This procedure is required whenever the needle case has been removed and reinstalled. Calibrating the needle case requires a rough calibration and a fine calibration.
The fine calibration is done with the Needle Plate removed and the needle is aligned to the Rotary Hook Center Post.
The rough calibration is performed with the Needle Plate installed and the needle is aligned to the center of the needle hole.
- Ensure Melco OS is open, machine is on and connected
- Remove the Bobbin Case Assembly and the Needle Plate
- In the Melco OS, got to Tools>Maintenance as shown below.
- Next, click on the Steppers tab as shown below:
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Next, click on the Color Change - Home button as shown below. This will move the needle case to the home position and finally come to rest at needle position 1.
- Next, click on the Calibration tab as shown below.
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Lower the needle to the Needle Depth position by holding down the Adjust button and then pressing the Down Arrow.
- Check to see where the needle is in relation to the rotary hook center post.
- It will help to use a flashlight and/or magnifying glass.
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It is also very critical that you observe the needle from directly in front of the hook. If you are looking from even a slight angle, it may cause you to incorrectly calibrate the needle position.
- Determine how far to the left or the right the needle needs to be adjusted.
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Move the needle to the Head Up position by holding down the Adjust button and pressing the Up Arrow.
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Micro-step the needle the distance and direction determined in the previous observation step.
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Micro-stepping is done by hitting the Trace button and the Left or Right arrow, depending on the intended direction.
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Each time the arrow is pressed, the needle case moves 8 one-hundredths (0.08) of a millimeter which is equal to 0.003 inches.
- Lower the needle to the Needle Depth position.
- Observe the relationship of the needle to the rotary hook center post.
- If further adjustments are necessary, repeat steps 7-13.
- If the needle is centered exactly to the post then you may move to the next needle.
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Using the Frame-Back key is the quickest way to get to the next needle in this situation. It will bring the needle to the Head Up position, move to the next needle, and bring that needle to the Needle Depth position.
- From there, you can repeat Steps 7-13 as needed until all 16 needles have been centered.
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Upon completion of the 16 needle calibrations, hit the “Get Table” key in the Melco OS. By hitting this key, you will be storing a backup copy of the calibration table in the computer.
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All needles should now point directly at the centre of the needle bar post and the machine can now have the hook timing procedure carried out.