A Brief History Of 3D Printing

3D printing has now become an omnipresent technology due to the wide media coverage it receives and the fact that it has successfully entered the market for consumer use. The origins of 3D printing can however be traced back to over 30 years ago during the 1980s. Contrary to popular belief 3D printing has been widely available for industrial use for a while, but has only recently penetrated the end user market for private consumers.

What we refer to as 3D printing today was appropriately called Additive Manufacturing or Rapid Prototyping in the late 1980s, a time when the technology was in its nascent stages. One of the first patents filed for rapid prototyping was by Dr. Kodama in Japan. Dr. Kodama however was unable to obtain a patent due to some delays. On the other hand, Charles Hull, who co-founded the company 3D Systems, successfully filed a patent for a technology known as Stereolithography Apparatus or Stereolithography as it is known today, in 1986. He is thus considered the father of 3D printing.

Large amounts of research was conducted in the 1990s, to build items which were readily applicable in manufacturing. However, the research only yielded processes that were good for prototyping purposes and hence the technology was limited when it came to printing original 3D models.

Early 2000s saw the rise of industrial 3D printers, which were suited to building complex parts, with high value and complex geometry. Around the same time, low cost 3D printers useful for concept modelling and functional prototyping arrived on the scene. These were however, not yet suited for use in the end user market and remained exclusive for industrial applications. In 2004, Dr. Bowyer successfully invented an open source 3D printer that used a deposition process for printing models. This was the origin of ‘Desktop 3D printing’. The BfB RapMan 3D printer, was the first commercial printer to use this concept. By 2012, Fused Deposition Modeling or FDM became the most popular 3D printing method and many new 3D printers were launched using this technology.

Today the 3D printing technology and 3D printers are being used across a wide range of industries like Aerospace, Healthcare, Defense, Education, Construction & Civil Engineering; to name a few. As the technology and processes concerned with 3D printing continue to mature, concerns are being raised about the effect it will have on employment of low skilled workers around the world. Needless, to say with emphasis on reducing pollution and efficient waste management the technology is here to stay.

Difference between SLA & SLS 3D Printing

 

Stereo-lithography, also known as SLA, is a 3D printing process where, prototypes are built layer by layer using light from a laser. Photo polymer resins like clear resin, standard resin, to name a few, are used to make prototypes in SLA. These resins, or ‘build materials’ as they are called are in a liquid state. The 3d printer’s build tray is submerged in a basin of photosensitive material. The depth to which a build tray is submerged depends on the strength of the laser being used, type of material and required tolerances. A part’s entire cross section is traversed by the laser as it builds up each layer.

SLA is better suited to printing parts with small and well defined features. The SLA process works with polymers & resins, not metals. When printed using SLA, parts generally yield higher dimensional tolerances a better surface finish.

SLA presents a challenge when printing larger parts, as they need support during the printing process. This becomes a major hindrance when printing parts with complex geometries.

Selective Laser Sintering or SLS, is when prototypes are 3D printed using powdered building materials. The technique uses polyamide and polystyrene powders as building materials. The materials are binded together to create desired structures. Layers of the materials are carefully on the build tray using a leveler or roller. Cross sections of the prototype are then sintered layer by layer by a laser. Just like SLA, thickness of the layers being printed depends largely on the strength of laser being used, type of material and required tolerances.

SLS can work with metals like steel, titanium and nickel in addition to polymers. Parts built using SLS are generally tougher than the ones built using SLA.

Once printed, the parts need to be cooled down. Efforts to speed up the cooling process may result in variations from the intended designs. When using metals in the SLS process, one has to take extra caution not to breathe in the fine particles that may be harmful.

Liquid photopolymers required for SLA cost around $80 to $100 per liter, whereas SLS powders cost somewhere between $300 to $600 per kilogram. SLS requires high peak energies as compared to SLA to compress metal powders, making it a costlier alternative. When it comes to surface finish, SLA parts are preferred due to their mold like finish, however, SLS is more suited to printing parts with higher tolerances.

How can we lower our 3D printing cost?

 

1. Choose a reliable printer with an upgraded room

What factors will a Newbie consider before he/she is going to get started to do 3D printing? Practicability, reliability, and affordable price are factors worth being considered.

Starting with a pre-assembly process, makers can get a comprehensive understanding of 3D printers and their accessories.

