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Integrated Manufacturing and Assembly
Integrated Manufacturing and Assembly M. Weck ( l ) , U. Dern, Laboratoriurn fur Werkzeugmaschinen und Betriebslehre, R W H AachenFRG
Factory automation with the aid of computer-assisted systems makes possible substantial cost reductions, which help improve efficiency and competitiveness of the company on an international scale. Solutions based on the building-block principle consisting of largely standardized elements and interfaces have contributed a great deal to the fact that the so-called flexible manufacturing systems no longer have the reputation of beeing prestigious but risky experimental installations: rather they now constitute practicable and, above all, economical production facilities also for small and middlesized companies. What is required most today are machine and control concepts - and this applies both to manufacturing and assembly - which combine an adaptive flexibility of the equipment and a high level of automation. A production system that meets this requirement to a particularly high degree has been developed at the Laboratorium fiir Werkzeugmaschinen und Betriebslehre, RWTH Aachen, and set up with the support of leading companies. In this "Integrated System" the manufacturing and assembly processes have been linked as regards both the material and information flow, thus permitting a substantial reduction of turnaround time and intermediate buffer inventory. SUMMARY:
1.
INTRODUCTION
The "Factory of the Future" is no longer associated with the problem of a further increase in productivity. In almost all areas of production there is a growing demand for a fast and economical adaptation to varying market situations. Modern production systems therefore require a high degree of functional flexibility, which can be attained economically only be means of a correspondingly intensive exploitation of all facilities. This consideration has led to a constantly growing demand for automated flexible machine and system concepts. This demand is not confined to the area of manufacturing. With the right selection and design of products, automation of assembly tasks is a feasible objective. The next logical step is the integration of both manufacturing and assembly with regard to material and information flow. Such an "Integrated System" (Fig. 1 ) has been developed at the Laboratorium fiir Werkzeugmaschinen und Betriebslehre. Fig. 2: Survey on the production parts 2.1.
MANUFACTURING CELL
The manufacturing cell for machining the two structural components of the valve housing consists of two numerically controlled machines and a six-axis industrial robot for workpiece handling (Fig. 3 ) . The manufacturing cell is decoupled from the material flow system by means of a buffer which is of ample capacity that while one job order is on operation the next can already be put on standby. Depending on the type of valve, a job may consist of up to eight valves which are provided on two pallets according to assembly groups.
A clearly defined position of all single parts, which is an essential prerequisite for automatic workpiece handling, is ensured by a uniform workpiece-specifically molded plastic insert. This insert accepts all variants of a family of parts and can be easily exchanged to hold another type of workpiece.
ntegra
manufacturing an' assembly system
Fig.
1:
2.
SYSTEM OVERVIEW
As a product sample, a nonreturn pipe valve is manufactured and assembled by the system in seven size variants (Fig. 2 ) . For this purpose, cast iron blanks which are provided on standard transport pallets are first machined and then assembled to a finished product using outside bought parts. The entire process is automated and controlled by means of a supervisory computer. The system is divided into two functional areas, namely manufacturing and assembly, which are designed as self-contained cells, with a view to providing defined interfaces for the material and information flow. The external link between the individual cells and the connection with the associated storage as well as with other company areas is assured by an Automated Guided Vehicle System (AGVS).
Annals of the CIRP Vol. 34/1/1985
In the first operation, the flange coupling joints are turned. For this purpose, the chuck jaws of the turning machine first have to be adjusted to the appropriate chucking diameter with the aid of the industrial robot. After this machining operation the workpiece is turned over for a second chucking without being set down. This is carried out by means of a special-type gripper within the working space of the machine. The option of program-controlled exchange of grippers lendeffectors) of the industrial robot permits adaptation to diverse workpiece geometries and handling tasks. This, in conjunction with the possibility of chuck jaw adjustment, increases the flexibility of the system decisively. Even interchangeable jaws are conceivable in this context. For the subsequent operation-drilling/tapping of the holes of a bypass - the workpiece has to be transferred to the second machine, a machining centre, with a privileged orientation. For this task, a self-contained station has been provided for, where the part is layed down by the robot, rotated into a defined position found by scanning the outer contour of the
45
Fig. 3 : Overall view of the system valve and picked up again (Fig. 4 ) .
completed with a flow guidance cone and the corresponding fastening bolt and nut. The second assembly group is pre-assembled in the same manner at the orientation station (Fig. 5).
