The process of Hot rolled AISI 5140 steel flat bar rapid prototyping is as follows:

l) Construction of product three-dimensional model. Since the RP system is directly driven by the 3D CAD model, a 3D CAD model of the workpiece to be machined must be constructed first. The three-dimensional CAD model can be constructed directly using computer-aided design software (such as Pro/E, I-DEAS, Solid Works, UG, etc.), or the two-dimensional drawings of existing products can be converted to form a three-dimensional model, or the product entity can be Perform laser scanning and CT tomography to obtain point cloud data, and then use reverse engineering methods to construct a three-dimensional model.

2) Approximate processing of three-dimensional models. Since products often have some irregular free-form surfaces, the model must be approximated before processing to facilitate subsequent data processing. Because the STL format file format is simple and practical, it has become a quasi-standard interface file in the field of rapid prototyping. It uses a series of small triangle planes to approximate the original model. Each small triangle is described by 3 vertex coordinates and a normal vector. The size of the triangle can be selected according to accuracy requirements.

STL files have two output forms: binary code and ASCll code. The binary code output form occupies much less space than the ASCII code output form, but the ASCII code output form can be read and checked. Many CAD software have the function of converting and exporting STL format files.

3) Slicing processing of three-dimensional models. Select the appropriate processing direction according to the characteristics of the model to be processed, and cut the approximated model with a series of planes at certain intervals in the forming height direction in order to extract the profile information of the section. The interval is generally 0.05mm~0.5mm, and 0.1mm is commonly used. The smaller the interval, the higher the molding accuracy (PolyJet technology layer thickness can reach 0.0016mm, so the accuracy of the model is very high), but the longer the molding time, the lower the efficiency. On the contrary, the accuracy is low, but the efficiency is high.

4) Forming processing and model accuracy. According to the cross-sectional profile processed by slicing the model file, under computer control, the corresponding forming head (laser head or nozzle) performs a scanning motion according to the cross-sectional profile information, stacks materials layer by layer on the workbench, and then layers each layer. Bonding (some technologies are layer accumulation and curing, completed simultaneously, such as Objet's Polyjet technology), and finally a prototype product is obtained.

5) Post-processing of molded parts. Different molding processes have different levels of complexity and simplicity in post-processing. Some molding processes require the molded parts to be removed from the molding system and then subjected to grinding, polishing, complicated secondary curing, removal of support materials, etc., or post-sintering in a high-temperature furnace to further improve its strength, such as SLA. Some molding processes require only very simple post-processing, without the need for grinding and secondary curing.