Original Date: 04/24/2006
Revision Date: / /
Best Practice : Shearing and Turret Punching
Midwest Metal Products changed its shearing process from a push to a pull system. The machine tool cell workload is now driving the quantity of material needed to be sheared. The development of a standard and dedicated tooling turret has reduced the company’s average tool requirements by 50%, with tooling maintenance now performed only when required.
Midwest Metal Products (MMP) has two laser punch presses and six Amada turret punch presses – two Vipros 358 King presses and four Vipros 255 hydraulic presses. The material to support the operation of these machine tools for three shifts was formerly sheared up to three days in advance. Part programs were created to use any tool in any station, and shear operators sheared material to sizes specified inside a project folder. The project folder was delivered directly to the shear area from engineering and consisted of a drawing, setup sheets, route, traveler, and material information. This process increased work-in-process (WIP) and a lead-time increase of 8%. With floor space at a premium, the three-day supply of sheared material was taking up to 250 square feet of floor space. Because of the large volume, material would occasionally be missing, and punch operators were spending 5% of their day looking for material that had been sheared three days earlier. Punch operators in the shear area were spending 10% of their day sorting through project folders looking for job numbers that were showing up on their order of work queue and were constantly changing tools to agree with the part programs and setup sheets inside the project folders.
MMP decided to reduce WIP and lead-time in its shearing process by developing standard and dedicated tooling locations in the turret loads to shear material 4 to 8 hours ahead of the turrets or lasers. Project folders are now delivered to punch operators who sort the project folders by order of work queue and tell the shear operators what material needs to be sheared, creating a pull system in which punch operators are driving the workload from the shear area. Sheared material is then delivered directly to the machine tool in portable carts, eliminating the search for material and creating available floor space.
By creating part programs for use on dedicated toolings (specifically the turret loads stored directly at the machine tool), MMP has minimized setup times – one turret load each for the Vipros 358 King and the Vipros 255 turret punches..
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