Fig. 4 : Orientating of the workpiece On the machining centre all size variants of the part are chucked into a universal-type fixture. The clamping position and the dimensional accuracy of the premachining are checked with the aid of a swicching probe. The results obtained can be used immediatly to correct the NC-program. Upon termination of the machining the part, while still in the working space of the cent.re, is cleaned of chips and finally placed on the pallet aqain. 2 . 2 . ASSEMBLY CELL
In the assembly cell a five-axis gantry-type robot performs all handling and assembly tasks. Pallets with premachined parts can be provided at as many as four stations to ensure an uninterrupted j o h sequence also in this area. The two principal assembly groups of the valve are preassembled at two separate stations: The robot picks up a valve chamber from one of the pallets standing by and places it at an orientation station, s j - m i l a r to that in the manufacturing cell. Subsequently the part is transferred in the proper position to 3 second assembly station where the first assemb1.y group is
Fig. 5 :
Pr?-assembly of out-let valve
For the insertlng of the stud screws to join the two assembly grcrups, the station continues to be stepped around in accordance with the thread holes. For each one of these operations a special gripper or screwdriving t-ool is required which the robot can automatically pick 'up from a magazine. Variants-spesific outside bougnt components are provided on the pallet, together with the premachined workpieces. Standard parts like studs and nuts are supplied by separate rriagazining systems and are directly taken over by the handling device with the aid of the appropriate too1.s. After completion of the pre-assembly,the industrial robot joins t-he assembly groups and bolts the two flanges. Finally, t h e so assembled valve is placed again onto onr of the pallets.
2. 3
.
. r d i r L a t i u n uf m d n u f a r t u r i r i g and a s s e m b l y s e q u e n -
MATERikL FLOW
T r a n s L m r t a t i o n of t!ie g a l i e ~LeCweeil ~ t h e Stmriaqe a n d t h e c e l l s i s c a r r i e d o u t b3- ST? R u t c n a ; e d T u ; d e d V e h i c l e S y s t e m ( F i g . 61.
-
agement. ,if st.!jrage arid ba coniinunicat i o n with o p e r a t o r c o l l e c t i o n a n d p r o c c s s i n q sf
The z o n t r a l l e r s o f rrhe 3:arl~ous s y s t e m e l e m e n t s , if n o t p r o v i d e d wizh a p p r o p r i a t e i n t e r f a c e s f o r t h e c o x n u n i , c a t i o i i with t h e s i i p e r l - i s o i y c o m p u t e r , 3 r e lLnKed w i t h f a ni i c 1-0'3r o c e sso r - c o n t r ol1e d i~c- h "us e . T h r ou yh arid i t ic n a 1 grammable l o y i c f x n c t i o n s , t h i s lievi. the s u p e r v i s o r : . c o m p u t e r of c o i n c i d i n g tasks a n d f a c i l i t a t e s i n d e p e n d e n t c o o r d i n a t i o r . of t h e i n d i v i d u a l s e q u e - c e s i n t!ie c e l l s . T h i s p ~ i n c i ~ of l e hierdrchical structurization into f u n c t i o n a l modules and d e c e n t r a l i z a t i o n o f i n t e l l i g e n c e , c o n s i s t e n t l y a d h e r e d to, n o t only p e r m i t s a a r t i a l l y a u t o m a t i z e d o p e r a t i o n of t h e s y s t e m i n t h e v e n t Qf f a i l u r e o r b r e a k d o w n of t h e c o m p u t e r , b u t I s 0 f a c i l i t a t e s considerably t h e t e s t i n g , p u t t i n g int o o p e i a t i o n , a d a p t ; i t - i o n and. e x p a n s i o n of t h e s y s t e m . The d a t a t r a n s v i s s i s n b e t w e e n t h e s x p e r v i s o r y c o m p u t e r and t h e c o n t r o l l e r s is c a r r i e d o u t v i a a f i b e r o p t i c
Fig.
