaller than 0.035 mm. The system measurement uncertainty is better than ±0.040 mm. The measuring time is less than 2 s. The proposed measuring system features high automation and high efficiency, and is most promising for on-machine applications in large geometric dimensional measurement.

Geology and age model of the Lower Pleistocene Nojima, Ofuna, and Koshiba Formations of the middle Kazusa Group, a forearc basin‐fill sequence on the Miura Peninsula, the Pacific side of central Japan

AbstractWe present field and core observations, nannofossil biostratigraphy, and stable oxygen isotope fluctuations in foraminiferal tests to describe the geology and to construct an age model of the Lower Pleistocene Nojima, Ofuna, and Koshiba Formations (in ascending order) of the middle Kazusa Group, a forearc basin‐fill succession, exposed on the northern Miura Peninsula on the Pacific side of central Japan. In the study area, the Nojima Formation is composed of sandy mudstone and alternating sandy mudstone and mudstone, the Ofuna Formation of massive mudstone, and the Koshiba Formation of sandy mudstone, muddy sandstone, and sandstone. The Kazusa Group contains many tuff beds that are characteristic of forearc deposits. Thirty‐six of those tuff beds have characteristic lithologies and stratigraphic positions that allow them to be traced over considerable distances. Examination of calcareous nannofossils revealed three nannofossil datum planes in the sequences: datum 10 (first appearance of large Gephyrocapsa), datum 11 (first appearance of Gephyrocapsa oceanica), and datum 12 (first appearance of Gephyrocapsa caribbeanica). Stable oxygen isotope data from the tests of the planktonic foraminifer Globorotalia inflata extracted from cores were measured to identify the stratigraphic fluctuations of oxygen isotope ratios that are controlled by glacial–interglacial cycles. The observed fluctuations were assigned to marine isotope stages (MISs) 49–61 on the basis of correlations of the fluctuations with nannofossil datum planes. Using the age model obtained, we estimated the ages of 24 tuff beds. Among these, the SKT‐11 and SKT‐12 tuff beds have been correlated with the Kd25 and Kd24 tuff beds, respectively, of the Kiwada Formation on the Boso Peninsula. The Kd25 and Kd24 tuff beds are widely recognized in Pleistocene strata in Japan. We used our age model to date SKT‐11 at 1573 ka and SKT‐12 at 1543 ka.

Use of digital terrain models in morphometric analysis of tectonic structures and prospecting of placers of alluvial genesis

Approaches have been developed to the application of the geomorphometric method for identification of neotectonic structures from maps of datum and summit planes by using the territory of Perm krai as an example. We carried out a comparative analysis of the resulting maps with existing neotectonic maps of local uplifts to reveal their good correlation. We substantiate the possibility of using the suggested approaches in forecasting deposits of sand-gravel raw materials.

Chronological and paleoceanographic constraints ofMiocene toPliocene ‘mud sea’ in theRyukyuIslands (southwesternJapan) based on calcareous nannofossil assemblages

AbstractTheCenozoic sedimentary succession inOkinawa‐jima, including the upperMiocene toPleistocene siliciclastic deposits (ShimajiriGroup) and thePleistocene reef to shelf deposits (RyukyuGroup), suggests a drastic paleoceanographic change from a ‘mud sea’ to a ‘coral sea.’ To delineate the paleoceanographic evolution of the mud sea, we quantified the stratigraphic distribution of the calcareous nannofossil assemblages from theShimajiriGroup in a 2119.49 m‐deep well (NanjoR1ExploratoryWell) drilled in southernOkinawa‐jima (RyukyuIslands, southwesternJapan). Four lateMiocene andPliocene datum planes were found in the studied interval: the first occurrence ofAmaurolithusspp. (7.42 Ma), the last occurrence ofDiscoaster quinqueramus(5.59 Ma), the first occurrence ofCeratolithus rugosus(5.12 Ma), and the last occurrence ofReticulofenestra pseudoumbilicus(3.70 Ma). The calcareous nannofossil assemblages from theTomigusukuFormation and the lower part of theYonabaruFormation are characterized by a lower total number of coccoliths and abundantSphenolithus abiesthat is associated, at times, with commonDiscoasterspp. Overall, these suggest the existence of oligotrophic conditions between 5.3 and &gt;8.3 Ma. The total number of coccoliths increased and smallReticulofenestraspp. became more common in the middle part of theYonabaru Formation, suggesting that eutrophic conditions were present between 3.5 and 5.3 Ma. The rare occurrence of calcareous nannofossils in the upper part of theYonabaruFormation indicates a return to oligotrophic conditions at 3.5 Ma. Micropaleontological evidence suggests that these oceanographic changes were likely caused by local tectonic movement (shallowing of the sedimentary basin in which theShimajiriGroup was deposited).

Thickness maps of Neogene and Quaternary sediments in the Kloštar Field (Sava Depression, Croatia)

The Kloštar Oil Field is situated at the north-western part of Sava Depression in the Croatian part of the Pannonian Basin. It is a typical geological structure that evolved through the Neogene and Quaternary and that is why the structural evolution is reconstructed using palinspastic mapping (i.e., using selected chronostratigraphic horizons as datum planes). The total map set includes six structural and 15 palaeostructural maps interpolated over five E-log markers and one border. The mapping has been performed using the Ordinary Kriging. The maps were used for the interpretation of geological evolution during the Neogene and Quaternary, and particularly a description of hydrocarbon reservoir formation and migration pathways. The structural development can be explained through two phases of transtension and two of transpression that existed regionally in the Sava Depression. However, the maps and cross-sections that are described locally show changes of dominant tectonic styles, particularly during the Quaternary when most of the field was a depositional centre.

Minimum Zone Evaluation of Flatness Error Using an Adaptive Iterative Strategy for Coordinate Measuring Machines Data

In this paper, an adaptive and iterative neighborhood search strategy is proposed to precisely evaluate the flatness error. Firstly, an initial datum plane produced by least squares method (LSM) is calculated. And then, a group of candidate planes are generated by adjusting the direction angles of the LSM datum plane. The flatness errors conform to the minimum zone condition for each candidate datum plane that can be worked out. The one with minimum flatness error will be selected as the new start plane for the next search. The new search area is the zone between the new and old datum planes, with which the new search step is computed until the terminal condition is met. Numerical examples are given to validate the proposed strategy. The results show that the proposed method could get the precise value of the flatness error from the data of coordinate measuring machines and other equipment.