Paul Siodmok answers all your questions on CAD
Which system to choose?
A good way of selecting a CAD system is to write out a list of your requirements. This might include features such as 2D plotting, parts libraries, construction history, ease of use etc. Then benchmark evaluation copies of CAD software against your specific criteria.
Where can I get training?
Initially it is worthwhile going through the software manual and the set examples and case studies provided when you buy the software. This should give you familiarity with the interface and the basic geometry creation and manipulation tools. After this period you can either choose to go on a course provided either by the CAD software company or a value added reseller (VAR). It is often worthwhile considering using a specialist independent trainer who can create a course for your specific requirements.
Solid or surface modelling?
The CAD software business is fairly split between these two areas - there are some systems which claim to cater for both areas - although rarely successfully in my experience. Solid systems tend to have better engineering capabilities including parametric construction history - where a part has 'intelligence' about the effects of changes to it or an assembly. Surface systems tend to be able to describe more complex forms and often have more sophisticated rendering or visualisation capabilities.
How do I exchange data with suppliers?
There are two main routes to ensure successful data exchange. Often suppliers to, say, the automotive industry adopt the same CAD system. This has the advantage of data exchange with the construction tree of the model intact allowing either side to make amendments. The other route is to use a neutral file format such as DXF, IGES or STEP. These are commonly used to exchange data between various systems, and can now be 'flavoured' to suit the target system. Files such as STL (triangle data file) are also neutral to allow rapid prototype machines to build parts from any system that can output STL.
How do I deal with corrupt files?
Backing up data everyday, preferably over the network at night, and storing off site is your best bet to ensure you do not lose data. If data is corrupted then check the following:
- Is the file truncated in some way - check the file size and header?
- Has binary or ASCII data translation affected your FTP results?
- Are you using the same version - often CAD files are not backwards compatible?
- Have you used the correct construction tolerances for the target system? Ensure the file is a solid or volume model - if you are using a surface system make sure it stitches.
- Check your co-ordinate system - millimetres or inches?