c a b l e w i t h i n t h e f r a m e w o r k of a t r a n s m i s s i o n p r o t o c o l . ir. t h i s way a f a s t a n d sboof all r e l i a b l e i n f o r m a t i o n e x c h a n g e is g u a r a n i e e d , i n d e p e n d e n t l y o f t h e d i s t a n c e s b e t w e e n t h e s y s t e m s a n d o f ti:e e ? . v i r o n m e n t a l c n n d i & . ~ i o i i s ir. t n e p l a n t .
6 : A u t o m a t e d A i d e 3 V e h i c l e S-;Ts:em
The v e h i c l e c a r r i e s , a:? do a t i t r a n s f e r s t d t i o n s on its travelling route, ensure pickup and t r a c a p a c i t y of t h e s y s t f o f a d d i t i o n a l c e l l s o r o t h ~ i -s h o p a The s y s r e m s t o r a g e , a s t s c k s h e l f l o c a t e d i n t h e n i t y of t h e p r n d u r t i : r e q u i r e d f o r a .jive7 o f t h i s a t r J r a g c c a n LI w i t h t h e number o f s t i o r d e r - ?r w o r k p i c c 3.
71.21-
Bat* t i n e s o f t w a r e s y s t e m o f
t h e s u p e r v i s o r y coniputer and t h e p r o q r a m s o f !he m i c r o p r o c e s s o r c o n r r G l l e r s irave been p r e p a r e d i n t h e h i q h e r programming l a n g u a g e PASCAL. The o v e r a l l s o t t w a r e i s , t o a qrea! e x t e n t , of m o d u l a r s t r u c t u r e i n o r d e r to f a c i l i t a t e a d a p t a t i o n s and e x p a n s i o n s . df a c o r , f i g u r a t i d t h e user can t Ynmpan; a n d
CONTROL. S'ISTEP?
The b u i l d i n g - b l o c k s t r i i i s f o u n d a l s o i n t h e co e l e n i e n t s are c o n t r c l l e d systems operating indep ier. A s u p e r v i s o r y computer c o o r d i n t u r i n g , assernijly a n d m a t e r i a l - f l o w s p c ' f I<: p m r c s (Fig. 7 ) .
i n o r d e r t o a s s u r e a h ~ g l isystenl s a f e t i - and a v a l l a b i s ;If l ~ a n d l i r ~ cm ;,achining
F-----.------p
prsduction system supIts LL d definable limited
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ZY
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ONC
DNC
ONC
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t i o n o f o b l c c r s , d e s ; g n and a p p l i c a r i o n o f s e n s o r s , 5iy1?a1 analysis a n d measL1res t i 3 b e t a k e n . ~ a tf e w e x a m p l e s , E s s e n t i a l f u n c t i o n s , t o name j s u p p o r t . i n g ri,e p u t t i n q l n t o o p c r a t ion a n d t h e p r o d s c tion itself are:
-
w o r k p i e c e i d e n ~ ~ t i c a i i oby n medsdr;ng w o r k p i e c e k ~ q j l i ta n d f l a n g e d i a r n - t . t r ,
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prograrnmiriy a n d m o n i t i r j . n g o f p e r m i s s i b l e f o r c e s for iid:vid.~alhandling operations,
-
a p p l i c a t i o s uT A ; , i s i o n s y s t e m f o r v e r i f i c a t i o n and c o r r e c t i o n of i n a r c u r a c i e s I I? w o r k p i e c e p o s i t i o n ,
teach-in)
Fig.
