The Fuse Sift doser assembly dispenses a mix of fresh and used powder from the hoppers into a powder cartridge. If the doser gears are jammed due to powder buildup, the Fuse Sift will be unable to dispense powder properly, leading to spills or work slowdowns.
Use this guide to clean the Fuse Sift doser assembly.
Required supplies:
Estimated time: 45–60 minutes
Preparing the workspace
Overview: Prepare the Fuse Sift and your workspace for cleaning the doser assembly.
Step 1: Remove and store printed parts
Remove any printed parts from the Fuse Sift workspace to prevent them from being damaged inadvertently.
Step 2: Clean the workspace
Using the vacuum attached to your Fuse Sift, clean the workspace. Vacuum any loose powder inside the workspace, under the hood, on the print bed and the surrounding port, and on the vent filter.
Step 3: Empty the hoppers
Both the fresh and used powder hoppers must be emptied before replacing the doser to prevent powder spills.
If the doser is still functional, you can empty the hoppers into one or more powder cartridges. Set the refresh rate to 100% to dispense only fresh powder, then fill an empty powder cartridge as you would normally. Similarly, set the refresh rate to 0% to dispense only used powder. Repeat until both hoppers are empty. You can transfer the powder from the cartridges to other clean containers if necessary. Label the containers to avoid contaminating your powder after you replace the doser.
If the doser is not functional, you can scoop the powder out of the hoppers from above. To access the used powder hopper, remove the surface grate and sieve. To access the fresh powder hopper, use a 2 mm hex driver to loosen and remove the four screws holding the fresh powder hopper lid in place. Set the screws and lid aside.
Step 4: Unplug the Fuse Sift
Power off the Fuse Sift, then unplug the power cable from the rear panel.
Danger:
Performing this procedure on the Fuse Sift while it is plugged in increases the risk of electric shock. After disconnecting the power from the Fuse Sift, wait at least five minutes before servicing.
Step 5: Unscrew the Wi-Fi antenna
Remove the Wi-Fi antenna, if present.
Warning:
Use appropriate personal protective equipment when handling loose or unsintered powder. Refer to the support article Safety with Formlabs SLS products or your powder’s safety data sheet (SDS) for more information.
Removing the upper front enclosure panel
Overview: Remove the upper front enclosure panel to begin accessing the doser assembly.
Step 1: Unscrew the upper front enclosure panel mounting screws
Using a 2.5 mm hex driver, loosen and remove the four black 8.0 mm M4 button screws underneath the upper front enclosure panel lip. Remove the three black 8.0 mm M4 button screws from the left-hand side of the same panel. Set the screws aside.
Step 2: Remove the upper front enclosure panel
Slide the panel downwards to remove it from the Fuse Sift. Set the upper front enclosure panel aside.
Removing the lower front enclosure panel
Overview: Remove the lower front enclosure panel to access the front of the doser assembly.
Step 1: Unscrew the lower front enclosure panel mounting screws
Using a 2.5 mm hex driver, loosen and remove the 18 black 8.0 mm M4 button head screws securing the lower front enclosure panel to the Fuse Sift. Remove the two chrome 8.0 mm M4 button screws holding the top of the lower panel to the inner frame. Hold the botton of the panel with one hand has you remove these screws to keep it from falling. Set all 20 screws aside.
Step 2: Remove the lower front enclosure panel.
Separate the lower front enclosure panel from the Fuse Sift. Set the panel aside.
Removing the rear enclosure panel
Overview: Separate the rear enclosure panel from the Fuse Sift in order to access the back of the doser assembly.
Use a 2.5 mm hex driver to remove the 16 black 8.0 mm M4 screws securing the rear panel to the Fuse Sift. Set the screws aside.
Separate the rear enclosure panel from the Fuse Sift and set it aside.
Vacuuming the doser assembly
Overview: Vacuum the doser assembly and the surrounding components
Disconnect the doser motor and encoder cables from the doser assembly. The encoder cable has a locking tab that must be squeezed before it can be unplugged. Be sure to pull on the plastic connectors, not the wires themselves.
Disconnect the vacuum hose and power cable from the Fuse Sift and connect it to a power source. Use the vacuum with a brush tool to vacuum powder deposits around the back of the doser assembly.
Switch to a crevice tool to access deposits between the doser assembly and hopper bases in the back of the Fuse Sift. Proceed to vacuum powder deposits directly below the doser motor, as well as deposits in between the doser gear and doser assembly base.
Visually inspect the back and sides of the doser assembly for any remaining deposits of powder and continue cleaning as needed.
Step 3: Clean the front of the doser assembly
Move to the front of the Fuse Sift. Switch back to the brush tool and vacuum powder deposits around the front of the doser assembly.
