Process manufacturing is the branch of manufacturing that is associated with formulas and manufacturing recipes, and can be contrasted with discrete manufacturing, which is concerned with discrete units, bills of materials and the assembly of components.
Process manufacturing is common in the food, beverage, chemical, pharmaceutical, consumer packaged goods, and biotechnology industries. In process manufacturing, the relevant factors are ingredients, not parts; formulas, not bills of materials; and bulk materials rather than individual units. Although there is invariably cross-over between the two branches of manufacturing, the major contents of the finished product and the majority of the resource intensity of the production process generally allow manufacturing systems to be classified as one or the other. For example, a bottle of juice is a discrete item, but juice is process manufactured. The plastic used in injection moulding is process manufactured, but the components it is shaped into are generally discrete, and subject to further assembly.
Formulation is a simple concept, but it is often incorrectly equated with a bill of materials. Formulation specifies the ingredients and the amounts (e.g., pounds, gallons, liters) needed to make the product. The first thing to recognize is that to be able to work with a formula, the units of measure must correspond; a flexible unit of measure conversion engine running under an ERP software cover is needed. Furthermore, conversion rules must be specified to account for the unique requirements of the business in question.
The proportions of ingredients in a formula also highlight the need for another feature, namely scalability. A formula to make 500 liters of a chemical must be scalable to make 250 liters or 1,000 liters. Another aspect of scalability is that it makes possible manufacturing based on how much of an ingredient is available. An example will illustrate this point. If you are making a car and only have two of the required four tires, you cannot make half a car. In other words, you must have all the parts in the required quantities to make the finished product; they are not scalable. But in process manufacturing, if you want to make 1,000 gallons of soda and you only have 500 gallons of the required 1,000 gallons of carbonated water, you have the option of making half as much soda. In process manufacturing you can make as much of a finished product as is specified in the formula for the smallest quantity in stock of one of the ingredients.
A packaging recipe is similar to a formula, but rather than describing the proportion of ingredients, it specifies how the finished product gets to its final assembly. A packaging recipe addresses such things as containers, labels, corrugated cartons, and shrink-wrapping. In process manufacturing, the finished product is usually produced in bulk, but is rarely delivered in bulk form to the customer. For example, the beverage manufacturer makes soda in batches of thousands of gallons. However, a consumer purchases soda in 12-ounce aluminum cans, or in 16-ounce plastic bottles, or in 1-liter bottles. And a restaurateur may have the option of getting a 5- or 50-gallon metal container with the beverage in syrup form, so that carbonated water can be added later.