that the u201c hook u201d is not fastened to a frame that will keep it steady at the time of heat exposure as a consequence at the time of exposure the zone experiences a certain degree of thermal expansion enough to move the piece inside of the mold cavity causing failures in register at the time of closing the matrix it was necessary to make millimetric modifications to the cavities to provide the necessary space for the expansion of the material since synthetic paper is a bad heat conductor a great amount of it will dissipate towards the upper part due to the reduced area of the tab and a smaller amount towards the lower part due to the joint of three materials synthetic paper double sided adhesive and cover with double sided adhesive this phenomenon implied developing a method that would help to distribute heat homogeneously on the desired area to thermoform the method consisted on introducing a mesh between the heat source and the material to thermoform once the forming process was found the strip 1 with caliber 12 and a larger diameter r of 0 7 cm to a diameter of 1 2 cm fig3 was worked on however once it was thermoformed this strip showed deformation during operation then it was decided to try with a different caliber maintaining the diameter r of 0 7 cm and experimenting with different diameters up to 1 2 cm the results obtained were optimal for the objectives of this invention since the piece.