Future of Society with 3D Printing Technology
3D printing technology is destined to transform the industry as more and more production challenges involving three dimensional objects can be solved faster, in a better way, says Parag Nanavaty.
Additive manufacturing or 3D printing is a process which makes solid objects from virtual drawing prepared with Computer Aided Design (CAD). To print an existing model, a 3D scanner, which has the capability to create a digital drawing of a model, is used. Once the digital drawing is ready, it is sliced in hundreds or thousands of horizontal layers, with the help of Slicer software, which is then uploaded in the machine or printer. The object is created by using the additive processes, laying down successive layers of material until it is ready as per the drawing.
In use since 1986, during the initial phase additive manufacturing process was limited to Product Design, Rapid Prototyping and Concept Modelling, and was the domain of select companies, and the machines could process only a few materials. But after 2009 many new models with advance technology as well as capability to process many new materials have entered the market. Today technocrats in all fields have routinely started accepting 3D printing, and new applications are rapidly emerging. Objects thus ‘printed’ can be directly used as final products. These are light in weight achieving overall weight reduction.
The applications are many, across industries:
Aerospace: Mainly used for weight reduction of parts. It is economical since low volume requirement. In future complete aircraft may be printed by a machine. It is very useful in defence industry to print parts directly on the battle field. Food can be printed in the orbiting space shuttle.
Health Care: Main use is in prosthetics, orthotics, hearing aids, dental braces and dentures, also likely for use in printing tissue and organs for transplants. Digitally produced implants are more consistent and hence give better results after operation. Virtual surgery planning and customised instruments reduce overall time and final result is very good; also in future printing of nano scale medicines and complex organs.
Automobile: Great tool for prototyping and concept testing. Light weight components will be great boon in future electrical vehicles (EV). Designer cars will be printed by machine.
General Manufacturing: In future all manufacturing plant layouts will change. Applications in R&D, product prototyping, concept modelling and test market phase. It reduces overall product development time as well as cost, as printed product models will be used for marketing presentation, exhibitions and training purposes.
Consumer Items: Customised novelty products will open new areas of market. Gifts or display pieces, light shades, trophies, etc., may be printed as per their own design, not possible with traditional methods.
Supply Chain: There will be reorganisation in this as manufacturers will support customers to print spares at customer location. They will work in coordination with companies to supply spares of old machines, and there will be no need to keep stock of old spare parts.
Other Industries: Extensive applications in jewellery and architecture industries.
The American Society for Testing and Materials (ASTM) group – “ASTM F42” Additive Manufacturing, has developed a set of standards that classify additive manufacturing processes in different categories. Each technology is capable of processing certain materials only. Object finishing, aesthetics, dimension accuracy and their strength are different for each technology.
Major categories of 3D printing technology are:
VAT Photopolymerisation – Uses UV curable resin, basic material plastics base
In this process container filled with photopolymer resin is hardened by UV light source. For each layer, the laser beam traces a cross-section of the part pattern on the surface of liquid resin. Exposure to ultraviolet laser light cures and solidifies the pattern traced on the resin and joins it to the layers below. Object is floating in resin tank hence supporting structure is required wherever necessary. It will be removed manually after object is ready and out of tank.
- Selective Laser sintering (SLA) – Material curing by laser.
- Digital Light Processing (DLP) – Material curing by projector beam.
- Continuous Digital Light Processing (CDLP) – Material curing with LED and oxygen.
Pros & Cons: Relatively quick process, achieves high level of accuracy and good finish, and very good for small and artistic objects. Lengthy post processing time is required to remove resin, requires post curing for parts, limitation of material photo resins and relatively costly machine.
Material Extrusion – Uses filament spool, basic material plastics base
Filament is unwound from coil, feeds to the extrusion nozzle. It is heated to melt, moves in horizontal and vertical directions by CAM software. The object is produced layer by layer with melted material. Hot melted layer material gets hardened immediately before second layer starts. This technology is widely used with ABS and PLA material though there are many more material options are available.
- Fused Deposit Modelling (FDM) – Material melts in extruder
Pros & Cons: Very popular technology, widely used in industry due to economical in cost. Accuracy and speed are low, constant pressure of material is required to increase quality of finish.
Material Jetting – Uses resin
In this process, material is applied in droplets through a small diameter nozzle. It is applied layer to layer to build platform making 3D object then hardened by UV light.
