... We are forging a range of automotive and truck parts, from brackets and other automotive hardware to various gear shapes that include spur, pinion, and ring gears. We have sought advice from various sources and they all seem have the “best system,” but they differ in approach.
A: I have contacted sources for automation in presses and upsetters, too, including Livernois Engineering and Feedall, as well as some European firms involved in automating hot-forging of gears and crankshafts. For example, there are Eumuco presses in this country that include automation for many of the post-forging operations as well as for operations in the press. Also, in Europe I’ve observed Eumuco and Weingarten press lines that include some nifty automation in and out of the press lines.
For example, at a German plant forging gears, near-vertical coils heating slugs helped to improve the neutral atmosphere inside the coils. A combination of nitrogen and natural gas is used to protect the heated steel in the automated induction heaters (to about 1,900ºF). The heated slugs are then transferred by catch-and-carry system where the slugs are caught from the exiting coil and placed quickly onto the first forging station and blocked, transferred (by a pinch-and-carry system (similar to Livernois can transfers) to the finishing station and finish-forged at reduced temperatures (about 1,800ºF). This is followed by rapid cooling to prevent decarburization.
Another plant I visited included a vibratory bowl feeder for the induction heater that was then fed into a chute with a plunger feeding the slugs into a horizontal induction heater. In this case, the slugs were coated with a dry graphite mixture in the bowl feeder before heating to minimize decarburization and scale. The slugs were transferred via a chute, combined with a pick-and-place system, to the first and second stations. However, the trim and qualifying station was manually handled in this case.
I am familiar with automation for Kurimoto presses that are used to forge wheel spindles and crankshafts. The latter are similar to the lift-and-carry walking-beam types, with more positive clamping for each forging station.
Now, my primary experience has been with walking-beam types where the product is picked up and carried to successive stations in a press. The systems I was responsible for varied in the number of forging positions, ranging up to nine stations for cold forging, where five stations were for forging and the four were for re-orienting the forgings.
This nine-station system was designed internally with only vertical lift-and-carry, no lateral motion. Magnets were used to maintain the cold bars in position after orientation. This was simpler than using spring clamps that tended to weaken after time. We also used position sensors to be sure the parts were in the right stations and oriented properly. This complex system was developed for cold forging of relay rods for rear-wheel-drive cars and trucks, and has been used in modified form for other shapes. This system would not be useful for forging gear shapes or other compact shapes.
For warm forging tie-bar ends, the modified walking-beams were more of the clamp-and-carry type, where clamps held the cold end of the bars as the products progressed through horizontal upsetters (Etchelles). There was no lift by the beams, but by a cam that simply lifted the forgings and then dropped them in position at each of the three blows.
All three stations were loaded at the same time, producing one part per blow of the upsetter. Again, this system was home-designed and homemade (under tool contract). It would not be suitable for forging gear shapes.I have not seen any true lift, carry, or slide systems in use for ring gears — just modified robotic systems at one plant in the U.S. and another in Germany.
For more than 40 years H. James Henning held key technical positions in the forging industry, including as director of technology for the Forging Industry Association, and as president of Henning Education Services, a Columbus, OH, firm specializing in customized education and training in forging technologies.
Guidelines and recommendations offered in this column are based on information believed to be reliable and are supplied in good faith but without guarantee. Operational conditions that exist in individual plants and facilities vary widely. Users of this information should adapt it, and always exercise independent discretion in establishing plant or facility operating practice.