In the development of transparent components for sectors such as automotive, optics, lighting, electronics or medical devices, the choice of the right manufacturing technology is a decisive factor. It is not only a question of achieving an adequate visual appearance, but also of guaranteeing optical properties, mechanical resistance, dimensional stability and economic viability according to the final application.
At Gestión de Compras, we have extensive industrial experience in the production of transparent parts using multiple technologies, from the injection of technical thermoplastics to advanced solutions in 3D printing and precision machining. In this post we take an in-depth look at the main technologies available and their technical implications, with a comparative approach based on real cases and demanding industrial requirements.
Polycarbonate and PMMA Injection Molding: Industrial Transparency with High Repeatability
Thermoplastic injection molding remains the most widely used technology for the mass production of transparent parts. Polycarbonate (PC) and polymethylmethacrylate (PMMA) are the most frequently used materials, each with very different properties:
- Polycarbonate stands out for its high impact strength (above 600 J/m) and good thermal stability (up to 120 °C), making it ideal for functional components subjected to mechanical stress or demanding environments, such as automotive headlights, visors and protective shields. However, its transparency is slightly lower than that of PMMA, with light transmission close to 88-90%.
- PMMA, on the other hand, offers excellent optical transparency (light transmission > 92%), UV resistance and better scratch resistance, but is more fragile to impact. It is therefore often used in lenses, diffusers and aesthetic elements where visual clarity is a priority.
Both materials require polished steel molds with very tight tolerances and specific texturing to achieve optical finishes. In Gestión de Compras we are specialized mold makers, we have mirror polishing processes to guarantee an impeccable visual quality, adapted to the most demanding standards.
3D Printing with Transparent Resins: Advanced Prototypes and Short Runs
3D printing has evolved to offer viable solutions for transparent parts in functional validation phases or even in short series. The most relevant technologies in this field are:
- SLA (stereolithography): allows parts with high surface resolution (<25 microns) to be manufactured using transparent light-curing resins. The most advanced resins allow good light transmission and can be post-processed by sanding and varnishing to obtain almost optical finishes. However, these parts have lower mechanical and thermal resistance than industrial thermoplastics, and their stability against humidity and UV rays is limited.
- DLP and LCD technologies also work with transparent resins, with better manufacturing times and reduced costs, but with similar limitations in physical properties.
These technologies are especially useful for prototype lenses, sensor covers, design validations or components for electronic devices under development. At Gestión de Compras we combine SLA printing with manual post-processing and UV treatments to optimize both aesthetics and functionality.
CNC Machining of Transparent Polymers: Optical Precision in Low Volume
Machining solid blocks of PMMA or PC is an excellent solution for obtaining transparent parts with high dimensional accuracy, controlled surface finishes and without the need for molds. This method allows:
- Total control over tolerances, optical channels, grooves or complex geometries.
- Application of mechanical or chemical polishing treatments to achieve levels of transparency comparable to glass.
- Use of stable industrial polymers, without the structural limits of light-curing resins.
The main disadvantage is its high unit cost, so it is a technology suitable for very small series, tooling, customized lenses or critical validation elements. Gestión de Compras has CNC centers specialized in technical polymers and we develop 5-axis milling and assisted polishing processes that guarantee high quality finishes.
Thermoforming of Transparent Sheets: Cost-Effectiveness and Flexibility
When it comes to producing housings, covers, or large elements with relatively simple geometries, thermoforming represents an excellent alternative:
- Pre-polished and protected PMMA or PETG sheets are used, which are heated and formed on a mold.
- The tooling cost is significantly lower compared to injection molding, allowing for savings in short or medium-sized runs.
- Subsequent anti-UV, anti-scratch, or optical coatings can be applied.
Although dimensional tolerances and repeatability do not reach the levels of injection molding or machining, thermoforming is ideal for sectors such as signage, industrial equipment housings, or protective covers.
Technical Comparison
| Technology | Optical Precision | Mechanical Resistance | Ideal Volume Range | Tooling Cost | Post-Processing Required |
| Injection (PC/PMMA) | High | High (PC) / Medium (PMMA) | Medium to High | High | Mold polishing / texturing |
| SLA / DLP (3D Printing) | Medium | Low | Prototypes, short runs | Very low | Sanding, varnishing, UV curing |
| CNC Machining | Very high | High | Very low volume | None | Mechanical/chemical polishing |
| Thermoforming | Medium | Medium | Medium | Low | Laser cutting, protective films |
Our Experience
In Gestión de Compras, we have developed customized solutions for industrial customers requiring high quality transparent parts. Our multidisciplinary approach allows us to choose the most suitable technology according to design, volume, optical requirements and budget.
Whether by high-precision injection molding, CNC machining of PMMA, or rapid prototyping with SLA resins, we accompany our customers from design to delivery, ensuring results that meet the most stringent technical and aesthetic demands.
If you are working on a project that requires industrial quality transparent components, do not hesitate to consult us: we will help you find the ideal technology with the best balance between cost, performance and functionality.
