We have seen the overview of a welding process, Arc welding process, Gas welding process, types of flames in Gas welding and Difference between Arc welding and Gas welding, difference between DC welding and AC welding, soldering and brazing, common welding defects and Safety precautions and PPE required during welding activities with the help of our previous posts.
Hand screens or hand shields or welding helmets provide protection to eyes by using an assembly of following mentioned parts or components
Helmet shell - It must be opaque to light and also resistant to heat, impact and electricity.
Outer cover plate will be made of polycarbonate plastic. It protects from impact, UV radiation and also from scratches.
Filter lens will be made of glass consisting of a filler that reduces the amount of light which is passing through to the welder's eyes. Filters will be available in various shade numbers i.e. from 2 to 14. The higher the shade number, the darker the filter will be and hence the lesser light will pass through the lens.
Clear retainer lens will be made of plastic. It prevents any broken pieces of the filter lens from reaching the welder's eyes.
Gasket will be made of heat insulating material. It will be between the filter lens and the cover lens. It protects the lens from sudden changes in the heat that could result in it breaking. There are some welding helmets models where the heat insulation will be given by the frame mount instead of a separate gasket.
We will now see “Different parts of the lathe machine and their functions” and we will also study the complete specifications of the lathe in our next post.
Reference
Engineering Practices By Mr. S. Suyambazhahan
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