In the footwear industry, Computer Aided Design and Computer Aided Manufacturing are used for designing and grading shoe upper patterns and, manufacturing of cutting dies, shoe lasts and sole moulds, respectively.
CAD was introduced in the shoe industry first in 1970s. Initially, it was used primarily for pattern grading. It enabled manufacturers to easily and quickly perform complex grading.
Today, CAD systems are used in a wide range of functions. Logos, textures and other decorations can be incorporated into product designs of both the uppers and soles to help reinforce branding on all areas of a model. CAD automates routine procedures, increasing speed and consistency whilst reducing the possibility of mistakes. CAD data can now be used effectively for a wide variety of activities across footwear manufacturing business. CAD/CAM generates data at the design stage, which can be used right through the planning and manufacturing stages.
Latest improvements in the CAD/CAM technology are:
- Graphic capabilities and interconnectivity have improved enormously
- Software developments have progressively made systems more intuitive and easier to use
- With 2D sketch and paint modules, a serviceable sketch can be produced and then color and texture can be added
- 3D systems enable the last and design to be viewed from any perspective and several angles even simultaneously.
With CAD/CAM software, footwear manufacturers can cut their time to market dramatically and hence, increase market share and profitability. In addition, the power and flexibility of the software can overcome restrictions to the designer’s creativity imposed by traditional methods.
Pattern grading
Shoe upper patterns need to be graded for the whole scale of the assortment of the required shoe sizes, which can be European, British or American sizing. Individual parts are graded instantaneously, which enables the designer to check the graded parts on the monitor. If any discrepancies are found, the designer can change the grading specifications immediately and re-grade the parts in no time.
Die making
Cutting dies made of steel are used in the shoe production to cut uppers from leather, textile or synthetics. Some CAD systems offer modules that enable long-distance transfer of data for shoe production preparation via modem or the Internet. The graphics data of patterns designed can then be transmitted easily to the die producer. The system also calculates the circumference of the die, which is the key factor of the die cost.
Automated leather
Automated cutting machines are widely used today in the footwear industry to cut uppers from leather, when die costs are relatively high for samples or low quantity styles. Computerized cutting systems use graphics data output of CAD systems as input.
Cost calculation
Using the graphics data generated, the CAD software can perform instant and highly accurate calculations for material consumption and product cost of the shoe, eliminating grueling and time-consuming work. It also helps in the introduction of detailed documentation and in effective staff training.
Shoe last design
Lasts can now be produced on a selection of numerically controlled lathes and milling machines using data output from CAD systems. Last shapes can be modified and new lasts created in the CAD systems. Variations in toe shape, heel curve and toe spring are easily achievable. Combining parts of different lasts also takes a few minutes with CAD technology.
It is possible to develop shoe design and tooling before the last physically exists because they are all derived from the same source data in the CAD system.
Easy modification of last shapes through CAD has enabled the development of software and procedures for orthopedic and customized footwear. Modules for materials and labor costing, lay planning and style specification sheets can be used early in the development of shoe styles.
Complex shapes can be generated, both rapidly and accurately, from the 3D computer representation of the appropriate last.
Sole design
CAD/CAM software can be used to generate machining data for shoe sole models and moulds. Shoe sole mould makers are able to strengthen their capabilities of mould design and production techniques to meet the market demands for shorter product life cycle, quality improvement and handling versatile pattern design. This helps especially sports shoe producers to manufacture products rapidly and to introduce them earlier than their competitors.
3D CAD/CAM is the core technology for shoe sole mould in the footwear industry and develops towards specialization.
Benefits of CAD/CAM in the mould manufacturing are:
- Total modeling for rapid generation of design concepts and variations
- Reverse engineering from existing models or parts
- Easy design modification and morphing capability
- Completely accurate designs regardless of complexity
- Group grading of soles and uppers
- Advanced decorating techniques
- Realistic onscreen visualization
- Rapid generation of molds from product designs