Robotic Application

5.Application Information

For several years robots have been applied to manufacturing tasks. Their usesspan many Industries from aerospace to the foundry. The process of imple-menting robotic technology can be more efTlclent If the results of those applica-tions and research already accomplished arc reviewed.

The capabilities of robots arc limited, and for a successful application, theproper selection of the robot itself is only one of the important applicationingredients. A total system approach should be used. This chapter will addresssome of the additional information that will be useful in designing and imple-menting a robotic system.

CURRENT AREAS OF APPLICATION

The spectrum of robot usage Is very broad. Because of the advances of thestate of the art in robotics and in computer technology, the potential applica-tions arc almost without limit. Six categories of robot applications are identi-fied here.

. P(cfc-and-place-This is the utilization of the robot in moving ob-jects from one place to another and positioning materials in themanufacturing process. Tasks include material handling, grasping.transporting, and heavy-duty handling.

Application [nCormatlon / 75

. Machine loading-In this application, the robot Is combined with

another machine and accomplishes the material loading and toolchanging. Examples are robot loading of numerically controlled mill-ing machines. lathes, and automatic presses.

. Continuous path-This application involves a process in which aprecise rate of motion may be required. Spray painting and welding(see Fig. 5-1) arc common examples. In both, the motion of the robotmust be synchronized with the rate of application or speed of theassociated process.

. Manufacturing processes-A robot for this application Is one that isdedicated to cutting, forming, finishing, or otherwise processingmaterials for manufacture. In industry, robots are being used to drilland rout aluminum sheet metal and graphite composite panels. Thisapplication generally requires extensive tooling design work asdescribed in Chapter 4.

. Assembly-This Is largely still a research area and most of the cur-rent literature la from research programs. A robot for assembly wouldbe designed to mate or fasten parts together Into an assembly. As-sembly applications characteristically require a relatively more artic-ulate robot with high-level sensory feedback and control capabilityand complex tooling and parts feeders. Vision acquisition and forcefeedback system;; that will provide better adaptability arc areas re-ceiving much attention In assembly applications.

* Inspection-These systems appear very similar to assembly systemsin that they may require precise control. A robot for this applicationgenerally will either position material, parts, or the precision mea-suring instrument itself for the purpose of checking some aspect ofthe parts or material. Examples of components used with robots forinspection are television cameras, linear diode arrays, fiber optics.lasers, and photoelectric control modules.

Information for a particular application can be obtained from severalsources. A number of articles describing specific applications have been pub-lished: many of these arc listed in the Bibliography. Additionally, many robotmanufacturers have extensive information on applications for which theirproducts have been or can be applied.

mmtmnmmmmm

_l I

I I I I I I L

K) 20 30 40 SO 60 70 80 90%

Fig. 5-1. Comparison of welding arc time.

76 / Industrial Robotics Handbook

IMPLEMENTATION FACTORS

The question of whether or not to implement robotics technology usuallyarises from a realization of a problem In the flow of production where roboticstechnology offers a possible solution. Other solutions to the situation may beavailable, and a Justification analysis should be performed to determine whichapproach is most desirable with all factors considered. If the analysis Indicatesa robotics solution, everyone who Is to play a major role In the Implementationprocess must be familiarized with the technical approach chosen.

Upper management needs to know what the system can do for the company.These people are the ones who will decide the basic policy toward robotictechnology and who will take most of the risks. Therefore, all data, the advan-tages and the disadvantages, must be presented accurately.

Middle management needs the same Information as upper management,but they need more technical detail. Middle management will be responsible forsetting up the implementation mechanism once the go-ahead Is given, and theymust realize the need for training the engineering staff in their new technology.Clear, deliberate planning is essential to successful robotics implementation.

Others to be Included In preliminary planning are the plant and assistantplant manager and operation and engineering managers. They must be fullyInformed as to how the Implementation will affect them. They must agree totake an active part In the Implementation, or serious problems or more proba-bly failure will occur. Persons in this management group must display an activeInterest. Signing an appropriations request prepared by lower management Isnot necessarily an active interest. At this level of presentation, the abilities andlimitations of robotics must be explicit. Special emphasis should be given tothe Importance of related equipment, because whether the robot or its supportmalfunctions, the robot is usually blamed. TWo areas often neglected in orderto cut costs arc training of support personnel and the procurement of sufficientancillary equipment to support the maintenance of the robot. Neglect In theseareas could easily mean failure. One should be careful about ovcrzcalousncssand the rush to "get that thing Into production." Full and complete productionplanning is absolutely essential; this point cannot be overemphasized.

Production supervision should be included In all planning and engineering.Few people have a more intuitive feel for the actual process In question thanthose who watch and participate in it every day. Effective production super-vision knowledge can save considerable time.

The engineering staff should be fully trained at the manufacturer's facili-ties. Hands-on experience for this group Is highly desirable. The engineersmust know the robot thoroughly in order to design an efficient system aroundit. Much time and money are wasted In false starts and changcovers whendetails concerning capabilities and limitations are overlooked because of ahasty uninformed approach. The training is well worth the time and effort andshould not be neglected.

A successful education phase will create an environment favorable to thesmooth Implementation of this new technology-a group of knowledgeableengineers and technicians backed by enlightened management.

The next step begins the work. A thorough analysis of the area of applicationshould be performed to determine the functional requirements and technical

Application Information / 77

specifications that will determine the form of the robotic system. Some itemsthat should be considered before choosing a robot for the application are toler-ances. work volume, layout, data storage, tooling, environment, and laboratorytesting.

Tolerances

For the Intended application, a careful and thorough study should be madein order to determine whether the positioning ability of the robot is within therequired tolerance. Repeatability Is a critical parameter for programs that, oncetaught, will be run repeatedly for an extended period of time. The maximumallowable error must be determined. The long-term repeatability error of the

robot must be less than this value for successful results. If the tolerances

cannot be held with currently available robots, the difference may be compen-sated for by compliant tooling or active sensory feedback control schemes.These alternatives may be developed by the manufacturer or by the user. Incither case, reducing positioning errors of a robot below lis off-the-shelf capa-bilities costs money. For quick economical implementation, applications thatdo not require the robot system to operate at the limits of Its optimum capabil-ities are best.

