Infrared Helps Automatic Plastic Welding
One of Hepworth's drainage-system product lines is a polypropylene chamber that provides surface access for inspection of below-ground drainage systems. The product consists of a base unit with multiple connections to clay or plastic drainage systems. The addition of two or four raising pieces creates the required depth of the inspection chamber. An important step in the manufacturing process is joining the raising pieces, first to the chamber's base unit and then to each other. A hot-melt adhesive had been used to join the pieces. Changing environmental protection requirements and the need to keep down costs led the British company to investigate more efficient solutions.
The new infrared system from the Duluth, Ga., infrared equipment maker has shortened the complex automated process to just 22 sec. The processing system uses a robot to bring component tubes into an infrared welding cell and then welds them together. As a result, production cycle times for plastic inspection chambers at Hepworth have fallen. In contrast to the previous hot-melt adhesive system, the heating process produces little fumes, making it environmentally friendly.
The process improvements were possible because quartz glass emitters were shaped to match the product three-dimensionally. As a result, heat is generated only where it is required.