2. Scale down or hollow out your model

If it doesn’t necessarily require a big size or solid structure for your prints, scaling down or hollowing out your model will substantially decrease the cost.

3. Eliminate unnecessary support structure

It is commonly known that prints can’t stand naturally on the hotbed if the model is designed with some angles. Support is necessary for FDM printing, but cost materials and more time, even additional post-processing for further smoothness and polish.

What if 3D-printing goes 100X faster?

 

3D printing as known as additive manufacturing, has been developing at rapid speed to exert more convenience in various industries. However, due to certain limits, it always takes a long time to get prints out from the printing machine. As Joseph DeSimone, the CEO of Carbon3D, said “3D printing always takes forever. There are mushrooms that grow faster than 3D prints.”

With two-year research collaborated with his partner on the 3D printing area, Joseph DeSimone shared the research findings at TED talks. He considered that 3D printing is a misnomer, which in fact is a repetitive 2D printing process. Let’s imagine ink-jet printer making letters on papers, and continue doing it over and over again, layer and layer added, thus taking a long time to build up a 3D object. Besides, the layer by layer process leads to defects properties. Moreover, material choices are far too limited. If we could use self-curing material, more breakthroughs can be pulled off.

They pondered over all those questions and problems faced by 3D printing when they got inspired by a Terminator 2 scene from T-1000. Why couldn’t a 3D printer be operated in this fashion? We had an object arising out of the liquid with essentially real-time completion and no waste to make great objects. Whether we could get this to work would be our true challenge.

The approach they applied in the research was to use standard knowledge in the field of polymer chemistry to harness light and oxygen for uninterrupted manufacturing. Light and oxygen work in different ways. Light converts the liquid resin into a solid, which converts the liquid into a solid. Oxygen can inhibit this process. Therefore, from a chemical point of view, the effects of light and oxygen are opposite to each other. If we can control light and oxygen three-dimensionally, we can control the production process (CLIP).

CLIP has three functional components. The first is a container for storing liquids, just like the robot T-1000 in Terminator 2. There is a special window at the bottom of the container. Component 2 is a platform that can be lowered into the container to pull the object straight out of the solution. The third part is a digital light projection system located below the container to provide illumination in the ultraviolet light area. The key is the window at the bottom of the container. A very special window is not only transparent but also oxygen permeable. Nature is similar to contact lenses.

With the special window, we can let oxygen enter from the bottom. When the light hits oxygen, oxygen will inhibit the reaction and form a dead zone. The dead zone is about a few tens of microns thick, about two or three times the diameter of the red blood cell, and it can still remain liquid at the window interface. Then we pull the object out. The thickness of the non-sensitive area can be changed by changing the oxygen content.

The result was very staggering, which was 25 -100 times faster than traditional 3D printers. In addition, with the improved ability of the control interface liquid adjustment, he believed that the printing speed can be 1000 times faster. As a result, water-cooled 3D printers may appear in the future because printing is too fast. Because of our growing manufacturing method, the traditional laminate manufacturing is abandoned, the integrity of the components is improved, and you can't see the surface layer to the structure.

A smooth surface at the molecular level can be obtained. When you print in a growing manner, the characteristics of the object do not change due to the orientation of the print. These look more like pour parts, which is quite different from traditional 3D manufacturing. In addition, we can use the knowledge of the entire polymer chemistry textbook to design the right chemical materials to create the characteristics you really expect in a 3D printed part.

In this way, we can produce ultra-high-strength materials, high strength to weight ratio, true ultra high strength materials, and truly super elastic materials. These are great material properties.

The immediate opportunity is that if the results produced can be the final product and can be transformed at the speed of the industry, it can really change the face of manufacturing. In the current manufacturing industry, the so-called "digital line" is being applied in the field of digital manufacturing. We range from CAD drawing and design to prototyping to manufacturing.

It is often the case that digital line production is stuck in the prototyping process because it cannot be manufactured directly because most of the components do not have the characteristics of being the final product. Now we can connect every step of the digitization line from design and prototyping to manufacturing. This opportunity really opens up the possibility of making all kinds of items. For example, it is possible to reduce the fuel consumption of a car by using a high-strength weight ratio mesh type material, a new turbine blade, and many other superior parts.

In a word, this real-time manufacturing technology that makes parts manufacturing a finished product really opens the door to 3D manufacturing. For us, this is very exciting because it really realizes the interaction between hardware, software, and molecular science.