Cold Headed Parts and Warm Christmas Cookies
by Joanna Dykhuis, IQS Editor
During these dog days of summer when pop cans drip with condensation immediately when removed from the cooler, when beach towels take days to dry and when no hair product can stand up to the humidity, I catch myself thinking fondly of the upcoming winter season. As much as I complain about the blustery weather and the complications of snow, I also get warm fuzzies just thinking about all the winter activities I love like getting the Christmas tree, drinking hot chocolate in front of the fire and baking cookies. Baking sugar cookies in the shape of stockings, trees and stars is an annual tradition for me and though making cookies may seem like just a fun way of producing delicious treats, it actually has a number of similarities with manufacturing cold headed parts.
Despite the name, these products have nothing to do with winter or frosty temperatures. Cold headed parts are shapes that have been produced through working and forming processes performed at ambient temperatures. Cold extrusion, cold drawing, cold roll forming and cold heading are all cold working methods through which these parts are made. The parts themselves are widely varied and include rivets, electrical contacts, pins, threaded fasteners, discs, balls, nuts, stainless steel pins, bolts and more. Cold headed parts are incredibly useful and are found in all industries around the world. The most common materials used are metal and include cold formed steel, copper, aluminum, titanium, iron and brass. Like the ingredients in a cookie recipe, simple products are used to begin the process. In the case of cold headed parts, metal wire, plates and sheets are the basic components. The materials and equipment are usually at room temperature whereas cookie dough often requires refrigeration.
Cold extrusion is similar to cookie guns in that the material is pushed through a die. Instead of being pulled, the metal is forced through the shape, creating a cross section and leaving excess material behind. Cookie guns do the same thing: a plunger pushes dough out of the shaped tip to product many identically shaped and sized cookies. Cold drawing is another popular process that is similar to extrusion except that materials are pulled through the die. Round, square, hexagonal or flat rods are drawn through the die multiple times to achieve the desired shape and complexity. Cold roll forming machines are among the most commonly used machines used in a cold working shop. A roll forming machine has a series of roller dies and products strips and sheets of metal with smooth surfaces and precise thicknesses. Sound familiar? The machine is akin to a rolling pin that flattens cookie dough into a uniform thickness.
Cold heading is also widely used. Header machines use one or more die to create complex products from blanks or slugs that retain the same volume as the final product. First, a punch transfers force from the machine to the material to permanently deform it, leaving the shape of the punch in the metal. Punching is similar to using a cookie cutter. When the cookie cutter is pushed down into the soft dough, its imprint is left behind and the cookie has the same size and shape of the cutter. After the metal is punched, a die is applied to produce necks, lugs, fins or other additional part features. There are multiple advantages to cold headed parts. They produce less scrap, have increased strength performance, are produced quickly in high speed manufacturing lines and allow for intricate shapes and cross sections that would otherwise require secondary processes. As for baking cookies, there are many benefits but my favorite is eating them.