Purpose

This guide is meant to help students 3D print their parts using the SBME Makerspace Form 3B+ printer. For more detailed guidance and visual assistance, search on support.formlabs.com.

Getting Started

To print with the FormLabs Form 3B+, you will need:

1. A 3D modelling software (SolidWorks, Blender, Fusion 360, etc.. ). Design specifications for 3D models for the Form 3B+ are given on https://support.formlabs.com/s/article/Design-specifications-for-3D-models-form-3?language=en_US
2. The PreForm software from FormLabs. This can be downloaded from https://formlabs.com/software/

Note: If this is your first time using PreForm, an onboarding tutorial will appear and walk you through the software’s capabilities. Click Help > Show Onboarding Tutorial to review this information at any time.

Loading a file into PreForm

After creating your part in a 3D modelling software, export it as an *.stl file. Load this file into PreForm by either opening the File menu or by drag-and-dropping the file into the software. Multiple *.stl files can be imported at once but ensure that they do not overlap with each other on the print bed.  

Orienting the Part

When you import your part into PreForm, it will be in some default orientation which might not be ideal for printing and must therefore be reoriented. In 3D printing, orientation is defined as the alignment of an object within the space of the build volume. It impacts stability, surface finish, and printability. The orientation of your part can be adjusted using the third icon from the top-left, the “Orientation” menu left (see Figure 1). You can change the orientation of your part either with the auto selected, select a face as the base, or “Orient Axes” values. When orienting a part, minimize the following in order of priority: (1) the surface area of each layer, (2) the amount of overhang needing supports, and (3) the total height of the part. Minimizing the surface area of the layers reduces the risk of warping of the part. Minimizing the overhang reduces the amount of support material required, and minimizing the part height reduces the print time. An example of a well oriented part is shown in Figure 2. More detailed examples are shown in Figure 3 and on https://support.formlabs.com/s/article/Model-Orientation?language=en_US.

Generating Supports for the Part

Supports are the cornerstone of a successful SLA print as they hold the model in place throughout the entire printing process. Supports consist of three components: rafts, scaffolding, and touchpoints. The raft forms a base that adheres to the build platform. Scaffolding stems from the raft to secure your part as it prints. Touchpoints are areas of contact where the scaffolding meets the model (see Figure 3).

Generate supports by selecting the fourth icon from the top-left, the “Supports” menu. Then select “Auto-Generate All” to produce the necessary supporting structure, scaffolding, and print bed raft. Check that the generated supports do not negatively impact the final part, as they will be removed upon the completion of the print. If a touchpoint from a support is in contact with a critical feature, select the “Edit-All” button, highlight the specific touchpoint, and either move or delete it. More detailed guidance and visual assistance can be found on https://support.formlabs.com/s/article/How-supports-work-in-SLA-printing?language=en_US.

Print Bed Part Layout

After orienting your part(s) and generating the necessary support, they need to be laid out on the print bed. A correct multi-part layout does not have overlapping parts and has sufficient space between parts to allow for easy removal of each part once printing is completed (see Figure 4).  Generate a part layout by selecting the fifth icon from the top-left, the “Layout” menu. Then select the “Layout-All” to automatically layout all the parts on the print bed. You can also manually move the parts to the desired locations by clicking and dragging the parts.

Form 3B+ Elements

The Form 3B+ display includes a touchscreen and status lights. The touchscreen displays print information, settings, and error messages. It serves as the user interface for the Form 3B+. The status lights indicate the printer’s state. Refer to messages on the touchscreen to understand the meaning of the status lights (see Figure 5).

Preparing a Print Job

Before starting a print, use the SBME Book A Space calendar to reserve the Formlabs 3B+. If you do not have access to the calendar, please ask one of your TAs to book the printer for you.

Connect to the Form 3B+ via the provided USB cable. Choose “ImpossibleAsp” which is the Makerspace printer by clicking on the “Job Setup” dialog box on the top-right (see Figure 1), then “Edit Job Setup”. To determine what “Material” to select, you can look at the resin cartridge label inserted in the printer (see Figure 5). Typically, this will be Clear V4 but this may change over time. Finally, select the desired “Layer Thickness”. Layer thickness affects both the speed and quality of a print. Thicker layers print faster but sacrifices detail. Thinner layers print more slowly but can capture finer details. For most parts, the 100μm thickness will be sufficient. For finer resolution the printer also supports 50μm, and 25μm layer thicknesses. The printer also supports adaptive layer thickness which is a setting that balances speed and quality to give you the best of both worlds. For more information, visit https://support.formlabs.com/s/article/Adjusting-layer-thickness?language=en_US#change.

Starting a Print

With the print job prepared and your computer connected to the printer, select “Upload Job”. Once transferred from PreForm to the printer, print jobs must be confirmed on the printer’s touchscreen to start the print. To start a print job on the Form 3B+:

1. Tap the print job from the Home screen, or from Queue. A new screen appears.
2. Tap Print to confirm. A new screen appears.
3. Follow the prompts on the touchscreen to check consumables are inserted correctly, then tap Confirm. The print starts.

Before printing, always make the following steps are completed:

1. Check the build platform. Make sure the build platform is clear, clean, and affixed in place with the lever.
2. Open the resin cartridge vent found on the top back right of the resin cartridge (see vent button in Figure 5).

Stay near the printer until the first layer of print is finished before leaving the printer unattended!

Post-Processing a Print

Once the print is complete, you will remove the build platform from the printer, wash any remaining liquid resin off your printed part, and post-cure and remove supports. As you will work with resin and solvents during post-processing, gloves are required.

Removing Parts from the Build Platform

The first step of post-processing a printed part is to safely remove it from the build platform. It is important to close the cover immediately after removing the platform to prevent ambient light from curing the liquid resin in the resin tank. Raise the UV shield of the printer, lift the securing lever to release the build platform, and with your print facing upwards, push the build platform onto the jig until it sits secure (see Figure 6). Close the UV shield of the printer. To release parts from the build platform, slide a removal tool under the angled edge of the base and the part should come off (see Figure 7). Once all parts have been removed from the build platform, replace the platform on the printer and ensure the UV shield is lowered.

Isopropyl Washing Parts

The next step in post-processing parts involves washing the excess resin off the parts. Isopropyl alcohol (IPA, 90% or higher) is the recommended solution for rinsing parts and cleaning liquid resin after each completed print. Use Form Wash to rinse the remaining liquid resin from printed parts’ surfaces as shown in Figure 8. This bath should take approximately 10 minutes for Black and Clear resins. For other materials, wash times are described on https://support.formlabs.com/s/article/Form-Wash-Time-Settings?language=en_US.

Figure 9: Form Wash container and time adjustment knob. From https://support.formlabs.com/.

UV Curing Parts

After the parts have been washed, allow at least 30 minutes for isopropyl alcohol (IPA) to fully evaporate. Use Form Cure to expose printed parts to light and heat to stabilize the parts for performance. Select the correct curing schedule for the resin used, for Clear resin see Figure 9. A full guide can be found on the FormLabs website: https://support.formlabs.com/s/article/Form-Cure-Time-and-Temperature-Settings?language=en_US.

Once a part has been UV cured and the supports have been removed with the tweezers provided, your part is fully post-processed and ready to be used. If your part still feels sticky after curing, it could mean that your part still has residue resin on it. Use the IPA squirt bottle and manual wash your part before UV curing your part again. Do not overcure your part as long UV exposures will degrade the mechanical properties of your material (i.e., part becomes more brittle and porous).