15,575 research outputs found
Study to Determine the Optimum Method in Writing a CNC Milling Program for a Specific Product
The trend towards automation of production equipment is having great demands from people. Since the early 1970s, manufacturers have worked to increase productivity, quality, process capability, reliability and flexibility. They used technologies to improve quality and productivity. This study studies the differences of a few CNC milling program – relating to time scale and machining accuracy. For experiment, a few programs are being written to machining a simple product. Each program has its own features. By running all the written programs, the effectiveness and goodness of each program could be analyzed. On the other hand, by machining the product and testing them, the product accuracy also can be analyzed. The results show that, the number of command lines will affect the simulation time. More command lines in the program will need more time in running the simulation. Besides that, results show that using the Canned Cycle command will give a more accurate machining compared to those conventional and CAD/CAM metho
PCPro a Novel Technology for Rapid Prototyping and Rapid Manufacturing
PCPro stands for Precise Cast Prototyping, which is a combination of casting technologies and
milling. This method was developed at Fraunhofer IWS in Dresden, Germany. It is patented in
Germany [1] and is applied in the USA under US 10/794,936. The main goal for this
development was to shorten the process chain for making plastic prototypes accompanied by
higher quality. The casting technology was integrated in a machining center in order to enable a
high degree of automation and to avoid an external casting system. This means that Rapid
Manufacturing can be easily implemented using such an automated combination of casting and
machining.
This article describes the PCPro method by means of the fabrication of sample parts. The
advantages and the limitations in comparison to common Rapid Prototyping and Rapid
Manufacturing process chains will be discussed. In addition, the manufacturing of a prototype
machine is presented.Mechanical Engineerin
Distributed machining control and monitoring using smart sensors/actuators
The study of smart sensors and actuators led, during the past few years, to the development of facilities which improve traditional sensors and actuators in a necessary way to automate production systems. In an other context, many studies are carried out aiming at defining a decisional structure for production activity control and the increasing need of reactivity leads to the autonomization of decisional levels close to the operational system. We suggest in this paper to study the natural convergence between these two approaches and we propose an integration architecture dealing with machine tool and machining control that enables the exploitation of distributed smart sensors and actuators in the decisional system
Pembangunan Modul Pengajaran Kendiri (MPK) keusahawanan dalam topik isu keusahawanan bagi pelajar diploma di politeknik
Terdapat pelbagai kaedah pembelajaran yang telah diperkenalkan termasuklah
kaedah pembelajaran yang menggunakan pendekatan pembelajaran bermodul secara
kendiri. Kajian ini adalah bertujuan untuk mengkaji kesesuaian Modul Pengajaran
Kendiri Keusahawanan dalam topik Isu Keusahawanan yang telah dihasilkan bagi
pelajar yang mengikuti pengajian Diploma di Jabatan Perdagangan Politeknik. Antara
aspek yang dikaji ialah untuk menilai sama ada rekabentuk modul yang dihasilkan dapat
memenuhi ciri-ciri modul yang baik, MPK yang dihasilkan dapat membantu mencapai
objektif pembelajaran, MPK ini bersifat mesra pengguna dan MPK yang dihasilkan
membantu pensyarah menyampaikan pengajarannya dengan lebih berkesan. Kajian ini
dilakukan ke atas 110 orang pelajar semester en am yang mengikuti pengajian diploma
dan 4 orang pensyarah yang mengajar subjek Keusahawanan di Jabatan Perdagangan
Politeknik Sultan Salahuddin Abdul Aziz Shah, Selangor. Kaedah analisa data yang
digunakan dalam kajian ini ialah skor min dan peratus. Hasil daripada kajian ini
menunjukkan bahawa rekabentuk modul yang dihasilkan memenuhi ciri-ciri modul
yang baik, MPK ini membantu untuk mencapai objektif pembelajaran, MPK ini
bersifat mesra pengguna dan MPK yang dihasilkan dapat membantu pensyarah
menyampaikan pengajarannya dengan lebih berkesan. Ini bermakna secara
keseluruhannya, hasil kajian menunjukkan bahawa modul yang dihasilkan oleh pengkaji
adalah sesuai digunakan oleh pelajar-pelajar semester enam yang mengikuti pengajian
diploma di Jabatan Perdagangan peringkat politeknik. Seterusnya, beberapa pandangan
telah dikemukakan bagi meningkatkan rnutu dan kualiti MPK yang dihasilkan. Semoga
kajian ini dapat memberi manfaat kepada mereka yang terlibat dalam bidang
pendidikan
The Factory of the Future
A brief history of aircraft production techniques is given. A flexible machining cell is then described. It is a computer controlled system capable of performing 4-axis machining part cleaning, dimensional inspection and materials handling functions in an unmanned environment. The cell was designed to: allow processing of similar and dissimilar parts in random order without disrupting production; allow serial (one-shipset-at-a-time) manufacturing; reduce work-in-process inventory; maximize machine utilization through remote set-up; maximize throughput and minimize labor
Toolpaths Programming in an Intelligent Step-NC Manufacturing Context
The current language for CNC programming is G-code which dates from the
beginning of the eighties with the norm ISO 6983. With the new technologies,
G-code becomes obsolete. It presents drawbacks that create a rupture in the
numerical chain at the manufacturing step. A new standard, STEP-NC, aims to
