For the basic knowledge of 3D printing technology, if you want to understand different kinds of 3d printers, can know it from the process of molding. We do a systematic arrangement for everyone to introduce in detail the rapid prototyping 3d printer, in order to uncover the mysterious veil of 3D printing for you.
At the same time, for each specific process, we also have more detailed analysis and interpretation.

Rapid prototyping, according to the different materials and processing equipment, technically, there are several major categories:

Part 1.SLA 3D Printer: Stereo Lithography Appearance

Material: photosensitive resin

Stereo lithography Appearance is the earliest rapid prototyping technology. The principle is based on the photopolymerization principle of liquid photosensitive resins. When the liquid material is irradiated by ultraviolet light of certain wavelength (x=325nm) and intensity (w=30mw), the photopolymerization can happen rapidly, and the molecular weight increases rapidly, and the material changes from liquid to solid. Stereolithography is the most studied method and the most mature method at present. The general thickness is between 0.1 and 0.15mm, and the formed parts have higher precision. Years of research have improved the cross section scanning method and resin forming performance, so that the processing accuracy can reach 0.1mm, and now the highest precision can reach 0.05mm. But this method has its own limitations, such as the need for support and resin shrinkage.
Lead to lower precision, light curing resin has certain toxicity.

SLA process has the advantages of high accuracy, good surface effect, the completion of the production of parts, after grinding, will be stacked layers of traces removed.

Stereo Lithography Appearance

The SLA process has the highest operation cost, low component strength, no elasticity, and can not be assembled. The raw material of SLA process equipment is very expensive, but there are not many kinds of materials. After the completion of the parts of the UV curing equipment, it needs to be solidified two times in the UV curing box to ensure the strength of the parts.

Photosensitive resin in liquid Cao after six months to a year will expire, so there must be a prototype service to ensure that the resin liquid Cao was promptly run out, otherwise the new resin mixed together, will lead to a decline in the strength of the parts of the shape deformation. If you need to change the different grades of materials, you need to replace all the photosensitive resin of a liquid tank, the workload is great, and the resin is wasted a lot. Liquid resin must be used up in a year, otherwise it will deteriorate, and users need to invest nearly one hundred thousand yuan to purchase photosensitive resin. Three hundred thousand end pumped solid UV laser can only use 10 thousand hours, after two years, the laser replacement requires two inputs, three hundred thousand of the cost. Vibration mirror system is also vulnerable parts, re replacement will require more than ten million yuan investment. Because of the high cost of running equipment, such equipment is generally purchased by large groups or enterprises with sufficient funds.

Part 2. FDM 3D Printer: Fused Deposition Modeling

Material: wax, ABS, PC, nylon and so on

Fused Deposition Modeling (FDM) process materials are generally thermoplastic materials, such as wax, ABS, PC, nylon, etc., to filamentous feeding. The material is heated and melted in the nozzle. The nozzle moves along the section contour and the filling track of the component, and the molten material is extruded at the same time, and the material is quickly solidified and bonded with the surrounding material. Each layer is stacked on the upper layer, and the upper layer plays a role in positioning and supporting the current layer. Along with the increase of height, the slice size and shape will change, when the shape is changed, the upper contour is unable to provide sufficient current layer positioning and supporting role, it needs to design some auxiliary structure - "support", to provide support for the positioning and subsequent layer, in order to ensure the forming process the smooth realization of.

Fused Deposition Modeling

This process does not use laser. It is easy to use and maintain, and the cost is low. A prototype made of wax can be used directly in lost wax casting. Prototypes made with ABS are widely used in product design, testing and evaluation because of their high strength. In recent years, PC, PC/ABS, PPSF and other higher strength forming materials have been developed, which makes it possible to directly manufacture functional parts. Because of the remarkable advantages of this process, the process has developed very rapidly, and the share of the FDM system in the world now installed RP systems is about 30%.

Meanwhile all of alunar 3d printer use FDM technology, if you want a best home 3d printer or other Diy 3d printer can visit Alunar online store.

Part 3. SLS 3D Printer: Selective Laser Sintering

Material: powder of different materials

Selective Laser Sintering also known as selective laser sintering, was developed by C.R. Dechard of University of Texas-Austin in 1989. The SLS process is made of powdered material. The material powder spread on the surface of formed parts, and leveling; CO2 laser with high strength in just laying new layer scan section part; powder material in high intensity laser irradiation are sintered together, get the parts in cross section, and has formed part of the adhesive as below; a layer of cross section after sintering, covered with a new layer of powder material, selective sintering layer section.

