Manufacturing Strategy

How Bar Feeders Can Improve CNC Turning Machine Performance

April 2, 2013

CapBarStockToday’s turning machines and horizontal machining centers (HMC) are more accurate and repeatable then ever before and provide increasingly faster spindle speeds. Sophisticated, intelligent controls like the Okuma OSP THINC system easily execute complex programs while managing extensive production schedules. And with designed-in features that compensate for thermal influences, help you avoid turret crashes and make setups and programming easier, CNC machine shops can make accurate parts faster and more cost-effectively.

If you use cut-to-length or 12-foot bar stock in your manufacturing process, you can optimize the performance of these machine tools and your overall productivity by adding an automatic bar feeding system. Although you might think that efficiently loading bar stock is a simple process, in fact there are a number of factors to take into consideration including: The range of bar stock diameters to be machined, production volume, the necessity for fast changeovers, part finish requirements and dimensional tolerances.

For example, if your shop makes small quantities of unique parts, pre-cutting the bar stock into slugs and hand loading them into the turning machine may make the most sense. However, if you’re using longer lengths of bar stock, or very heavy material you’ll probably need additional support for the work piece inside the lathe. A complex or very large diameter shaft, for instance, may require special chucks or a custom designed automatic work holding solution.

High-volume production definitely requires a continuous supply of well supported bar stock, but using 12-foot lengths of bar stock without a bar feeder creates a number of serious issues. There was a time when machine operators typically loaded 12-foot lengths of bar stock by hand. Most of the bar hung out of the back of the machine and, since the bars are far from perfectly straight, the end dangerously whipped around and could even bend or break off. Meanwhile the lathe lumbered along at relatively slow spindle speeds, creating vibrations that prematurely wore machine components and affected the accuracy of the cut.

Today, automatic loading bar feeders fully enclose the bar stock, safely and smoothly feed it into the turning machine, and provide substantial and necessary support that reduces vibration and enables the machine spindle to operate at optimum speeds. Additionally, many bar feeder models store large quantities of bar stock so they can continuously feed the material into the lathe for unattended and lights-out production. Smaller, short-load bar feeders that take up about 1/3 of the floor space required by 12-foot bar feeders are also available to load headstock-length bar stock.

Using the right bar feeding system can have a major impact on your CNC machine’s performance, safety and productivity. Gosiger has the experience and expertise to determine the best bar feeder and CNC machine solutions for your applications.