Several Common Rapid Prototyping Methods
So which industries are precision users of prototype factories or prototype companies? We searched for the keyword prototype, and found that the demand is relatively strong in the automotive, home appliances, electrical appliances, toys, medical equipment, technology and other industries. Prototypes and rapid molds for these industries are commonly used in China: CNC machining, SLA, SLS, SLM, FDM, vacuum complex mold, low pressure infusion, sheet metal production. We will compare these prototype processing methods in terms of definition, materials used, software used, machinable parts, advantages and disadvantages.
CNC machining is a computer numerical control machine tool, which is formed by cutting a whole plate by controlling the tool path according to a programmed program. It is currently the most widely used prototyping method in China. The operation method is complicated, and the operator needs to have rich experience.
Mainly used in the processing of plastic and metal plates. It can be processed on all materials on the market and is a material reduction technology. Only rounded parts with a certain degree of curvature can be processed, but products with inner right angles cannot be directly processed. Right-angle parts should be realized by processes such as wire cutting / sparking.
SLA is three-dimensional light curing molding method, a kind of 3D printing technology. Most of the materials used are resins, which are focused on the surface of the photosensitive resin with ultraviolet lasers of specific wavelengths and intensities to solidify them 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 prototyped from CAD digital models. The processing speed is fast, the production cycle is short, no cutting tools and molds are needed, and prototypes and molds with complex structural shapes or difficult to form using traditional means can be processed.
SLA equipment is expensive and requires high factory environment. After the prototype is formed, the strength, rigidity and heat resistance are limited, which is not conducive to long-term storage.
SLS is selective laser melting, a kind of 3D printing technology, and the currently mature process materials are wax powder and plastic powder. The laser beam selectively sinters the tiled powder during printing. After the first layer is completed, the powder box is lowered, and then the next layer of powder is laser sintered. Take out the powder box and remove the excess powder, and you can get a sintered part.
The prototype mold made by SLS has high strength and good toughness. Can be used to make bearings, gears, precision components, electronic components, because no support is required, the material utilization rate is high; However, it is polluted during prototype processing; The speed is relatively slow.
SLM is the selected area laser melting molding technology, which is currently the most common technology in metal 3D printing molding. The finely focused light spot is used to quickly melt the pre-set metal powder to directly obtain parts with any shape and complete metallurgical integration, and the resulting manufacturing density can reach more than 99%.
In the process of making prototype molds by SLM, because the parts are usually more complicated, support materials need to be printed. After the part is completed, the support needs to be removed and the surface of the part needs to be treated, so the production time will be longer and the cost is higher.
FDM is a fusion forming method. The material of FDM is generally a thermoplastic material, such as wax, ABS, nylon, etc., which is fed in a filament form. The material is heated and melted in the nozzle. The nozzle moves along the section profile and filling trajectory of the part, and at the same time extrudes the molten material, the material quickly solidifies and condenses with the surrounding material.
In the process of making prototype molds by FDM, the price is relatively low, the materials are safe and harmless, and there is no mold fee. Can produce a variety of colors, but can not print hollow products.
The prototype processed by FDM has obvious stripes, and the forming accuracy is relatively low. The support structure needs to be designed and manufactured, and the molding time is longer.
Vacuum compound mold is to use product prototype (such as: SLA or prototype processing) to produce silicone mold under vacuum. And using the PU material for pouring under vacuum, so as to clone the same copy as the product prototype. Vacuum lamination is currently the most commonly used prototype replication technology in the world; Technology can be used to change the material of product prototypes, assemble prototypes, or perform small batch production of products. To meet the needs of performance testing, market promotion, inspection and approval during product development; Using different PU materials, you can copy rubber parts, transparent parts, high temperature parts, etc. Ordinary PU materials are relatively brittle, tough and high temperature resistant.
7. Low pressure perfusion
Low-pressure infusion, also known as low-pressure reaction injection molding, is a new process applied to the rapid production of molded products. After mixing the two-component polyurethane material, it is injected into the rapid mold under normal temperature and low pressure environment. Products are formed through chemical and physical processes such as polymerization, crosslinking and curing of materials.
The low-pressure infusion generation 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 process of product development, as well as the production of small-volume production of simpler covering parts and large thick-walled and uneven-walled products.
8. Sheet metal production
Sheet metal production is the processing of metal plates such as steel plates, aluminum plates, copper plates, including laser cutting, stamping, bending, etc. The significant characteristic of the raw materials for sheet metal processing is the same thickness of the same part.