7:
Control sy5te1~ structure
O r d e r f i l e s a n d NC p r o g r a m s a r e p r e F a r e d b : ~ a plan! management s y s t e m v i a c o m p u t e r l i n k o r L u i l t - ~ ipn o p e r a t o r d i a l o g u e . I n t h i s way i t i s p o s s i b l e t o as-s i g n job p r i o r i t i e s a n d h a v e t h e system g i v e p r e f e r e n - . t i a l t r e a t m e n t t o u r g e n t jobs. A l l s u h s e c y e n t o p e r a t i o n s are c o n t r o l l e d b y t.he s u p e r v i s o r ; T c o m p u t e r . I n t h e e v e n t of t e c h n i c a l or o r g a n i z a t i o n a l f a i l u r e s i t i s p o s s i b l e a t any t i m e f o r t h e o p e r a t o r t o i n t e r v e n e a n d s p e c i f i c a l l y m a n i p u l a t e ilie e l e m e n t func-. tions. The s o f t w a r e syst.eni t.hus r e a l i z e 6 i n c ; u d e s t h e f o l l o w ing functions:
-
N C p r o g r a m management a n d d d t a d i i ; t i - i b u t i o n ,
-
o r g a n i s a t i o n of m a t e r i a l f l o w ,
l o b management a n d f o l l o w - I l p of jot. p r q r c s s ,
.
lities f o r s u p p o r t i n g t h e p r o q r a m l n g t . r i a l r o b o t s ( o f f - l i n e a s well a s
i n a d d i t i o n t o tile f d n c t i o i i a l r e l i a b i l i t y o f a s y s t e m , s p e c i a l i m p o r t a n c e must b e a t t . r i b u t e d t o t h e p r o t e c t i o n of p e r s o n n c l , a f a c t o r t h a t i s f r e q u e n t l y u n d e r estimated. This holds p a r t i c u l a r l y t r u e f o r highlya i l t o m a t e d p l a n t s w h i c h , b e c a u s e of t h e i r m o t i v e p o w e r a n d s p e e d f e a t u r e s , h a v e a h i g h p o t e n t i a l of d a n g e r f o r the operator. X a L i t d a t i o n arid n o n - o b s e r v a n c e of e l e m e n t a r y p r e c a u tions d u r i n g t h e p r o g r a n m i n g a n d t e s t p h a s e s a r e f r e q u e n t l y t h e c a u s e s o f endangerment and a c c i d e n t s , because during these phases t h e o p e r a t o r ' s presence is r e q u i r e d i n t h e w o r k i n g s p a c e of Ehe e q u i p m e n t , b u t h i s a t t e n t i o n i s c o n c e n t r a t e d on o n l y a p a r t of t h i s . H e r e , s a m p l e s o l u t i o n s a r e shown f o r t h e p r o t e c t i o n o f p e r s o n n e l t h r o u g h i u i t a b t e p r o t e c t i o n of t h e d a n g e r o u s a r e a s , s u p e r v i s i o n o f t h e w o r k i n g s p a c e s of t h e h a n d l i n g a n d c o n v e y i n g s y s t e m s a n d r e d u c t i o n of t h e pot e n t i a l f o r d a n g e r when p e o p l e a r e p r e s e n t w i t h i n t h e 2rotected areas.
47
5.
CONCLUSION
With the "Integrated Manufacturing and Assembly System" described in this paper a concept has been developed and realized which meets in a high degree todays objectives:
-
-
maximum flexibility for a wide and varying parts spectrum, extensive coordination of manufacturing and assembly, economic automated production of small series and even single parts high system reliability and availability.
It is not our intention to offer a complete system solution, but rather a variety of specific solutions. 'Phe modules of the system described in this paper can be individually put together into other combinations, depending on the respective tasks and the production volume required. This adaptive solution is made possible by a consistently modular structure of the hard and software together with standardized material and information-flow specific interfaces. In particular, this offers the possibility of a step-by-step installation of the system with the option of expansion at a later date. In this connection it has not been possible to give more than an overview of the multitude of details contained in the "Integrated Manufacturing and Assembly System".
