Sheet 3 Charting and diagram Chapter 9

8/18/2019 Sheet 3 Charting and diagram Chapter 9

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Faculty of Engineering

Industrial Engineering Department,3rd year

Sheet 3 Charting and Diagram

1- A foundry uses the following steps in its procedure for high production

of investment casting process: (1) The rst step is to produce waxpatterns by injection molding (!) The wax patterns are transported toan assembly wor" area where they are manually assembled to a waxsprue forming a pattern tree The entire tree is made of wax (#) Thepattern tree is moved to a separate room where the tree is coated witha thin layer of refractory material ($) %n the same room& the tree iscoated with success layers of refractory material to ma"e it a rigidstructure that will become the mold for casting (') The tree is movedto a furnace room& where it is held in an inverted position and heatedto melt the wax out of the mold cavities ith the wax removed& the

rigid structure is now a multiplecavity mold with runners leading toeach cavity from the sprue cavity (*) %n the same furnace room& themold is now heated to a high temperature to ensure that allcontaminants are removed from the mold (+) ith the mold stillheated at an elevated temperature and in an upright orientation&molten metal is poured into the sprue and ,ows through the runners toeach cavity (-) After cooling and solidication of the metal& theassemblage is moved to a nishing room& where the mold is bro"enaway from the cast metal and the parts are separated from the runners

and sprue (a) .evelop the ,ow process chart for this casting process(b) /ased on your ,ow process chart& what are some changes in theinvestment casting procedure that you would recommend0

Solution: (a) low process chart 2o times or distances are included

The application of the ,ow process chart analysis for this problem is

somewhat unusual because the materials being processed change

several times during the se3uence The starting material consists of

wax patterns& which are used to fabricate the mold for the casting

operation inally& the mold is used to produce investment castings of

an unspecied metal


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.ate:

445xx5!444

low 6rocess 7hart6age 888 of

8888

Analyst: 96 Approval: ;ummary of Activities

, %)

?

se3uence 9oves (→& 9) $

.elays (@& .) !

;torages (& ;)

;e

3

Activity description ;ym

bol

Tim

e

.istan

ce

Analysis notes

1 %njection molding of wax

patterns

=

! Allow patterns to cool .# 9ove patterns to assembly

wor" area

9

$ Assemble patterns to spruefor pattern tree

=

' 9ove pattern tree torefractory room

9

* 7oat pattern tree with

refractory material

=

+ 7oat tree with refractory

multiple times

=

- 9ove tree to furnace room 9B %nvert pattern tree and heat

to melt wax

=

1? Ceheat tree to removecontaminants

=

11 6osition mold upright& pour

molten metal

=

1! Allow time for cooling and

solidication

.

1# 9ove tree and casting to 9


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nishing room

1$ /rea" mold and separate

sprue from casting

=

1 7hange the casting process from investment casting to die casting& which is a muchsimpler process consisting of fewer steps unctional re3uirements of the part mayargue against this recommendation

! ;et up all processing steps in one room to eliminate moves between separate rooms

# %n addition to all steps being carried out in one room& could a wor" cell be designed toprovide a more se3uential wor" ,ow between operations

$ here are the inspections0 2o inspection operations are listed among the investmentcasting steps or a rather complex se3uence& inspections should be included to ma"esure that further processing is not performed using defective patterns or molds

2- A supplier of machined components for industrial machinery (eg&power tools& pumps& motors& compressors) operates a factory that

includes a forge shop& machine shop& and nishing department 9anyof the parts produced by the company are fabricated through thesethree departments /ecause of this& the factory is laid out as threelarge s3uare rooms& arranged inline to form a rectangle with an aspectratio of threetoone Dach room is !?? ft by !?? ft The rectangle runsfrom north to south& with the forge shop on the south end and thenishing department on the north end Earge doors are located on thesouth wall for wor" entering the factory and on the north wall fornished products exiting the factory or one part of particular interest

here& the raw material is a steel billet that is purchased from a steelwholesale supplier The billets arrive in pallet loads of 1?? billets at theshipping and receiving department& which is a building that is #' ft by'? ft located !' ft from the south wall door of the factory The shippingand receiving department inspects the parts and sends them by for"lifttruc" to be stored in the companyFs warehouse that is located inanother building '?? ft away from the factory in a southerly direction

The warehouse is !?? ft by !?? ft with its entrance door on the northwall hen a production order for the part is received& a factory for"lifttruc" is dispatched to the warehouse to retrieve the billets The for"lifttruc" must wait while the warehouse crew locates the billets instorage& ta"es a pallet out of storage using the same type of for"lifttruc"& and delivers the pallet to the doc" where it is transferred to thefactory for"lift The pallet is then brought bac" to the factory anddelivered to the forge shop The billets must wait their turn in theproduction schedule before being pressed into the desired shape byone of the forge presses rom the forge shop& the parts are moved tothe machine shop where they are machined on two diGerent machine


