standard data system! - Debrina`s Blog as Industrial Engineer

STANDARD DATA SYSTEM!
ANALISA DAN PENGUKURAN KERJA
Debrina Puspita Andriani
e"Mail':'debrina@ub.ac.id'
Blog':'http://debrina.lecture.ub.ac.id'
12
METODE PENGUKURAN
[WAKTU] KERJA
PENGUKURAN)[WAKTU])
KERJA)
DIRECT'
INDIRECT'
STOPWATCH'
STANDARD'
DATA'
WORK'
SAMPLING'
PMTS)
Regression'
Analysis'
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Standard Data
Systems
A'standard'data'system'(SDS)'in'
work'measurement'is'a'database'
of'normal'time'values,'usually'
organized'by'work'elements'that'
can'be'used'to'establish'time'
standards'for'tasks'composed'of'
work'elements'similar'to'those'in'
the'database.''
'
Standard'data'is'a'catalog'(list)'of'
elemental'time'standards'
developed'from'a'database'
collected'over'years'of'motion'and'
time'study.'
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Standard Data System Defined
!  The'normal'time'values'for'the'work'elements'are'usually'compiled'from'
previous'direct'time'studies'(DTS).''
!  Using'a'standard'data'system,'time'standards'can'be'established'before'
the'job'is'running.'
!  When'a'predetermined'motion'time'system'is'used'to'develop'times'for'
a'standard'data'system,'it'is'for'either'of'the'following'purposes:'''
!  to'supplement'the'database'of'direct'time'study'values'because'some'
of'those'data'are'missing,'or''
!  to'develop'the'SDS'database'of'work'element'normal'times'from'the'
basic'motion'element'times'in'the'PMTS.''
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PMTS and SDS Compared
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Why do we need Standard Data?
Reduce)time)required)to)
develop)time)standards)(as)
compared)to)time)study).''
Reduce)cost)of)developing)
time)standards)(due)
primarily)from)reduced)
time)required)to)develop)
the)standards).''
Permit)the)establishment)
of)accurate)time)standards)
before)the)job)is)
performed.'
Time)standards)from)
standard)data)are)more)
consistent.'
Standard)data)time)
standards)are)more)
accurate.'
Simplifies)issues)
associated)with)unions.''
Could)be)used)as)a)check)
for)time)study.'
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Similarity)in)tasks'
Batch)production'
Large)number)of)
standards)to)be)set'
Need)to)set)standards)
before)production'
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When a SDS
is Most
Suitable ?
Developing)a)SDS'
!  A' standard' data' system' is' almost' always' custom"engineered' and'
developed'for'the'facility'that'will'use'the'system.''
!  Because' each' plant’s' products,' production' methods,' and' policies,'
including'its'policy'on'time'standards,'tend'to'be'unique'!'
a' standard' data' system' developed' for' one' company' cannot' be'
readily'migrated'to'another'company.''
!  The' general' steps' in' an' SDS' development' project' are' outlined' in'
Table'15.2.'
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Classification of Work Elements
•  The'database'in'a'standard'data'system'is'organized'by'work'
elements.''
•  The'classification'of'work'elements'in'a'standard'data'system'
must'account'for'differences'between'the'following'element'
types:'
1.  Setup'versus'production'elements'
2.  Constant'versus'variable'elements'
3.  Worker"paced'versus'machine'elements'
4.  Regular'versus'irregular'elements'
5.  Internal'versus'external'elements'
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Setup vs. Production Elements
•  Setup)elements)"'associated'with'activities'required'to'
change'over'from'one'batch'to'the'next'
–  Performed'once'per'batch'
•  Production)elements)"'associated'with'the'processing'of'
work'units'within'a'given'batch'
–  Performed'once'per'work'unit'
•  Batch)time)
'
''
!
!
!
Tb)=)Tsu)+)Q'Tc'
'where'Tb'='batch'time,'Tsu'='setup'time,'Q'='quantity,'and'Tc'='cycle'time'
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Constant vs. Variable Elements
•  Constant)elements)"'same'time'value'in'all'time'studies'and'
tasks'
–  Replace'cutting'tool'in'tool'post'
–  Dial'telephone'number'of'customer'
'
•  Variable)elements)"'same'basic'motion'elements'but'normal'
times'vary'due'to'differences'in'work'units'
–  Load'work'piece'into'machine'
–  Keypunch'address'
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Operator-Paced vs. Machine Elements
•  Operator`paced)elements)"'manual'elements'
–  Can'be'setup'or'production'cycle'elements'
–  Can'be'constant'or'variable'
•  Machine`controlled)elements'"'machine'time'depends'on'
machine'operating'parameters'
–  Once'parameters'are'set,'the'machine'time'can'be'determined'with'
great'accuracy'
–  Characterized'by'little'or'no'random'variations'
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Other Work Element Differences
•  Regular)elements)"'performed'once'every'cycle'
•  Irregular)elements)"'performed'less'frequently'than'once'per'
cycle'
–  Must'be'prorated'in'regular'cycle'
•  External)elements)"'manual'elements'performed'in'series'
with'machine'elements'
•  Internal)elements)"'manual'elements'performed'at'same'
time'machine'is'running'
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than'dividing'the'task'into'work'elements'and'
determining'element'normal)times)
!  When'appropriate:'
!  Work'elements'of'task'are'highly'variable'
!  Elements'are'difficult'to'separate'or'identify'
!  Task'consists'of'many'elements'
!  Many'elements'are'similar'
!  Time'standard'will'not'be'used'for'wage'incentive'
purposes'
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Work Cycle Standard Data
!  A'SDS'that'uses'normal'times'for'the'entire'task'rather'
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1. 