Selective Laser Sintering

SLS technology has the advantages that the material is widely used, such as nylon, ABS, wax, resin coated sand (sand), polycarbonate (poly carbonates), metal and ceramic powder can be used as sintering objects. A supporting structure in which the sintered parts are not sintered as part of the sinter, so the support system (hardware and software) is not considered. The relationship between the SLS technology and the casting process is very close, such as sintered ceramic can be used as casting shell and core wax do wax, thermoplastic material sintering model can be used in epc.

Part 4. LOM 3D Printer: Layered Solid Manufacturing

The LOM process, called layered solid manufacturing, was developed in 1986 by the Helisys Michael Feygin of the United states. The company has introduced LOM-1050 and LOM-2030 two models forming machine. LOM process uses sheet materials, such as paper, plastic film and so on. The surface of the sheet is coated with a layer of hot melt adhesive.

Layered Solid Manufacturing

When machining, press roller pressing sheet, workpiece bonding and make the following has been formed; the new layer with CO2 laser in just bonding cut out parts contour and the workpiece frame, and between the contour and outer region cut out redundant grid alignment; laser cutting after completion of work piece the pedestalarouse has formed decreased, and a strip sheet (strip) separation; feeding mechanism rotating rewinding shaft and a feeding shaft, drive belt moving, make new layer to the processing area; the table up to the machining plane; hot pressing and hot pressing, the workpiece layers increase a layer, increasing the height of a thick material again; cutting contour in the new layer. This is repeated until all the sections of the component are bonded and cut to achieve the layered manufacturing of the solid parts.

In addition to the Helisys company, LOM, Japan, Kira, Sweden, Sparx, Singapore Kinergy Precision Technology Pte Ltd, Tsinghua University, Huazhong University of science and technology. But because LOM process materials are limited to paper, the performance has not been improved, so as to gradually go into decline, most manufacturers have or are ready to give up the process.

Part 5. 3DP 3D Printer: Three Dimensional Printing

The 3D printing (3DP) process was developed by Emanual Sachs and others at Massachusetts Institute of Technology. E.M.Sachs applied for the 3DP (Three-Dimensional Printing) patent in 1989, which is one of the core patents in the field of non forming material and micro droplet injection molding. The 3DP process is similar to the SLS process by forming powder materials such as ceramic powders and metal powders.

Three Dimensional Printing work

The difference is that the material powder is not connected by sintering, but by the use of an adhesive (such as silica gel) through the nozzle, the cross section of the component is printed on the material powder. Adhesive bonded parts are of lower strength and must be treated later.

The specific process is as follows: a layer of adhesive after the molding cylinder drops a distance (equal to the thickness: 0.013 ~ 0.1mm), and a powder cylinder rising height, launched a number of powder, and powder roller to molding cylinder, paving and compaction.

The nozzle is controlled by a computer, and a construction layer is selectively sprayed by pressing the forming data of a construction section. The excess powder is collected by the powder collecting device when the powder roller is used for laying powder.

Thus, the powder, the powder and the spray binder are sent round and round, and finally the bonding of a three-dimensional powder is completed. The place where the adhesive is not sprayed is a dry powder, which plays a supporting role in the forming process and is easy to remove after the end of forming.

Part 6. PCM 3D Printer: Patternless Casting Manufacturing

PCM (Patternless Casting Manufacturing) is developed by the laser rapid forming center of Tsinghua University. The rapid prototyping technology is applied to the traditional resin sand casting process. First, the casting CAD model is obtained from the part CAD model. The STL profile of the casting CAD model is layered to obtain the profile information, and then the level information is used to generate control information.

Patternless Casting Manufacturing

Other, the first nozzle in each layer paved sand by computer control injection adhesive accurately, second nozzles along the same path between the two injection catalyst, crosslinking reaction, curing and forming layers of sand accumulation. Where the bonding agent and catalyst are combined, the molding sand is solidified together, and the sand in other places remains in a granular state. When the layer is cured, the next layer is bonded. After all the layers are glued together, a space entity is obtained. The original sand in the adhesive does not spray the place is still dry sand, relatively easy to remove. By removing the intermediate uncured sand, a mold with a certain wall thickness can be obtained and applied to the casting of the metal after being coated or impregnated with the paint on the inner surface of the sand mold.

Compared with the traditional mold manufacturing technology, patternless casting manufacturing technology has the superiority of the There is nothing comparable to this it not only makes the casting process, high degree of automation, agility, reduce the labor intensity of workers, but also break through the many obstacles in the traditional process technology, the constraint conditions of design and manufacture is greatly reduced. Specific performance in the following aspects: short manufacturing time, low manufacturing cost, without pattern, the integration of other type, at the same time, the core forming, no draftforgings, manufacturing containing free surface (curve) of the mold.