Production Machining

OCT 2017

Production Machining - Your access to the precision machining industrial buyer.

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Equipment Capabilities Regardless if the job involves running a single part all night on a Swiss-type machine or multiple parts on a fixed headstock turning machine, it is critical to consider every aspect of the process that could impede production. CNC turning machine. e heart of a lights-out work cell is the turning machine or machining center. Overnight operation requires a machine that is capable of continuous, unattended operation. Reliability is the chief concern, and this leans heavily on the stability and rigidity of the machine's construction. Other considerations are advanced interconnectivity that allows the machine tool and peripherals to share complex, bi-directional data; a part scheduler program; adequate coolant capacity and chip evacuation; and suffi- cient tooling stations. Bar feeding. Second only to the machine tool itself, an automatic bar feeder is essential for lights-out produc- tion. Like the turning machine, the bar feeder must have the strength and reliability to continu- ously load barstock and provide material support necessary for optimal spindle speeds. It must also have the capacity to hold enough barstock to produce the required part volume. If the production run includes a variety of parts to be made from the same diameter barstock, the bar feeder must be able to automatically change over from one program to the next. With LNS bar feeders, this can be accomplished by communications between the machine tool scheduling program and the bar feeder's Part Library. When it's time to change programs, the turning machine tells the bar feeder what part it wants to make next, and the bar feeder calls up the corresponding program from the Part Library, which then loads the appropriate parameters and automatically adjusts itself accordingly. is interconnectivity, which can be facilitated via the LNS e-Connect communications system, provides another important benefit when running multiple part programs overnight. e bar feeder continuously keeps track of material usage and communicates the information to the turning machine's master schedule. e machine tool can then compare the lengths of the various parts to be run with the available material. If the material is adequate to complete the required part run, and the total quantity has not been produced, it does so. If not, it determines the length of the remnant and selects another part from the schedule that it can make using the remaining barstock. Both the machine tool and the bar feeder automatically adjust themselves to optimize material usage. When this cycle is complete, the master scheduler selects the next part program, the turning machine and bar feeder make the appropriate adjustments, a new bar is loaded and produc- tion continues. Whether to choose a 12-foot or short-loader bar feeder for lights-out operation depends on the specific applica- tions. In many cases, a 12-foot bar feeder is preferable because it holds a larger amount of material and has only one remnant per 12-foot bar. Short loaders can be used for overnight production of parts with certain requirements, such as when running parts with long cycle times, and when using profiled material or bars that are not perfectly straight. Also, in conjunction with a shaped spindle liner and custom workholding, short loaders can run a variety of extruded shapes as well as square and rectangular bars, allowing the machining of parts that would previously be milled. Regardless of which type of bar feeder best suits the appli- cation, it must have the ability to continuously load barstock of the required diameter without misfeeds. Otherwise, production will grind to a halt. Unloading parts. What goes in must come out, albeit in a more refined form. e standard parts catcher may be perfectly adequate to handle the output, depending on the size and quantity of parts produced overnight. If not, options are available such as the LNS Blaze Air vacuum unloader, which uses suction to unload parts as long as 48 inches and deposit them into its storage tray. Blaze Air is primarily used with twin-spindle or subspindle machines with through-hole to remove the part through the back of the secondary spindle when both ends have been machined. It can also be used on single-spindle machines in many cases. Another approach is to add a robotic arm to remove parts from the unloader tray or parts catcher and place them in containers. With recent advances in both touch and vision sensing capabilities, robots can locate and move large, long or small parts to appropriate receptacles. Chip management. A buildup of chips can compromise the cutting area and create a bottleneck that slows or stops production, and fines can clog and damage coolant pumps. Tooling used for lights-out production must adequately break up chips to prevent bird nests of stringy chips that can break tooling and produce bad parts. Receptacles that can't contain the volume of chips Tooling used for lights-out production must adequately break up chips to prevent bird nests of stringy chips that can break tooling and produce bad parts. BAR FEEDERS/MATERIAL HANDLING 34 PRODUCTION MACHINING :: OCTOBER 2017

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