perm filename PROP3[1,VDS] blob sn#080050 filedate 1974-01-02 generic text, type T, neo UTF8
00300			December 31, 1973
00500		A continuation of Prop2.
00800		The totally automated machine shop.
01000		The concept of the totally automated machine shop was brought
01100	up in Prop1.   This earlier discussion outlined some of  my  thinking
01200	regarding  the  possibilities  of  developing  a completely automated
01300	machine shop in  which  the  operator  would  be  a  computer  and  a
01400	mechanical  arm.   The input would be an interactively created design
01500	and the output a finished part or eventually a  product  manufactured
01600	to the description created by the designer.
01800		As a starting point, I will give a brief description of how I
01900	see the general prupose shop working.  First lets look at the layout.
02000	Imagine that we have a large timeshare computer, and a high data rate
02100	link to a machine shop.  In this shop are a number  of  machines  all
02200	n.c. type or else powered such that either electrical switching or at
02300	the most low mechanical forces are required to make them perform  all
02400	tasks.   They are all located in known locations, and each has a well
02500	stocked accessory holder.  A stock room with a good supply  of  stock
02600	material  is  near the tools.  This stock is stored so that it can be
02700	removed and placed in a shear or saw very easily  by  a  manipulator.
02800	Besides   these   machines   there  exists  one  or  more  mechanical
02900	manipulators which can move around to all of the machines and perform
03000	various operational tasks on these machines, just as a human operator
03100	does.      The  machines,  the  manipulators,  and   the   associated
03200	accessory  and  sensing devices are all interfaced to the computer so
03300	that  they  are  directly  controlled  (thru   a   mini-computer   if
03400	necessary).
03600		Now  lets  look  at  a  typical  sequence of operation.    An
03700	engineer sits down at a graphics display console.   His  task  is  to
03800	create  a  working  device  of  some sort.   This device is part of a
03900	system.    There are several parts to  the  device,  some  purchased,
04000	others  made  from purchased stock, and still others modifications of
04100	purchased completed components.   These parts must all  fit  together
04200	and  operate as a device, and the device must operate properly in the
04300	completed  system.         Using  GEOMED  or  a  similar  interactive
04400	display-graphics program, the engineer can reate shapes and structure
04500	on his console and manipulate these developed  bodies  at  will.   As
04600	engineer  are  generally rather realism oriented people, the graphics
04700	program will probably be oriented to display shapes and  forms  in  a
04800	manner  which  is  easily  interpreted  by  the design engineer.    A
04900	library of pruchased component dimensions  and  specifications  along
05000	with  standard  engineering dimensions and details can also be called
05100	by the designer or directly by the computer, as  would  be  the  case
05200	when placing screw holes, or selecting screw or shaft sizes.
05400		Assume that the design is done, the designer looks over  what
05500	he has created on the screen and sees that everything is correct; the
05600	program has picked the proper screws, has matched  up  all  the  bolt
05700	patterns  properly,  and  has  chosen  the  right  tolerances.  Now a
05800	manufacturing operations program can be called in.   This  gives  the
05900	operator  a  list  of the proposed machining operations and a list of
06000	the stock required, and the estimated time  and  cost.   A  breakdown
06100	gives  the  details,  so  that  the designer can change dimensions or
06200	specifications to reduce costs, or get around difficult or impossible
06300	operations.  Once this iterative operation is completed, the required
06400	setup list and stock list is compared with the shop inventory.     If
06500	they are complete, the machining can begin.
06700		Following  the  computer  generated  sequence  commands   the
06800	machining  operations  are  performed.    The individual machines are
06900	directly controlled by  the  computer  using  position  feedback  and
07000	feedback  from  permanently  mounted  motor  current  and temperature
07100	sensors, force sensors,  etc.   Setting  up  each  machine,  changing
07200	tools,  and  transferring  material  are the mechanical manipulators.
07300	These arms serve the same  purpose  as  the  human  operator  in  the
07400	typical  n.c.   machine shop.  In addition, they provide the computer
07500	with a device for  positioning  measuring  instruments,  checking  on
07600	surface  finishes, and making all the necessary observations that are
07700	required of a human macchine  operator.    This  information  is  fed
07800	directly  back  the computer for updating of the machining sequences.
07900	In this way, the shop need not be a very  precisely  set  up  layout.
08000	Real  machines  setup almost casually can be used in such a situation
08100	where feedback is sufficient.
08300		The task is complete when the finished parts are delivered to
08400	the  output  box,  just  like  line  printer output.   Possibly, even
08500	assembled into  a  complete  assembly,  properly  inspected,  tested,
08600	documented and certified.
08800		Certainly,  the  development  and  execution  of  a complete,
08900	general purpose  system  such  as  has  just  been  described  is  no
09000	overnight  task.    A number of man years effort is involved, both in
09100	the programming and the engineering of such a system.  The  execution
09200	of  such  a  problem  is  beyond  the  cope  of  a  single PhD thesis
09300	dissertation, but a thorough study of the problems  and  approach  to
09400	such  a  project  may  very  well  be a good thesis topic. But, as an
09500	alternative to a paper study of such  a  general  purpose  completely
09600	automatic system, it seems reasonable to attempt the development of a
09700	special purpose automatic shop as  a  more  realistic  initial  goal.
09800	What  follows  are  some  thoughts  on  a  special purpose completely
09900	automated shop.
10100			The automated sheet metal shop.
10300		Prototype sheet metal parts are very  expensive  relative  to
10400	production  quantities.    As an example, it is frequent to find that
10500	the cost of just two of a kind is only 5% more than the  initial  one
10600	piece. Why is this so.  Well, there has never been much automating of
10700	sheetmetal processes, other than  blanking  and  stamping  which  are
10800	restricted  to  large  production  runs.  Other than n.c. punches and
10900	n.c. stops on hand fed shears, there are no  other  really  automatic
11000	machines  used  in  this  field.   It  has  been considered a hard to
11100	automate field, because of the types of machines used and the need to
11200	do  a  lot  of  manipulating  of the material which can frequently be
11300	large floppy sheets, of  varying  thicknesses,  yield  strength,  and
11400	stock dimension.