November 6, 2008 - Designing products that can be easily manufactured is one of the key challenges of companies nowadays. Missler Software’s philosophy has always been to make Designs which can be manufactured and is the cornerstone of the company’s baseline Integrated CAD/CAM/ERP. In fact the greater the integration between the design and manufacturing stages the easier it is to manufacture – as we know designs which cannot be manufactured have little real value in today’s industrial society. The TopSolid integrated CAD/CAM product range offers complete integration between design (CAD) and manufacturing (CAM) which thereby offers important productivity gains in the industrialisation of products. However, what happens when TopSolid’Cam (Missler Software’s CAM solution) is used with another CAD package? 2 solutions will be explored in this article: TopSolid’Gmi and model comparison.

The need to improve CAD/CAM links

The externalisation of certain jobs and the globalisation of many sectors have meant that design and manufacturing tasks are often now carried out by different companies who often use different CAD/CAM packages (in addition these companies are often located hundreds and thousands of kilometres apart). In addition, even if some companies still manage the complete design to manufacturing chain they do not always use functions available in the design stage which would facilitate and optimise subsequent manufacturing. As there are so many different CAD/CAM systems available such companies do not benefit from the full benefits of integrated CAD/CAM. The need to automate the design and manufacturing of parts as much as possible (in order to reduce costs and optimise turnover times) as well as last-minute changes in CAD designs due to shorter cycle times demand a maximum of interoperability between CAD and CAM systems.

Manufacturers and sub-contractors are familiar with life-cycle issues relating to their products. In order to respond to many different needs, designs are often changed, even after the manufacturing phase has started. This often happens because design and manufacturing stages are carried out at the same time to be able to deliver end-products as quickly as possible – commonly known as “Concurrent engineering”. Any changes carried out on the design imply of course a change to the CAM program. However, as lead-times are increasingly being reduced it is important that companies only spend time amending changes made and in not redoing the entire CAM program.

Here are the solutions offered by Missler Software to tighten the links between CAD and CAM systems and thereby reduce time wasted because of concurrent engineering:
Naturally enough the best solution to the CAD/CAM communication issue is the use of a fully integrated CAD/CAM solution – i.e. TopSolid, one software which offers both CAD and CAM functions. In this case full communication is guaranteed because only 1 software is used for design and CAM programming for manufacturing. When this option is not possible Missler Software offers 2 alternative solutions to optimise communication between TopSolid’Cam and other CAD software packages:

•        TopSolid’Gmi for the automatic machining of features
•        Comparison and replacement based on the topological analysis of modified models.

TopSolid’Gmi

Many standard interfaces exist to transfer data between CAD and CAM software systems. Such interfaces transfer the dimensional characteristics of CAD models to the CAM software. The major weakness of these interfaces is that they do not transfer the features defined and used by the CAD operator, i.e. the nature and quality of holes, tolerances, etc. are lost.

A number of years ago Missler Software created an internal team dedicated to improving the communication between TopSolid and other CAD/CAM software systems on the market. This team is called the “Interoperability Team” and works intensively on the recuperation of CAD features from major CAD packages by TopSolid’Cam. The result of the team’s work can be found in the work tool « TopSolid’Gmi » which is a technological interface for CAD systems. TopSolid’Gmi enables the transfer of model geometries, technological data and feature characteristics to TopSolid’Cam. With this information in hand the CAM programmer can automatically assign CAM machining cycles such as drillings, borings, tappings, etc. to features generated by the CAD software. Not only does TopSolid’Cam benefit from all the information contained in the feature from the CAD software but in the case where the part is modified it is no longer necessary to re-program the machining of the part. Thanks to TopSolid’Gmi model changes become associative which means that they are very simply recalculated by TopSolid’Cam in a click of the mouse. TopSolid’Gmi represents therefore an optimal means of communication between major CAD solutions and TopSolid’Cam.

Missler Software created TopSolid’Gmi to respond to the needs of customers who have particularly important needs in terms of the creation of holes. For those companies who manufacture parts containing many types of different holes it is an essential tool which allows much greater manufacturing automation. Programming times and errors are greatly reduced – Experience shows that errors often happen in the case of the manual change of machining cycles which is no longer necessary thanks to TopSolid’Gmi.

Comparison and replacement based on topological analysis

TopSolid’Cam also offers a function to compare the initial and modified models as a solution to managing changes in CAD models designed with CAD solutions other than TopSolid’Design (and where features are not used thereby not permitting the use of TopSolid’Gmi). In this case TopSolid’Cam compares the initial model generated with the modified model. This function, which is based on a topological analysis, identifies the differences between the 2 models. The aim of this function is to clearly identify the machining processes impacted by the geometry modification and to show how to subsequently change the machining process and/or to create a new machining process. This function highlights only what has to be updated following the modifications of the CAD model. In this way the operator does not have to re-program the entire machining process which generates significant time gains.

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