(1) The significance of repairing defective products
In the production of electric heating elements, defective products will inevitably occur. Due to the inconsistent technology and management level of each factory, the number of defective products varies greatly. In some enterprises with strong technical force and high management level, the defective product rate can be controlled at 0.5 % Below, and in some poorer enterprises, the defective rate is 3-5%. If the defective products in production can be repaired and the percentage of defective products can be reduced to a minimum, this is the goal pursued by every enterprise. Reducing defective products can not only reduce the loss of the enterprise, reduce the cost, and increase the economic efficiency of the enterprise, but also save raw materials, Auxiliary materials, save labor, and meet the requirements of delivery time.
(2) Possibility of repairing defective products in the production of electric heating elements
Generally speaking, after the heating element is made, it is found that the defective product is difficult to repair, but in practice, we have found that some of it can be repaired.
1. Which types of defective electric heating elements can be repaired:
When the electric heating element filler-magnesium powder has some of the following problems that make the element into a defective product, this kind of electric heating element may be repaired.
A The quality of the original magnesium powder is good. Due to uneven mixing during modification or other reasons, after the heating element is made, its tidal resistance is low, about 100MΩ. When the element is placed in the air, the resistance will continue to drop, and the two ends will be injected. Red ink, the ink can be sucked in, the two ends of the pipe are cut open, and the red ink is sucked in> 2mm.
B During the processing of the heating element, the magnesium powder was slightly damaged:
Such as oil radiator pipe, water dispenser pipe two-end flange welding, water boiler pipe end welding and pickling in the electroplating process, (hydrochloric acid, nitric acid) and electroplating solution immersion.
C Some other situations: For example, after the tube is made, the electric heating tube has not passed the furnace or has passed the furnace, but the temperature of the furnace is too low or the temperature has reached, but the furnace time is too short, etc.
2. What are the circumstances that cause defective electric heating elements that cannot be repaired:
A. Reasons for magnesium powder: poor quality of the original magnesium powder, high content of ferromagnetic substances and other harmful impurities, low density or uneven density.
B. Pipe material defects: such as cracks in the pipe, burrs in the pipe, or bubbles, shrinkage holes, slag inclusions, etc. in the pipe.
C. Problems in the process of pipe production: such as broken heating wire, heating wire, eccentricity of the lead rod or hitting the wall, etc.