Why and when to combine SLA and Micro 3D Printing?

SLA (stereolithography apparatus) and Micro 3D Printing (projection micro stereolithography (PµSL)) both use high-powered laser light to cure a photopolymer resin – but that is where the similarity ends. These 3D printing technologies are excellent at what they do, yet each has its limitations. When you combine the two, you can benefit from the advantages of both.

In this article we look at why and when you might combine SLA and Micro 3D Printing, and the benefits of doing so.

SLA 3D Printing

SLA is a versatile, cost-effective and quick technology for 3D printing prototype and end-use parts. Here at Prototype Projects, we have a range of SLA machines with build envelopes ranging from 250 x 250 x 250 mm up to 450 x 450 x 400 mm, so we can 3D print small, medium-sized and relatively large parts.

Furthermore, we build SLA parts in a choice of resins so the finished parts possess the required material properties:

• Matrix Clear: a tough, durable clear resin.
• Matrix Cream: a tough, durable, cream-coloured resin, this resin offers a little more flexibility than Matrix Grey.
• Matrix Grey: a tough, durable, grey-coloured resin.
• Matrix HT300: an ultra-high temperature-resistant rigid plastic engineered to withstand the harshest thermal environments

Parts made from these materials are non-porous and we offer a number of finishing options. Matrix Clear can be polished and lacquered for creating parts with improved clarity. In addition, the materials can be primed and painted, and have blackout/RFI/EMC coatings applied to internal ‘B’ surfaces. The materials are sufficiently tough that they can be tapped or have threaded inserts installed, depending on the thread size.

Micro 3D Printing

Micro 3D Printing takes 3D printing to a level that was not previously possible. With far better resolution than other 3D printing technologies, Micro 3D Printing delivers exceptional accuracy and smooth surfaces. The disadvantages with PµSL are that it is a slower process because the layer thickness is so small, and the parts themselves are smaller. Our Micro 3D Printing printer has a build envelope of 100 x 100 x 75 mm, which is much less than our smallest SLA 3D printer.

We use three different materials in our Micro 3D Printing printer, all of which are relatively stiff and strong when cured. Prototype and end-use parts, therefore, benefit from good dimensional stability and fine details that retain their as-built accuracy.

• Matrix HTL: A high-temp, low-viscosity engineering material with excellent strength and rigidity. Finished parts can withstand temperatures up to 114°C, making them ideal for demanding environments.
• Matrix BIO: A biocompatible resin suited for non-implantable medical applications. This material is sterilisation-friendly and has passed multiple ISO 10993 biocompatibility tests.
• Matrix HTA300: Industry-leading, ultra-high temperature (300°C) resistant rigid plastic suitable for the harshest thermal environments.

In theory, the Micro 3D Printing materials could be finished in much the same way as SLA parts. However, secondary finishes are seldom requested because they would have an adverse impact on the parts’ tight tolerances and fine details.

Combining technologies

Sometimes you might need the size, speed, accuracy and cost-effectiveness of SLA while at other times the extreme accuracy of Micro 3D Printing might be required for small components. Inevitably, there are occasions when you need a relatively large part that incorporates high-accuracy detailed features. Making such parts entirely using Micro 3D Printing would be expensive, slow, and it may be necessary to 3D print the part in multiple sections for subsequent assembly.

An alternative approach is to use SLA and Micro 3D Printing to 3D print different sections of the same part then assemble them so you have the best of both worlds. Not only will the part benefit from the size, speed, accuracy and cost-effectiveness of SLA, but the critical features also have the high accuracy and smooth surface finish of Micro 3D Printing.

SLA parts can have location features 3D printed to enable Micro 3D Printing elements to be positioned accurately ready for snap-fitting or adhesive bonding. Alternatively, an SLA part can be CNC machined accurately for accepting Micro 3D Printing inserts; this can be a particularly useful method if two or more Micro 3D Printing elements need to be positioned accurately relative to each other. Another option is for a CNC machined element to be used for locating the Micro 3D Printing features prior to the whole sub-assembly being fixed within the SLA part, or a CNC machined fixture can locate the parts accurately while they are bonded in position.

Applications for combined SLA and Micro 3D Printing parts

Combined SLA and Micro 3D Printing parts can be suitable for producing one-offs or multiple prototypes, perhaps for proof-of-concept studies or functional testing. The combined 3D printing technologies are equally useful for manufacturing low volumes of end-use parts.

Typical fields of application include microfluidics, drug delivery devices, life sciences and biotechnology, though other sectors can also benefit from combining SLA and Micro 3D Printing.

Production speeds

Assembling parts that have been made by SLA and Micro 3D Printing requires more time than just 3D printing parts due to the additional process steps involved, so we cannot offer an Overnight production speed. However, if you tell us what you need and how quickly, we can quote for making combined SLA and Micro 3D Printing parts that meet your requirements.

Talk to us

If you would benefit from combining SLA and Micro 3D Printing for prototyping or end-use applications, talk to our experts on 01763 249760, or complete the enquiry form below to request a quote.