48
Factory automation with the aid of computer-assisted systems makes possible substantial cost reductions, which help improve efficiency and competitiveness of the company on an international scale. Solutions based on the building-block principle consisting of largely standardized elements and interfaces have contributed a great deal to the fact that the so-called flexible manufacturing systems no longer have the reputation of beeing prestigious but risky experimental installations: rather they now constitute practicable and, above all, economical production facilities also for small and middlesized companies. What is required most today are machine and control concepts - and this applies both to manufacturing and assembly - which combine an adaptive flexibility of the equipment and a high level of automation. A production system that meets this requirement to a particularly high degree has been developed at the Laboratorium fiir Werkzeugmaschinen und Betriebslehre, RWTH Aachen, and set up with the support of leading companies. In this "Integrated System" the manufacturing and assembly processes have been linked as regards both the material and information flow, thus permitting a substantial reduction of turnaround time and intermediate buffer inventory. SUMMARY:
1.
INTRODUCTION
The "Factory of the Future" is no longer associated with the problem of a further increase in productivity. In almost all areas of production there is a growing demand for a fast and economical adaptation to varying market situations. Modern production systems therefore require a high degree of functional flexibility, which can be attained economically only be means of a correspondingly intensive exploitation of all facilities. This consideration has led to a constantly growing demand for automated flexible machine and system concepts. This demand is not confined to the area of manufacturing. With the right selection and design of products, automation of assembly tasks is a feasible objective. The next logical step is the integration of both manufacturing and assembly with regard to material and information flow. Such an "Integrated System" (Fig. 1 ) has been developed at the Laboratorium fiir Werkzeugmaschinen und Betriebslehre. Fig. 2: Survey on the production parts 2.1.
MANUFACTURING CELL
The manufacturing cell for machining the two structural components of the valve housing consists of two numerically controlled machines and a six-axis industrial robot for workpiece handling (Fig. 3 ) . The manufacturing cell is decoupled from the material flow system by means of a buffer which is of ample capacity that while one job order is on operation the next can already be put on standby. Depending on the type of valve, a job may consist of up to eight valves which are provided on two pallets according to assembly groups.
A clearly defined position of all single parts, which is an essential prerequisite for automatic workpiece handling, is ensured by a uniform workpiece-specifically molded plastic insert. This insert accepts all variants of a family of parts and can be easily exchanged to hold another type of workpiece.
ntegra
manufacturing an' assembly system
Fig.
1:
2.
SYSTEM OVERVIEW
As a product sample, a nonreturn pipe valve is manufactured and assembled by the system in seven size variants (Fig. 2 ) . For this purpose, cast iron blanks which are provided on standard transport pallets are first machined and then assembled to a finished product using outside bought parts. The entire process is automated and controlled by means of a supervisory computer. The system is divided into two functional areas, namely manufacturing and assembly, which are designed as self-contained cells, with a view to providing defined interfaces for the material and information flow. The external link between the individual cells and the connection with the associated storage as well as with other company areas is assured by an Automated Guided Vehicle System (AGVS).
Annals of the CIRP Vol. 34/1/1985
In the first operation, the flange coupling joints are turned. For this purpose, the chuck jaws of the turning machine first have to be adjusted to the appropriate chucking diameter with the aid of the industrial robot. After this machining operation the workpiece is turned over for a second chucking without being set down. This is carried out by means of a special-type gripper within the working space of the machine. The option of program-controlled exchange of grippers lendeffectors) of the industrial robot permits adaptation to diverse workpiece geometries and handling tasks. This, in conjunction with the possibility of chuck jaw adjustment, increases the flexibility of the system decisively. Even interchangeable jaws are conceivable in this context. For the subsequent operation-drilling/tapping of the holes of a bypass - the workpiece has to be transferred to the second machine, a machining centre, with a privileged orientation. For this task, a self-contained station has been provided for, where the part is layed down by the robot, rotated into a defined position found by scanning the outer contour of the
45
Fig. 3 : Overall view of the system valve and picked up again (Fig. 4 ) .
completed with a flow guidance cone and the corresponding fastening bolt and nut. The second assembly group is pre-assembled in the same manner at the orientation station (Fig. 5).
