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Gräbener sizes up PM opportunity
Gr ibener sizes up PM opportunity or large volume production r u n s of powder met a l l u r g y (PM) p a r t s , Gr~bener of Netphen-Werthenbach, Germany, has developed a sizing p r e s s e q u i p p e d with an automatic feed system with integrated p a r t s lubrication and hydraulic docking s ~ t e m for the tool adapter. A u t o m a t i n g t h e p r e s s o p e r a t i o n in this way, according to Gr~bener, allows fast a n d economical p r o d u c t i o n of high-quality parts. The feed system consists of several wear resistant belt conveyors with an oil dipping station and an optoelectronic aligning station.
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Defined uniform lubrication The p a r t s are loaded onto the buffer belt, a u t o m a t i c a l l y or manually, and piled in front of a stopper. As soon as the queue of p a r t s in front of the aligning station falls below the required length, the s t o p p e r releases further parts. The PM p a r t s are t h e n t r a n s p o r t e d onwards indi-
vidually over a chute. Conveying t h e p a r t s individually prevents t h e m sticking on the c h u t e and bringing the p r e s s to standstill, says Grfibener. Next, the p a r t s are transp o r t e d on a conveyor belt to t h e automatic dipping station with oil t a n k (Figure 1), which, the c o m p a n y says, is an i m p o r t a n t innovation in t h e lubrication process. The conveyor belt with pick-up chain t r a n s p o r t s the PM p a r t s individually t h r o u g h the oil t a n k All p a r t s are uniformly ~vetted' with lubricant. The syst e m p r e v e n t s t h e p o r o u s PM p a r t s from being s a t u r a t e d with oil because they p a s s t h r o u g h t h e tank at tightly defined intervals. This time defined lubrication facilitates p r o d u c t i o n of higher-quality p a r t s to tighter tolerances in t h e sizing operation, Gr~bener says. The conveyor belt taking t h e p a r t s t h r o u g h the oil t a n k does not stop immediately w h e n t h e total system malfunctions b u t only after all the p a r t s have e m e r g e d from t h e tank. This p r e v e n t s PM p a r t s a b s o r b i n g
FIGURE 1: The automatic feed system with oil dipping station.
22 MPR October 1997
t o o m u c h oil, w h i c h w o u l d r e n d e r t h e m useless. With p r e v i o u s l u b r i c a t i o n m e t h o d s , t h e p a r t s were imm e r s e d in t h e oil at a specially designed dipping station, b u t this proved a bottleneck with limited batches. Moreover, this multi-function facility was p r o n e to faults. In Gr~bener's design, t h e c o m p a c t size of t h e d i p p i n g basin is achieved by a d a p t i n g it to t h e s h a p e of the conveyor belt. This minimizes the a m o u n t of oil required, t h u s reducing b o t h the environmental impact a n d t h e fire hazard. From the dipping station, the p a r t s are fed over a c h u t e onto a n o t h e r conveyor belt - the drip stretch - on which superfluous lubricant can drip into collecting gullies to be r e t u r n e d to the oil tank for re-use. At t h e end of the buffer belt, the PM p a r t s accumulate again.
Parts transport The p a r t s are individually released, a n d conveyed to a lifting station to be raised to the level of the transfer unit for onward t r a n s p o r t to the optoelectronic aligning station. Here, the p a r t s are aligned visually with t h e help of a charge coupled device (CCD) c a m e r a a n d turnstile. Afterwards, ~m additional mechanical check is carried out at a n o t h e r control station, which is located imme~liately before the sizing operation. This eliminates any possibiliVy of p a r t s t h a t are not accurately aligned travelling t h r o u g h t h e press. After alignment, the p a r t s are t r a n s f e r r e d to the tool for f a c e t i n g and sizing. A n o t h e r t r a n s f e r unit: carefully t r a n s p o r t s t h e finished, sized PM p a r t s over a chrome leatherlined conveyor belt out of t h e p r e s s s y s t e m for s u b s e q u e n t packaging. According to the company, the d e p l o y m e n t of different types of belts in the feed system ensures t h a t the p a r t s are always t r a n s p o r t e d individually and carefully t h r o u g h the dipping station.,; a n d t h e entire press. The buffer zone is flexible, and can be adjusted to accommodate different parts and different diameters. In addition, the feed system can be custom-designed. By decoupling press operation from the direct, work cycle of the press, Gr~bener says its
a u t o m a t i o n system allows a red u c t i o n in m a n p o w e r . W h e r e formerly two o p e r a t o r s h a d to m a n t h e press, it can now be o p e r a t e d by j u s t one.
