Abstract
In the manufacturing process of electric heating tubes, powder filling and tube reducing are the two core steps that determine product insulation and thermal efficiency. This article provides a detailed interpretation of the Standard Operating Procedures (SOP) for these two processes.
The core of the powder filling process lies in the filling density of magnesium oxide (MgO) powder and the accurate positioning of the center rod.
Parameterized Control
The operator must enter the parameter mode via the touchscreen to precisely set the following speed, delayed oscillation frequency, and tube length. By 2026, mainstream equipment has achieved microsecond-level response, ensuring uniform powder distribution.
Automated Process
In automatic mode, the system guides the placement of empty tubes using indicator lights. The critical step is the wire hanging stage: the heating wire must be accurately hung on the hook, and after being pulled into the tube, the tightness between the terminal pin and the lower plug must be checked.
Fault Interception
If any deviation occurs in the length of the guide tube or mandrel, an emergency stop must be triggered and the origin reset to prevent the heating wire from breaking or incomplete filling.
Tube reducing is not only about reducing the tube diameter, but more importantly, about achieving a dense state of the internal magnesium oxide powder.
First-Piece Inspection System
Before starting the tube reducing machine, the hydraulic block pressure must be checked. After processing the first piece, a first-piece self-inspection of tube diameter dimensions and surface smoothness is required. Mass production can only proceed after passing this inspection.
Lubrication & Die Maintenance
During operation, an appropriate amount of lubricating oil must be applied to reduce frictional heat and surface scratches. If scratches are found on the tube wall, the machine must be stopped immediately, and the die must be polished or repaired to ensure the product’s appearance meets export standards.