Fig. 4 : Orientating of the workpiece On the machining centre all size variants of the part are chucked into a universal-type fixture. The clamping position and the dimensional accuracy of the premachining are checked with the aid of a swicching probe. The results obtained can be used immediatly to correct the NC-program. Upon termination of the machining the part, while still in the working space of the cent.re, is cleaned of chips and finally placed on the pallet aqain. 2 . 2 . ASSEMBLY CELL
In the assembly cell a five-axis gantry-type robot performs all handling and assembly tasks. Pallets with premachined parts can be provided at as many as four stations to ensure an uninterrupted j o h sequence also in this area. The two principal assembly groups of the valve are preassembled at two separate stations: The robot picks up a valve chamber from one of the pallets standing by and places it at an orientation station, s j - m i l a r to that in the manufacturing cell. Subsequently the part is transferred in the proper position to 3 second assembly station where the first assemb1.y group is
Fig. 5 :
Pr?-assembly of out-let valve
For the insertlng of the stud screws to join the two assembly grcrups, the station continues to be stepped around in accordance with the thread holes. For each one of these operations a special gripper or screwdriving t-ool is required which the robot can automatically pick 'up from a magazine. Variants-spesific outside bougnt components are provided on the pallet, together with the premachined workpieces. Standard parts like studs and nuts are supplied by separate rriagazining systems and are directly taken over by the handling device with the aid of the appropriate too1.s. After completion of the pre-assembly,the industrial robot joins t-he assembly groups and bolts the two flanges. Finally, t h e so assembled valve is placed again onto onr of the pallets.
2. 3
.
. r d i r L a t i u n uf m d n u f a r t u r i r i g and a s s e m b l y s e q u e n -
MATERikL FLOW
T r a n s L m r t a t i o n of t!ie g a l i e ~LeCweeil ~ t h e Stmriaqe a n d t h e c e l l s i s c a r r i e d o u t b3- ST? R u t c n a ; e d T u ; d e d V e h i c l e S y s t e m ( F i g . 61.
-
agement. ,if st.!jrage arid ba coniinunicat i o n with o p e r a t o r c o l l e c t i o n a n d p r o c c s s i n q sf
The z o n t r a l l e r s o f rrhe 3:arl~ous s y s t e m e l e m e n t s , if n o t p r o v i d e d wizh a p p r o p r i a t e i n t e r f a c e s f o r t h e c o x n u n i , c a t i o i i with t h e s i i p e r l - i s o i y c o m p u t e r , 3 r e lLnKed w i t h f a ni i c 1-0'3r o c e sso r - c o n t r ol1e d i~c- h "us e . T h r ou yh arid i t ic n a 1 grammable l o y i c f x n c t i o n s , t h i s lievi. the s u p e r v i s o r : . c o m p u t e r of c o i n c i d i n g tasks a n d f a c i l i t a t e s i n d e p e n d e n t c o o r d i n a t i o r . of t h e i n d i v i d u a l s e q u e - c e s i n t!ie c e l l s . T h i s p ~ i n c i ~ of l e hierdrchical structurization into f u n c t i o n a l modules and d e c e n t r a l i z a t i o n o f i n t e l l i g e n c e , c o n s i s t e n t l y a d h e r e d to, n o t only p e r m i t s a a r t i a l l y a u t o m a t i z e d o p e r a t i o n of t h e s y s t e m i n t h e v e n t Qf f a i l u r e o r b r e a k d o w n of t h e c o m p u t e r , b u t I s 0 f a c i l i t a t e s considerably t h e t e s t i n g , p u t t i n g int o o p e i a t i o n , a d a p t ; i t - i o n and. e x p a n s i o n of t h e s y s t e m . The d a t a t r a n s v i s s i s n b e t w e e n t h e s x p e r v i s o r y c o m p u t e r and t h e c o n t r o l l e r s is c a r r i e d o u t v i a a f i b e r o p t i c
Fig.