Retooling in half the time Grftbener claims that the innovative hydraulic docking system for t h e tool a d a p t e r (Figure 2) halves t h e t i m e r e q u i r e d for retooling. The a p p r o a c h h e r e involves newly designed, automatic multi-coupling systems. A hydraulic socket is m o u n t e d on a p l a t e in t h e tool assembly area, with a m a t c h i n g plug o n t h e adapter. The roller-mounted t o o l a d a p t e r w i t h p l u g is wheeled into t h e tool assembly area, docked in t h e socket a n d locked in position. All t h e s e steps are automatic. Guides e n s u r e b o t h coupling e l e m e n t s are securely fastened. Before a d a p t e r change, t h e nine hydraulic c o n n e c t i o n s are decoupled by applying hydraulic p r e s s u r e against t h e spring tension, t h e plug a n d socket connections are released, a n d t h e tool a d a p t e r moved out.
FIGURE 2: Gr~bener's sizing press with automatic feed system and hydraulic docking system.
T h e s e m u l t i - c o u p l i n g syst e m s a r e d e s i g n e d for h i g h connecting frequencies, thus allowing t h e p r e s s to b e deployed flexibly to p r o d u c e dif-
f e r e n t p a r t s or for use w i t h small batches. Additionally, a special sealing m e t h o d prev e n t s a n y soiling of t h e hyd r a u l i c circuit. Ill
R E P R I N T S H E L P SA LES A N D REDUCE COSTS Promotey o ~ c : m p ~ d ~g:medYl~:: •
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MPR October 1997 23
F
Defined uniform lubrication The p a r t s are loaded onto the buffer belt, a u t o m a t i c a l l y or manually, and piled in front of a stopper. As soon as the queue of p a r t s in front of the aligning station falls below the required length, the s t o p p e r releases further parts. The PM p a r t s are t h e n t r a n s p o r t e d onwards indi-
vidually over a chute. Conveying t h e p a r t s individually prevents t h e m sticking on the c h u t e and bringing the p r e s s to standstill, says Grfibener. Next, the p a r t s are transp o r t e d on a conveyor belt to t h e automatic dipping station with oil t a n k (Figure 1), which, the c o m p a n y says, is an i m p o r t a n t innovation in t h e lubrication process. The conveyor belt with pick-up chain t r a n s p o r t s the PM p a r t s individually t h r o u g h the oil t a n k All p a r t s are uniformly ~vetted' with lubricant. The syst e m p r e v e n t s t h e p o r o u s PM p a r t s from being s a t u r a t e d with oil because they p a s s t h r o u g h t h e tank at tightly defined intervals. This time defined lubrication facilitates p r o d u c t i o n of higher-quality p a r t s to tighter tolerances in t h e sizing operation, Gr~bener says. The conveyor belt taking t h e p a r t s t h r o u g h the oil t a n k does not stop immediately w h e n t h e total system malfunctions b u t only after all the p a r t s have e m e r g e d from t h e tank. This p r e v e n t s PM p a r t s a b s o r b i n g
FIGURE 1: The automatic feed system with oil dipping station.
