CAD/CAM Systems -6 What is a Good CAD/CAM System?
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WARNING: Machine tools present a safety hazard. Improper operation can result in severe injury. These topics are for non-laboratory study only and are not to be used in conjunction with the operation of any tool or machine described herein. Never use a machine tool without the supervision of a qualified instructor.
A good CAD system has the following characteristics:

Easy to learn: It should be a step by step process done in a logical manner. It should be menu driven and highly graphic with as much data as possible displayed on the screen. It also should have an online tutorial so the new user can get started quickly, online context help accessible from any point in the program, and online documentation.

Simple to use: It should be adaptable to a particular application and should not require a specialist to operate it.

Macro commands: Like CNC macros this is a single key or command that causes the execution of a string of commands.

Embedded programming language: The CAD software should have its own customized language or script.

Expandable: It should be able to grow with the needs of a company. You should be able to change peripheral devices such as display monitor or plotter.

Open database: It should do more than just create drawing. It should be able to generate bill of materials and maintain prices and other database information as well as offering some level of data protection.

Compatible: It should be compatible with other CAD/CAM and analysis programs. It should easily be able to exchange geometric models with other programs using standard model interchange file format such as IGES, DXF , and STL and others

But which CAD/CAM system is the best? The best CAD/CAM system will usually be the system that is simply the most productive. In some cases the type of machined parts produced can dictate productivity and the choice of the system. However, more often the productivity factor is based on the programming staff. If a staff has a significant amount of experience on the LIBRA CAD/CAM system then there would a great deal of expensive training and ramp-up time involved in changing to the ARIES CAD/CAM system. Also note that it is rarely the case that new features of the LIBRA or ARIES CAD/CAM systems are compelling enough to make a switch. Each system chases the other with new features so that in less than a year the new feature - if of value - will be added to the next release. Remember this: For a programmer the best system may be the one that gets them steady employment. For a shop owner the best system may be the one that allows them to find many pre- trained employees. R.S.

As part of a United States Department of Labor program in 2000 our campus in Southern California was asked to conduct a survey of the machine tool trades. Of particular note was that out of approximately 500 respondent machinists only 15% were captive employees of a company that engineered the product they machined. This left 85% to work in job-shops which bid on and machined product for the designing and engineering companies.

70% of the job shops in 2000 had at least one CNC machine and used an in house CAD/CAM system to program them (read very few manual programers). However the majority of the shops bid from an orthographic blue print or a DWG or DFX file and did not import or accept solid models. in 2000 R.S.

Just a follow-up thought having only a loose connection to CAD/CAM: Should the aforementioned survey have taken place in 1988 I suggest that 75% of the job shops in southern California would have been strongly dependant upon aerospace/military work. However due to the collapse of that industry (the Berlin wall came down in 1989) a great many shops went out of business. Those that survived diversified and tend to blend a little aerospace with commercial work today (2000).

However there was a large segment of manual machine shops that were barley touched. Particularly those that had an inventory of large machines (like this vertical lathe) and had never become completely dependent on aerospace and used little if any CNC machinery or CAD/CAM. A CNC vertical lathe like the one shown would be very expensive so there is an economic advantage to having manual machines that are paid for. These shops continue with large one-ups like ships propellers or offshore drilling hardware.  Right now (2000) they can't find machinists who can run these old manual machines.. R.S.

One paragraph needed to explain how things are today? Are there still large non-CNC machines in use? Where?

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label: cad/cam, system, integration, comparison, use of, teaching