Custom machined parts usually refer to parts that are machined according to customer’s specific requirements. Customers typically choose a manufacturer to fulfill their requirements, from idea design to production delivery, the entire process takes only a few days to ten days. It can promote the operation of the project very well. There are five main methods to machine parts in the prototype field.
1. CNC Machining: CNC is the shorthand for Computer Number Control. The direct meaning is that computer digital control is a processing technology widely used in the manufacturing industry. It can also be said that it is the symbol of the current manufacturing industry. It can easily realize multi-axis linkage machining with CNC, for example, curved surface machining. It is almost impossible to machine with a normal machine.
There are many materials suitable for machining in CNC machining centers, such as copper, stainless steel, iron, 45#steel, aluminum alloy and composite materials(plastic, like ABS, PP,PA,PMMA,etc). Among them, aluminum alloy is the most commonly used metal material. If the machining center is to process materials with very high hardness, the tools used must be harder than the workpiece material. Otherwise, not only can it not be processed successfully, it will also damage the tool.
CNC machining is the most common way to process machined parts. A variety of materials and post-processing methods can be selected, and the customer’s requirements can be completed quickly and well.
2. Vacuum Casting: Vacuum casting is a process specially designed for making delicate rapid prototype and small batch reproduction, and is widely used for proofing of injection products. The commonly used plastic materials for vacuum casting are ABS, PP, PA, etc. The color selection and strength of molded parts are very flexible, which is very suitable for product designers to make customized products.
The most common problem in vacuum casting is shrinkage, so the volume of the product should be considered in the design process (suggested to be within 2.5kg of the individual part), because the larger the volume of the product, the bigger the cooling shrinkage of the product when it is prototyped by vacuum casting.
3. Reaction Injection Molding: Reaction Injection Molding (RIM)-it is a new process applied to the production of rapid moldings. It mixes the two-component polyurethane material into a rapid mold under normal temperature and low pressure environment, and forms the product through chemical and physical processes such as polymerization, crosslinking and solidification of the material. It has the advantages of short production cycle and simple process. It is suitable for small batch trial production in the product development process, as well as the production of small-volume, simple-structured covers and large-wall thick and uneven wall thickness products.
Due to the high strength, high elongation material properties, and extremely strong weather resistance, the mechanical properties and impact resistance of the product can be increased by adding a composite material such as filler and glass fiber. The RIM process is ideal for large-scale covers with simple structures, such as automotive housings and medical devices. The product does not require uniform material thickness and meets the free design and surface shape from 3 to 20 mm different wall thickness.
If the customer designs a custom product with a larger size, you can learn more in knowing how to choose to use the RIM.
4. SLS: SLS is called powder sintering. It captures two key words, powder and sintering, which is the characteristic of SLS. SLS printing technology uses a powder layer to lay a layer of powder material on the upper surface of the molded part and heat it to just below the powder. At a certain temperature of the sintering point, the control system controls the laser beam to scan the powder layer according to the cross-sectional profile of the layer, raising the temperature of the powder to the melting point, sintering and bonding to the formed portion below.
SLS does not require a support structure, and the suspended layer that occurs during the lamination process can be directly supported by unsintered powder, which should be one of the biggest advantages of SLS. SLS can use more materials. The materials that can be used include polymers, metals, ceramics, gypsum, nylon, etc. However, due to the refinement of the market, metal materials now call it SLM, and because of the current SLS on the market. The material used should account for 90% of the nylon material, so we usually default to SLS for printing nylon. Commonly used in several 3D printing technologies, the material utilization rate is the highest, and the price is relatively cheap, but it is more expensive than the SLA.
5. SLA: SLA, Stereolithography. The liquid tank is filled with liquid photosensitive resin, which is rapidly solidified under the irradiation of the ultraviolet laser beam emitted by the laser (SLA is different from the laser used for SLS, SLA uses ultraviolet laser, and SLS uses infrared laser).
SLA has the longest development time, the most mature technology and the most widely used. Among the rapid prototyping machines installed worldwide, photocuring systems account for about 60% and nearly 70%. It forms faster and the system works stably. The accuracy of SLA is relatively higher than that of SLS, and it can basically be done on the micron level. In addition, the surface quality of the product is also smoother than SLS.
The biggest disadvantage of SLA is that the model needs support structure.
For example, if your model chooses SLA, then our engineers will help it to support the structure, and this support needs to be removed when the model is not cured. A disadvantage compared to SLS. In addition, since the material is a resin, the temperature is too high to melt, and the operating temperature cannot exceed 100 °C. And after curing, it is brittle and easy to break.
Conclusion: No matter what custom machined parts, you can find the right process in the prototype field. The five most common processes are outlined above. You can choose according to your requirements and contact the appropriate prototyping manufacturer to help you achieve it.