System for fabricating muntin bars from sheet material

A method of making muntin bars comprising:

• a) providing a supply of thin sheet material having a finished surface in the form of a coiled ribbon;
• b) uncoiling the ribbon;
• c) feeding the ribbon along a travel path to a first forming station comprising a ribbon punching mechanism;
• d) punching the ribbon at first precisely predetermined locations along the ribbon to form spaced cut-outs that extend inward from an edge of the ribbon and define a region of intersection with one or more transversely extending muntin bars in a muntin bar grid;
• e) delivering the ribbon from the first forming station along said travel path to a second forming station comprising a succession of forming rolls;
• f) passing the ribbon through a succession of forming roll nips to produce a hollow muntin bar tube defining a closed cross-sectional shape having openings therein at said first locations;
• g) delivering said muntin bar tube from said second forming station along said travel path to a third forming station comprising a muntin bar severing apparatus;
• h) severing said muntin bar tube at second precisely predetermined locations to form completed muntin bars;
• and
• i) delivering said completed muntin bars from said third forming station onto a conveyer to move a batch of said completed muntin bars that form a muntin bar grid away from said third forming station in a direction transverse to said travel path for subsequent assembly into said muntin bar grid.