When positional accuracy Is a critical factor, a well-defined and precisereference index Is essential. This is especially true when the limits of themanipulator

'

s working range are approached or when off-line programming Isanticipated. Robots generally arc aligned to a reference plane, and most of them

require fastening to a secure base that can be used as the reference. Using aplane or axis on the robot manipulator itself as a reference may be advan-tageous for a more accurate reference Index, not only for the robot but also forthe equipment associated with It. This method will eliminate possible align-ment errors in the robot mounting and will assist In better defining the work-space of the robot.

An accurate automatic indexing procedure may reduce the requirement fora precise alignment of the components In the work station. The accuracy withwhich the position of all components is known, however, will be essential in theplanning of those tasks that approach the limits of the working range of therobot.

Work Volume Selection

The size and shape of the work volume for a particular application areselected through an analysis process In which the application and certainconstraints are considered.

The application, whether pick and place, manufacturing process, assem-bly. or Inspection, will establish basic criteria and a minimum working range.For example, selecting a work volume that will accommodate working in ahorizontal plane or orienting the wrist In a unique position would be applica-tion criteria. Assembling small components is an application that possiblywould require only a small work volume: It also may require a robot with a highdegree of articulation.

Constraints on work volume selection may be found In two areas: Installa-

78 / Indiutrlal Robotics Handbook

tlon environment and in-housc design ability. Economic factors also exist andwill be discussed in later sections.

The first constraint, the area available for robot Installation, may restrictwork volume selection because of the nature of the facility or because ofmanagement-directed limitations. The available area must be able to accommo-date the work volume, associated equipment, parts flow, and maintenance andoperator activities. As the work volume of a manipulator Increases, the numberof things it can collide with also increases. For example, the floor and ceiling ofa normal room arc within the reach of a Unimate robot when It holds an

18-in.-long (45-cm) tool. Arrangement of the work area so that the requiredwork volume is minimized Is advantageous, provided crowding docs not inter-fere with production. The second constraint, management limitations, couldindicate a less-than-favorable attitude toward robotics that should be dealt

with early for project success.The extent or desired depth of tool design for a particular application can be

an Important factor In selecting work volume. Under certain conditions, fix-tures. part positioners, or end effectors may have to be designed quite differ-ently because of the work volume. As previously mentioned, an assembly robotmay require only a small work volume: however, this surely will necessitateextensive tooling designed to supply and transfer parts to-and-from and withinthe work area. Use of a robot with a larger work volume possibly could reducethe tool design task.

As shown, simple quantification does not supply adequate information forwork volume selection. The application and design constraints discussed herearc correlated with the production facility layout in making the final decisionon a robotic system design.

Production Facility LayoutThe selection of an appropriate layout requires consideration of the infor-

mation discussed concerning applications, manipulators, control systems,tooling, and control architecture. There generally arc two opposed schools ofthought related to facility layout: the "In-line*" school and the "centralized**school. A third approach, the "intermediate,** combines features of the other

two.

. /n-L(ne-Proponents of the In-line school maintain that it will bemost cost effective to arrange several relatively simple robots along amore-or-less conventional transfer line and make each robot do a few

simple operations on a part as it comes by. This approach cfTcctlvclyreplaces people on an assembly line with robots, onc-for-onc. Anadvantage of this arrangement is that it can be relatively easy to pullout a malfunctioning robot and replace it temporarily with a person.

. Central Ized-The centralized school of thought recommends a fewcomplex high-performance robots that perform many complex orprecise operations on the same workpiccc. One advantage of thisarrangement is that some duplication of equipment can be avoided;a disadvantage is the inevitable crowding and inaccessibility thatresult from the number of part feeders and transfer lines sur-rounding the robot.


. Intermediate-An intermediate approach is to use the In-line ap-proach to put together kits of parts. Jigs, and perhaps some special-ized tools on general-purpose pallets. A single transfer line wouldthen carry a stream of these kits in and out of a centralized stationwhere a high-performance robot would quickly put the various partstogether and create a subassembly. This would allow the centralizedarm(s) to operate without the obstruction of part feeders and toolholders. and any cameras used would have a clearer view of the workarea.

Data Storage

The amount of data storage required for the application should be consid-ered when choosing a robotic system. The size and number of programs to berun determine the storage requirements. In some installations, the capacity ofthe internal system storage is Insufficient for complete operation. If It Is notfeasible to remedy this with the addition of more storage capacity, then the nextoption Is generally the increased use of data transfers. With this technique, theoperation is divided into parts and transferred sequentially after each part isaccomplished.

Tooling

The tooling requirements arc at least partially determined by the intent ofthe application and the performance capabilities of the robot, e.g., tolerancesor load capability. Some tools can be purchased from the robot manufacturers.while other tool concepts will have to be developed by the user. Since the toolingcan drastically affect the costs, choosing a robot that will allow for the min-imization of tooling costs would be advantageous.

Environment

The robot system must be able to withstand the extremes of the environ-ment in which it will operate. Temperature, vapors, dust, vibration, and elec-tromagnetics all must be taken into account and compared to the limitationsof the robotic system. This requirement also applies to any peripheral systemthe user intends to install with the robot system. Generally, the reliability of theentire system will depend on the reliability of each Individual critical com-ponent. Failure will occur if this aspect is overlooked.

In general, the requirements of the application should be analyzed verythoroughly and compared to available features offered by the various manu-facturers. If the available systems cannot meet these requirements, a system tomeet some of the requirements should be chosen, and the remaining require-ments should be compensated for by manufacturer/user development. Careshould be taken to ensure that those specifications left unsatisfied can becompensated for In an economic manner. The goals are minimum total costand optimum system performance under the existing conditions. A good anal-ysis at this stage will determine the future of the project more than any othersingle factor.


