Process Planning and Reliable Equipment are Keys to Successful Lights-Out or Unattended Production

BAR FEEDING

A competent bar feeding system is essential to a reliable CNC machine when machining bar stock. Whether using a long bar or spindle-length bar feeder, lights-out production requires flawless loading of a range of bar types and diameters, exceptional vibration dampening, and adequate support that enables precision machining at optimal spindle speeds. Above all, the bar feeder must be real-world and proven reliable under the demands of continuous operation.

INTERCONNECTIVITY

If the goal is to run multiple-part programs and maximize material usage, the CNC machine tool master scheduler must be able to communicate bilaterally with the automatic bar feeder. For example, the LNS e-Connect system enables the CNC machine to inform the bar feeder it is ready to change from one part program to another. The bar feeder, then, finds the new part program within its onboard Part Library and quickly accomplishes the program change.

The bar feeder continuously tracks material usage for additional efficiency, communicating this information to the CNC machine’s master schedule. Using these data, the machine tool compares the lengths of various scheduled parts to available material. If there is adequate material to complete the required part run, and the total quantity has not yet been produced, it does so. If not, it determines the length of the remnant and selects another part from the schedule that can be made using the remaining bar stock. When this cycle is completed, the master scheduler selects the next part program. The turning machine and bar feeder now make the appropriate adjustments; the bar feeder loads a new bar, and production resumes.

HIGH-PRESSURE COOLANT

In many applications, precise delivery of high-pressure coolant is critical to extending tool and coolant life while maintaining consistent spindle speeds and feed rates – all of which are essential for successful lights-out production. Moreover, running various parts overnight may require coolant pressure and flow rate adjustments. In these cases, a programmable high-pressure system is necessary for optimum productivity.

COOLANT FILTRATION

Keeping machine coolant clean and maintaining its useful life is challenging when lights-out machining “dirty” materials such as cast iron or cast aluminum. These materials require continuous coolant filtration to prevent particles from harming workpieces and CNC machines. Bag-type coolant filters that reach capacity with no one there to change the media can create significant problems. On the other hand, a stand-alone Cyclone filter reliably filters coolant as low as 5 microns, continuously polishes the machine tool sump, and deposits particulates removed from the coolant into a sludge settling tank. As a result, there are no filter bag alarms, no interrupted production due to dirty coolant, and machine tool coolant tank cleanout time is cut in half. 

OIL/COOLANT MIST COLLECTORS

Air filtration devices may not be top-of-mind when planning for lights-out production; however, they benefit employees' health and safety, reduce maintenance costs, and extend turning machine life. Because oil/mist collectors remove mist, aerosols, and smoke produced by the machining process, these harmful pollutants don’t find their way into HVAC systems and coat walls, floors, and fixtures where they pose a safety risk during non-lights-out work shifts and degrade machine tool performance.

CHIP MANAGEMENT

The humble chip conveyor is an often overlooked and undervalued lights-out production component. Even if every other link in the production chain operates perfectly, an inadequate chip conveying system can halt overnight production through backups, cause premature tool wear from recutting chips, diminish part quality when recirculated chips mar surface finish, and allow chip fragments into the machine sump that can shorten coolant pump life. 

Although conventional hinge belt conveyors are adequate in many applications, self-cleaning, filtering chip conveyors are better suited for lights-out production because they eliminate the above concerns. Advanced filtering chip conveyors efficiently process all chip sizes, types, and materials, filter coolant as low as 50 microns, and serve a broad range of applications.

PARTS UNLOADING

Overnight production volume may exceed a CNC machine’s standard parts catcher, and part finishes may suffer from the extraction method. An LNS Blaze Air vacuum unloader uses suction to unload parts up to 48 inches long and deposit them onto its large capacity, non-marring storage tray. Typically, the Blaze Air is used with twin-spindle or sub-spindle machines with through-hole to remove the part through the back of the secondary spindle when both ends have been machined. In some applications, it can also be used on single-spindle machines. Vacuum unloading is ideal for parts with strict surface finish requirements.

MONITORING

Even with a sound production plan and best-in-class equipment, problems can occur. Fortunately, LNS bar feeders monitor production and use a built-in Web server to transmit trouble alerts. It also sends machine status data, including Availability, Mode, Machine Status, Alarm State, Alarm ID, and Alarm description. In cooperation with major OEMs and input from end users, the LNS e-connect system and MTConnect provide connectivity for part programs and production schedules.

The system provides data such as part number, diameter, length, production volume, and remaining parts. This information helps analyze results to improve production efficiencies.

RELIABILITY AND SUPPORT

Only LNS builds, sells, services, and supports the peripherals your CNC machine needs for successful lights-out production. This single-source approach, in effect since 1973, is evidenced by worldwide installations of more than 200,000 bar feeders, 175,000 chip conveyors, 46,000 coolant systems, 22,000 air filtration systems, and 7,200 work holding systems.

All LNS products are backed by technical and application professionals who serve customers worldwide from facilities in Switzerland, North America, the United Kingdom, Italy, Turkey, China, Taiwan, and Japan. To learn more, call: 513-528-5674 or email: allproducts-sales@LNS-northamerica.com.