According to the processing objects, lamp work is divided into the following three basic types.

①Glass deformation processing. Heating and softening the glass, using external force and air blowing in the inner cavity to perform operations such as bending, bubble blowing, drawing, flanging edges, sealing the bottom of tubes, etc. The processing of condensation tube spherical cores, serpentine cores, thermos flask round bottoms, test tube round bottoms and other products falls into this example.

② Glass parts are welded to each other. After the glass is melted, it is welded and shaped to form a whole body, such as butt joints of glass pipes, T-joints, ring joints of inner and outer pipe sleeves, etc. Welding of the same type of glass is the safest. If the thermal expansion coefficient of products welded from different types of glass is too different, there will be a shrinkage difference when cooling after welding, causing volume effects and structural stress. When the stress exceeds the strength of the glass, it will cause explosion. The welding of quartz glass and ordinary glass belongs to this example. The solution is to use several glasses with varying thermal expansion coefficients as intermediate transition glasses. Generally speaking, the difference in thermal expansion coefficient of the two glasses should be less than 6×10-7/℃.

③Welding seal between glass parts and metal. Try to use glass and metal with similar thermal expansion coefficients for matching sealing. When the difference in thermal expansion coefficient between the two is too large, intermediate transition glass, softer metal filaments or thin foils can be used for non-matching sealing with the glass. The structural stress generated at the sealing point can be compensated by metal deformation.