SLA 3D Printing.
We get it. Your biggest challenges in product design and development are not necessarily the technical ones. You’re up against customer needs and expectations, user needs and expectation, manufacturability, costs, competition and, of course, that increasingly pressing issue of sustainability.
Everyone now knows that 3D printing is cost-efficient; it’s quick; materials are relatively robust and often watertight; and above all, it allows for design freedoms like never before. This 5 minute read offers insights into why SLA (stereolithography) might not just be a technical solution, but could help overcome some of the other challenges facing industrial and product designers
Stereolithography or SLA 3D printing
SLA is the grandfather of industrial 3D printing. This is largely for its ability to produce fast, highly accurate, infinitely detailed, highly polished, water-resistant parts. One of the greatest benefits of SLA is its versatility. The 3D print materials innovators have come up with a range of resins with mechanical, thermal and optical properties that match standard-, industrial- and engineering-grade plastics.
With a print bed of 800 x 800 x 600mm, the NEO 800 is one of the largest, fastest industrial SLA printers available in the UK. This outstanding machine has a scanning resolution of 1 micron, ensuring side wall quality (with a <0.5mm potential) is superb; intricate detailing is easy; and the smoothest of finishes is possible. With three of these award-winning, industrial sized printers in our 3D printing stable, we have significant capacity and can work to tight turnaround times.
Designing for Large Bed SLA 3D Printing
Our downloadable infographic for designing for SLA 3D Printing can be found here. It’s worth noting, though, that if you want your printed parts to live up to their reputation for being some of the smoothest, most detailed around, special attention should be given to the following.
- SLA printing requires support structures. The larger the part, without clever positioning on the print bed, the more support structures there will be. You can minimise A-surface support structures easily enough; but should your part contain overhangs, you’ll need to factor these in. As a rule of thumb, overhangs greater than 1mm or at an angle greater than 19º require support. We suggest that for large parts, particularly cylindrical ones, you should consider hollowing the part out. This will save on both material costs and finishing time. Don’t forget to leave drainage holes.
- Minimise corners. Sharp corners increase stress areas and can lead to print failures or cracks.
- Wall thickness impacts build quality. With its super resolution, the NEO 800 provides fantastic side wall quality. However, walls of less than 0.5mm thickness will require supports, especially for larger prints.
- SLA lets you incorporate holes in your design. However, regardless of machine resolution, holes are notoriously hard to incorporate because they may close off during the printing process. Ask your provider for a minimum hole size, and design with the belief that anything smaller may have to be drilled by hand – or laser beam.
- Threads inside apertures on SLA prints will not necessarily have the same hold power that prints using more industrial processes such as FDM or DLP will have. You simply can’t have that super smooth, layer-free finish and maintain material super strength. We suggest that you opt for threaded inserts.
- Embossing and debossing. Infinitesimal detailing is easily achieved with an SLA print, whether large or small. However, you don’t want your impressions to clog with excess resin, so a minimal depth of 0.1mm is recommended. For debossed detail, 0.4mm is recommended.
We run two exceptional resins on our three NEO 800 SLA machines.
Somos® EvoLVe 128 is a shiny off-white, durable resin that produces highly accurate, highly detailed parts. Designed for easy finishing (it boasts an exceptional A-side surface finish), EvoLVe has a look and feel that is almost indistinguishable from traditional thermoplastics. It can be bonded to other plastics and metal and can be painted when a plastic-friendly primer is applied. For parts that might be handled a lot, this slightly flexible material is probably a good bet.
Somos® WaterShed XC 11122 is a crystal clear, highly water resistant, very hard engineering resin with ABS-type properties. Again, it has been designed to deliver on intricate detailing, thinner walls of less than 5mm, and an exceptionally smooth finish. Beloved by model makers for creating pattern masters and mould cores, it can be primed easily. WaterShed parts are rigid but not shatterproof. They’re great for lenses (with a glass-like finish achieved through post-processing) and fluid flow analysis.
For much smaller parts (less than 500 x 500 x 580mm), we run a grey resin, Somos® Taurus. This robust and durable resin does have a trade-off – more finishing is required to produce a smooth surface and fine detailing may be lost as a result. As this material is not run on our NEO 800s, it may also take longer to print. You can find out more about our other SLA technologies here.