Laboratory Testing

When the robot arrives, establishing a development laboratory situation Isconvenient. The robot should not affect the production operations until it hasbeen developed completely and shown to be reliable. This is best accomplishedin a laboratory situation. A plan should be prepared for the Installation andcheckout of the robot, performance studies, development of compensationschemes, fabrication of peripheral compensation systems, tooling studies andfabrication, system integration, testing and debugging, trials, reports, anddemonstrations. A realistic plan will help to maintain schedules. One mustallow sufficient time to do the work as well as to report and demonstrate lissuccess. This stage is the opportunity to ask for time: plan ahead. Asking forand receiving a loose schedule at the beginning and flnishing early is far betterthan overcommlttlng the project and having to slip the schedule repeatedly. Ifthe robot Is not production ready as initially projected, few people will besympathetic. A pressure situation will develop and will result In hasty andsometimes disastrous decisions that become irreversible.

A production-ready system formed in the laboratory and thoroughly testedIs ready for integration into the factory operations. From this point forward, nofundamental changes In the system should be attempted. Under close super-vision. the robotic system should be dismantled and carefully relocated in thefactory production area. This relocation is another critical milestone In theimplementation process: the robotic system must not be damaged or changedduring the move. After installation on the factory floor, the system must againbe checked out and debugged thoroughly in order to confirm that the systemfunctions exactly as it did before the move. The operating personnel should bechecked out on the system and trained further If necessary. If all checks well.the system is ready for production.

SYSTEMATIC APPROACH TO ROBOT APPLICATIONS

The following steps provide a systematic approach to robot applications.These major action steps will help organize your approach for using industrialrobots.

I. Applications Development

A. Become familiar with basic capabilities and limitations of availablerobots.

B. Make Initial survey of potential applications. Look for tasks that meet

certain criteria:

1. Operation within robot's capabilities.2

. Operation does not require Judgment by robot.3. Operation Justifies use of robot.

C. Initial survey yields list of potential applications: make more detailedstudy.

D. Choose first application.1. Suggestion: for first application, pick simplest Job on list.2

. Study the job: make sure you know everything that must be done.3. Consider any alternatives other than robot.4

. Look at possible advantages of mounting robot In other thanusual fcct-on-thc-floor attitude.

Appllcalion Information / 81

5. Consider reversing the usual bring-the-tool-to-the-work ap-

proach by having the robot carry the work to the tool.6

. Try to anticipate all the things that could go wrong with anythingassociated with the Job.

7. Consider backups for the robot.

8. Consider the environment.

9. Consider equipment relocation and revisions.10. Consider space requirements.11. Consider future requirements.

11. Applications EngineeringA

. Select robot with sufficient reach, speed, memory, program capacity,and load capacity to do the Job. Provide some extra capacity if possi-ble.

B. Consider protection of robot from contamination from environment

(dust, paint, overspray. metal particles, excessive heat. etc.). Intrinsicsafety or explosion proofing may be required.

C. Make layout of installation: determine location, possible inter-ferences. facilities changes required.

D. Determine Interfaces required between robot and other equipment.E. Determine changes required to other equipment.0

. IMPORTANT: Provide adequate interlocks and guards to protect per-sonnel In the area (also, protects robot from material-handling equip-ment or other possible damage).

H. Provide cnd-of-ann tooling: look at various alternative ways of picking

up part.I. If line tracking is required, provide for installation and inter-

connection of suitable feedback device.

J. Provide for backup equipment or plan to protect production when

robot is down.

K. Provide for spare parts and test equipment for maintenance.

III. Implementation ProceduresA

. Do as much preparatory work for installation as possible ahead oftime.

1. Service drops.

2. Floor preparations.3. Interfacing.4. Equipment relocation.5. Equipment revisions.6. Development of end-of-arm tooling.7. Development of guarding.8

. Maintenance of programming training.9. Human relations: prepare personnel for robot.

D. Installation and start-up.

1. Generally, robot manufacturer will provide some assistance.2

. Anticipate some start-up problems. (Programs may have to berefined, tooling adjusted, timing and Interlocks tuned in. etc.)

C. Monitor the operation.1. Keep track of downtime to Identify recurring problems, not only

with robot, but also with external equipment

-


2. Make comparison between estimated and actual costs, savings.and performance for future reference.

3. Continued surveillance of operation may suggest ways to Improveit.

D. Maintenance and service.

1. Develop in-housc programming and maintenance capabilities.a. Train your own people.b. Make sure you cover aU shifts.c. Make sure they have adequate tools, test equipment, and

spare parts to do their Job.d. Provide for regular retraining.

2. If possible and practical, provide a spare machine.3. Give maintenance people total responsiblllly for robot's per-

formance.

IV. SafetyA

. Discussed before, but cover some points again:1

. Keep people away from robot and vice versa, but do not build acage around it. Guard rails 142 in. high (1-m) minimum) aroundarea outside the robot

'

s range (removable section or access toremove robot if required).

2. Emergency stop outside robot's range.

3. Comply with OSHA. local regulations, and company standards.4. TValn maintenance people thoroughly-if possible, use two peo-

ple for maintenance and programming-"Buddy System."5. Do not use barriers to restrict robot movement-one is less likely

to be Injured by a robot knocking a person down than by pinninga person to a steel post.

6. Only reasonable exception to guardrails is "cage" where robotoperates in untended area-then interlock access gate withemergency stop (do not lock the gate) so unauthorized entry willshut the robot down.

CASE STUDIES OF ROBOT APPLICATIONS

The major industrial robot applications, including die casting, investmentcasting, forging. Injection molding, stamping, machine loading, material han-dling, wxlding. finishing, assembly, inspection and other applications arebriefly described in this section. The key characteristics arc divided into de-scription. unique considerations, economics, typical savings, and alternativesfor each application case study.I. Die Casting

A. Description.1

. Common robot application in material forming-15% of totalrobots are in die casting (largest single application after spotwelding).

2. Applications involve unloading (one or two machines), quench(programmable to control distortion), trim or degate. load in-serts, die cleaning (blow off-in programmed pattern) and lubri-cation. and ladling.