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tools& a milling machine and a drill press rom the machine shop& theparts travel to the nishing department for painting and ba"ing (tocure the paint) rom the nishing department& the parts are movedbac" to the machine shop& where additional milling is accomplished toprovide two machined metal surfaces that will mate with othercomponents in the nal product The parts are then moved to theshipping and receiving department for shipment to the customer (aDe!elop the "o# process chart

;olution :

Date: XX/xx/2XXXFlow Process Chart

Page ___ of ____

Analyst: MPG Approval: Summary of Activities

Job: Forged machinery part Part No: Activity (symbols !ount "ime #istances

Material: Steel billet $perations ( ⃝ , $ %

#escription: Steps in processing of steel billets& 'nspections (>, '

$b)ect of study is steel billets& Moves (→* M + +,,- ft

#elays (Ⅾ& #)

Storages ( * S

Se.

&

Activity description Sym " #is Analysis notes

/nloading of pallet load at S01 #ept $

+ 'nspection of billets '

2 Move billets to 3arehouse M -44 ft "ransport by for5lift truc5

6 Move billets into storage at 3arehouse M 44 ft #ifferent for5lift inside 3arehouse

- Storage at 3arehouse* a3aiting order S

(For5lift dispatch from factory to 3arehouse M -44 ft 7illets are not moved yet

(For5lift 3aits at 3arehouse # For5lift 3aiting for billet retrieval

8 Pallet of billets retrieved from storage M 44 ft

% For5lift transports billets bac5 to forge shop M -44 ft


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, 7illets 3aiting to be processed #

9 7illets moved to forge press M 44 ft

4 Forging operation on billets $

"emporary storage after forging #

+ Move forgings to machine shop (milling M +44 ft #ept centertocenter distance

2 "emporary storage before milling # "ypical of batch production

6 Milling operation $

- "emporary storage after milling # "ypical of batch production

8 Move parts to drill press M 44 ft #istance 3ithin machine shop

% "emporary storage before drilling # "ypical of batch production

, #rilling operation $

9 "emporary storage after drilling # "ypical of batch production

+4 Move machined parts to finishing dept M +44 ft #ept centertocenter distance

+ "emporary storage before painting # "ypical of batch production

++ Painting operation $

+2 Move parts directly to ba5ing operation M 84 ft

+6 7a5ing operation to cure paint $

+- "emporary storage after ba5ing # "ypical of batch production

+8 Move parts bac5 to machine shop M +44 ft #ept centertocenter distance+% "emporary storage before milling # "ypical of batch production

+, Milling operations on t3o surfaces $

+9 "emporary storage after milling # "ypical of batch production

24 Move parts to S01 #ept for shipping M 2+- ft 1oute is through forge shop

3- %n igure B+ in the text& which refers to Dxample !1 in 7hapter !&consider the allocation of time between the right hand and left hand inthe activity chart (a) %f the wor"place were redesigned using a wor"

holding xture& and the wor"er were trained to use both handssimultaneously to perform the tas"& construct a righthand5lefthandactivity chart for the revised method& estimating the amounts of timefor each step in the method (b) hat is the percent reduction in cycletime0

1- $riginal case (#or%er use left hand to holding and use the other hand topic%s leg


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2- the #or%place #ere redesigned using a #or% holding &'ture, and the #or%er#ere trained to use oth hands simultaneously to perform the tas%

Solution:


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Left hand Time Right hand Cum. time

Pick up board, put in workholder 0.08 min 0.08 min

0.04 min Close workholder 0.! min

Pick up 4 pegs from tra" 0.0# min Pick up 4 pegs from tra" 0.$ min

%nsert 4 pegs into holes in board 0.0 min %nsert 4 pegs in holes in board 0.!$ min

0.0& min 'pen workholder 0.&0 min

Remo(e board, place in tote pan 0.0$ min 0.&$ min

The cycle time is reduced from ?*! min to ?#+ min& which is a $?H reduction in cycletime

)- The repetitive wor" cycle in a wor"ermachine system consists of thewor" elements and associated times given in the table below As thetable shows& all of the operatorFs elements are external to the machinetime (a) 7onstruct a wor"ermachine activity chart for this wor" cycle(b) 7an some of the wor"erFs elements be made internal to themachine cycle0 %f so& construct a wor"ermachine activity chart for therevised wor" cycle hat is the approximate cycle time for the revisedcycle0

(A)

Se*+ or% element description or%er time achinetime

1 or%er #al%s to tote pan containing ra# stoc% .+13 min+ (idle

2 or%er pic%s up ra# #or%part and transports tomachine

.+23 min+ (idle


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3 or%er loads part into machine and engagesmachine semi-automatic cycle

