Overview:
3D printing is a method ofcreating physical 3D modelsfrom digital files. There are many different kinds of 3D printing but in essence they work a lot like 2D printers except instead of the head moving in 2 dimensions to create a pattern of ink on paper, the printer head can move in up and down as well to build up a 3D object layer by layer. Each layer is a thin slice or cross section through the object that is created from the CAD model using 3D printing software.
Despite the perception that 3D printing is very new, the first printer was actually made in 1987. However, it is only recently that the technology has become simple and cheap enough for the average person to access.
What are the different types of 3D printing?
These are the most common types of 3D printing:
FDM- These melt plastic filament and push it out through a computer controlled nozzle, somewhat like a glue gun. This builds up your model layer by layer by tracing out the shape of each cross section on a glass plate. There are often different quality options based on individual layer height. A larger layer height will be much quicker but may be more visible once the print is finished especially on curved surfaces where it can create a stepped appearance. Post processing is sometimes done to remove this.
FDM tends to be the fastest and cheapest 3d printing method but the least accurate.
SLA and DLP- Use point lasers or UV light sources to cure a layer of plastic resin. SLA is more complicated but can create smoother finishes and transparent parts making them good for visual prototypes. As they use a UV resin to cure, they should be kept away from the sun, or they will yellow. They also tend to be weaker and more brittle than other kinds of print which often makes them less suitable for functional parts.
There are more ways to 3D print, but they tend to have more niche uses or still be quite early in their development.
SLS, DMLS and SLM, Use lasers to selectively fuse a tiny section of powdered material. This can be plastic or metal. A thin layer of powder is deposited onto a platform at a time and the structure slowly builds upwards. The un-sintered powder can act as a support material. These parts tend to be very strong but somewhat powdery in appearance which can be improved with post processing. This process is one of the more expensive to run due to the large amount of maintenance and cleaning.
What is support material?
Support material is a structure that is not part of the model being printed but is used to support it like a scaffold during printing. This is necessary for undercuts in FDM or for any SLA/DLP. In FDM this can sometimes be a separate material. PVA is often used as it is water soluble so to remove it from the print requires soaking the part in a bath of water. In SLA this will be the same resin from which the part is made, instead it is designed to have a weaker structure. This must be removed by hand after the part is printed.
The used of 3D printing in design
Can I use 3D printing to manufacture my product?
For most products 3D printing is unlikely to ever become the most economical option for manufacture. Whilst there are great news articles about everything from 3D printed hearts to 3D printed homes, a lot of these fall into 3categories:
3D printing a bespoke design
This is the most common use of 3D printing and includes 3D printing prototypes. Handmaking a custom product with traditional methods can be very expensive and labour intensive.
Many of the mass manufactured products that you use each day require tooling for plastic and metal parts. This tooling is an expensive upfront investment that allows manufactures to create many identical products relatively cheaply compared to fabricating products from sheet or bought-in parts. A tool must be used to make many products in order to be cost effective, so making single bespoke products has always had a high cost.
In making a bespoke product or prototype there are 2 main associated costs: design and production. 3D printing drastically reduces the production cost as there is much less labour involved. Designers can also take some shortcuts when designing for 3D print as the tooling does not need to be designed and parts do not require draft angles or similar.
3D printing a complicated design
Products including high precision industrial parts, art pieces and even biological organs are only possible because of developments in 3D printing.
Some complex shapes are very difficult to manufacture, especially those with a lot of detail on both the inside and the outside surfaces and/or undercuts. In the past these were often made by breaking the design into smaller pieces which were then assembled. This was both expensive and created more points of failure.
Because 3D printers create everything layer by layer, they can access areas of the part that would otherwise be hidden. This has created a boom in innovative new designs that rely on 3D printing to create ‘impossible’ shapes.
3D printing small batches quickly and cheaply
This is the most common use of 3D printing and includes 3D printing prototypes. Handmaking a custom product with traditional methods can be very expensive and labour intensive.
Many of the mass manufactured products that you use each day require tooling for plastic and metal parts. This tooling is an expensive upfront investment that allows manufactures to create many identical products relatively cheaply compared to fabricating products from sheet or bought-in parts. A tool must be used to make many products in order to be cost effective, so making single bespoke products has always had a high cost.
In making a bespoke product or prototype there are 2 main associated costs: design and production. 3D printing drastically reduces the production cost as there is much less labour involved. Designers can also take some shortcuts when designing for 3D print as the tooling does not need to be designed and parts do not require draft angles or similar.
Products including high precision industrial parts, art pieces and even biological organs are only possible because of developments in 3D printing.
Some complex shapes are very difficult to manufacture, especially those with a lot of detail on both the inside and the outside surfaces and/or undercuts. In the past these were often made by breaking the design into smaller pieces which were then assembled. This was both expensive and created more points of failure.
Because 3D printers create everything layer by layer, they can access areas of the part that would otherwise be hidden. This has created a boom in innovative new designs that rely on 3D printing to create ‘impossible’ shapes.
Designing a product for manufacture is a long and expensive process. Generally, in mass manufacture, the more time is spent up-front, engineering the product and working with manufacturers to create the most effective tools, the cheaper and more reliable the end product will be. A typical time for making an injection moulded tool for a plastic part (such as the lid for a biro) could be around 6-10 weeks. Often for small parts such as these, the tool will have multiple ‘impressions’ in them which allow them to make many pen lids at once. This reduces the cost per pen lid.
Perhaps you need a prototype to test before you commit to tooling? Perhaps you want to try out two different variations in the market and see which is more popular. Perhaps you just want a small number of units to show to investors. If you don’t yet have the time or money to commit to tooling, 3D printing is a great option.
3D printing is very commonly used for prototypes, small testing batches and promotional items. This is the main way we use 3D printing at Bang. 3D printing is a great way to test
The (current) limits of 3D printing
High quality
Specific material properties
Mix of materials
3D printing is a very useful tool but it has limits. Generally it can only use a limited selection of materials and cannot print dissimilar materials at the same time such as plastics and metals.
3D prints are often more either fragile than the final production product or lack some of the functionality (flexibility, transparency)
To get the most out of a 3D print they still need a lot of finishing. A lot of examples of 3D prints you may have seen will not have come straight off the printer like that, they will have been cleaned up and finished by a professional. Burs and excess material need to be removed, the surface often needs to be smoothed either by sanding or using chemical baths, and colour or graphics are added.
Behind the scenes of creating a good 3D print
3D printing makes it easier to take an unfinished design and make a rough prototype quickly and has given the ability to make models to a greater number of people but to get the most out of 3D printing, some design expertiseis needed. We have followed 3D printing developments closely and have learned how to make things quicker, stronger and more accurately. Simple changes to the design can save a lot of time and money and make the print more likely to succeed. Without this thinking there will likely be a few failed prints before the final success.
Why should I 3D print my design?
3D printing is an excellent way to test the design early on. Making physical models early on lets you get a feel for the design, especially for anything that is to be held in the hand. Learning.
We often use high quality 3D prints that have been finished and painted as demonstration models to sell the idea to a company or investor. Most crowd funding such as Kickstarter is done using early prototypes, many of which are 3D prints. Having a detailed and relatively cheap model can help secure funds for your project.
How much does 3D printing cost?
The price of 3D printing varies a lot based on what materials you want and how complicated they are or how large. For something roughly the size of a cup, you could be looking at anything from about £50-£2000 for the print itself without finishing, depending on materials. Generally if you are printing in plastic, the more time consuming and expensive with be the creation of the CAD model from which the print is made as there is design thinking needed here.