3 Computer aided draughting When computers were first used by product designers, software was developed that enabled them to draw products.These products ranged from architectural models to car components. The main purpose of these drawings was for engineers and manufacturers to have the necessary information to make the product.Drawing packages enabled designers to quickly convert hand drawings of products into an electronic format for safer storage and easier communication. This is called computer aided draughting (drawing).
4 Computer aided designing Computer aided draughting led software engineers to create computer packages for product designers which would enable them to create designs, rather than just draw diagrams.Special tools and functions were developed so that designers could quickly create and change the features of a design.Various types of CAD software emerged, enabling designers to create and develop designs in 2D and 3D forms within an electronic environment.
5 Computer aided testing Once product designers were able to create and develop products in an electronic format, they realized the great benefits this brought.Software engineers began to further develop the product information to give it mass and volume, enabling product designers to imitate various materials and conditions under which the product would function.This led to product testing. Product designers can now conceive, develop and test a product with a very short lead time. We can see products actually working before they are even made. This has reduced the cost of developing new products.
7 Types of CAD Two-dimensional (2D) Create simple shapes in the X and Y directions.Does not show the Z direction (depth).Can be used for drawing, pattern draughting and for drawing images that appear to have three dimensions but are still in a 2D format.3D modellingCreates shapes in three dimensions (x, y and z).Uses intuitive tools such as dimensioning, extruding and rounding edges to create wireframe and solid models.Wireframe models show the product as a coat hanger model with no solid surfaces, so the features behind and on the rear of the product are visible.Solid modelling shows the product with a skin over the top of the wireframe. Solid models are easier to visualize because they look like the real product.
8 Photo realistic rendering These models were produced using Pro/DESKTOP 3D Design Software by PTC. They show designs for vacuum cleaner accessories:Product 1 is a sanding attachment for a vacuum cleaner powered by the suction power of the cleaner.Product 2 is a hose attachment for a vacuum cleaner.Product 3 is an animal grooming brush designed to be attached to a vacuum cleaner.
10 Computer aided manufacturing Computer aided manufacturing (CAM) uses a computer to control manufacturing machinery. When combined with CAD, computer aided manufacturing is a very useful production process.CAD/CAM is the process of linking computers used to aid design with computers used to aid manufacture.A CAD drawing is essentially visual information. When this information is changed into numerical data to control the operation of a machine, it is called computer numerical control – C.N.C.
13 Programming a CNC machine CNC CAM machines interpret the information provided byCAD software. Many CNC machines use a special softwarelanguage called FANUC.FANUC software reads the CAD file and then produces machine code for the CNC machine to use.Much of this special language is made up from information called G code and M code.G codes provide the CNC machine with information about the direction of movement of the cutting tool.M codes refer to miscellaneous functions such as starting the cutting tool and turning on the coolant.
14 Programming and coordinates Below is a list of selected G and M codes which are used in milling operations. If you have access to a CNC milling machine, see if you can spot some being used.G00 – rapid movementG01 – straight line cutting moveG02 – clockwise cutting moveG03 – anticlockwise cutting moveG71 – metric unitsG81 – drilling cycleG90 – absolute programmingG91 – incremental programmingM03 – start spindle forwardsM04 – start spindle reverseM05 – stop spindleM06 – tool changeM08 – coolant onM09 – coolant offM39 – close automatic chuckWhen a CNC machine moves, it must have a datum so that it knows how far to move. Incremental and absolute are two types of programming which use the datum in a different way.
15 Incremental programming Incremental programming determines each move in relation to the position of the last one. In other words, every move starts where the last one finishes.XY-1+2-2+3-y+y+x-xcutterDatum (start)
17 Absolute programming X Y Absolute programming determines each move in relation to a single datum point (usually in the bottom left corner).In other words, every move starts from the same start point.-y+y+x-xXY-12-2-357cutterDatum (start)
19 Types of CNC machinery – milling machine A milling machine uses a rotating cutting tool to shape a range of metals and plastics.The work is clamped to a bed which moves in the X and Y directions.The cutting tool is placed in a chuck connected to a rotating spindle.The spindle moves in the Z direction.Photo courtesy of Denford Ltd (
20 Types of CNC machinery – router A router uses a rotating cutting tool to shape a range of timbers.The work is clamped to a bed.The cutting tool is placed in the router chuck connected to a high-speed rotating spindle.The router moves in three axes on a complex arrangement of mechanisms.Video courtesy of Denford Ltd (
21 Types of CNC machinery – lathe A lathe is used to produce cylindrical objects.Materials are held in a chuck and rotated at different speeds.The cutting tool is held in the tool post and is inserted into the material as it rotates. It moves in the X and Y axes.The final shape of the material depends on the path taken by the cutting tool.Photo courtesy of Denford Ltd (
22 Types of CNC machinery – laser cutter A laser cutter uses a concentrated laser to cut or mark materials.Laser cutters can cut several materials including wood, plastic, fabric, leather, paper and rubber. They will also mark glass, ceramic and stone.Lasers can perform the following functions: cutting, deep engraving, precision scribing and decorative etching.They are extremely fast and efficient to use.Photo courtesy of Techsoft (
23 Types of CNC machinery – embroidery machine Computerized embroidery machines are capable of embroidering onto fabrics, paper, card and board.Images can be created using CAD software, taken from clipart or hand drawn and then scanned in.Machines can be driven directly from the PC.Image courtesy of Techsoft (
24 Types of CNC machinery – vinyl cutter Vinyl cutters, like the one shown here, can cut and score paper, card and vinyl. They are available in various sizes from A5 to A0 and beyond. The video clip below shows how labels for sandwich packaging are designed on computer, and then cut out using a computer controlled vinyl cutter.Video courtesy of Techsoft (
25 Types of CNC machinery – rapid prototyping There are three main types of rapid prototyping.Resin based systems use a resin which sets hard when hit by a laser.Laminate systems build up a solid model from layers of material positioned on top of each other.Wax based systems are similar to an inkjet printer and squirt wax onto a moving platform.Photographs reproduced courtesy of Techsoft (These models have been produced using a rapid prototyping 3D printer, like the one pictured.
26 Computer integrated manufacturing CAD CAM working togetherWhen CAD and CAM are used together, it is often referred to as CIM (Computer Integrated Manufacturing).CIM incorporates all aspects of the design and make process.Product designers from different countries can work on all stages of the design and manufacture of a product.Photo courtesy of Denford Ltd.For more information about CIM systems see
27 Computer integrated manufacturing (CIM) All aspects of the design and manufacture process are involved in CIM.Research &developmentProductionplanningDesignCIMMarketingQuality control& assuranceManufacturing& productionLogistics