.+12 min+ (idle

) achine semi-automatic cycle (idle .+/0 min+

0 or%er unloads &nished part from machine .+1. min+ (idle

or%er transports &nished part and depositsinto tote pan

.+10 min+ (idle

otals .+/3 min+ .+/0 min+

(/)

Solution (a or%er-machine acti!ity chart+ his is ased on E'ample 2+1.

in Chapter 2+

)orker Time *achine Time Cum.

time

)alk to tote pan 0.& 0.&

Pick up raw workpart and

transport to machine

0.!& 0.&+

Load workpart and engage

automatic c"cle

0.! 0.48


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*achine c"cle 0.$# .!&

nload finished part from machine 0.0 .&&

Transport part and deposit in totepan

0.# .48

( 4e!ised #or%er-machine acti!ity chart+

)orker Time *achine Time Cum.

time

nload finished part from machine 0.0 0.0

Load raw part, engage auto c"cle 0.! 0.!!

Transport finished part, deposit in

tote pan, walk to raw parts tote

pan, pick up and transport to

machine

0.#*achine c"cle

0.$# 0.-$

Summary he cycle time for the re!ised cycle is .+5/ min, a 306 reduction

from the original cycle time of 1+)7 min+

4elationship Chart


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0- A factory has ve production departments: 9 (milling)& . (drilling)& T(turning)& (grinding)& and (nishing) 6roducts are routed forprocessing through these departments in the 3uantities and se3uences

indicated in the table below (a) /ased on these data& construct thefromto chart (b) .evelop the activity relationship chart for these vedepartments& given that the fromto chart is the only basis for it

8roduc

t

9uantities per

day

Se*uence

1 20 -D-:

2 0 -:-F

3 1. -F

) 0. D--D-:-F

0 20 --F

10 -:

Solution: (a) romto chart and (b) activityrelationship chart To

determine the closeness ratings in (b)& the following divisions were used:

IAJ K number of trips L +'M IDJ K number of trips K '? to +'M I%J K

number of trips K !' to $BM I=J K number of trips K 1 to !$& and INJ K

Oero trips

(a From-to chart ( ;cti!ity-relationship

chart

From<o

D : F D : F

- /0 20 10 - ; I $ =

D 0. - /0 D - = E =

- 0 30 - $ I

: - 00 : - E

F - F -


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- A college oPce building has ve departments: A (accounting oPce)& /(bursarFs oPce)& 7 (credit department)& . (data processing department)&and D (educational support services) 6aper forms are routed forprocessing through these departments in the 3uantities and se3uencesindicated in the table below (a) /ased on these data& construct thefromto chart (b) .evelop the activity relationship chart for these vedepartments& given that the fromto chart is the only basis for it

8rodu

ct

9uantities per

day

Se*uence

1 2. ;->-D

2 13 >-E-;

3 1. E-C

) 3. D-;->-D

0 20 ;-C-E->

17 C->-E-D-;

Solution: (a) romto chart and (b) activityrelationship chart To determine thecloseness ratings in (b)& the following divisions were used: IAJ K number of trips Q '?IDJ K number of trips K #' to $BM I%J K number of trips K !? to #$M I=J K number of

trips K 1 to 1B& and INJ K Oero trips

(a From-to chart ( ;cti!ity-relationship

chart

From<

o

; > C D E ; > C D E

; - 0. 20 ; - ; I E $

> - 0. 31 > - $ ; ;

C 17 - 20 C - = E

D )7 - D - $

E 13 20 1. 17 - E -


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/- A manufacturing plant has six production departments: 9 (milling)& .(drilling)& T (turning)& (grinding)& (nishing)& and A (assembly)6roducts are routed for processing through these departments in the3uantities and se3uences indicated in the table below (a) 7onstruct the

fromto chart for the data (b) .evelop the activity relationship chart forthe six departments& given that the fromto chart is the only basis for it

8rodu

ct

9uantities per

day

Se*uence

1 ). -D-F-;

2 0. -:-F

3 2. -D-F

) . :-F-;

0 /. -D--:-

F

3. --F-;

/ 1. --:

Solution: (a) romto chart and (b) activityrelationship chart To

determine the closeness ratings in (b)& the largest total number of trips

(1-?) was divided by $ to specify divisions The following divisions were

used: IAJ K number of trips K 1#' to 1-?M IDJ K number of trips K B? to

1#$M I%J K number of trips K $' to -BM I=J K number of trips K 1 to $$&

and INJ K Oero trips

From<

o

D : F ; D : F ;

- 11

.

1. /. 3. - ; $ I $ =

D /. - 2. . D - $ = I =

3. - . - I = =

: - 17

.

: - ; =

F - 13

.

F - E

; - ; -

Documents

Sheet 3 Charting and diagram Chapter 9