If you’re a PolyJet user, there is a good chance you’ve experienced under-cured or over-cured parts at least once—especially if the UV Calibration Wizard hasn’t been run in a while. In this blog, I’ll explain the effects of a poor UV calibration (low and high) and how to avoid running into these problems.
Importance of UV Calibration
Before I explain the effects of a poor UV calibration, it is important to know which of the two versions of the Stratasys PolyJet 3D printers you are working with.
- 3D Printers With Built-In UV Sensor: Some PolyJet 3D printers such as "V3" Objet printers (Objet 24, Objet 30, Objet30 Pro, Objet30 Prime), have the UV sensor built in to the printer. This is the small glass cover near the bottom right-hand side of the build tray. These machines make it accessible for clients to calibrate their own UV light.
- 3D Printers Without Built-In UV Sensor: Machines that don’t have this sensor/cover, such as "V2" Objet printers, generally need a Stratasys technician to calibrate their machine with a UV meter.
Regardless of which version you have, to print parts at the highest quality, it is essential that the UV light be at the right intensity. Like any working machine, the intensity of the UV will dip overtime and will need to be occasionally maintained by replacing or recalibrating the UV lamp.
Effects of a low UV calibration
If you are experiencing low UV intensity, the first thing you'll notice is that your part is drooping (for lack of better words). I like to compare the effect to a melting candle. It’s also common that the part will have a wavy surface finish, and the part will feel tacky when you touch it. To avoid this poor quality, check your UV light before every build.
Effects of a high UV calibration
Having a high UV calibration is a lot less common than a low UV calibration. Over time the intensity tends to dip rather than rise, but there is a small chance that the UV sensor could be mis-calibrated at the time of calibration. Parts that are over-cured tend to get brittle. This will be less noticeable on thicker parts than thinner but still poor quality none-the-less.
How to avoid running into these problems
If you are running a V3 machine, than you have been shown how to run the UV calibration. It doesn’t hurt to run the UV calibration wizard more frequently than needed. In fact, we recommend doing it, at least, once every few months. However if you are running a machine without the UV calibration sensor, then you will need to contact Stratasys Support for help troubleshooting the issue.
Did you know that keeping up with your 3D printer maintenance can help prevent future issues? Download our PolyJet Maintenance Checklist to make sure you're covering all your bases.