Checkout'of'customers'at'supermarket'counter'
!  Simpler'to'determine'time'per'customer'than'to'break'the'
time'into'elements'
2. 
Prepare'legal'document'for'client'
!  Start'with'standard'document'form'(e.g.,'will)'and'edit'for'
specific'needs'of'client'
3. 
Proofreading'a'document'
!  Time'estimate'based'on'the'number'of'pages'to'proofread'
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Work Cycle Standard Data
!  Examples:'
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Machine-Controlled Elements
•  Examples:'
–  Power'feed'motion'of'a'machine'tool'
•  Once'activated'by'worker,'machine'time'depends'on'feed'and'
speed'settings'and'dimensions'of'work'piece'
–  Semiautomatic'cycle'of'a'machine'
•  Machine'cycle'operates'under'computer'numerical'control'
(CNC)'
–  Fully'automated'cycle'
•  Operator'periodically'attends'machine'
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Machine Times for Machining
•  Machining'"'family'of'processes'in'which'excess'material'
is'removed'from'a'starting'work'piece'by'a'sharp'cutting'
tool'so'the'remaining'part'has'the'desired'geometry'
–  Common'machining'operations:'
•  Turning'
•  Drilling'
•  Milling'
•  Machining'times'can'be'calculated'or'measured'with'
great'accuracy,'given'the'machine'settings'(feeds'and'
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Turning Operation
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Drilling Operation: Through Hole
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Milling Operation: Peripheral Milling
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Peripheral Milling: Approach Distance
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Milling Operation: Face Milling
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Face Milling: Approach and Over Travel
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Calculation of Machining Times
•  Basic'approach'to'calculate'machining'times:'
–  Determine)the)length)of)the)cut)
'
'
'L)=)mm)or)inch)
•  Add'allowances'for'approach'and'over'travel'if'applicable'
–  Divide)by)feed)rate,'which'is'the'travel'speed'of'the'cutting'tool'in'
the'direction'of'the'length'
'
'
'fr'=)mm/min)or)inch/min)
•  Thus,'machining)time))
'
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'
'
'Tm)=)L/fr'
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(a))
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Let’s Try!'
Example
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Example
•  Bila'speed'(v)'='240'm/menit;'maka'putaran'spindle'dapat'
dihitung'dengan'formulasi':'
''
v ×1000 240 ×1000
N=
=
= 1530rpm
'
τ ×D
τ × 50
•  Bilamana'mesin'bubut'diatas'memiiki'maximum!spindle!speed!
1.000'rpm;'maka'putaran'(n)'='1.000'rpm'bisa'diaplikasikan'
untuk'pengerjaan'pembubutan'dan'waktu'pemotongan'dapat'
dihitung'dengan'formulasi'sebagai'berikut'':'
'
L×i
256 ×1
t
=
=
= 0,67 menit
'
s × n 1000 × 0,38
'(i!='frekuensi'pemotongan)'
'
•  Ketidak'telitian'dari'problematika'diatas'bisa'di'sebabkan'
oleh':'
'(a)'Bekurangnya'putaran'spindle'(kecepatan'spindle)'selama'
pemotongan'berlangsung'(bisa'di'check'dengan'“tachometer”)'
'(b)'Variasi'dari'jarak'pahat'ke'benda'kerja'saat'pemotongan'
(distance!approach)'
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!  Associated'costs'savings'
2.  Capability)to)set)standards)before)production)
3.  Avoids)need)for)performance)rating)
!  Controversial'step'in'direct'time'study'
4.  Consistency)in)the)standards)
!  Based'on'averaging'of'much'DTS'data'
5.  Inputs)to)other)information)systems)
SDS Advantages
1.  Increased)productivity)in)setting)standards)
!  Product'cost'estimating,'computer"assisted'
process'planning,'MRP'
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!  Developing'a'SDS'requires'considerable'time'
and'cost'
2.  Source)of)data)
!  Large'file'of'previous'DTS'data'must'exist'
3.  Methods)descriptions)
!  Documentation'still'required'
4.  Risk)of)improper)applications))
SDS Limitations
1.  High)investment)cost)
!  Attempting'to'set'standard'for'tasks'not'
covered'by'SDS'
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“Knowing exactly what you want to do,
and then seeing that they do it
the best and cheapest way.”
F-­ede-­ick W. Ta.lo-­
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