How to select a 3D Printer
If you are planning to buy a new 3D printer to speed up product prototyping, here is a guide for choosing the most suitable printer for your application
The idea of 3D printing technology was first introduced back in 1984. Though 3D printing is now utilised in a variety of applications, this concept is relatively new for the Indian industry.
In the field of electronics
Karan Chaphekar of KCbots says, “3D printing has yet to percolate everyday life, but at present, the main application is in rapid prototyping by an engineering and design team (at a start-up, SME, etc) or by hobbyists who want to make unique things.”
CubeX Duo 3D printer
Brahma3 Anvil 3D printer
A basic 3D printer can be of great advantage for electronic product designers or innovators. According to Paul Anand of Biotz, “The most important part lies in mechanics designs of any electronic gadget they design. In this era, user-centric design is becoming the key differentiator for product optimisation.” A 3D printer lets the user create rapid prototypes of different designs, which can be sent for user feedback and optimisation. It reduces the size of product considerably and saves time and effort.
Attributes to consider
The speed of a printer can be defined as the time taken to print a specific distance in the Z-axis. It is usually represented in millimetres per hour or inches per hour. With larger print speed, we get the model printed faster. However, print speed may depend on some other factors such as complexity of the model to be printed or type of printing material used. Print speed determines how fine and dense your structure will be printed. The speed generally has an inverse relationship with print complexity and quality. The faster the print, the lower the quality. The greater the complexity the lesser the print speed. It is important to select a model that offers a trade-off between speed and quality of print.
Complexity of design that can be printed is determined by three factors: slicer software support, support structure generation and print speed. Some applications require composite design features, such as multiple layers and complex curves. So it is necessary to first define the demands of your specific application.
The size of the print platform determines the maximum dimensions that can be printed using a particular printer. It is usually measured in inches or centimetres in XYZ dimensions. For electronics designer, 203×203×203mm would be a good start. Print platforms of 229×229×229mm or more are used in industries. If the printing job can be split into smaller parts and combined later, you can go for smaller build area. Larger print area avoids the need for this scaling and slicing of the print.
Resolution can be of two types:
Vertical Z resolution/layer height/layer thickness is usually defined by the thickness of each layer the printer can create in one pass. The smaller the layer thickness, the higher the resolution. Small resolution gives smoother and more realistic print outputs, but this also increases the time to produce the final product as the number of layers increase.
On the other hand, larger resolutions provide models with lesser finish in lesser time. Models that let the user choose layer thickness are also available. 0.2mm and 0.3mm are the commonly available resolutions.
Horizontal resolution/XY resolution/feature resolution is the minimum displacement that can be made by a print head in the XY plane. It is measured in micrometres (µm) or dots per inch (dpi). Smaller feature resolution corresponds to finer features in the print.
High resolution or reduced error is particularly important if the casting is printed in parts and assembled separately. Low dimensional accuracy models may lead to misfit of parts whilst they are combined to create the final model.
There are several methods of 3D printing. These can be categorised into six core processes:
Uses: Concept models, patterns and prototypes
For example: Stereolithography (SLA/SL), digital light processing (DLP), multi-jet modelling (MJM) and polyjet technology
Uses: Functional prototypes, low-volume production of complex components and investment casting
For example: Selective laser sintering (SLS) and direct metal laser sintering (DMLS)
Uses: Functional prototypes, low-volume production of complex components and tooling components
Electron beam melting (EBM) and direct metal printing (DMP)
Uses: Wood-like models and concept models
For example: Laminated object manufacturing (LOM)
Uses: Functional and durable models, production parts and manufacturing tools
For example: Fused deposition modelling (FDM)/fused filament fabrication (FFF), plastic jet printing (PJP) and thermoplastic extrusion
Uses: Large objects, fast and cheap models and smooth models with lots of fine details
For example: Powder bed and inkjet head/3D printing (3dp), MJM, smooth curvature printing (SCP) and DMP
The key advantage of FDM is reusability. Since raw thermoplastic materials are used here, this technology is less susceptible to dimensional changes, unlike other technologies. This technology offers easy material changeover. FDM has fair levels of accuracy which fulfils the needs of a basic perspective making it the most popular in low-end, economical devices. But this method mostly lacks the resolution and finish of a professional-grade output.