D. Unique considerations.

1. Die caster.

a. Interlocks with die cast machine-signal dies open for robotto advance, robot clear with part signals die cast machine tocycle.

b. Sensors adjacent to casting machine to check for complete

casting removal-limit switches or Infrared sensor array-Ifcomplete part If not detected. Inhibit die cast cycle and soundalarm (flashing light).

c. Ejector pins must free casting from cavity without sprue dis-placement parallel to platen face (primarily for trim oper-ations).

d. Cycle count for die lubrication If not done on each cycle.2. Trim press.

a. Sense position of casting in press-may vary due to flash oncasting-Inhibit press if off location and sound alarm (flash-ing light).

b. Automatic ejection of part and blow-off of trim die to remove

flash, chips, etc.c. Automatic lubrication of trim dies.

C. Economics-die casting.I. Eliminate labor cost, including fringes, gloves, rags. etc.2. Reduced scrap (consistent cycle time, less damage from dies and

tie bars)-20%-and reduced remelt cost.3. Eliminate hand degating and handling of gates, storage of parts

and trimmings, material handling.4

. Run through breaks and lunch-more parts per day.5

. Increased production-up to 30%.6

. Better quality on long and flat parts by controlling quench se-quence.

7. Run two machines.

8. Less mold repair-automatic lubrication, constant die tem-

perature (oil-based vs water-based lubricants-smoke vs die life).9, Avoid cost of safety equipment-as much as $20,000/machine.

D. TVpical savings: Payout period 9 months to 2i years (depends onheads, shifts, etc.)

E. Consider alternatives: One scrvo-controllcd robot @ $40,000 for twomachines vs two non-servo robots @$36,000 ($18,000 each) for twomachines.

II. Investment CastingA

. Description.1. Relatively recent application-aircraft parts, outboard motors.

recreational vehicles-alloy steel, stainless steel, aluminum.bronze.

2. Process Involves making wax duplicates of parts (plaster or rub-

ber molds), assembling series of wax patterns around centralsprue to make "tree," coat tree with slurry and sand, dry, melt outwax leaving shell, fire shell to cure and heat, pour metal into thehot shell, break shell from parts. Each shell used only once.


3. Robots are used In making shells to dip trees into slurry, drain.dip in sand (stucco), drain, repeat-usually about six coats.

4. Servo-control required due to program complexity and variety ofparts usually run.

B. Unique considerations.

I. Continuous rotation of roll axis-at various speeds (or specialrotary drive on tooling).

2. Some steps of program timed (spin steps).

3. Interlocks with slurry mixers (oft-on).4

. Interlocks with sand (stucco) bed (turn air off-cn) or waterfall.5. Interlocks with dust collectors on fluldizcd bed.

6. Multiple program storage-may be interfaced with computer for

mass program storage.7

. Automated system Interlocks with conveyor carrying trees dur-ing drying cycles (incoming and outgoing).

C. Investment casting economics.1. Labor savings.2. Uniform shell and better castings-consistent timing, draining.

faster spinning.3. Faster than humans.

4. Can handle heavier trees-e.g., wax cluster with 100 turbine

blades in same time as 50-bladc duster, whereas a human could

not handle a 100-blade tree.

ID. ForgingA

. Description.1. Forging applications may simply involved moving a part from a

furnace to a press, from one press to another, from press to trimdie, from press to draw bench.

2. More complex applications may involve handling a heated barthrough several dies in an impactcr, reorienting and re-positioning the part as required.

B. Unique considerations.1

. Hlgh-tempcrature parts |20O0oF (1094,'C) or morel require spe-cial materials in robot's hands. Insulation and heat shielding.

2. In some instances, the tooling must handle a part whose size or

shape is changed in the process-perhaps while held in thegrlppcr.

3. Roll forming'swaging induces shock loads or ejects the part withconsiderable force, which the tooling must absorb without losingits grip or transmitting the forces back to the manipulator wristand arm.

4. Heavy parts may be involved-up to 300 pounds (136 kg) in somecases.

5. Infrared sensors used to check part temperature-Interlocked tointerrupt robot cycle if part is too cold-robot then puts part inscrap bin.

6. On multiple blow-impactcr applications-robot is interlocked toensure part is positioned properly before machine cycles.

7. When several blows are struck and part is relocated between


blows, It Is Important that part movement be done quickly toavoid part cooling too much. Thus, the robot

's hand is often left

In the press to reduce lost time-tt Is simply moved to a "safeposition

'*

close to the part.8. Robot may also be programmed to lubricate the dies.

C. Forging economics.1. Manpower savings-no relief required.2. Heat.

3. Dirt, smoke.

4. Noise.

5. Safety.6. Hot trim with robot Instead of cold trim improves part quality.7. Higher production, especially on heavy parts where a person re-

quires help (second person and/or hoist).8. Improved product quality:

a. In die forging, due to consistent lubrication:b

. Due to consistent part placement (reduces scrap):c. Due to properly timed operations.

IV. Injection MoldingA. Description.

1. Growing area of application for robots-presently about 3% ofinjection molding applications-should reach 12%.

2. May unload one, two. or even four molding machines.3. Also perform secondary operations-trim (dcflash) and dcgatc.

drill, palletize or pack, assemble.B

. Unique considerations.1. Tooling to handle very large parts, quantities of small parts, del-

icate parts.2

. Interlocks with Injection molding to Initiate robot cycle whenmolds open and to close molds when arm is clear.

3. Photoelectric or limit switch to check that all parts are removed-or interlocks on grlpper/toollng.

4. On multiple machine Installations, random program selectionand multiple programs enable operating with one or more unitsout of services.

C. Justification.

1. Manpower savings.2

. Stable cycle times-especially on more than one unit.3. Faster production on large parts-large machines or on molds

with more than two cavities.

4. Improved quality-no damage, no contamination.

5. Safety-heat, fumes.

6. Secondary operations-trim, palletize, pack.

7. Compliance with OSHA regulations involving dies.

V. Stamping

A. Description.1. One of the earliest applications of robots, along with die

casting-has been more or less dormant, but no-hand-in-dierules will encourage expansion.


