The distance that the tool must travel between the workpiece and the location that is required for a tool change. This distance is traversed at the rapid travel rate before and after a tool change. This distance depends upon both the workpiece and the tool, so the average distance should be used.
The rate that is paid to any workers for a specific task based on the weight of material processed during that task. This rate does not include any costs associated with material, equipment, or overhead. If the number of workers is not specified, the labor rate is the amount paid to all workers.
The pressure inside the mold cavities caused by the injection of molten material during the mold filling stage. Cavity pressure depends on the material, injection pressure, and the geometry of the cavities and runner system. For most polymers, the cavity pressure is between 4,000 and 10,000 psi.
When a bar feeder is used as the fixture, one piece of bar stock is loaded and simply advanced into position before each cycle, rather than loading a new workpiece. The bar advance time is the amount of time (in minutes) required to advance the bar into position for the next part to be machined.
A substance that is added to the raw material used in a process in order to alter some material property. Examples of additives include colorants, flame retardants, and UV protectants. The additives ratio describes the weight of additives that may be added relative to the weight of raw material.
The offset of the walls of a part by a slight angle, referred to as the draft angle. A draft angle is often required on the surfaces of a part that are parallel to the tooling direction in order to facilitate removal from a mold. However, some processes do not require a part to have any draft.
A graph in which stress (load divided by the original cross sectional area of the test piece) is plotted against strain (the extension divided by the length over which it is measured). The slope of the sress strain curve, in the elastic region, is used to determine the modulus of elasticity.
The force that is applied to a mold by the molding machine in order to keep it securely closed while the material is injected. The clamp force is typically some factor of safety greater than the separating force, which is the outward force exerted on the mold halves by the injected material.
