3D scanning supports 3D printing
Green values and ecological thinking are accelerating the development of lightweight and efficient structures, while new generations are placing a lower burden on the environment by consuming less energy and materials. In order to continue this trend, product development requires ever increasing amounts of accurate information about product application areas. This ensures that products can be produced as efficiently as possible and that they meet their set requirements. 3D scanning and 3D printing are complementary technologies that are coming strongly to the fore in this regard.
In lightweight and optimised structures, it is of particular importance to have thorough knowledge of the surrounding environment, as a part or product can be included in a complex or cramped entity. Traditionally, boundary surface management and shape measurements have been demanding and labour-intensive tasks. The advent of 3D scanning has solved this problem; it can produce highly accurate measurements of complex shapes in a fraction of the time required by conventional measurement techniques.
3D printing, on the other hand, is a production method that allows more complex and free shapes than traditional production methods. This means that design can strive to deliver optimal features for a product, e.g. being lightweight and flexible, while at the same time taking life cycle loads into consideration. If a product is used or operated in a flow or heat transfer environment, for example, the flow resistance and heat transfer properties of the product can be optimised.
3D printing and design challenges
In product development the design process of printed and optimised products is more complex than that of traditional design methods. This is due to the fact that the goal is to develop a product that meets the increasing amount of requirements more closely. In this case, more information is produced and used in product design than with traditional products and production methods. The product’s physical demands are met with the help of technical analysis, which strives to gain as clear a picture as possible of the load levels the product will be exposed to during its life cycle.
3D printing allows optimised structural design as the production method allows the production of more complex shapes. This means that heat and strength loads, as well as flow demands can be met more closely. Topology optimisation is the term used to describe the geometrical optimisation of a product.
In the end, products need to be tested even if they were analysed and developed with the help of technical analysis. This is due to the fact that the material characteristics are dependent on the printing process and materials used. In order to control the quality of printed products the printing environment, material, and the part placement in the printer are standardised.
The duration of optimised product development projects is not greater than of traditional products, even though significantly more data is produced and used in the former. This is due to the fact that designers and analysts nowadays have extremely efficient tools at their disposal. A technical analysis project that took days to perform in the 1980s, can nowadays be done in a few hours. Optimised product design, however, requires designers with higher know-how levels so that the right information is at the right place at the right time.
Limits of 3D printing
As with other production methods, the possibilities and limitations of 3D printing as a production method need to be understood.
Metal prints are almost always sandblasted. In addition, the surfaces of printed parts require finishing if roughness under Ra10 is required. The surfaces of printed pieces remain rough and it is a feature of the production method. In many cases rough surfaces are not a deterrent. Production tools, for example, can be used in the form they are printed. In consumer products aesthetic features and handling comfort are of greater importance and, therefore, require surface finishing.
3D printing is not currently suited to mass production as it is too slow. New printing methods and more efficient devices are, however, continuously being developed and in future we may see 3D printing used even in mass production.
3D scanning produces accurate information for design
3D scanners for individual parts have been available for years already. Scanners aimed at consumers are commonly available, even though they are not sufficiently accurate to be used in industrial projects. The great supply of consumer-targeted devices has also been affected by the high price of better quality accuracy scanners.
With the help of scanning a 3D model can be created of an existing part or its environment. The digitised materials can be used in producing a replacement part or to create a better optimised entity in design. Hand-produced prototypes can also be digitised into production models, while shape analysis can be conducted by comparing scanned materials with the design model. Scanning can furthermore be used to evaluate production success, quality or to identify errors.
As a measurement method, scanning is at its most efficient when double-curved surfaces have to be measured. The measurement of even complex parts can usually be done in an hour. The point cloud surface model is usable practically immediately after scanning. Often a point cloud model is sufficient as surface and solid modelling is not always needed. Design programs have also developed rapidly with regards to the import and use of scanned materials.
Combining scanning and printing
Tools that wear during use need to be stored as they tend to have long delivery times. If tools are printed they can be produced cheaply according to demand – there is no need to store tools. Part of the price of an individual tool also does not change significantly as the production amount increases.
Vibrating feeders transfer small components to assembly stations. The feeders are often produced as castings or plate structures. For some components optimised vibratory feeders can be printed one at a time, instead of producing a large series that is kept in storage. Because the tool can be tested quickly, its development cycle is markedly faster than that of a casting.
A significant benefit can be gained when all the printed structure’s functions are combined into a single part. Brackets, grips and supports are typical examples of customised parts of products.
By combining 3D printing and scanning cost and time savings can be achieved. It also allows required spare parts to be produced quickly. This means that large amounts of spare parts are not required in storage, which eases warehousing and logistics. Parts produced with this method fit within a millimetre’s accuracy, even in double-curved shapes. Material losses can also be reduced in lightweight and demanding structures.
3D scanning and 3D printing video
Authors: Teemu Launis and Samu Sundberg