What are my options for manufacturing a clear part? We look at Formlabs 3D printing.
Clear parts may be required when you need to visualise internal features, or possibly to direct light, but what’s the best process to get the transparency you want?
We use SLA with Formlabs 1+
Plunkett Associates have covered CNC’d and Objet 3D printed enclosures, which have demonstrated differing levels of transparency. After seeing an impressive example of an optical lens on the Formlabs website, our interest in the Form 1+’s capacity to build similar parts was peaked.
Printing in Formlabs ‘CLEAR’ resin, developed for use in their machines, the enclosure used in the aforementioned article was built.
The Form 1+ is based on SLA technology, which builds your desired part layer-by-layer; tracing out each 2D slice with a UV laser. Whilst this machine uses SLA technology, it caters to a prototyping rather than production market, and we would not expect results to match those from established professional-grade SLA machines costing over 100 times more..jpg "Unfinished enclosure")
The Form 1+ can produce layers at thicknesses of 25, 50, 100 and 200 microns, with a break-away support structure built at the same time as the actual part. The enclosure displayed in the images, was built at a layer thickness of 100 microns
As with the Objet enclosures, those built using the Formlabs machine have visible layers. Additionally, small marks can be observed on some of the surfaces, created during the removal of the support structures. (Photograph 1)
Finishing is required to achieve an optically clear part
These, along with the layering inherent to additive manufacturing processes, require finishing to achieve an optically clear surface. In the case of the Formlabs resin, supports were removed flush to the part, and then the entire part was sanded, incrementally increasing the grade of the emery paper, to ensure all layering/markings were removed. After this sanding procedure, a number of polishing stages were followed, with a finishing coat applied for presentation. (Photograph 2)
Access to surface faces is critical
For an end part, polishing will come down to ease of access; therefore cost, time, and quality of surface finish, can be geometry sensitive.
If you are interested in getting some clear parts made, be it for prototyping or production purposes, and aren’t sure of the best route; get in touch with us. We would be happy to help you with design advice, sourcing parts, and any other questions you may have.
