End-Use SLS Parts in Vibrant Colors: Dyeing Nylon 12 White Powder (With Ken Pillonel)

The most successful businesses are always evolving, able to respond to changes in the market and customer demand. That’s true for massive Fortune 500 companies and small businesses just getting started. Ken Pillonel’s small business is about as small as it can get — he’s a ‘one-man plastics factory’ that nevertheless has designed, manufactured, and shipped thousands of products to customers worldwide. 

Pillonel has grown an extremely successful business based on his design for an AirPods case that converts Apple’s proprietary Lightning port to the new standard USB-C port, tackling forced obsolescence and extending the lifetime of many people’s favorite technology. He’s been able to do it all himself with the Fuse Series and Nylon 12 Powder, delivering end-use, functional parts that rival injection molding for aesthetics and cost. 

Well, for some people, the aesthetics left something to be desired. Specifically, the color. Pillonel had people commenting on his videos and product website saying that the dark grey color of the Nylon 12 Powder was ‘a bit unsightly,’ while others went even further. But start-up founders don’t become successful by listening to the minority of detractors. “I don’t really see this as criticism. Everyone’s got different tastes. When I see that, it just tells me, maybe there's a way to improve it and get even more people as potential customers from my product,” says Pillonel. 

So, what was his solution? A range of vibrantly colored, dyed SLS products. Taking advantage of the Fuse Series’ scalability and the new Nylon 12 White Powder, Pillonel was able to scale up his operation and respond to customer demands. 

After trying out the popular workflow with RIT fabric dyes, Pillonel wasn’t happy with his results. He turned to the French company Techniques Chimiques Nouvelles and immediately saw a difference. “As soon as I tried them, I got the perfect result….I didn’t look back,” he says. 

To get that perfect result consistently, Pillonel found that he had to keep an eye on two factors: heat and agitation. Heating the solution to 80 degrees, continuously mixing the solution, and making sure the part is consistently exposed (i.e., not lying flat on a metal dipping cage) were paramount to getting a successful result. 

Pillonel’s first version was to purchase this ultrasonic cleaner, available on Amazon. The advantages of this are that it’s inexpensive and extremely straightforward. To use this type of dyeing solution, you mix your dye into the water in the cleaner, heat, agitate, and then dip your part in for a short time (this should be tested and determined for color depth previously). 

Pillonel was able to achieve a great color solution quickly and easily. “This scales up in size really well. These cheap ultrasonic cleaners go from 1 L to 30 L, or even more. So if you’ve got big parts or you want to do big batches at once, that’s a great solution.” 

The color gets darker the longer you leave the parts in the ultrasonic cleaner, so Pillonel was able to get multiple shades of colors by adjusting the soak time. “You can get great results this way. No spots or anything, it was great,” he says. 

Despite the ease, Pillonel found a few drawbacks to this solution, and it led him to continue tweaking the workflow. 

The glass container, no-mess solution, worked so well, Pillonel decided to stay on that thread and iterate from there. The ultrasonic cleaner was too noisy, but there were other ways of agitating the liquid inside the glass container. Pillonel called back to chemistry class to find a unique solution. 

Hot plates have a magnet attached to a motor — Pillonell dropped a magnet inside the glass container, placed the container on top of the hot plate, and let the rotating magnetic forces to the agitation. “That's great because we get great heating. Usually, the hot plates are really powerful. It stirs really well. And most importantly, it's super quiet,” says Pillonel. 

One note of difficulty may be sourcing the appropriate glass containers — they need wide mouths, can be resealed, and have very flat bottoms. For a popular solution from IKEA, the issue of a slightly curved bottom can be mitigated by placing the container in a metal pot for conduction on top of the hot plate. Though this solution may not work perfectly for very large parts, for small consumer goods like Pillonel’s AirPods cases, it’s been engineered to perfection. 
 

In Pillonel's guide to dyeing SLS 3D printed parts, he shared several tips and tricks to achieve the best, most saturated color for both Nylon 12 White Powder and regular dark grey Nylon 12 Powder. 

• Control contact and oil from handling the parts by always using gloves.

• Control humidity to avoid slight water absorption by the SLS parts, which can have a slight effect on the dye penetration. 

• Rinse your parts as soon as possible once they’re taken out of the dyeing solution inside the glass container. This avoids any spots with extra dye turning a slightly darker color. 

• Dry your parts well. Pillonel uses a food dehydrator at 70 °C. 

• Stay consistent. Record your process!

  • Dye your first part with a recorded soak time. Seal this part in a plastic bag — this is your Golden Sample, from which you’ll measure your subsequent dye jobs. 

  • Dye 5-10 parts at a time, and check back on your Golden Sample between rounds to ensure your dye remains the same strength. 

  • Record when the dye strength starts to fade, and then lower that number a little for safety, then use that going forward as your reminder to change your dyeing solution.