c a b l e w i t h i n t h e f r a m e w o r k of a t r a n s m i s s i o n p r o t o c o l . ir. t h i s way a f a s t a n d sboof all r e l i a b l e i n f o r m a t i o n e x c h a n g e is g u a r a n i e e d , i n d e p e n d e n t l y o f t h e d i s t a n c e s b e t w e e n t h e s y s t e m s a n d o f ti:e e ? . v i r o n m e n t a l c n n d i & . ~ i o i i s ir. t n e p l a n t .
6 : A u t o m a t e d A i d e 3 V e h i c l e S-;Ts:em
The v e h i c l e c a r r i e s , a:? do a t i t r a n s f e r s t d t i o n s on its travelling route, ensure pickup and t r a c a p a c i t y of t h e s y s t f o f a d d i t i o n a l c e l l s o r o t h ~ i -s h o p a The s y s r e m s t o r a g e , a s t s c k s h e l f l o c a t e d i n t h e n i t y of t h e p r n d u r t i : r e q u i r e d f o r a .jive7 o f t h i s a t r J r a g c c a n LI w i t h t h e number o f s t i o r d e r - ?r w o r k p i c c 3.
71.21-
Bat* t i n e s o f t w a r e s y s t e m o f
t h e s u p e r v i s o r y coniputer and t h e p r o q r a m s o f !he m i c r o p r o c e s s o r c o n r r G l l e r s irave been p r e p a r e d i n t h e h i q h e r programming l a n g u a g e PASCAL. The o v e r a l l s o t t w a r e i s , t o a qrea! e x t e n t , of m o d u l a r s t r u c t u r e i n o r d e r to f a c i l i t a t e a d a p t a t i o n s and e x p a n s i o n s . df a c o r , f i g u r a t i d t h e user can t Ynmpan; a n d
CONTROL. S'ISTEP?
The b u i l d i n g - b l o c k s t r i i i s f o u n d a l s o i n t h e co e l e n i e n t s are c o n t r c l l e d systems operating indep ier. A s u p e r v i s o r y computer c o o r d i n t u r i n g , assernijly a n d m a t e r i a l - f l o w s p c ' f I<: p m r c s (Fig. 7 ) .
i n o r d e r t o a s s u r e a h ~ g l isystenl s a f e t i - and a v a l l a b i s ;If l ~ a n d l i r ~ cm ;,achining
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t i o n o f o b l c c r s , d e s ; g n and a p p l i c a r i o n o f s e n s o r s , 5iy1?a1 analysis a n d measL1res t i 3 b e t a k e n . ~ a tf e w e x a m p l e s , E s s e n t i a l f u n c t i o n s , t o name j s u p p o r t . i n g ri,e p u t t i n q l n t o o p c r a t ion a n d t h e p r o d s c tion itself are:
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w o r k p i e c e i d e n ~ ~ t i c a i i oby n medsdr;ng w o r k p i e c e k ~ q j l i ta n d f l a n g e d i a r n - t . t r ,
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prograrnmiriy a n d m o n i t i r j . n g o f p e r m i s s i b l e f o r c e s for iid:vid.~alhandling operations,
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a p p l i c a t i o s uT A ; , i s i o n s y s t e m f o r v e r i f i c a t i o n and c o r r e c t i o n of i n a r c u r a c i e s I I? w o r k p i e c e p o s i t i o n ,
teach-in)
Fig.
