Improving Productivity With Retrofits
- July 31, 2002
by Jim Ward
Given the competitive pressure of today’s market, productivity may need a boost, even if equipment is performing well. Stampers can achieve measurable gains in their production efficiency through various types of upgrades to their coil handling and feeding equipment.
Upgrading the controller
Replacing the controller provides a relatively easy way of simplifying setups while increasing functionality to improve productivity. Many new servo controllers are designed to be quickly implemented into existing or new lines, capable of upgrades over a week-end.
Many servo feeds in operation today were introduced when servo technology was being developed. While they were a great replacement to the old air and mechanical feeds, many were built on unsupported hardware and software platforms. A stamper can face extended downtime in the event of the failure of a critical drive, motor or motion controller.
Many straighteners and reels in coil feeding systems were designed with simple drive mechanisms, while today’s variable speed controls are programmable. This allows custom parameters to be developed to optimize machine performance used in uncoiling and straightening functions to provide the proper torque necessary for these operations.
Many roll feeds have outdated operator interfaces. These are often simple devices that only offer basic set-up functions of feed progression and speed percentage, limiting their effectiveness. With an upgrade to a modern device, users gain new features such as storage recipes, operator prompts, servo feed diagnostics, multi-lingual programming, and direct downloading of parameters from the host press.
Loop control upgrades help with accurate sensing of the loop position and precise feedback to the straightener or reel drive, crucial to effective operation of the coil feeding system. Where original loop control systems are often simple on/off switches or Potentiometer devices, modern loop controls are based on ultra-sonic, photoeye, and laser beam non-contact technology for higher quality requirements. Loop height and response output signals are programmable to achieve optimum coil line performance for each job set-up.
Other potential areas for press line optimization may lie in upgrades to the coil, feeders or straightening equipment. Improvments in these areas can help manufacturers achieve the following:
As manufacturers are pushed for higher output rates, they may be constrained by the linespeed capability of their straightener or reel. Many press lines were originally specified to run at maximum linespeeds of 40-60 FPM. With upgrades to the machine drive and reducer package, coil rate speeds of 80-100 PPMK can be obtained.
Improved straightener capacity
The increased use of higher strength materials in the stamping industry has created problems for stampers as much of the existing equipment was designed to straighten only mild steels with lower yield strengths, whereas today it’s common for yield strength ratings to exceed 50,000 PSI. Straighteners can be upgraded to meet this demand by installing new higher HP drives and motors, improved reduction packages, and by adding a center back-up assembly to prevent deflection of the straightening rolls.
Optimized process flow with line configuration changes
Press and auxiliary equipment are often shuffled to make room for new presses or improve the flow of the stamping process. Feed and loading directions of the coil can limit flexibility and options for optimizing plant layout.
Improved coil containment
Along with higher strength materials, many stampers are challenged to process a wider range of material thickness. Existing equipment can benefit with upgrades to the threading drive system, as well as the addition of hold down arms, lower hold-up arms, and motorized endwheels.
To see where efficiency gains can be made to existing equipment, companies should have their coil processing equipment supplier perform mechanical and electrical inspections of the equipment. Then recommendations can be made that will help increase overall line speed.
Jim Ward is general manager, COE Press Equipment