2. Major problem Is lack of speed-presses are very fast, humans arc

fast, but arc being slowed down by safety devices-robots are notso fast.

3. On larger parts robots can nearly equal production rate of

many-example: 24-pound (11 kg) parts run at 340 parts/hrabout 10011r less than manual, but consistent pace evens out netproduction (almost).

4. Advantage on batch run parts where common press automation

(for load/unload or dlc-to-dtc transfer) lacks (Icxlblllty-example:bumper line (several presses)-die changes took 4 hr. but auto-mation between presses. had to be removed, reinstalled andadjusted-took day and a half.

B. Unique considerations.1

. Interlocks with press arm:a. First, check to see If arm Is at top center and whether press

cycles once (Indicated part was made).b. Second, deactivate press clutch to prevent cycling.c. After removing part from die. check upon leaving press to

ensure part Is In hand (photocell, limit, or proximity switch).d. Once clear, activate press clutch for next cycle.

2. Dual hands-unload finished part and load green part withoutmoving out of die area-reduces cycle time.

3. If press loading, must feed blanks or green part without movingout of die area-reduces cycle time.

4. Since robots move in an arc. presses arranged in straight linerequire extra articulations-on press-to-press transfer, may beable to relocate presses to match radial movement of robot.

C. Justification.

1. Manpower savings-particularly large parts.2

. Reduced changeover time for different parts as compared withusual press automation.

3. Avoid purchase of safety equipment required with manual pressoperations.

4. Interlocks can be expensive-a recent Installation, for example:two lines of three presses, two robots per line transferring partsfrom press 1 to press 2 and from 2 to 3: third line with twopresses and one robot-five robots In all at about $35,000 each-Interlocks between robots and presses cost about 8100,000-about 45% of total Installation cost.

VI. Machine LoadingA

. Description.1. Anticipated as one of the first applications-only recently be-

coming common.2

. Owing to long process times (actual machining times), efficientonly If robot kept busy with other tasks-such as tending severalmachines.

3. Above often requires relocation of machines-generally requireslarge robots with long reach or access to several machines.



1. Robot-machine interlocks.

2. "Priority**

interrupt or program selection on parallel operations.3. Dual-hand tooling for holding finished part after removal while

loading green part to minimize cycle time.4. Dual-function tooling (such as ID/OD gripper) for handling part

through several serial operations.5. Intermediate (between operation) locators/stands for reor-

ientation of part.6. Machine relocation within robot's reach.

7. Incorporation of blow-off system for chip removal from chucks.spindles, etc.-no operator to do.

8. Ovcrcyde. etc. Detectors (alarm to alert machine tender If some-thing malfunctions).

C. Justification.

1. Manpower savings.2

. Improve work conditions-no cutting oil, chips, smoke, or noise.3. Handle heavy parts.4. Reduce in-proccss handling by arranging machines in "cell.**5. Relocation of machines may be a major expense.

VII. Material HandlingA. Description.

I. One of most common applications-range from very simple tovery involved.

2. Used to advantage in handling heavy or fragile parts, hot or cold

parts.3. Used to palletize and dcpalletlzc, sometimes with sensor-

equipped tooling.4. May Involve moving conveyors with or without tracking.5. May handle several parts at a time.6. May be faster than person, especially if handling several parts at

a time.


1. Part orientation for pickup.2. Interlocks with conveyors.3. Magnetic, vacuum tooling instead of grlppcrs.4. Multipart tooling.5

. Proximity sensors/probes for depalletlzlng.6. Programming for palletizing.7. Not good on random parts or pickup from overhead monorail.

C. Justification.

1. Manpower savings.

2. Elimination of tedious, heavy, hot tasks.3

. Reduction of damage to delicate or fragile parts (powder metalparts, for example).

4. More uniform packing, higher density.5. Avoid need for hoists, mechanical aids. etc.. on heavy parts.6. Faster than people on long reach (no walking).7

. Require part orientation, which may be costly.

88 / InduslrlaJ Robotics Handbook

VUI. WeldingA

. Description.1. Veiy common and extensive application In auto industry (spot

welding).2

. Requires servo control, generally six axes and large memory, loadcapacity, and work envelope.

3. One of few "tool handling" applications where the robot docs notmanipulate the part.

4. Usually Involves multlrobot systems with conveyors, flxturing,etc.

5. Arc welding beginning to develop-using point-to-point robot in"continuous path

"

mode or continuous-path (spray painting) ro-bots.


1. Interfacing to system, weld controller, etc.2. Multiple-program capacity, random access, large number of

steps in programs.3. Generally not as fast as a human, but consistent placement may

permit reduction of number of welds for same net output.4

. Spot weld guns or mounting brackets must be self-destruct.5. Arc welding requires control of wire electrode feed and weld power

as well as torch position.6. Part fit-up and flxturing more critical for robot than for humans

when arc welding.C. Welding.

I. Manpower savings (on multlshift operations).

2. Improved quality (arc welding).

3. Reduction of weld spots due to consistency means less energyconsumption and less ctcctrodc/wcld tip replacement.

4. Requires precise flxturing. indexing, lines or line-tracking capa-bility in robot, which adds to costs.

5. Gets people off undesirable Jobs.6. Can reduce administrative and training costs for replacement of

welders In arc welding operations where labor turnover tends tobe high.

IX. FinishingA

. Descrlptlon/palntlng.1. Finishing applications Include application of paint, stain, por-

celain frit, plastic powder, etc.. with continuous-path robot.2

. Also includes buffing, polishing, grinding with point-to-point orcontinuous-path robot-may hold tool and move to part or holdpart and move to stationary grinder, belt sander. buffer, etc.

B. Unique considerations.1. Often Involves moving lines (OHM conveyors)-robots do not pro-

vide programming while stationary and playback with part mov-ing. Therefore, programming requires some skill and Is bestdone by a good spray person.

2. Robots arc available with Intrinsic safety for operation In ex-plosive atmosphere.


3. Need to protect from fallout and ovcrspray.4. Need to synchronize with moving line.5. Polishing, etc.. requires compliant mounting of tool or gripper.

