Maximum Material Requirement Research Articles

Statistical model for setting up a machining center to achieve geometric tolerances at maximum material requirement

The production adjustment on a machining center aims to manufacture parts that conform to their manufacturing specifications. To achieve this, the adjustment operation consists of determining a set of setting variables associated with a geometric model of the machine. The maximum material requirement proves very useful in guaranteeing the conformity of parts to intended functional requirements. This is the case, for example, for ensuring part assembly by linking the tolerances of dimensional and geometric specifications. However, setting up a machining center to achieve geometric tolerance with the maximum material requirement needs decoupling geometric tolerance from the associated dimensional tolerance(s). In particular, the dimension to be targeted by the feature of linear size must be determined with the performance of the production means from a dimensional and geometric point of view. Therefore, the article aims to develop a computation model for setting the target dimension to be machined, ensuring maximum production of parts conforming to a geometric specification at maximum material requirement. This model is based on the statistical distributions of the history of dimensional and geometric measurements taken on different parts produced by the production means under consideration. A case study is carried out to validate the proposed model.

Flipped Learning using Video Training Material and Face-to-Face Training Materials for ISO GPS Education

In Japan, drafting education and drafting implementation based on ISO GPS is inadequate, and only a few companies use ISO GPS or GD&T. One of the reasons for this is not only a lack of appropriate teaching materials, but also a lack of training opportunities. The least understood matter of ISO GPS in Japan is the meaning and application of the maximum material requirement. Another matter is whether a feature should be controlled by size tolerance or geometrical tolerance. Therefore, the authors have created video teaching materials that can be viewed on Internet video sharing sites, and in addition, we have also developed training materials that can be used face-to-face to deepen understanding. The method used here is called "flipped learning", where learners (mainly university students) acquire knowledge at home and deepen their knowledge through face-to-face training. This not only saves training instructors time on knowledge transfer, but also allows them to spend more time on face-to-face training. This study reports on the results of using this set of video teaching materials and face-to-face training materials at companies and universities.

An Explanation of Maximum Material Requirement (2nd)

An Explanation of Maximum Material Requirement (2nd)

Computer aided explanation of geometrical tolerancing

The recent developments of the application Geometrical Tolerancing that has been consequently developed by the authors over the last years to facilitate geometrical tolerancing explanation and appropriate application in industry are presented. The application general structure and main capabilities are initially outlined. The paper is focused on the maximum material requirement (MMR), particularly on the difference between the MMR specification for a toleranced feature and a datum feature.

An Explanation of Maximum Material Requirement (1st) What is the “(M)” in Mechanical Drawing?

An Explanation of Maximum Material Requirement (1st) What is the “(M)” in Mechanical Drawing?

On the usage of Least Material Requirement for Functional Tolerancing

ISO 2692 core concepts: Maximum Material Requirement (MMR) and Least Material Requirement (LMR) are well established for functional tolerancing and are used to guarantee assemblability, extremal values of clearance and minimum wall thickness. The LMR has not been extensively investigated in research and still not enough considered in industrial practices. In this paper, LMR’s capability to devise requirements on assemblies with clearance is shown, and the conformity assessment, in dimensional metrology, based on Least Material Virtual Size is presented. A case study demonstrates the effectiveness of this work. New insights for virtual size representation within tolerance zone are also discussed.

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.

New Multimedia Geometrical Tolerancing Course

The new application Geometrical Tolerancing developed for usage during lectures at technical universities as well as for the enhancement of vocational trainings for design, manufacturing and metrology engineers working in industry is presented. The application capabilities are shown and discussed on base of the selected screen shoots. The suggestive 3-D animations and multicolour drawings with intuitive user interface are employed to effectively familiarize the application user with definitions of form, orientation, location and run out tolerances. The tolerance zones for toleranced integral or derived features are clearly visualized and then shrunk to show particular deviations. The role of the datums and datum systems for establishing involved tolerance zones is explained in details. The restrictions for the part geometry imposed by specified maximum material requirement or least material requirement that combine requirements for size of the features of size and the geometrical tolerance to one aggregated functional requirement are shown. The concepts of the geometrical deviations evaluation by coordinate measuring techniques or workpiece verification by hard gauges are demonstrated for the selected tolerances with case studies.

Animated visualization of the maximum material requirement

The usage of animation technique applied as a powerful tool to explain the complex concept of the maximum material requirement (MMR) is shown. The concepts of datum system and the maximum material virtual condition envelope, that is located by theoretically exact dimensions are highlighted. The maximum material virtual condition state, that limits the collective effect of the feature maximum material size and the maximum acceptable geometrical deviation for that size is examined. The tolerances of perpendicularity and position with the maximum material modifiers applied in the tolerance frames for the toleranced features or respectively for the datum features are explored. The simplicity of the verification of the conformance with the specification employing the MMR by the gauge that represents the matting counter part is emphasized.

Application d'un solveur à l'identification de surfaces réelles et au contrôle des spécifications ISO

In three-dimensional metrology, the determination of an ideal surface associated to a real surface is not easy. Since the 1970s, the least-squares criterion has been used with a simple matrix method. Nowadays, the minimax criterion and the R mini (or R maxi) criterion are easily accessible using the numerical solvers. This article proposes methods for identification of geometrical surfaces based on a solver without small displacements hypothesis. The choice of the association criterion and the calculation of the form deviation are in conformity with the standards ISO 5459 and ISO 1101. The analysis of measured points for plane and cylindrical surfaces will be developed on real parts and validated with tests available in the literature. The presented application deals with two practical problems that are difficult to solve using the currently available approaches: the construction of a datum-system and the inspection of a maximum material requirement.