Bad pressure of the thermal head
1. The picture is printed, but not completely. Or Picture is too light
This is a common mistake for beginners. There is a black spring on top of the yellow thermal head. It is necessary for the hot tip to be pressed against the surface of the plywood with effort.
Why it is happened?
In order for the thermal head to press down on the sting, two main conditions must be met:
1. The spring should create downward pressure (green arrow)
2. The thermal head should rotate freely around the screw (red arrow)
Accordingly, if the spring has stopped pressing properly or the thermal head has stopped rotating, as a result, the hot tip either presses poorly on the surface of the plywood. Or the hot tip hangs completely over the surface of the plywood and does not touch it at all.
How To Solve This Issue
1. Check out the spring:
- It must be inserted on both sides. One end must be inserted into the white plastic on the moving part of the machine. The second end of the spring should be inserted into the hole in the yellow thermal head.
- The wire next to the spring should not engage the spring and pull it away, thus reducing the pressure on the hot tip.
2. Check the screw that connects the thermal head to the white moving part of the machine.
The thermal head has two round bearings with a hole in the middle. A screw is inserted into this hole. There is a nut on the back of the thermal head.
If you tighten the thermowell too tightly to the white moving part of the machine, the nut will be too tightly drawn to the bearing. As a result, the nut will jam the bearing. And it won’t be able to rotate freely. The thermal head can either rotate with jamming, resisting the pressure of the spring, or be fixed in one position as in this photo:
How to solve the problem with bearing jamming:
- Unscrew the thermal head completely from the white plastic part.
- Loosen the nut on the screw and immediately tighten it back with your fingers (do not use spanners).
- Screw the thermal head back to the white moving part of the machine so that there is a small gap between the nut and the white plastic. It is allowed that the nut slightly touched the white plastic.
When you install the thermal head in place, pull the wires and spring from above. Lift the right edge of the thermal head 1 inch above the table surface and release. The spring should immediately press on the thermal head and lower it down.