C. Justification.

1. Spraying:a. Material savings-ovcrspray, trigger control (see Fig. 5-2).b

. Less booth cleanup from reduced ovcrspray.c. Removing people from booth reduces makeup air require-

ments. allows concentration of solvents for recovery or emis-sions control.

d. Safety-electrostatic spraying.c. Quality-consistent film build and coverage.f

. Manpower savings.g. Removes people from undesirable environment.

2. Grinding, etc.:

a. Safety.b

. Quality.

MANUAL AIR SPRAY AUTOMATIC HOT

AIRLESS SPRAY

ROBOT HOT AIRLESS

ELECTROSTATIC SPRAY

3.000.000

2.500,000

2.000,000

1.500.000

1.000.000

500.000

PAINT USAGE

1.350.000

LABOR COSTS

1,000.000

PAINT COSTS1

.010,000

250.000

JL.

PAINT COSTS

370.000

CAPITAL INVESTMENT

200.000

CAPITAL INVESTMENT CAPITAL INVESTMENT5

.000 30,000

Fig. 5-2. Hen-year cost of paint finishing systems.


c. Productivity.d. Manpower savings.

X. AssemblyA

. Description.1. Relatively new area of robot application-although some early

applications In loading assembly machines.2

. Most research In this area related to sensory feedback and adap-tive control to handle get variations, misorlentatlon. etc.

3. Most applicable to medium-volume assembly or batch assembly

of families of parts where programmability and (Icxiblllty can beused to advantage.


1. Part feeders.'orI enters.

2. Quick-change (under program control) or "Universal" end or arm

tooling.3. High-speed, high-accuracy robots required.4. Parts to be assembled must be uniform and defect-free.

5. Sensors development for feedback and software. Development for

case of programming critical and may be costly.6. In most assembly applications, robot cost will be small part of

whole system-part feeders, grippers. orlenters. sensors, pro-gramming, assembly pallets and conveyors, etc., required-inother words, assembly requires more of a systems approach thanmost other robot applications.

C. Justification.

1. Manpower savings.

2. Capita] expenditures (avoid obsolescence).3. Higher productivity-especially in systems with robots and peo-

ple. If robots arc set up to pace operation.4. Better quality-no missing parts, no mlsassembled parts, no

defective parts used (if defects are visible).5

. Can often combine assembly and test or in-process Inspectionwith 100% assurance of test performance (people tend to skipsuch steps since It Is not obvious when not performed).

XI. InspectionA. Description.

1. May involve part handling-into and out of gage or tool/gage

handling.2. New systems use solid-state camera either fixed or mounted on

robot.

3. May involve measuring (metrology) or visual inspection for de-fects.


1. High rcpeatibllity for robot-hold gage so that excessive error is

not introduced, also good flxturing of part.2. Robot must be able to branch to different programs/subroutines

in disposal of parts (i.e.. sorting "good" from "bad").C. Justification.

1. Consistent results-with data recording system, no reading or

recording errors.


2. High productivity-faster than a human.

3. Visual inspection can often be combined with handling (transfer)operation for further savings.

4. Can provide 100% inspection on operations where sampling was

formerly done.5. Avoids cost of expensive custom-made gaging devices.6

. Can inspect moving parts.XII. Other Applications

A. Foundry.1

. Casting shakcout.2. Mold clamping.3. Core handling.4. Snag grinding.

B. Plastics.

1. Handling compression-molded parts and charging molds-

large parts-too big for one person.2

. Unloading large structural foam molding machines.3. Fiberglass layup-spraying chopped glass and resin, rolling out

layup.C

. Powder metallurgy.1. Handling compacted preforms from press.2. Loading and unloading sintering furnaces and forming presses.

10. Socioeconomic Impactof Robotics

A number of socioeconomic Impacts have been identified as noted below:

* Productivity and capital formation. Labor

Unemployment, displacement, or Job shiftingPositive or negative c (Tec is on the quality of the working environment(such as exposure to hazards. Job boredom, and employer/employeerelations)

. Education and trainingNeed for technological specialistsNeed for a technologically literate work forceNeed for retraining workers

. International ImpactsImport/export of robotics technologyContribution to economic competitiveness

. Steps to resolve human relation problems

Bach of these sets of issues is discussed briefly below.

PRODUCTIVITY AND CAPITAL FORMATION

As previously stated, much of the literature on robotics contains referenceto the contribution robotics can be expected to make toward improving Indus-


trial productivity. Since a major concern Is the strengthening of U.S. industry.It Is Important to examine this Issue.

Some experts warn about making simplistic assumptions that exaggeratethe Importance of robotics, by itself. In Improving productivity. Two reasonsarc offered:

1. Robotics is only one part of a wide array of technologies available toautomate manufacturing and to increase industrial productivity.

2. Productivity is a subtle and complex concept with several definitionsand measurements. Furthermore, even after some specific definitionis chosen, industrial productivity depends on many factors that Inter-act with one another. Hence it is difficult to attribute productivityImprovements to any single technology.

These warnings do not suggest that robotics is not an Important productiontechnology. Most experts seem to feel that it Is. However, they state that therearc dangers Inherent in taking an overly narrow definition of the technologywhen assessing impacts on industrial productivity.

While most applications of robots to date have been made by large firms, thefuture diffusion of robotics and related technologies can also affect small busi-nesses in several ways. For example, there are likely to be many new businessopportunities for small firms to develop and produce software and specializedtypes of equipment. Secondly, it can be argued that robotics and flexible auto-mation may in some cases lower the minimum scale for efficient production.and therefore that new manufacturing opportunities could be created for smallbusinesses. Third, the adoption of robotics and related technologies by largefirms may foreclose some manufacturing opportunities for small firms thatcannot afford to invest in new equipment. This situation frequently ariseswhen major equipment technologies change.

Capital formation Is another issue that has been raised. The Importantquestion seems to be whether there is adequate capital for three purposes:

L To fund the modernization of industrial plants for the use of auto-mation technology. The financial need would be particularly great ifit were necessary to rebuild entire plants to make the most effectiveuse of robotics.

