Notching is a process which cuts stock without the formation of chips or the use of burning or melting. Strictly speaking, if the cutting blades are straight the process is called shearing. The most commonly sheared materials are in the form of sheet metal or plates. We have a number of metal workers (Notching machines) at Stratford Metal Fabrications, each with different capabilities, which gives us great flexibility.
Technical bit: A punch (or moving blade) is used to push the work piece against the die (or fixed blade), which is fixed. Usually the clearance between the two is 5 to 40% of the thickness of the material, but dependent on the material. Clearance is defined as the separation between the blades, measured at the point where the cutting action takes place and perpendicular to the direction of blade movement. It affects the finish of the cut (burr) and the machine’s power consumption. This causes the material to experience highly localised shear stresses between the punch and die. The material will then fail when the punch has moved 15 to 60% the thickness of the material, because the shear stresses are greater than the shear strength of the material and the remainder of the material is torn.