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