2. To fund the construction and expansion of plants to produce robotsin quantities necessary to have a significant economic impact.

3. To fund entrepreneurs who wish to develop new types of robots fornew applications. The importance of the availability of this type ofcapital depends on how Important It is that the technology be pushedforward rapidly.

The lack of capital or high interest rates can reduce the growth of therobotics Industry or the expansion of the use of robots in manufacturing.However, some experts believe that a tax policy that encourages Investment Inrobotic systems would be an important stimulus to overcome currentconstraints.

There is some disagreement about the availability of private capital to fundr&d. Robot manufacturers maintain that they have been Investing largeamounts of money in r&d. Other experts suggested that these expenditures are

Socioeconomic Impact of Robotics / 161

principally aimed at short-term product development and adapting existingproducts to specific tasks.

LABOR

Unemployment is an issue that is constantly raised in discussions about thesocial impact of robots, but one that seems in this context not to be wellunderstood as yet or even to have been widely studied by labor economists inthe United States.

Productivity improvements resulting from the use of robotics and relatedtechnologies can affect labor in a number of ways. These effects depend onfactors such as the following:

. The effects of new technology on the relative proportion of machineryto workers (the capital-labor ratio) in a given industry.

. The extent of change in prices and production volumes for U.S. firms

once the new technology is in use.. The supply of qualified workers with specific Job skills in a givenindustry.

U.S. employment In a given Industry may fall because of productivity im-provements, which, by definition, enable fewer workers to produce a givenvolume of product. U.S. employment In a given industry may remain constantor rise, however, if productivity improvements are combined with Increases inproduction volume. EfTcctivc labor compensation may rise or fall If productivityimprovements lead to shorter work weeks or new product prices or both de-pending in large part on production volume and profitability. Finally, averagewage levels will change with changes in the necessary mix of worker skillsresulting from the implementation of robotics and related technologies.

Definitions of unemployment, like those of productivity, require dis-tinctions between short-term and persistent Job loss, or between true un-employment (Job loss) and displacement (Job shift).

For some time, most experts In the United States have argued that more Jobsare created by new technology than arc eliminated. However. If these Jobs arein different industries and/or require different skills, the effect on an individualwho has been replaced by automation can be traumatic.

Production and servicing of robots and related technologies will create newjobs. The number of Jobs created and the rate at which they appear will dependboth on the growth rate of the robot industry and on the degree to which robotmanufacture and repair are themselves automated.

Additionally, the effects of modem microelectronics will be to lower cost.Improve performance, and widen the availability of automation technologysubstantially. Negative Impact on employment that. In the past, has been smallenough to be insignificant or undetectable may be much larger in the future.

To assess the effects of automation on future employment levels, a baselinemust be established against which Job loss or gain can be measured. Thisbaseline could be a simple extrapolation of current trends. But it may also needto be adjusted to reflect two other effects:

. Virtual employment-domestic Jobs that were not explicitly eliminated.

but that would have existed were robots not Installed.


. Virtual unemployment-domestic Jobs that would have been lost if theplant had not responded to domestic and international competition byautomating.

As is the case with productivity. It Is difficult to attribute employment effectsto any single component of an entire range of improvements in the manu-facturing process, in this case robotics. Any examination of the effects of robotson jobs would need to consider, at least in part, a much broader context ofautomation technology.

There seems to be two principal sets of questions concerning unemploy-ment. These questions are different in their focus, in their implication, and inthe data collection necessary to analyze them:

L Will the United States experience a long-term rise in the real un-employment rate due to the Introduction of robotics and other auto-mation? If so, will these effects be differentially severe by geographicallocation, social class, education level, race. sex. or other character-

istics? What might be the employment penalty of not automating?2

. Will the use of robots create displacement effects over the nextdecade? In what ways will these effects be specific to particular indus-try classes, geographic locations, or types of Jobs? How will they affectlabor/management negotiations?

Quality of working environment is another Issue that has been addressed.If robots are employed principally forjobs that are unpleasant or dangerous andif the new Jobs created by robotics arc better, the quality of workllfe will Im-prove. Productivity Increases may also, in the longer term, result in a shorter.more flexibly scheduled work week.

New forms of computer-based automation may in many cases relieve jobboredom and resulting worker dissatisfaction that many management expertshave been concerned with. Workers may be able to make use of more-complexskills and perform a greater variety of tasks. For Instance, they may be able tofollow the assembly of a product from beginning to end and assume greaterIndividual responsibility for the quality of the result.

The human working environment can also be Improved by segregating pro-cesses that create hazardous working conditions (such as heat or exposure tochemicals) from the section of the factory occupied by humans and staffingthem with robots. Furthermore, equipping a worker with a robot helper forstrenuous activities not only eases Job stress but also opens up employmentopportunities to those who have physical handicaps or other limitations.

Whether these benefits are realized depends. In part, on the particular waysin which Industry uses the technology. Many labor experts are concerned thatsome uses of robots will produce effects on the working environment that willnot be so salutary. For example, some argue that one long-term effect of robot-ics may be to "desklU" labor, requiring less ability on the part of humans as theyarc incorporated into a mechanized environment.

Some labor experts and others have also expressed concern that automationprovides Increased opportunities for employer surveillance of employees. Someunions also fear that automation could be used by employers to

"

downgrade"Jobs that require working with automated systems, or that robots might betargeted to replace unionized Jobs first.

Socioeconomic Impact of Robotics / 163

EDUCATION AND TRAINING

A number of education and training issues are raised by robotics. In robotInstallation, programming, and maintenance.

There Is a shortage of trained technical experts In the field of robotics. Ifthere Is to be any significant expansion In the pace of automation Includingrobotics, many more computer scientists, engineers, software programmers.and technicians will be needed in the next decade.

A shortage already exists in many fields of engineering and science. It seemsto be particularly critical in areas of computer software design and program-ming. Hence, the issue is not unique to robotics technology, at least In the caseof very highly skilled Jobs.

At the same time, the use of robots has already created some new technicalJobs. A few programs have been started at the community college level to trainworkers in robot installation, programming, and maintenance.

