Several Common Prototype Machining Methods

In some cases, the prototype is called the first edition. As the name implies, before large-scale production, a small number of samples are generally made according to the appearance and structure drawings of the product to check the appearance or structure of the product.

So which industries are precision users? Using the big data tool of the webmaster's house, we searched for the keyword prototyping and found that the industries that have relatively strong demand are automobiles, home appliances, appliances, toys, medical equipment, technology and other industries.

To produce prototypes and rapid molds for these industries, the commonly used methods in China are: CNC machining, SLA, SLS, SLM, FDM, vacuum re-molding, low pressure infusion, sheet metal production. We will define, use materials, software, and process Compare these several hand-board processing methods on parts, advantages and disadvantages.

CNC machining is a computer numerical control machine tool, which cuts a whole plate by controlling the tool path according to a programmed program. It is currently the most widely used method of making a prototype in China. The operation method is complex and requires operators to have rich experience.

It is mainly used for the processing of plastic and metal plates. It can be cut on all plates on the market. It is a subtractive technology. It can only process rounded corners with a certain radian, but cannot directly process the inner right angle. Cutting / sparking.

SLA is a three-dimensional light curing molding method and a type of 3D printing technology. Most of the materials used are resins. Ultraviolet laser light with a specific wavelength and intensity is focused on the surface of the photosensitive resin to cure it layer by layer. The final layer is superimposed to form a three-dimensional entity. .

All 3D printing is an additive technology, the process from 0 to 1. SLA is the earliest rapid prototype manufacturing process with high maturity. It is directly made from CAD digital models. The processing speed is fast, and the product production cycle is short. No cutting tools and molds are required. It can process complex structures or difficult to form using traditional methods. Prototypes and molds.

SLA equipment is expensive and has high requirements for the factory environment. The strength, stiffness, and heat resistance of the mold after molding are limited, which is not conducive to long-term storage.

SLS is a kind of selective laser melting and 3D printing technology. Currently mature process materials are wax powder and plastic powder. When printing, the laser beam selectively sinters the tiled powder. One layer of the finished powder box is lowered, and then the powdered layer is laser sintered. All the powder is sintered. Take out the powder box and remove the excess powder to obtain a sintered part. .

SLS hand molds have high strength and good toughness. They can be used to make bearings, gears, precision components, and electronic components. Because they do not require support, the utilization rate of materials is high; however, they are polluted during the processing of the hand plate; the speed is relatively slow. 

SLM is selected area laser melting molding technology. It is the most common technology in metal 3D printing molding at present. It uses a finely focused light spot to quickly melt the preset metal powder. It can directly obtain any shape and parts with complete metallurgical bonding. More than 99%.

In the process of manufacturing a hand mold by SLM, because the part is usually complicated, support materials need to be printed. After the part is completed, the support needs to be removed and the surface of the part must be processed, so the production time will be longer and the cost will be higher.

FDM is the fusion molding method. FDM materials are generally thermoplastic materials, such as wax, ABS, nylon, etc., and are fed in filaments. The material is heated and melted in the nozzle. The nozzle moves along the cross-section profile and filling trajectory of the part, while extruding the molten material, the material quickly solidifies and coagulates with the surrounding material.

In the process of FDM making hand molds, the price is relatively low, the material is safe and harmless, and there is no mold cost. A variety of colors can be made, but hollowed out products cannot be printed.

The FDM processed hand mold has obvious stripes and the molding accuracy is relatively low. The supporting structure needs to be designed and manufactured, and the molding time is longer.

Vacuum duplication is the use of product prototypes (such as SLA or Shouban processing) to make silicone molds under vacuum, and using PU material to cast under vacuum, so as to clone the same replicas as the product prototype.

Vacuum lamination is currently the most popular hand-board replication technology used in the world; the technology can be used to change the material of product prototypes, assemble prototypes, or perform small batch production of products to meet performance testing, market promotion and delivery in the product development process. Inspection, approval and other requirements; 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 resistance are poor.

Low pressure injection, also known as low pressure reaction injection molding, is a new process applied to the production of rapid molding products. It mixes two-component polyurethane materials and injects them into the rapid mold under normal temperature and low pressure environment. Chemical and physical processes such as bonding and curing form the product.

The low-pressure perfusion-produced hand 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, as well as small-volume production, simple structure cover and large thick-walled Production of uniform wall thickness products.

Sheet metal production refers to the processing of metal plates such as steel plates, aluminum plates, and copper plates, including laser cutting, stamping, and bending. The significant feature of raw materials for sheet metal processing is that the thickness of the same part is consistent.

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