7:
Control sy5te1~ structure
O r d e r f i l e s a n d NC p r o g r a m s a r e p r e F a r e d b : ~ a plan! management s y s t e m v i a c o m p u t e r l i n k o r L u i l t - ~ ipn o p e r a t o r d i a l o g u e . I n t h i s way i t i s p o s s i b l e t o as-s i g n job p r i o r i t i e s a n d h a v e t h e system g i v e p r e f e r e n - . t i a l t r e a t m e n t t o u r g e n t jobs. A l l s u h s e c y e n t o p e r a t i o n s are c o n t r o l l e d b y t.he s u p e r v i s o r ; T c o m p u t e r . I n t h e e v e n t of t e c h n i c a l or o r g a n i z a t i o n a l f a i l u r e s i t i s p o s s i b l e a t any t i m e f o r t h e o p e r a t o r t o i n t e r v e n e a n d s p e c i f i c a l l y m a n i p u l a t e ilie e l e m e n t func-. tions. The s o f t w a r e syst.eni t.hus r e a l i z e 6 i n c ; u d e s t h e f o l l o w ing functions:
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N C p r o g r a m management a n d d d t a d i i ; t i - i b u t i o n ,
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o r g a n i s a t i o n of m a t e r i a l f l o w ,
l o b management a n d f o l l o w - I l p of jot. p r q r c s s ,
.
lities f o r s u p p o r t i n g t h e p r o q r a m l n g t . r i a l r o b o t s ( o f f - l i n e a s well a s
i n a d d i t i o n t o tile f d n c t i o i i a l r e l i a b i l i t y o f a s y s t e m , s p e c i a l i m p o r t a n c e must b e a t t . r i b u t e d t o t h e p r o t e c t i o n of p e r s o n n c l , a f a c t o r t h a t i s f r e q u e n t l y u n d e r estimated. This holds p a r t i c u l a r l y t r u e f o r highlya i l t o m a t e d p l a n t s w h i c h , b e c a u s e of t h e i r m o t i v e p o w e r a n d s p e e d f e a t u r e s , h a v e a h i g h p o t e n t i a l of d a n g e r f o r the operator. X a L i t d a t i o n arid n o n - o b s e r v a n c e of e l e m e n t a r y p r e c a u tions d u r i n g t h e p r o g r a n m i n g a n d t e s t p h a s e s a r e f r e q u e n t l y t h e c a u s e s o f endangerment and a c c i d e n t s , because during these phases t h e o p e r a t o r ' s presence is r e q u i r e d i n t h e w o r k i n g s p a c e of Ehe e q u i p m e n t , b u t h i s a t t e n t i o n i s c o n c e n t r a t e d on o n l y a p a r t of t h i s . H e r e , s a m p l e s o l u t i o n s a r e shown f o r t h e p r o t e c t i o n o f p e r s o n n e l t h r o u g h i u i t a b t e p r o t e c t i o n of t h e d a n g e r o u s a r e a s , s u p e r v i s i o n o f t h e w o r k i n g s p a c e s of t h e h a n d l i n g a n d c o n v e y i n g s y s t e m s a n d r e d u c t i o n of t h e pot e n t i a l f o r d a n g e r when p e o p l e a r e p r e s e n t w i t h i n t h e 2rotected areas.
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5.
CONCLUSION
With the "Integrated Manufacturing and Assembly System" described in this paper a concept has been developed and realized which meets in a high degree todays objectives:
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maximum flexibility for a wide and varying parts spectrum, extensive coordination of manufacturing and assembly, economic automated production of small series and even single parts high system reliability and availability.
It is not our intention to offer a complete system solution, but rather a variety of specific solutions. 'Phe modules of the system described in this paper can be individually put together into other combinations, depending on the respective tasks and the production volume required. This adaptive solution is made possible by a consistently modular structure of the hard and software together with standardized material and information-flow specific interfaces. In particular, this offers the possibility of a step-by-step installation of the system with the option of expansion at a later date. In this connection it has not been possible to give more than an overview of the multitude of details contained in the "Integrated Manufacturing and Assembly System".
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