Control Analysisarpah.staff.ipb.ac.id/files/2010/04/Topik5.pdf · Acceptance sampling plan A plan (usually a table) stating the number of sample units to be included in the sample
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Analysis
Control
Analysis
ControlA. PENDAHULUAN
B. ACCEPTANCE SAMPLING
Pengendalian dan pengawasan mutu untuk mengetahuikesesuaian dengan standar tidak dapat diterapkan pada
semua produk karena jumlah produk sangat banyak
Analysis
Control
Sampling: adalah proses penarikan contohatau unit sampel baik dari suatu lot barang
maupun dari suatu proses produksi.
Pengukuran ktiteria mutu dilakukan hanyaterhadap unit contoh yang ditarik dari lot
atau proses produksi
PenimbanganPengukuran
tebal Analisa lainnya
Analisis dan pengukuran terhadap contohyang ditarik menghasilkan informasi yang digunakan untuk perbandingan denganstandar guna memutuskan status:
penerimaan (accept)
penolakan (reject)
negosiasi (negotiate)
terhadap barang atau proses dari mana
contoh tersebut diperoleh
“Acceptance sampling” adalah prosedur sampling berdasarkan tabel yang memuat ukuran contoh (sample size) dan kriteria penerimaan (acceptance criteria)
Tabel tersebut memuat:
Acceptance quality level
Inspection level
Lot size
Sample size
Acceptance number atau acceptance criteria
Suatu lot barang yang jumlahnya 4801 s/d 24000, harusditarik sampel dari padanya sebanyak 13
Lot ditolak bilamana setelah analisis 13 sampel tersebut, terdapat lebih dari 2 sampel yang tidak sesuai standar mutu
Acceptance sampling planA plan (usually a table) stating the number of sample units to be included in the sample as well as the corresponding acceptance and rejection criteria
LotA collection of units (products) that are offered for examination for determination of compliance during a single work shift and are of the same item description, weight range, date of acceptance, etc.
SampleThe collective number of sample units for the examination of a lot
Sample-size (n)The number of sample units which are to be included in the sample
Sample-unitAn individual item (roast, chop, steak, etc.) or designated quantity of product to be part of a sample
DefectAny nonconformance of any unit of product with specified requirements
Random-samplingA process of selecting a sample from a lot whereby each unit in the lot has an equal chance of selection
•Acceptable Quality Level (AQL)The maximum number of defects per defined quantity that, for the purposes of sampling inspection, can be considered satisfactory as a process average.
Acceptance-number (c)The number in a sampling plan that indicates the maximum number of defects permitted in a sample in order to consider a lot as meeting a specific AQL.
Example 1:
A lot consists of 1200 cases, packed 12 x 2.0 lb primary containers per case. A decision is made to use Inspection Level I with AQL = 6.5, since the goods are not in dispute and there is no history of controversy over quality.
A container is taken to be the sample unit (2.0 lb each sample)Lot Size (N) = 1200 x 12 or 14,400 unitsContainer Size = 2.0 lb
2.0 lb primary container
packed 12 x 2.0 lb per case (secondary
container)
A lot consists of 1200 cases
Example 1:
Sample size (n) = 13Acceptance Number (c) = 2
Hasil Analisa = 2 tidak sesuai standar.
Decision criteria: if there are no more than two (2) “defectives” in a sample size of 13 containers the entire lot (14,400 unit) is considered acceptable.
KESIMPULAN : Accept the Lot
If, however, there are three (3) or more “defectives”in the sample the lot is considered as failing to meet the requirements
A “defective” as used in the sampling plans should be defined very clearly, for example:
“defectives” = non-conformance with standard
SEANDAINYA 3 YANG TIDAK SESUAI STANDAR ?
Jumlah sampel yang ditarik (n=13) dari lot (N=14400),ditarik secara acak
Contoh penarikan contoh acakmenggunakan Excel
N = Nomor 1 s/d 14.400
Example 2:
Acceptance sample plan untuk uji mikrobiologi produk hasillaut seperti:
Θ Fresh and frozen fish
Θ Precooked breaded fish
Θ Frozen raw crustaceans
Θ Frozen cooked crustaceans
Seperti yang direkomendasikan ICMSF (1986).
1075 x 10525Frozen cooked crustaceans
10710635Frozen raw crustaceans
1075 x 10525Precooked breaded fish
1075 x 10535Fresh and frozen fish M4m3
Σ Bacteria/gor / cm2
c2n1Product
Recommended microbiological limits for fish and fish products (ICMSF, 1986).
Maximum recommended bacterial counts for marginally acceptable quality products
=M4
Maximum recommended bacterial counts for good quality products
=m3
Maximum number of acceptable sample units with bacterial counts between m and M
=c2
Number of representative sample units=n1
Dalam pemeriksaan mutu mikrobiologi frozen fish, dilakukan penarikan contoh dari suatu lot produksi. Hasil pemeriksaan laboratorium menunjukkan hasilsbb:
54321
No. Sampel
10E65x 10E5
10E310E6
10E4Jumlah bakteri
Example 2:
Decision criteria berdasarkan Acceptance sampling ICMSF:
n = 5c = 3
m = 5 x 10E5M = 10E7
Pertanyaan:
1. Apakah produk tersebut pass ataukah reject ?
2. Jika produk tersebut pass termasuk kelas mutu apakahproduk tersebut, good quality products ataukah marginally acceptable quality ?
Example 2:
Example 2:
Jawab:
1. Produk tersebut pass atau dapat diterima dan memenuhistandar
2. Produk tersebut termasuk kelas mutu good quality products karena terdapat 3 sampel yang kandunganbakterinya tidak lebih besar dari 5 x 10E5, yaitu sampelno. 1, 2 dan 5
Apabila analisa mikrobiologi memberikan hasil seperti tabelberikut :
Example 3:
54321
No. Sampel
10E65x 10E5
10E710E6
10E4Jumlah bakteri
Maka, produk tersebut pass atau dapat diterima dan memenuhi standarnamun termasuk kelas mutu marginally acceptable quality products karena terdapat 3 sampel yang kandungan bakterinya tidak lebih besardari 10E7 namun lebih besar 5x10E5, yaitu sampel no. 3, 4 dan 5
1. ICMSF, 1986 Recommended microbiological limits for fish and fish products.
2. MIL-STD-1916 : 1 April 19963. MIL-HDBK-1916: 10 February 1999
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