22 MPR October 1997
t o o m u c h oil, w h i c h w o u l d r e n d e r t h e m useless. With p r e v i o u s l u b r i c a t i o n m e t h o d s , t h e p a r t s were imm e r s e d in t h e oil at a specially designed dipping station, b u t this proved a bottleneck with limited batches. Moreover, this multi-function facility was p r o n e to faults. In Gr~bener's design, t h e c o m p a c t size of t h e d i p p i n g basin is achieved by a d a p t i n g it to t h e s h a p e of the conveyor belt. This minimizes the a m o u n t of oil required, t h u s reducing b o t h the environmental impact a n d t h e fire hazard. From the dipping station, the p a r t s are fed over a c h u t e onto a n o t h e r conveyor belt - the drip stretch - on which superfluous lubricant can drip into collecting gullies to be r e t u r n e d to the oil tank for re-use. At t h e end of the buffer belt, the PM p a r t s accumulate again.
Parts transport The p a r t s are individually released, a n d conveyed to a lifting station to be raised to the level of the transfer unit for onward t r a n s p o r t to the optoelectronic aligning station. Here, the p a r t s are aligned visually with t h e help of a charge coupled device (CCD) c a m e r a a n d turnstile. Afterwards, ~m additional mechanical check is carried out at a n o t h e r control station, which is located imme~liately before the sizing operation. This eliminates any possibiliVy of p a r t s t h a t are not accurately aligned travelling t h r o u g h t h e press. After alignment, the p a r t s are t r a n s f e r r e d to the tool for f a c e t i n g and sizing. A n o t h e r t r a n s f e r unit: carefully t r a n s p o r t s t h e finished, sized PM p a r t s over a chrome leatherlined conveyor belt out of t h e p r e s s s y s t e m for s u b s e q u e n t packaging. According to the company, the d e p l o y m e n t of different types of belts in the feed system ensures t h a t the p a r t s are always t r a n s p o r t e d individually and carefully t h r o u g h the dipping station.,; a n d t h e entire press. The buffer zone is flexible, and can be adjusted to accommodate different parts and different diameters. In addition, the feed system can be custom-designed. By decoupling press operation from the direct, work cycle of the press, Gr~bener says its
a u t o m a t i o n system allows a red u c t i o n in m a n p o w e r . W h e r e formerly two o p e r a t o r s h a d to m a n t h e press, it can now be o p e r a t e d by j u s t one.
Retooling in half the time Grftbener claims that the innovative hydraulic docking system for t h e tool a d a p t e r (Figure 2) halves t h e t i m e r e q u i r e d for retooling. The a p p r o a c h h e r e involves newly designed, automatic multi-coupling systems. A hydraulic socket is m o u n t e d on a p l a t e in t h e tool assembly area, with a m a t c h i n g plug o n t h e adapter. The roller-mounted t o o l a d a p t e r w i t h p l u g is wheeled into t h e tool assembly area, docked in t h e socket a n d locked in position. All t h e s e steps are automatic. Guides e n s u r e b o t h coupling e l e m e n t s are securely fastened. Before a d a p t e r change, t h e nine hydraulic c o n n e c t i o n s are decoupled by applying hydraulic p r e s s u r e against t h e spring tension, t h e plug a n d socket connections are released, a n d t h e tool a d a p t e r moved out.
FIGURE 2: Gr~bener's sizing press with automatic feed system and hydraulic docking system.
T h e s e m u l t i - c o u p l i n g syst e m s a r e d e s i g n e d for h i g h connecting frequencies, thus allowing t h e p r e s s to b e deployed flexibly to p r o d u c e dif-
f e r e n t p a r t s or for use w i t h small batches. Additionally, a special sealing m e t h o d prev e n t s a n y soiling of t h e hyd r a u l i c circuit. Ill
R E P R I N T S H E L P SA LES A N D REDUCE COSTS Promotey o ~ c : m p ~ d ~g:medYl~:: •
"
.
:
•
:
::
i ~h:tp intso an i.
MPR October 1997 23