Switch to a crevice tool to access deposits between the doser assembly and hopper bases, as well as deposits between the doser gear and the doser assembly base.
Visually inspect the front and sides of the doser assembly for any remaining deposits of powder and continue cleaning as needed.
Checking the doser gear teeth
Overview: Inspect the doser gear teeth for powder buildup and clean as necessary.
Step 1: Inspect the doser gear teeth
Use a flashlight to visually inspect the doser gear teeth nearest the doser motor. Refer to the images above for examples of clean and occluded teeth. Surface rust on the motor gear is normal and can be ignored unless oxidation goes below the surface.
If the doser gear teeth are clean, skip to step 52. Otherwise, continue.
Use a brass wire brush or a metal pick to scrape powder flakes out of the doser gear teeth.
Vacuum the powder flakes and debris removed from the doser gear teeth with the vacuum and crevice tool.
Use your fingers to rotate the motor gear at the back of the doser assembly to expose the doser gear teeth that were previously meshed with the motor gear. Take care not to pinch your fingers in the doser gear.
Repeat steps 2–3 with the doser gear teeth that were previously meshed with the motor gear.
Step 5: Locate the doser gear alignment tabs
From the front of the Fuse Sift, locate the doser gear alignment tabs positioned in between the two hoppers.
Step 6: Check the alignment tabes
Check that the doser gear tab and top plate tab are aligned. If they are not, use your hand to rotate the motor gear at the rear of the doser assembly until the tabs are aligned. Take care not to pinch your fingers in the doser gear.
Step 5: Reconnect the doser assembly cables
Connect the doser motor and encoder cables to the doser assembly. Ensure that the encoder cable locking tab clicks into place.
Reinstalling the rear enclosure panel
Overview: Mount and secure the rear enclosure panel after cleaning the doser assembly.
Step 1: Prepare the rear panel retention screws
Apply a small amount of Loctite 243 or other similar threadlocker to each of the 16 black 8.0 mm M4 button screws that secure the rear panel to the Fuse Sift.
Step 2: Mount the rear panel
Mount the rear panel onto the Fuse Sift.
Step 3: Secure the rear panel
Thread one 8.0 mm M4 button screw into each of the 16 screw holes in the rear panel. Use a 2.5 mm hex driver to tighten until snug.
Tip:
Start with the top three screws to hold the panel in place while you thread and tighten the remaining screws.
Reinstalling the lower front enclosure panel
Overview: Mount and secure the lower front enclosure panel after cleaning the doser assembly.
Step 1: Mount the lower front enclosure panel
Mount the lower front enclosure panel onto the Fuse Sift. Align the 20 screw holes in the panel with the corresponding screw holes in the machine.
Step 2: Secure the lower front enclosure panel
Apply a small dab of Loctite 243 or equivalent threadlocker to each of the 20 8.0 mm M4 button head screws that secure the lower front enclosure panel to the Fuse Sift. Thread one chrome screw into both of the screw holes on the top of the panel. Thread one black screw into each of the 18 screw holes in the front of the panel. Using a 2.5 mm hex driver, tighten all 20 screws until snug.
Reinstalling the upper front enclosure panel
Overview: After reinstalling the lower front enclosure panel, reinstall the upper front enclosure panel.
Step 1: Align the upper front enclosure panel
Align the upper front enclosure panel with the so that the black tab on the right-hand side of the panel and the two black flanges on the left-hand side of the panel are not visible. Start by aligning the smaller tab on the right first.
Slide the panel upwards until it locks into place. Note that the panel can still fall down if knocked or hit.
Step 3: Secure the upper front enclosure panel
Apply a small dab of Loctite 243 or equivalent threadlocker to each of the seven black 8.0 mm M4 button head screws that secure the upper front enclosure panel to the Fuse Sift. Thread one of the screws into each of the seven screw holes in the panel. Using a 2.5 mm hex driver, tighten the screws until snug.
Finalizing the procedure
Overview: After cleaning the doser assembly, power on the Fuse Sift and test the machine.
Step 1: Power on the Fuse Sift
Reconnect the Fuse Sift to its power source. Flip the power switch to the ON position.
Step 2: Reconnect the vacuum
Reconnect the vacuum hose and power cord to the Fuse Sift.
Step 3: Test the doser
Add the fresh and used powder you previously removed from the Fuse Sift back into their respective hoppers. Try filling a powder cartridge to verify that the doser is functioning properly. If the fill cycle completes successfully and no powder flows from the doser after the cycle is complete, then the cleaning was successful. If the doser encounters an obstruction error or if powder continues to flow from the doser after the fill cycle is complete, repeat the cleaning procedure.
