As an application of the computer aided design and computer aided manufacturing (CAD/CAM) technology in prosthetics, computer aided socket design and computer aided socket…
As an application of the computer aided design and computer aided manufacturing (CAD/CAM) technology in prosthetics, computer aided socket design and computer aided socket manufacturing (CASD/CASM) is becoming an active field in the prosthetics research. In this paper, a CASD/CASM method for prosthetic socket fabrication is described in detail. This is different from other fabrication methods in its novel combination of the CAD/CAM technology with fused deposition modeling (FDM) technology. Prosthetic sockets for volunteer amputees have been designed and fabricated in a FDM machine. In order to test the fabrication result, a final product was used to perform a clinical trial and some results are reported. In addition, the deficiency of the long fabrication time is addressed and some feasible solutions are discussed.
This paper focuses on the development of a distributed rapid prototyping system via the Internet to form a framework of Internet prototyping and manufacturing for the…
This paper focuses on the development of a distributed rapid prototyping system via the Internet to form a framework of Internet prototyping and manufacturing for the support of effective product development. The proposed methodology is targeted at a wide audience using a disparate range of computer systems to access remotely located rapid prototyping facilities via the Internet for prototype fabrication. The methodology is useful for both educational research for teaching evolving rapid prototyping technologies and remote scientific visualization. This approach is based on the merger of object‐oriented modular software architecture and client server communications for the remote control of rapid prototyping hardware (called fused deposition modeling) via the Internet. Other Web tools are used to allow the remote user to have higher interactivity with the server applications that have a direct link with the front‐end terminals controlling the rapid prototyping hardware.
The purpose of this paper is to present the results of an investigation into the effect of injection molding process parameters on the performance of direct metal laser…
The purpose of this paper is to present the results of an investigation into the effect of injection molding process parameters on the performance of direct metal laser sintered (DMLS) mold in producing quality Zytel nylon 66 plastic parts with consistency in part shrinkage and shot/part weight.
The injection mold for an industrial component (hub gear) was fabricated in EOS M‐250 machine using bronze‐based material. The effect of four injection molding parameters (injection pressure, melt temperature, speed, and injection time) on part shrinkage and weight were studied experimentally using L9 orthogonal array. The weight of the part just after ejecting from the cavity, and the average shrinkage measured after cooling, were used in grey relational analysis technique to assess the effect of each molding parameter. Further, surface properties such as surface finish, wear, scratch and corrosion resistance tests were conducted on DMLS mold material samples, in order to evaluate its use in rapid manufacturing applications.
The study found that injection speed and melt temperature have significant influence on part weight and shrinkage. The optimized molding process variables were slightly more in the case of DMLS molds as compared with the parameters suggested in the plastic datasheet. Scanning electro microscope (SEM) analysis of the mold surface after producing 5,000 glass filled Nylon 66 (Zytel) moldings did not indicate any surface degradation, confirming the use of DMLS mold in rapid manufacturing of few thousands of moldings.
The grey relational analysis does not compute the effect of any two or more variables together unlike ANNOVA. Second, this study alone is not enough to estimate life of DMLS mold, although 5,000 glass filled nylon 66 moldings are successfully produced without any damage on mold surface.
This investigation demonstrates a generic approach of using grey relational analysis to quantify the effect of different molding process variables on selected quality parameters. This method can be easily extended for new processes and materials. The preliminary tests on surface finish, scratch, wear and corrosion resistance performed on DMLS mold samples have highlighted the need for improving surface properties to enhance their life. The authors are currently working on hard coating of DMLS molds as one of the solutions.
Use of grey relational analysis is new to the problem of injection molding process optimization. Moreover, effect of injection molding parameters on part weight and shrinkage in DMLS mold has not been studied previously. This study helps while considering DMLS molds for manufacturing few thousands of parts.
The action taken by the Council of the British Medical Association in promoting a Bill to reconstitute the Local Government Board will, it is to be hoped, receive the strong support of public authorities and of all who are in any way interested in the efficient administration of the laws which, directly or indirectly, have a bearing on the health and general well‐being of the people. In the memorandum which precedes the draft of the Bill in question it is pointed out that the present “Board” is not, and probably never was, intended to be a working body for the despatch of business, that it is believed never to have met that the work of this department of State is growing in variety and importance, and that such work can only be satisfactorily transacted with the aid of persons possessing high professional qualifications, who, instead of being, as at present, merely the servants of the “Board” tendering advice only on invitation, would be able to initiate action in any direction deemed desirable. The British Medical Association have approached the matter from a medical point of view—as might naturally have been expected—and this course of action makes a somewhat weak plank in the platform of the reformers. The fourth clause of the draft of the Bill proposes that there should be four “additional” members of the Board, and that, of such additional members, one should be a barrister or solicitor, one a qualified medical officer of health, one a member of the Institution of Civil Engineers, and one a person experienced in the administration of the Poor‐law Acts. The work of the Local Government Board, however, is not confined to dealing with medical, engineering, and Poor‐law questions, and the presence of one or more fully‐qualified scientific experts would be absolutely necessary to secure the efficient administration of the food laws and the proper and adequate consideration of matters relating to water supply and sewage disposal. The popular notion still exists that the “doctor” is a universal scientific genius, and that, as the possessor of scientific knowledge and acumen, the next best article is the proprietor of the shop in the window of which are exhibited some three or four bottles of brilliantly‐coloured liquids inscribed with mysterious symbols. The influence of these popular ideas is to be seen in the tendency often exhibited by public authorities and even occasionally by the legislature and by Government departments to expect and call upon medical men to perform duties which neither by training nor by experience they are qualified to undertake. Medical Officers of Health of standing, and medical men of intelligence and repute are the last persons to wish to arrogate to themselves the possession of universal knowledge and capacity, and it is unfair and ridiculous to thrust work upon them which can only be properly carried out by specialists. If the Local Government Board is to be reconstituted and made a thing of life—and in the public interest it is urgently necessary that this should be done—the new department should comprise experts of the first rank in all the branches of science from which the knowledge essential for efficient administration can be drawn.
We have reprinted the powerful letter addressed to the Daily Mail by MR. H. W. WILSON, the author of “Ironclads in Action,” advocating the immediate adoption of a policy of reprisals for the Zeppelin murder raids. In our view it is the duty of every journal, whatever may be its raison d'être, to assist in keeping the attention of the public fixed upon this matter, to aid in preventing the general feeling of disgust and indignation from cooling down, and to support those who have the brains to understand the nature of the Hun in their efforts to compel the Government to adopt the most effective means at present available to put an end to the murderous excursions of the German vermin into this country. As MR. WILSON points out, the deliberate Hun policy of slaying women, children and non‐combatants is either permitted by the laws of war recognised by civilised nations or it is not permitted by those laws. If it is permitted, “then clearly the Power which refrains from making similar attacks on the enemy's towns, villages, and residential districts, loses greatly from the military standpoint.” If it is not permitted then the only course— “the force behind the laws of War”—is a policy of drastic reprisals. Moreover, it is the only course that the Hun can understand. The methods of “frightfulness” are definitely laid down in the German military system as methods to be ruthlessly followed whenever this can be done with impunity and the fear of reprisals is also definitely laid down as the only consideration which is to be allowed to operate as a check upn “frightfulness.” “The Power which fails to take reprisals when a great offence is committed is as the negligent judge or the faithless jury that acquits a murderer. It sins against humanity … it encourages the criminal in his crime.”