34 research outputs found
Huisbesoek
Get PDFPastoral visitsRegardless the fact that opposition to pastoral visits is mounting in the church, it remains unreplaceable. There is but no alternative for these visits. Attention is given to certain biblical and theological arguments in an attempt to justify the continuation of this practice in the church. Although urbanization plays an important role it must not be regarded as a negative factor. Pastoral visits is to be considered as one of those structures in use to proclaim the Gospel. The ward-system needs to be utilized to a much greater extend as is the case now
Gynaecological product development facilitated through RP and Rapid Tooling
Get PDFPublished ArticleAtkinson distinguishes between four types of prototypes, categorised through its end-use: •Design or aesthetic prototypes
•Geometrical prototypes
•Functional prototypes
•Technological prototypes
Shigley and Mitchell define the design process according to the following six phases:
Recognition of need
Definition of problem
Synthesis
Analysis and optimization
Evaluation
Presentation
The Centre for Rapid Prototyping and Manufacture (CRPM) of the Central University of Technology, Free State was asked to assist in the development of a newly developed gynaecological cream applicator. Apart from needing a freeform fabrication system to give form fit and function to the very complex design, the product needed Rapid Tooling / Rapid Manufacturing support to enable a first batch production for medical trials and evaluation. The paper will describe the total product development process alongside prototype categories described by Atkinson and design phases defined by Shigley and Mitchell (including some iterations enabled through timeous prototyping, including various Rapid Prototyping (RP) Technologies, soft tooling and vacuum casting). More importantly, results from Rapid Tooling for limited run production (due to the complexity of the product the cycle time of the Prototype Tool is fairly long), as well as the economical impact made possible through the support of CAD / CAM and RP Technologies, will be discussed
DIRECT METAL LASER SINTERING, USING CONFORMAL COOLING, FOR HIGH VOLUME PRODUCTION TOOLING#
Get PDFPublished ArticleExisting techniques to manufacture conventional tool steel inserts for the plastic injection moulding process are expensive and time-consuming. Complex mould inserts, difficult to manufacture with conventional processes, can be produced using Direct Metal Laser Sintering (DMLS) with Maraging tool steel (MS1). MS1 is an additive manufacturing (AM) material made available by Electro Optical Systems (EOS) GmbH. Contrary to material removal processes, DMLS can produce MS1 tool steel inserts directly from Computer-Aided Design (CAD) files suitable for high volume plastic injection moulding. Through DMLS it is possible to create conformal cooling channels inside the MS1 inserts that have advantages in reducing heat rapidly and evenly. This can result in a reduction of cycle times, cost per product as well as improving part quality by eliminating defects such as warpage and heat sinks.
This paper will present a comparison between Finite Element Analysis (FEA) simulations of the injection mould inserts with actual mould trails of AM and conventional manufactured inserts. It also includes the design and manufacturing of conventional and DMLS inserts and compares the manufacturing costs and lead times. Using FEA simulations, the design of conformal cooling channels is optimised by comparing the mould temperature of different cooling channel layouts.
Bestaande tegnieke vir die vervaardiging van matryse vir die plastiek-inspuit giet tegniek is duur en tyd rowend. Verder is dit nie altyd moontlik om konvensionele metodes vir die vervaardiging van matryse vir geomteries komplekse gietstukke te gebruik nie. Vir sodanige gietsukke kan invoegsels relatief vinnig vervaardig word, deur van direkte laser metal sinterings metodes (DLMS) met Maraging-staal (MS1) gebruik te maak. MS1 is ’n laag vervaardings materiaal wat onlangs deur Electro Optical Systems (EOS) GmbH beskikbaar gestel is. Dit is ’n pre-allooi, ultra hoë sterkte metaal met goeie meganiese eienskappe. In teenstelling met materiaal verwyderings prosesse (masjienerings prosesse), kan DMLS MS1 staal matryse of insetsels wat vir hoë volume produksie van plastiek gietsukke bruikbaar is, direk vanaf rekenaar-gesteunde ontwerp prosesse vervaardig word. Die gebruik van DMLS kan ook vir die ontwerp en vervaardiging van vorm getroue verkoelings kanale in matryse voorsiening maak, wat tot laer hitte asook die vinnige en eweredige verspreiding daarvan sal lei. Voorgenoemde behoort tot ’n aansienlike verlaging in produksie siklus tye te lei met ’n dien ooreenkomstige verlaging in die produksie koste asook ’n verbetering in die kwaliteit van die vervaardigde produkte a.g.v. die voorkoming van defekte soos kromtrekking en hitte-putte wat normaalweg deur oneweredige hitte verspreiding veroorsaak word
Evaluating the Suitability of Alumide Tooling for Injection Moulding of Different Polymers
Get PDFPublished ArticleThis paper describes the possibility of using laser-sintered Alumide® as an alternative material for producing rapid tooling (RT) inserts. To determine the durability of Alumide® inserts for the injection moulding (IM) process, a product with geometrical features was developed, and Alumide® inserts were manufactured. Polypropylene (PP), acrylonitrile-butadiene-styrene (ABS), polycarbonate (PC), and polyamide 6 (PA 6) were used for IM trials with the Alumide® inserts. From these trials, it was concluded that polymer materials with a processing temperature of about 230 ºC, similar to PP and ABS, can be used with Alumide® inserts as RT inserts for the IM process
