LOM process is called Laminated Object Manufacturing, and is one of the most mature rapid prototyping manufacturing technologies. By the American Helisys company Michael Feygin developed in 1986, due to low production cost, high precision, and the wooden prototype manufacturing has a unique inner beauty and some special qualities, since it was invented, has received widespread attention, has been the rapid development and application.
Introduction to Laminated Object Manufacturing(LOM) Process Principle
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. During processing, the hot roller rolls the sheet material so that it is bonded to the workpiece that has been formed. CO2 laser is used to cut out the sectional contour and the outer frame of the workpiece on the new layer which is newly bonded, and the upper and lower meshes are cut in the excess area between the outline and the outer frame.
After the laser cutting is completed, the worktable drives the formed workpiece to decrease and is separated from the strip material. The feeding mechanism rotates the feeding shaft and the feeding shaft to drive the material belt to move, so that the new layer is moved to the processing area.
The work goes up to the processing plane, and the hot roller is hot pressed. The number of layers of the workpiece increases by one layer, and the height of the workpiece is increased by one thickness.
Then cut the cross section on the new layer. Repeat until all parts of the component are bonded and finished. Finally, the shredding of excess parts is removed to obtain the layered manufacturing of the solid parts.
Laminated Object Manufacturing(LOM) Advantages
1.LOM process cuts only the outline of the parts section on the sheet instead of scanning the entire section. As a result, the forming of the heavy wall parts is faster and easier to manufacture large parts.
2.There is no material phase change in the process, so it is difficult to cause warpage.
3. the redundant material between the outer frame and the profile of the workpiece plays a supporting role in the process, so the LOM process does not need to be supported. At the same time, excess material is easily removed.
4.The raw material used in LOM process is cheap, so the manufacturing cost is very low, and it is suitable for forming large size workpieces.
Laminated Object Manufacturing(LOM) Disadvantages
Material waste is serious, surface quality is poor. Because of the low utilization ratio of molding material and LOM technology, the waste of materials has been seriously criticized. With the development of new technology, LOM process will be phased out. 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.
Laminated Object Manufacturing(LOM) Process
First, a 3D digital model of STL format is accepted by the computer and sliced in the vertical direction, and the cross sectional data of the model are obtained.
The cross section data model, cutting section contour trajectory, and generate laser beam cutting control command; material feeding mechanism of the bottom is coated with hot melt adhesive paper or plastic film to the work area above the hot pressing roller pasting mechanism will make the material. The material under the paste together.
According to the laser slice plane geometry information of CAD 3D model of the bottom to spread on paper for contour cutting, laser power selection can cut a thick layer of paper, while the previous layer has no effect, while the non cutting model area into grids for forming postprocessing remove.
Then the table down a material thickness (a 0. 025mm -0.125mm), the material transfer mechanism to a layer of paper, and with the heating roller, and the cement, in accordance with the corresponding data for laser contour cutting, we repeat this process until the completion of three-dimensional parts manufacturing.
Laminated Object Manufacturing(LOM) has special requirements for lasers and their control
1.The laser output energy is stable and can vary with the scanning speed. Therefore, the equipment needs to be equipped with automatic matching software to automatically adjust the laser output power according to the instantaneous cutting speed of the laser. There is enough cutting power to cut the straight line, and the cutting power is low when cutting the arc curve at low speed.
2.The laser can be switched on and off quickly.
3.The laser beam spot size can be automatically compensated automatically recognition section of the inner and outer boundary, according to the spot size of laser automatic offset inward or outward half spot size, so as to ensure the actual contour and contour line theory.
Considerations for the use of the Laminated Object Manufacturing(LOM)
When forming a section section with an outline formed by a broken line, the laser head has many start and stop phenomena. When cutting a broken line, the laser head starts and accelerates at the beginning and finally reaches a uniform speed.
At the end of the cut, the scan speed is reversed, starting at constant scan speed, slowing down, and finally turning to zero.
If the length of the broken line is very short, the transition process occupies a large proportion in the cutting process.
If the output power is constant, when the scanning speed is smaller, the laser head stuck in a certain distance in time, forming paper absorption energy increases, laser heat affected area to expand the incision width, decreased the dimension precision.
When the scanning speed increases, the laser head stays within a certain distance and the laser energy is hard to cut.
Therefore, the matching of laser power and scanning speed is very important in LOM forming. It is very important that the laser output energy is stable and can change with the scanning speed.
Laminated Object Manufacturing(LOM) 3D Printer
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.
Laminated Object Manufacturing(LOM) Material Requirements
Applicable consumables: LOM process adopts sheet material, such as paper, plastic film, etc.. In the paper, PVC plastic film printing materials, with special glue, glue and glue solution solution for printing auxiliary pen.
The forming material of layered solid is heat sensitive thin layer material. At present, it is mainly coated with hot melt adhesive on one side. When the hot roller is heated to 210 - 250 DEG C and the paper is rolled, the hot-melt adhesive melts and produces viscosity. The cost of the paper is low, the raw material is easy to obtain, the molding process is always solid, without phase change, warpage is small, molding is easy to process. The interior of the paper contains modified additives which can improve the properties of paper and forming parts, with good viscosity, mechanical strength, hardness, polishing, shrinkage, working temperature, etc..
Laminated Object Manufacturing(LOM) Application Area
Industrial design, machinery manufacturing, auto parts manufacturing, mold design, art, animation industry, aerospace, military and security units of higher education, building decoration, medical and surgical (Department of orthopedics, used) children's toys manufacturing, shoe industry etc.. It is widely used in product concept design visualization, modeling design evaluation, assembly inspection, investment casting and so on.