Como você deixa as peças claras?

How do you make the pieces clear?

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Posted on: January 21, 2020, From project manager Mandy

Transparent parts are widely used in today's society, such as automotive, aerospace, and bottles and cans in our daily lives. How do you get clear parts? Here are 3 blueprints for manufacturing solutions. You can consult specific cases, analyze the advantages and disadvantages and then choose the appropriate manufacturing option.

Produce transparent parts with 3D printing

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3D printing cannot print transparent parts directly due to material limitations. The transparent parts printed by 3D printing are translucent, which means they look a little blurry. If we want to obtain completely transparent pieces, we have to sand and polish them with sandpaper. Sanding involves polishing the sandpaper from coarse to fine, followed by polishing with wax. The process is similar to acrylic.

Discover more about optical prototyping here.

The biggest advantage is that it can be manufactured as a whole without having to disassemble any parts. The 3D printing process for obtaining transparent parts is still deficient. The first point is the structure, because some of the internal structures are complex and some of the subtle structures cannot be manually polished over the entire surface of the part, so it is more difficult to achieve a fully transparent effect in this model. At this point, the CNC-acrylic bonding method may be slightly dominant. The second point is that SLA material is liquid, so some air may enter during the printing process. As a result, we will see some small bubbles on the transparent parts that cannot be removed from inside the parts. If your clear piece is so aesthetically demanding that it won't work next time, you need to rethink the process.

Below is an example of SLA transparency. If you have any ideas, you can leave a comment.

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Technology: 3D Printing Stereolithography (SLA)

Material: Liquid photosensitive polymer

Post-treatment: sanding + polishing

Defects: It can be seen that the inner diameter of the entire tube is too small, some local areas cannot be polished manually, and the effect of full transparency is not achieved. There are small bubbles highlighted in red in the image.

Advantage: Due to these two defects, they are clearly visible and accepted by the customer. Because this part is used for functional testing of gas valve lines and not for display. The transparency effect is present as long as you can see the transport effect of the internal air flow. According to the analysis, 3D printing meets customer requirements. The customer saves costs and completes product testing in a short time.

Material options for CNC machining of transparent parts

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The materials commonly used in CNC machining of transparent parts are acrylic and PC. Acrylic polishing and PC steam polishing. Although acrylic and PC materials are transparent, there is a difference in application.

Acrylic itself is more transparent than PC, has better penetration, and is relatively easy to polish compared to PC. Acrylic is very popular in exhibition prototypes. However, the disadvantage of PMMA is its fragility, which is not as high as that of PC. The J machining process can only be achieved through CNC machining. If the product has an inverted or functional structure and the inside is hollow, this type of disassembly will leave a sticky thread. PC has high hardness and resistance to high temperatures, which makes polishing difficult. Furthermore, if we carefully observe PC materials from various angles, we will notice that they reflect a slightly purple light and cracks may appear during fumigation.

Below is an example of a CNC transparency. If you have any ideas, please leave a comment.

Technology: CNC Machining

Material: transparent PMMA

Post-treatment: sanding + polishing

Advantages: CNC parts processing and subsequent adhesive solution can save processing time and costs and facilitate polishing.

Manufacture of transparent parts by vacuum casting

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Castings can be made from a variety of resin materials. There are two types of materials used to make transparent prototypes using vacuum casting technology. Axson PX 5210 from France, whose material performance is similar to that of engineering production plastics, transparent PMMA. Axson PX 527 from France, whose material performance is similar to that of engineering production plastics, transparent PC.

Vacuum casting is best suited for small volume production. A silicone mold can cast 10 to 12 parts, specific structural analysis. Vacuum casting can cast a variety of post-processing parts, such as: Such as color requirements, texture requirements, matte finish, etc. This can save a lot of labor costs, such as: B. manual sanding and polishing as in CNC solutions.

Below is an example of a clear part. If you have any ideas, please leave a comment.

Technology: vacuum casting

Material: Axson PX 5210 (transparent PMMA-like resin material)

Defects: Silicone molds have a certain shelf life. If your quantity is more than 500, vacuum casting is not economical. It may be a good option to use injection molding.

Advantages: It can be processed as a whole part, saving a lot of post-processing labor costs and shortening the delivery time of the entire project.

Final considerations

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