Methods and steps of repairing worn screw and barrel

[screw and barrel repair procedure]
① Place the screw on a lathe, find the center, check the deformation and coaxiality.
② The second step is to polish, peel off the existing chromium, and immerse the root screw or barrel into the acid tank to remove the chromium plating.
③ Move to grinder and grind to normal size. Weld the missing parts with surface material.
④ After welding, move the parts to the grinder again for rough grinding.
⑤ The side of the stud is trimmed with a screw edge grinder. After that, rough polishing will be carried out.
⑥ Then, the chromium plating process is carried out for the repaired parts, and the last step is polishing the workpiece.
Repair method
TIG welding is the most common method in screw repair.
There are four common methods:
（1） Inert gases TIG of oxyacetylene and tungsten
（2） Protection of plasma transport argon arc PTA
（3） Metal inert gas MIG
（4） Protect welding. Before applying surface hardening material, apply a layer of stainless steel to the stud to control the dilution of surface materials
It is more difficult to repair the screw barrel than to repair the screw. If the body wear is more than 0.5mm, the overall barrel can be finely ground to a larger diameter, and an excessive screw shall be installed in the machine accordingly. The obvious disadvantage of this method is the nonstandard size. Therefore, screws from other machines cannot be used in nonstandard machines any more.
If the barrel wear occurs near the barrel, a bushing can be installed in the barrel. However, in most cases, for such cylinder wear, it is more meaningful to replace the barrel than to install the bushing or increase the inner diameter with fine grinding.