4. Adjustments

This step is only for Bear frame MK2.5(S) and MK3(S).

y_axis_end_stop

Clip the y_axis_end_stop on the left smooth rod, at the front, as shown in the image

This part prevents the PINDA to crash into the screws on the back of the heated bed for MK2.5(S) and MK3(S)

ptfe_collet_clip

Slide a PTFE tube into the collet. The length does not matter. The end needs to be cut flush.

Move up the collet while keeping the PTFE in place. Clip the ptfe_collet_clip to secure the collet.

The ptfe_collet_clip isn't mandatory, you can use the Hemera without it. We recommend to use it if you like to have to have things tight and secure

Hot-tighten the Hemera nozzle to 3Nm at 285°C. Follow the official instructions of the E3D Hemera assembly guide here (step 18): https://e3d-online.dozuki.com/Guide/02+-...

Let the extruder cool down.

Place a sheet of paper on the heated bed. Manually lower the X axis until the Hemera nozzle is touching the paper.

Make sure the X axis is flat (you can slowly move the Hemera left and right while looking at the nozzle distance from the bed).

Loosen the PINDA locking screw and place an object of 1mm thickness under the Pinda (like the middle section of a zip tie).

Gently move the PINDA down until it is touching the zip tie.

Tighten the PINDA locking screw to secure it in place.

Use a plier if it is hard to reach the probe with your fingers during adjustment.

Plug in and turn on the printer

Using the screen menu, move the X axis up until it crashes into the Z tops. The stepper motors will skip, making a noise - this will not damage the motors

Using the screen menu, move the X axis down until the nozzle is approximately 10mm from the heated bed

If the X axis is stopping before crashing into the Z tops, move the X axis a little further down and power cycle your printer. You will then be able to complete the step

It is possible that with the weight of the Hemera the X axis is moving down on one side when the printer is off for some time. If this happens, move the X up until it crashes as explained here. Note that his can also happen to stock Prusa printer (and so stock Prusa extruder)

If you have applied tension to the belt, unscrew the belt tensioner on x_end_idler until the belt is relaxed.

Loosen the screws that secure the trapezoidal nuts. This is to ensure that the Trapezoidal nuts 'self-centre' on the lead screws.

Make sure the trapezoidal nuts are moving freely.

Alternate between all 4 screws evenly while tightening (alternate between both sides during the process). Don't apply any lateral force on the trapezoidal nuts.

Loosen the two pulley set screws a little.

Align the pulley with the belt hole of the x_end_motor.

Tighten the set screws alternately.

Verify that the belt is not touching the x_end_motor.

Verify that the drive pulley is not touching the X motor.

Grip the X motor shaft with pliers to prevent it moving (grab the flat side of the shaft).

Tension the belt, by tightening the screws in the x_end_idler. Do this while trying to move the extruder to the left or right. The belt should stay straight and should not bow up and skip over the drive pulley teeth.

No need to be very precise with the belt tension here as the final tension will be improved in a further step.

Not all X axis have the exact same length because of tolerances. This step will adjust the X end idler to your X axis length.

Adjust both M3x10 screws to have the x_end_idler parallel to the frame.

First image, top left: shows when the X axis is too short. In this case you need to tighten the two M3x10 screws.

First image, bottom left: shows when X axis is too long. In this case you need to unscrew the two M3x10 screws.

If you have difficulty to see if the x_end_idler is parallel to the frame you can use a thick ruler or a square like on the first image.

It might happen that with excess tension on the M3x10 screws, the Z smooth rods will start to be off center on the Z tops. In this case release tension on the M3x10 screws even if the x_end_idler is not totally parallel to the frame.

Download and install the Pano Tuner application (developed by Kaleloft LLC) on your smartphone. Android Google Play link. Apple Store link.

Turn off the printer (if your hotend is higher than 50°C, let the hotend cool down first until the hotend fan stops spinning)

Launch the Pano Tuner app and place your smartphone on the heated bed. Make sure there is no noise in the room that could disrupt the measure (like a ceiling fan).

Move the extruder to the middle of the X axis.

Pinch the lower belt to make it vibrate. Don't pinch too much as it might touch the carriage and produce a wrong frequency

Adjust the belt tension until you have a value around 90Hz. Between each measurements, move the extruder to full left and right and then center it again.

It is very important to move left and right the extruder between each measures to relax some tension in the belt.

If your belt is new, you can repeat this procedure after few prints. A new belt will loosen on the first hour of use.

Verify the x_end_idler_tensioner is not sticking out of the x_end_idler.

If x_end_idler_tensioner is sticking out then your X axis calibration might fail.

As a starting point to adjust the extruder tension, E3D recommends to rotate the tensions screw until the white part is flushed with the front of the black part.