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Replacing the Form 4L Z-axis limit switch

The Z-axis limit switch helps home and position the Z-axis of the Form 4L. The Z-axis limit switch is located at the top of the Z-tower on the printer. A malfunctioning Z-axis limit switch may prevent the printer from printing properly.

Use this guide to replace the Form 4L Z-axis limit switch.

Required Supplies:

Formlabs:

Z-axis limit switch
2 mm hex driver (included in the Form 4L tool cap assembly)

Third-party:

Nitrile gloves
Ball-end 2 mm hex driver

Estimated time: 10 minutes

Preparing the workspace

Overview: Prepare the printer and a dust-free workspace for replacing the Z-axis limit switch.

Step 1: Remove the build platform

Remove the build platform first to avoid dripping resin onto the optical surfaces.

Step 2: Remove the resin cartridges

Remove the resin cartridges and close the vent caps to prevent resin from dripping off of the bite valve and into the printer.

Step 3: Remove and store the resin tank and mixer

Unlatch the mixer and resin tank. Remove the resin tank and cover it with its lid. Set the tank aside on a clean, flat surface.

Notice:

Wear gloves and hold the resin tank by the tank grips on either side to avoid contamination or damage to the underside of the tank.

Step 4: Prepare the workspace

Clear a workspace around your printer. Ensure that the workspace is well-ventilated and free of dust.

Step 5: Clean the printer cavity

Warning:

Resin may cause skin irritation or an allergic skin reaction. Wear gloves when handling liquid resin or resin-coated surfaces. Wash skin with plenty of soap and water.

Open the printer cover and clean any resin pooled on and around the LPU with paper towels. Dampen the paper towels with isopropyl alcohol if necessary to fully remove the resin.

Danger:

IPA is flammable and presents a fire hazard. Keep containers closed, and keep out of the reach of children.

Step 6: Lower the Z-axis

On firmware version 1.10.0 or later, tap Settings > Tools > Move motors on the printer touchscreen. The Move motors screen appears. Tap Start, then tap Mid or Bottom under Z Axis to lower the build platform mount.

Step 7: Unplug the printer

Disconnect the power cable from the printer before continuing with maintenance. Do not perform maintenance on the printer while it is connected to power. Wait five minutes after disconnecting the printer from power before proceeding.

Replacing the Z-axis limit switch

Overview: Replace the Z-axis limit switch.

Step 1: Disconnect the Z-axis limit switch cable

Release the cable that connects the Z-axis limit switch by pressing the plastic tab on the connector. Take care when unplugging the cables to avoid damage. Once the plastic tab is pressed, the cable slides out of the connector with minimal force. Do not pull on the wires.

Step 2: Remove the Z-axis limit switch retention screw

Using a 2 mm hex driver, remove the screw securing the limit switch to the printer tower. Set the screw aside.

Tip:

For easier repair, use a ball-end 2 mm hex driver in place of the 2 mm hex key included in the Form 4L tool caddy.

Step 3: Remove the Z-axis limit switch

Remove the Z-axis limit switch from the printer. Set it aside for disposal.

Step 4: Install the replacemnet Z-axis limit switch

Align the replacement Z-axis limit switch screw hole with the corresponding screw hole on the printer tower. Thread the screw into the screw holes. Using a 2 mm hex driver, tighten the screw until snug.

Step 5: Reconnect the Z-axis limit switch cable

Reconnect the Z-axis limit switch cable. The connector makes an audible and tactile click when secured. Do not pull on the wires.

Finalizing the repair

Overvier: After installing the new Z-axis limit switch, power on the printer and perform final checks.

Step 1: Power on the printer

Connect the power cable to the printer and the power supply. Turn on the switch at the back of the printer. The printer initializes.

Step 2: Run a test print

Insert any missing consumables and run a test print. Check that the print starts normally and the parts print successfully. Contact Formlabs Support or your authorized reseller to share the results of the procedure.