JEC COMPOSITES MAGAZINE - Issue #47 - March/April 2009 - 49

Cutting & laser tool How this is done can vary. When automated cutting was first introduced to aerospace firms almost 30 years ago, reciprocating-blade, multi-ply “static” (static meaning a nonconveyorized cutting surface) and ultrasonic cutting systems were the available technologies. Work orders were created to meet the long production schedules. For example, materials would have been cut and kitted to meet a month’s production requirements. The process usually involved the following steps: - pulling the material from freezer and thawing, - spreading multiple layers of material on the cutting table, - cutting standard pre-nested plies, - removing cut plies for off-line kitting and bagging, - returning kits to the freezer, - retrieving kits when ready to lay up. Since the technology used to cut the material was slow, it was designed to cut many layers at a time to deliver the required output. The process was limited by the available technology and was based on automation of the existing manual techniques. However, this process increased workin-progress (WIP) and included many added nonvalue steps. This waste of material and work effort was due to inefficient nesting, parts from kits being raided to NASA space suits require Gerber Technology cutters complete a job – and therefore for zero-default. leaving another kit incomplete – and cut material going unused or running out of shelf life. The above process violated many of today’s current manufacturing concepts, such as just-in-time (JIT), cellular, and lean manufacturing principles. Existing automated companies were forced to change the way they cut and kit. Newer and smaller manufacturers could not afford the US$500,000 to US$1,000,000 price tag for this type of equipment. Many evaluation steps are the same regardless of your application whether it is producing airplanes… Today, for many composite fabricators’ requirements, work orders can be reviewed on a shift-by-shift basis, cutting what you need when you need it. Daily work orders are generated, material is pulled from freezer as needed, nests are created automatically to meet the daily work orders and maximize material usage, the material is quickly cut on the table, and the material is removed from the table in kit order and delivered to the lay-up personnel. or bikes (Source: Cannondale). This process meets most requirements. However, there are other applications that require different approaches. For highervolume applications, such as interior floor and wall panels for commercial airline companies, multi-ply cutting is required to meet the high volumes. In one case, 20 layers of a woven carbon prepreg and honeycomb core are cut on a conveyorized reciprocating blade cutter, and then kitted off-line. Then the kits are delivered directly to the crush-core panel presses for fabrication in a JIT or lean environment. In other cases, a cutter may deliver parts to many different layup areas, and this might require multi-ply cutting, off-line kitting and/or freezer storage. Here, a conveyorized or single-ply cutter may be appropriate. However, there are some fundamental differences between conveyorized and static cutting systems that cannot be overlooked when evaluating this technology. For instance, nesting the material to minimize waste is critical to controlling material costs. Once the parts are cut, an efficient method for kitting is critical for controlling labour and WIP costs. Consider the following differences between static and conveyorized cutting process. Greater accuracy and less waste The answer? Newer, simpler, less-expensive and faster single-ply cutting static systems were introduced about 10 years ago. These new systems allowed manufacturers to cut material on demand with less waste, and in many cases, more accurately and with better edge quality. The new method for cutting developed into a more streamlined process. Single-ply static cutting • Allows for part identification on each ply. • Material is pulled onto the table either manually or automatically. No47 March-April 2009 / jec composites magazine 49
JEC COMPOSITES MAGAZINE - Issue #47 - March/April 2009

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #47 - March/April 2009