- Material Jetting (MJ) – Basic material plastics – Cured with UV light.
- Nano Particle jetting (NPJ) – Basic material metal – Cured with heat.
- Drop on Demand (DOD) – Basic material wax – Material milled to form.
Pros & Cons: High accuracy of deposition of droplets and therefore low waste, multiple parts and colours under one process are possible. Support material is often required, high accuracy can be achieved but limited materials like polymers and wax can be use.
Binder Jetting – Uses resin
Two materials are used in process, powder base material and liquid binder. Powder is spread in equal layers and binder is applied through jet nozzles that glue the powder particles in shape of digital drawing. The finish object is glued together by binder. After the print is finished remaining powder is cleaned off and is used for next object printing.
- Binder Jetting – Basic Material Gypsum Sand and Metal – Material joining with bonding agent.
Pros & Cons: Possible to use large variety of material like metal, polymer and ceramics, multi colour parts can be printed, faster operation compare to other machines, and allow large number of different binder-powder combinations and various mechanical properties. Not always suitable for structural parts, due to use of binder material, Additional post processing can add significant time to the overall process.
Powder Base Fusion – Uses powder
This technology uses a high power laser to fuse small powder particles of plastic, Metal, Ceramic or Glass. Laser selectively fuses the powder material by scanning the cross section or layers generated by 3D drawing on surface of powder bed. All untouched powder remains as it is and becomes a support for the object. Therefore there is no need for any support structure which is the main advantage of this process over all others.
- Stereolithography – Selective Laser sintering (SLS) – Basic Material Plastics – Cured by Laser light.
- Direct Metal Laser Sintering (DMLS) – Basic material Metal – Cured by laser light. This is also known as Selective Laser Melting (SLM).
- Multi Jet Fusion (MJF) – Basic material Plastics – Material fused with agent and energy.
- Electron Beam Melting (EBM) – Basic material Metal – Material fused with electron beam.
Pros & Cons: Powder acts as an integral support structure, available in a large range of material options, objects mainly suitable for visual models and prototyping. Relatively slow machine, lack of structure properties in material, size limitation; output finishing depends on powder grain size, and high power consumption.
Sheet lamination includes Ultrasonic Additive Manufacturing (UAM) and Laminated Object Manufacturing (LOM). The ultrasonic additive manufacturing process uses sheets or ribbons of metal which are bound together with ultrasonic welding. The process does require CNC machining and removal of unbound material. Laminated object printing is also operated similarly but instead of metal paper and adhesives as glue in place of ultrasonic welding will be used.
Directed Energy Deposition
It is also known as laser engineered net shaping, directed light fabrication, direct metal deposition, 3D laser cladding. This is relatively complex machine mainly used to repair or add material in existing components. Process is similar to extrusion process. The nozzle can move in multiple directions due to 4-5 axes. Material input either in wire or powder form is melted upon deposition in layer either with laser or electron beam. Process can be used with polymers, ceramics but mainly it is used with metal.
Objects prepared by 3D printing machine need post processing to make them acceptable to the customer. The machine has many moving parts hence considerable amount of maintenance is required. It is available with one year warranty but life of moving parts depends on the number of operating hours; once the operating hours of a part expire within warranty, it must be procured against payment. Cost of other spares is also very high. In lieu of this the user will spend more money against spares purchased within warranty. It will be either equivalent to the original machine cost or more.
All machine suppliers insist on the buyer to purchase materials for process directly from them which is also very costly. Material sourced from open market does not give guarantee of object printing quality or machine malfunction.
The success of 3D printing technology depends on:
o Model CAD drawing and Slicer software
o Material technology and properties
o Printer, spares and material cost
o Speed and quality of printed object
o Warranty and liability support by supplier or reseller, and
o Intellectual property issues.
Machines are available as DIY kit, consumer printer, professional desktop printer, medium size industrial printer and large size printer. Cost varies with technology, build size, print resolution, speed and material processing capability.
However there is a possibility that over a period of time machines will become more versatile and economical. Once technology matures and is able to give qualitative output and economical alternative is available, the 3D printer will be used by all industries and help a large number of professionals to remain competitive in the market place.
Parag Nanavaty, CEO, ForeKen Technology, is always looking for new business design challenges and helps medium scale companies to bring them on the top notch in their area of operation.