Stratasys PolyJet Resin 3D Printing on a Glass Substrate

Just when you think full-color Stratasys PolyJet printing couldn’t get any cooler (you’ve seen the banana, right?) now we can 3D print parts with one side as slick as glass. That’s because the part is actually printed on glass, or plexiglass, as the base substrate, and that smoothness forms the initial surface layer. (NOTE: you can print on other substrates and achieve other finishes, too – but that’s a story for another time.)

Here’s how I’ve been using this option on our J55 printer at PADT Inc.

Stratasys PolyJet 3D Printed parts, printed directly on the build tray without using any support.

Printing on glass, etc. is possible when you set up a build with GrabCAD Print Pro software. From the toolbar on the right-hand side, go to Tray Settings to find the “Print directly on tray” check-box.

In Stratasys GrabCAD Print Pro software, for PolyJet printing, select “Print Directly on Tray” under Tray Settings. This tells the printer do not deposit a base layer of support material – just start printing the model immediately on the build tray.

Printing the “Mosquito in Amber” Model on Plexiglass using the Stratasys PolyJet J55

Working with a fascinating CAD model from Stratasys (that channels our inner Jurassic Park fandom,) I set up a build of 19 custom-labeled mosquito-in-amber parts on our J55 full-color 3D printer.

J55 build-job set up in Stratasys GrabCAD Print Pro software. Each “mosquito in amber” part builds without support, directly on the temporary plexiglass substrate. Each part is also uniquely labeled with a sequential number and the PADT name, thanks to the labeling function within the Pro software tool.

The built-in wizard made it simple to adjust the tray height so it allowed for the thickness of my plexiglass sheet. Here are the steps I followed:

1. Measure thickness of the 18 inch-diameter glass/plexiglass (ex: 2.99 mm)

Measure the thickness (in millimeters) of the glass or plexiglass substrate. This value will be needed when stepping through the Wizard guide on the J55 control screen.

2. Place four pieces (about one inch squares) of very thin double-sided NITTO tape or equivalent ( Amazon.com: Nitto (Permacel) P-02 Double Coated Kraft Paper Tape: 1 in. x 36 yds. (White) : Tools & Home Improvement) directly onto the build tray, evenly spaced and close to the edges. Peel off top protective paper.

Roll of thin, double-sided sticky tape (suggested: Nitto from Permacel) to temporarily secure the plexiglass layer to the build tray.

3. Set circle of plexiglass on the tray, centered as best as possible. Press firmly to stick.

Plexiglass layer shown attached to J55 circular build tray using four pieces of Nitto tape.

4. Start Wizard for Tray Height on touch-control panel. Select Semi-Automatic Mode. Enter glass thickness value in millimeters in two places to confirm.

5. Wait for automatic height validation. (Approximately 6 to 7 minutes.)

6. Printer is ready to run.

7. Set up part in GrabCAD Print Pro software selecting:

              Tray Settings: Print directly on tray

              Model Settings: Glossy

8. Send file to printer. At printer, select Start Print job. Confirm “Keeping current (adjusted) Tray Height)” when asked.

9. When print job is finished, use clean, broad putty blade to pop parts off tray.

That’s it – your parts are done with no post-processing required, and the underside is smooth and shiny like a mirror.

Close-up (underside) of PolyJet printed-on-glass model: (left) looking straight-on and (right) looking at a slight angle to show the reflected shiny surface.

Here are a few other parts I’ve printed directly on plexiglass on the PADT J55 system:

Examples of print-on-glass parts produced on the Stratasys J55 PolyJet printer. Note the reflections.

Return to Standard Build-Tray Printing

When you want to go back to printing on the standard build tray, remove the plexiglass and pieces of tape. You’ll note that the J55 control panel will now display this warning message in orange: “Current tray height is different than original tray height.” The next time you send a job to the printer and hit Start, the control panel will say, “Confirm your tray height requirements for the next job.” It will then show two options:

• Restore the initial try height to the original setting and print. CLICK THIS IF YOU HAVE REMOVED THE PLEXIGLASS IN ORDER TO PRINT AS NORMAL ON THE PRINT BED.
• Keep the initial tray height at the current setting and print. CLICK THIS IF THE PLEXIGLASS IS STILL IN PLACE (or you removed it but decided to put it back) AND YOU WANT TO PRINT ON IT AGAIN.

Now you see how easy it is to 3D-print parts with a super shiny flat side. One application is signage – you can backlight these parts and they will look amazing on a wall or tabletop. Or, create your own embedded-in-amber creatures, if you dare.

Back-lit signs, printed directly on a glass substrate using Stratasys PolyJet technology. (Images courtesy Stratasys.)

For more information

For additional print-on-glass information, watch this Stratasys video:

Stratasys Academy | GrabCAD Print Pro for PolyJet: 3D Printing on Glass – YouTube

It is slightly dated (September 2024) simply because Stratasys releases monthly software updates to GrabCAD Print, but overall it follows the same steps as described here and the video images help clarify what you’ll see.

PADT Inc. is a globally recognized provider of Numerical Simulation, Product Development and 3D Printing products and services. For more information on Stratasys printers and materials, contact us at info@padtinc.com.

(All images courtesy Pam Waterman, except where stated.)