SLS is a very expensive but much faster technology, more effective where multiple parts are required. It also offers increased accuracy which is needed for precision engineering applications, and showcases better print quality than high-end FDM machines.
Extruder is the print head or the end of the printer where filament is melted and ejected. In extrusion method of printing, the number of print heads usually determines how many colours can be printed at once.
3D printers can be divided into three based on the colour options:
- Colour-choice printer. These printers have only single extruder and can print objects only in one colour at a time. This colour is determined by the colour of the material used for printing, i.e., the object would be green in colour if green filament is used and red in colour if red filament is used.
- Basic-colour printer. These models will have more than one extruder and can print a few colours in a single model.
- Full-spectrum colour printer. Allows to print an object in a zillion different colours. This is achieved by mixing CMYK colour model—cyan, magenta, yellow and key (black) and jetting it on each thin, plaster-based layer.
Filaments of all primary and secondary colours are easily obtained in the market. In addition to these, exotic colours such as gold, silver and fluorescent are also available.
Cost of parts
Ccost of parts is expressed in cost per unit volume. Cost of parts is provided by vendors for a specific part, or an average across a group of different parts. These need not necessarily represent the true cost of printing as they exclude the cost of support materials, process waste generated and other consumables used in the printing process.
When the design to be printed is created and fed to the printer software, most of it shows an estimate of the material consumed for that particular project. This will give the user an idea of the cost to produce a particular model. Nowadays, a kilogram of material is available for around Rs 4000.
The lowest cost of parts is found in powder-based printing technologies. Inexpensive gypsum is used as base material and the unused powder is continuously recycled and reused by the device. This results in the reduction of cost by one-third or even one-half compared to other technologies.
Usability, help and support
The model should be user-friendly. Check whether the company offers support by mail, telephone, live chat, etc. many companies do not provide warranty for the printer. So it is safe to double-check that the product you are buying has a warranty cover or not.
SD card and display support are some other factors one can look for in a 3D printer model. Machines that offer these features can work without being connected to a PC.
Challenges and constraints
A huge limitation in the 3D printing technology is that each object can be printed using only one material. It is not possible to use different types of materials at the same time to create a model. Printing in metal is also relatively new in this field. But extensive research is going on in this field and we should soon see mixed materials and fully assembled products coming out of the printer. “In the future, we are going to start to see mixed materials, electronics 3D printing and conductive materials as well,” says CarineCarmy, director of marketing, Shapeways 3D Printing Marketplace and Community.
MBotCube PVC 3D printer
Stratasys Objet1000 3D printer
Another hurdle is to increase the efficiency of the printing software. A smarter software could give real-time feedback of the project to be printed, optimise design taking into consideration the physical properties required for the product and the properties of material to be used. A lot of investment is being made in this field.
Our Facebook survey suggested that price of the machine is the major issue from a user’s point of view at present. A 3D printer with good specifications can be pretty expensive. One respondee from a professional design background commented on our survey, “3D printers are an expensive fad. For routine mechanical prototype makers, pay off could be sooner, but for occasional mixed technology makers it still does not make sense of buying one.” Alan Campbell, a member of our Facebook page EFY’s Electronics Design Community, commented that he would not prefer buying a 3D printer, “but if someone sets up a (local) shop printing parts made to order, I would give them my business.”
For people like Alan, who are not ready to buy their own 3D printer, there are services to get access to high-end industrial 3D printer machines. Such professional 3D printing services could offer high-quality prototypes in about 30 different materials, at affordable costs.
According to CarineCarmy, the home printer is still fantastic for prototyping, but not yet for end goods. There are several 3D printing service providers present today; Shapeways, 3Digiprints, Clarity 3D, 3D Hubs, KadKraft Systems, C4L, Netgains, Sculpteo, i.materialise, Ponoko, 3Ding and CADD Centre to name a few.
3D printing is improving the manufacturing and production of goods worldwide. It could create fast and easy prototypes at a decent cost. This technology makes it possible for you to hold your ideas in your hand, to create something that never existed before; imagination is the limit. 3D printing is going to revolutionise the world. Get ready for it!