Understanding Lift and Retraction Speed in 3D Printing for Tabletop Miniatures

In the realm of 3D printing, lift speed, retraction speed and rest time are crucial parameters that significantly influence the quality and efficiency of printing tabletop miniatures, including miniatures for your next D&D adventure. So, what do we mean by lift and retraction speed?

• Lift Speed: The speed of the build plate rising after each exposure phase
• Retraction Speed: The speed of the build plate lowering back onto the screen.
• Rest Time: The time between the plate being fully lowered and the next exposure to start.

Most 3D printer and resin manufacturer recommend using lift and retraction speeds of 40mm/min, up to 150mm/min. This gives great results for a variety of set ups; however, your 3D printer is capable of more. For example, printing a 9mm tall test print at recommended 40mm/min lift and retraction speed over 6mm lift and retraction height takes 2:34h, while the same test with 180mm/min takes only 1:18h.

Influence on Print Quality

Lift and retraction speed, as well as rest time have a significant influence on your print quality. To visualize that, our friend Maria from Cured Creatures has printed a variety of models with different configurations. Her tests were printed on the Phrozen Sonic Mini 8k, using Phrozen Aqua-Grey 8k resin.

While slow lift speeds generally reduce stress on the moving parts of your printer, slowly peeling off each partially cured layer from the nFEP sheet in your Resin-Vat puts a lot of force on your model. Ripping off a Band-Aid is a great example here. Doing it slowly is much less pleasant than doing it in one quick motion. Your future tabletop minis have the same feelings about this. It can lead to visible layer lines, as shown in the picture above.

Lift speed is only one part of each layer cycle. Another important part is your retraction speed. While too slow retraction speed only has an impact on your overall print time, too fast retraction has a negative impact on your miniatures known as blooming. Blooming occurs, when the resin in your Vat has almost no time to settle and is still moving while your next layer has already started to cure.

This is where rest time comes into play. Without any rest time in between the plate reaching the bottom position and the next exposure starting, the resin will not have settled fully. Rest time is a very resin dependent factor, that is heavily influenced by the resin’s viscosity. A more viscous resin needs longer rest time than a less viscous one.

Most printers today support a feature called Two Stage Motor Control, which separates the lift and retraction into two different sections. We can use this to reduce blooming and increase the quality of your prints while still taking advantage of higher lift and retraction speeds.

Our Recommendation

While each printer set up is different, we recommend starting with a slower lift speed for the first 1mm of your lift height. It helps to reduce strain on your 3D-printers Z-Axis, as well as on your vat’s nFEP-Sheet. Afterwards, you can safely lift at 180mm/min, 240mm/min or 300mm/min lift speed for your remaining lift height.
As for retraction, we recommend using a speedy retraction of 300mm/min until the plate has reached the last 2mm, when you should switch to 40mm/min. This prevents the resin from moving too much and causing blooming. Paired with a rest time of 1-2s, you will see a great increase in print speed without a loss in quality.

Special Cases, ACF & HDF Films

ACF and HDF films have recently been introduced to the market. Both films reduce the suction force of each lift greatly, while coming with a price of less detail sharpness due to their milky surface. For both films, you can achieve lift speeds of 600mm/min or more, however to achieve the best possible print quality we don’t recommend using either film as they blur out the finest details.