overtake these lacks. A STEP-NC file includes all the information for
manufacturing, as geometry description of the entities, workplan, machining
strategies, tools, etc. For rough pocket milling, the ISO norms propose
different kind of classical strategies as bidirectional, parallel or spiral
contour, etc. This paper describes a new way of toolpath programming by the
repetition of a pattern all along a guide curve. It presents several advantages
as building fastness and easiness. The integration of pattern strategies in
STEP-NC standard is an other step for the development of these strategies but
also for the enrichment of STEP-NC possibilities. A complete STEP-NC numerical
chain was built, integrating these pattern strategies. The implementation of
this approach of building pattern strategies was made by the development of
tools for the complete manufacturing cycle, from the CAD file to the machined
part. Several application cases were experimented on machine tool to validate
this approach and the efficiency of the developped tools
Topological model for machining of parts with complex shapes
Complex shapes are widely used to design products in several industries such
as aeronautics, automotive and domestic appliances. Several variations of their
curvatures and orientations generate difficulties during their manufacturing or
the machining of dies used in moulding, injection and forging. Analysis of
several parts highlights two levels of difficulties between three types of
shapes: prismatic parts with simple geometrical shapes, aeronautic structure
parts composed of several shallow pockets and forging dies composed of several
deep cavities which often contain protrusions. This paper mainly concerns High
Speed Machining (HSM) of these dies which represent the highest complexity
level because of the shapes' geometry and their topology. Five axes HSM is
generally required for such complex shaped parts but 3 axes machining can be
sufficient for dies. Evolutions in HSM CAM software and machine tools lead to
an important increase in time for machining preparation. Analysis stages of the
CAD model particularly induce this time increase which is required for a wise
choice of cutting tools and machining strategies. Assistance modules for
prismatic parts machining features identification in CAD models are widely
implemented in CAM software. In spite of the last CAM evolutions, these kinds
of CAM modules are undeveloped for aeronautical structure parts and forging
dies. Development of new CAM modules for the extraction of relevant machining
areas as well as the definition of the topological relations between these
areas must make it possible for the machining assistant to reduce the machining
preparation time. In this paper, a model developed for the description of
complex shape parts topology is presented. It is based on machining areas
extracted for the construction of geometrical features starting from CAD models
of the parts. As topology is described in order to assist machining assistant
during machining process generation, the difficulties associated with tasks he
carried out are analyzed at first. The topological model presented after is
based on the basic geometrical features extracted. Topological relations which
represent the framework of the model are defined between the basic geometrical
features which are gathered afterwards in macro-features. Approach used for the
identification of these macro-features is also presented in this paper.
Detailed application on the construction of the topological model of forging
dies is presented in the last part of the paper
On the optimal design of parallel robots taking into account their deformations and natural frequencies
This paper discusses the utility of using simple stiffness and vibrations
models, based on the Jacobian matrix of a manipulator and only the rigidity of
the actuators, whenever its geometry is optimised. In many works, these
simplified models are used to propose optimal design of robots. However, the
elasticity of the drive system is often negligible in comparison with the
elasticity of the elements, especially in applications where high dynamic
performances are needed. Therefore, the use of such a simplified model may lead
to the creation of robots with long legs, which will be submitted to large
bending and twisting deformations. This paper presents an example of
manipulator for which it is preferable to use a complete stiffness or vibration
model to obtain the most suitable design and shows that the use of simplified
models can lead to mechanisms with poorer rigidity
Asymmetric Dual-Arm Task Execution using an Extended Relative Jacobian
Coordinated dual-arm manipulation tasks can be broadly characterized as
possessing absolute and relative motion components. Relative motion tasks, in
particular, are inherently redundant in the way they can be distributed between
end-effectors. In this work, we analyse cooperative manipulation in terms of
the asymmetric resolution of relative motion tasks. We discuss how existing
approaches enable the asymmetric execution of a relative motion task, and show
how an asymmetric relative motion space can be defined. We leverage this result
to propose an extended relative Jacobian to model the cooperative system, which
allows a user to set a concrete degree of asymmetry in the task execution. This
is achieved without the need for prescribing an absolute motion target.
Instead, the absolute motion remains available as a functional redundancy to
the system. We illustrate the properties of our proposed Jacobian through
numerical simulations of a novel differential Inverse Kinematics algorithm.Comment: Accepted for presentation at ISRR19. 16 Page
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