Nowadays, the demand for rapid prototype service is relatively strong in automobiles, home appliances, electrical appliances, toys, medical equipment, and technology. For prototypes and rapid molds for these industries, the commonly used methods are CNC machining, SLA, SLS, SLM, FDM, vacuum complex mold, low-pressure infusion, sheet metal production. We will define, use materials, software use, and processable parts Comparing the advantages and disadvantages of these prototype processing methods.
1. CNC machining
CNC machining is a computer numerically controlled machine tool made by cutting a hole plate by controlling the tool path according to the programmed program. It is currently the most widely used method of making prototypes in China. The operation method is complicated and requires the operator to have rich experience. They were mainly used in the processing of plastic and metal plates. It can be cut on all plates in the market. It is a material reduction technology. It can only process rounded corners with a specific arc but cannot directly process inner right angles: cutting/sparking and other processes.
2. SLA
SLA is a three-dimensional light-curing molding method, a type of 3D printing technology. The materials used are primarily resins. Ultraviolet lasers with specific wavelengths and strengths are used to focus on the surface of the photosensitive resin to cure layer by layer and finally layer by layer to form a three-dimensional entity. All 3D printing is an additive technology, from 0 to 1.
SLA is the earliest rapid prototyping manufacturing process with high maturity. It is directly made into prototypes from CAD digital models. The processing speed is fast, the product production cycle is short, and there is no need for cutting tools and molds. It can process complex structures or is difficult to form using traditional methods. Prototypes and molds. SLA equipment is expensive and requires a relatively high factory environment. After the mold is formed, the strength, rigidity, and heat resistance are limited, not conducive to long-term storage.
3. SLS
SLS is selective laser melting, a type of 3D printing technology. The current mature process materials are wax powder and plastic powder. During printing, the laser beam selectively sinters the matte powder. The powder box is lowered in one layer, and then a layer of powder is laser sintered. Take out the powder box and remove the excess powder to obtain a sintered part.
The hand plate mold made by SLS has high strength and good toughness. It can make bearings, gears, precision parts, and electronic parts. Because it does not need support, the utilization rate of materials is high. But it is polluted during the prototype processing; the speed is relatively slow.
4. SAM
SLM, the selective laser melting molding technology, is currently the most common metal 3D printing molding technology. It uses a finely focused spot to quickly melt the preset metal powder to obtain any shape and complete metallurgical bonding parts. The resulting production density can reach More than 99%. In making prototype molds by SLM, because the parts are usually complex, supporting materials need to be printed, and the supports need to be removed after the parts are completed. The surface of the parts needs to be processed so that the production time will be longer and the cost will be higher.
5. FDM
FDM is the fusion molding method. FDM materials are generally thermoplastic materials, such as wax, ABS, nylon, etc., which are fed in filaments. The material is heated and melted in the nozzle. The nozzle moves along the part's cross-sectional contour and filling trajectory, and at the same time, extrudes the molten material. The material solidifies rapidly and condenses with the surrounding materials. In FDM making prototype molds, the price is relatively low, the materials are safe and harmless, and there is no mold cost. It can produce a variety of colors, but it cannot print hollow products. The FDM processed hand plate mold has conspicuous stripes, and the molding accuracy is relatively low. It needs to design and manufacture the supporting structure, and the molding time is longer.
6. Vacuum complex mold
Vacuum replica mold uses product prototype (such as SLA or prototype processing) to make a silicone mold under vacuum state, and use PU material for pouring under vacuum state, thereby cloning the exact copy of product prototype. Vacuum lamination is currently the most commonly used prototype replication technology globally; the technology can be applied to changing the material of product prototypes, assembling prototypes, or conducting small-batch production of products to meet performance testing, market promotion, and delivery during product development. Inspection, approval, and other requirements; different PU materials can be used to copy rubber parts, transparent parts, high-temperature resistant parts, etc. Ordinary PU materials are relatively brittle, have poor toughness and high-temperature resistance.
7. Low pressure perfusion
Low-pressure infusion, also known as low-pressure reaction injection molding, is a new process used to produce rapid molding products. It mixes two-component polyurethane materials and injects them into the rapid mold at room temperature and low pressure. Chemical and physical processes such as coupling and curing form products. The low-pressure infusion-generated prototype mold has the advantages of high efficiency, short production cycle, simple process, and low cost. It is suitable for small batch trial production in the product development process and small batch production, simple structure cover parts, and large thick walls and non-standard parts. Production of uniform wall thickness products.
8. Sheet metal production
Sheet metal production refers to the processing of metal plates such as steel plates, aluminum plates, and copper plates, including laser cutting, stamping, bending, etc. The significant feature of the raw materials for sheet metal processing is that the thickness of the same part is consistent.
