Replace Printhead Mixing Chamber Seals

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This guide shows how to replace the three seals inside the printhead mixing chamber. Use the video for the full demonstration and this page to quickly find each step.

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Goal: remove the 3 old seals and install 3 new ones.

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Dismount the Printhead

• Remove the printhead from the robot arm
• Place it on a flat, soft surface (not hard metal)

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Remove Protective Covers

Using a 3 mm Allen key

• Remove 8 screws
• Take off the 4 protective grids

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Separate the Housing

Using a 5 mm Allen key

• Remove the 4 screws from the top cap

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Using a size 10 wrench

• Loosen the 3 hidden bolts

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Then:

• Two people required
• Carefully split the parts
• Use a rubber hammer if needed

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Important:

• Do NOT hit the axle
• Do NOT use a steel hammer

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Remove Stuffing Components

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• Remove 3 screws and washers from the stuffing flange
• Push stuffing boxes slightly inward
• Pull them out

Discard them — they cannot be reused

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Clean All Parts

Before installing new seals:

• Thoroughly clean every component
• The seal housing must be perfectly clean

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This step is critical for proper sealing.

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Install New Seals

Insert seals one at a time:

1. Slightly shape seal into a circle
2. Press one side inside
3. Press remaining section evenly

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Seal positioning

• Install second seal at 120°
• Install third seal at 120° from the others
• Use the white alignment line as reference

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Notes:

• Third seal is the hardest (limited space)
• Use spacing tool so the shaft can slide in later

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Reinstall Stuffing Flange

• Insert washers
• Tighten screws evenly

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Target gap:

• Leave 5 mm gap between flange bottom and housing
• Use a 5 mm spacer to verify

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Reassemble the Housing

Two people required

Orientation:

• Bubble level → front
• Sensor → back

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Careful:

• Safety clip may pop out
• Tap only the aluminum casing
• Never hit the green seal

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Tighten Bolts

Using 5 mm Allen key:

• Tighten evenly

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Then:

• Gradually reduce gap from 5 mm → 2 mm
• Tighten the 3 bolts slowly and equally

(Patience required — fans limit access)

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Reinstall Protective Grids

• Mount grids
• Lightly tighten the top screws
• Only secure enough to hold position

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Reconnect the Printhead

• Mount printhead on robot arm
• Connect cables (twist to lock)
• Ensure spacer fits in slot
• Connect SHs wire
• Place wire in its mounting location

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The printhead is now ready for operation.