There is a need for a more technologically literate work force, one that hasa basic understanding of technology and mathematics. Improved technologicalliteracy would provide the following benefits:

1. To the extent that workers would be expected to instruct, oversee theprotection of, or repair robot units, they would need some basic un-derstanding of computers and systems, both mechanical and elec-trical.

2. A technologically literate work force would be less likely to resist theIntroduction of robots and other automation technology.

3. A knowledgeable, technologically skilled worker would be easier toretrain for some other Job. somewhere else In the plant.

One reason the Japanese work force seems to welcome robots In their plantsIs the high level of technological literacy reported for the average Japaneseemployee. This characteristic, accordingly, would give employers greater lati-tude In finding another and possibly even more skilled job for a displacedworker.

If the introduction of robotics Into a plant Is not to result In unemployment.a program of retraining displaced workers to take on new Jobs may be neces-sary. Retraining also may be required for those workers who remain, for theirexisting Jobs will change in form and function even If their Job titles remain thesame.

INTERNATIONAL IMPACTS

Concern about economic competition In robotic technology from Europeand Japan Is not uncommon for U.S. robot manufacturers. Large investmentsabroad both for research and development and for encouraging the use ofrobots Is increasing. This potential competition exists on two levels: (1) devel-oping and selling robotics technology Itself and (2) using robots to producegoods more competitively (for example, automobiles).

Some experts feci that the directions of robotics-related research are signifi-cantly different between the United States and other nations, notably Japan.U.S. researchers emphasize software and highly flexible systems, while manyInternational laboratories are concentrating on hardware. Some experts main-

164 / Induslrtol Robotics Handbook

tain that the International state of the art In robotics Is superior to that In theUnited States. "Technological leads" are hard. In general, to either prove ordisprove. However, there is a general feeling that the utilization of robots ismore advanced in several nations (possibly including the Soviet Union) com-pared to the United States.

The Issue of international competition creates conflicts in import/exportpolicy. Controls might be placed on exports of industrial robots either fornational security reasons or to limit foreign access to domestic high technologythat increases the competitiveness of U.S. firms. However, such controls alsodeny U.S. robot manufacturers access to foreign markets. Even if the totalinternational market in robots per se were to remain relatively small, robottechnology would be a vital component in the much larger international marketfor sales of complete automated factories.

STEPS TO RESOLVE HUMAN RELATIONS PROBLEMS

In order to help reduce the human relation aspects of Industrial robots Intoday's plants, several generic steps have been summarized to reduce the socio-economic impact of introducing robots.Individual Responsible for Robot Applications is Responsible Not Only for

Engineering and Technical Aspects. Training and Support, but also for Hu-man Relations Necessary for Success

These Human Relations Apply on Several Levels and Are DlfTercnt for EachLevel such as Upper Management, Middle Management. Production Manage-ment. etc.

Upper ManagementA. Characteristics

1. Not knowledgeable (usually).2. Mistrustful of gimmicky approaches.3. Interested In results, not details.

4. Economics oriented.

B. Approach1. Explain robots In terms of capabilities and advantages.2. Not "leading edge." but technology-proven, reliable.3

. Explain "What" In general terms and "Why" and explore pros and cons ofalternatives.

4. Show potential economic gains or other strong Justification.5. Provide feedback (good or bad).

Middle ManagementA. Characteristics

I. May not want to take risks.2. Not knowledgeable (usually).3

. Concerned with day-to-day problems.4. May want to solve the unsolvable problem with robots (grasping at

straws).B. Approach

1. Get upper management support and middle management will take the

risks.

Socioeconomic Impact or Robotics / 165

2. Provide technical Information on robots-In detail If necessary-get

manufacturers to show films, etc.

3. Show how robots can solve problems, but be careful not to be pushed intoimpossible application (good excuse is to start with easier Job first togain experience and confidence).

Production ManagementA. Characteristics

1. Skeptical, hostile.2

. Generally not knowledgeable.3. Do not like disruption of routines.4

. Concerned with output and problems.5. Impulsive and impatient.

B. Approach

1. Keep the salesmen away. Develop enough In-house expertise to approachintelligently-usually there are some "old hands" In the plant whom theyrespect, to get them on your side (not being deceptive. Just practical).

2. Try to show a plan that minimizes disruption.3. Approach from problem-solution basis rather than pure economics.4. Be sure plans include adequate practical backup.5. Do not be bulldozed Into speeding up installation, start-up. etc.-this

will backfire for sure.

Production SupervisionA

. Characteristics

1. Caught in middle between work force and management.2

. Not technically oriented.3. Overworked, harried.

B. Approach

1. Talk about solutions to people problems.2. Be sure they understand backup plans.3. Assure that maintenance can cope.4. Explain capabilities and advantages.5

. Ask for suggestions on where robots could help them.6

. Keep them informed of status, progress, etc.Englneertng and MaintenanceA

. Characteristics

1. Have enough problems now, do not need more.2. Generally short-handed and underskllled.

B. Approach1

. Assure them that their people will be trained and that tools and spareswill be provided. Also, manufacturer has service people available ifneeded.

2. Try to get budget relief for added maintenance burden.Hourly Skilled TradesA. Characteristics

I. May be unable to handle new technology.2. Do not want any more work,

B. Approach1

. Provide training-in basics if required, as well as specifics.


2. Provide tools, manuals, spares, etc.. to support.

3. Let them know that manufacturer's service people are available to help if

necessary (they generally won'

t call for help unless desperate, but like toknow they aren't alone).

4. Appeal to pride-they will be the "Elite" of the trades staff.Hourly WorkersA

. Characteristics

1. Concerned over possible loss of Jobs.2. Suspicious, antagonistic.

B. Approach1. Do not lay off-find other Jobs for displaced workers-not demeaning

Jobs, cither.2. Offer training to upgrade skills.3. Do not keep them In the dark-let them know that robots arc coming.4

. Stress that robots will do the undesirable Jobs.5

. Ask for suggestions-use their detailed knowledge In planning applica-tions. especially regarding randomly occurring problems.

Documents

Robotic Application