Here’s a question that’s often asked: How do materials used in 3D printing compare to injection-molded thermoplastics when the temperature rises? To answer that, I’ll briefly dissect the materials used in stereolithography (SL) and selective laser sintering (SLS) processes as these are commonly compared to injection molding.
SL involves a thermoset resin that is solidified by an ultraviolet laser, followed by a UV post-curing process to completely solidify the resin. As far as material properties, the big takeaway is that SL parts are built from thermoplastic-like resins, so they do break down over time in direct UV light.
SL uses materials that mimic ABS, polypropylene and glass-filled polycarbonate, and they offer an array of material properties still exist. But today we’re concerned with the thermal properties of the materials that are best suited to handle the heat — 3D Systems Acura 5530 and DSM Somos NanoTool. Both are offered in post-cured states and there’s an additional process for thermal post-curing that increases the operating temperatures.
The chart shows optimal heat deflections for SL materials. The other materials offered in SL have a much lower heat deflection ranging from 120˚F to 177˚F.
UV Post-Cure +
|DSM Somos NanoTool
Designing luminaires or lenses with clear materials? Our tip this week looks at the material selection and surface finishes available for prototyping and low-volume production of lighting applications.
Prototype built in clear WaterShed XC 11122 material with stereolithography.
If you haven’t considered using additive manufacturing (3D printing) for your lens design, you may want to check it out. Proto Labs offers stereolithography (SL) with three options for clear parts.
- Somos WaterShed XC 11122 — ideal for lens and high-humidity applications
- 3D Systems Accura 60 (10 percent glass-filled) — creates a clear part with slight blue tint and high stiffness
- 3D Systems Accura 5530 — high temperature resistance, suitable for under-the-hood applications
Prototyping small volumes of microfluidic parts has traditionally been difficult using CNC machining or injection molding, but Proto Labs offers microfluidic fabrication through additive manufacturing (3D printing) for just this purpose.
Microfluidics typically requires very flat surfaces, and clear and thin/shallow features that are difficult to produce in a mold that is milled and hand polished. These tiny features are not easily distinguishable, requiring careful polishing and injection molding pressures can sometimes role the edges even further, not to mention the effect that the ejector pins have on the part surface. Ejector pins play a huge factor in removing the part from the mold and can cosmetically impact microfluidic parts that are molded. We will continue to injection mold microfluidics, but please first discuss these projects with a customer service engineer at Proto Labs.
Additive microfluidics changes all of this as ejector pins are a non-factor. We use stereolithography (SL) to produce parts using an ultraviolet laser drawing on the surface of a thermoset resin, primarily our Somos WaterShed XC 11122 material. High-resolution SL is able to produce features as thin as 0.002 in. layers to provide the fine detail that microfluidics require. We recommend channel sizes of 0.025 in. square cross sections with a minimum wall thickness of 0.004 in. for X and Y dimensions and 0.016 in. for the Z dimension. Of course, we can produce features smaller than this, but it would need to be carefully reviewed by our engineers before the build begins.
Proto Labs’ corporate headquarters are in Maple Plain, Minn. (above). With the Alphaform acquisition, Proto Labs now has manufacturing plants in the United States, United Kingdom, Germany, Finland and Japan.
Proto Labs closed this week on the purchase of select assets and operations of German-based manufacturer Alphaform AG, which significantly extends its additive manufacturing (3D printing) capabilities across Europe.
Alphaform is a leading service bureau headquartered in Feldkirchen (Munich), Germany. The purchase includes Alphaform divisions operating in Germany, Finland and the United Kingdom. This acquisition will significantly expand Proto Labs’ recently launched additive manufacturing capabilities in Europe by adding selective laser sintering, direct metal laser sintering and additional stereolithography capabilities. The acquisition also includes the injection molding service currently offered by Alphaform Claho, in Eschenlohe, Germany. MediMet Precision Casting and Implants Technology GmbH, a 100 percent subsidiary of Alphaform AG, is not part of the transaction.
Proto Labs entered the additive manufacturing market last year with the purchase of Fineline in Raleigh, N.C. Proto Labs is spending $25 million to expand that plant, which is set to open in 2016.
You can read the full press release here.
Selective laser sintering (SLS) is an industrial-grade 3D printing process. It builds durable nylon prototypes and functional parts using a laser that “draws” slices of a CAD model in a bed of material, fusing micron-sized particles one layer at a time. The result is fully functional plastic parts that might have been otherwise challenging to manufacture using machining or injection molding.
This month’s tip discusses:
- Properties and applications of various nylon materials
- Managing the SLS build process
- Design elements to improve eventual moldability
- Surface finishes and post-processing
- Maximum part size, achievable tolerances and other considerations.
Read the full design tip here.