Mechanical. Engineering UMY

(1)

Material Requirements Planning

(MRP)

UMY

Mechanical

Engineering

(2)

MRP

• Tiga akronim MRP yang berbeda tapi

saling berkaitan, yaitu:

– MRP-I

– Closed-loop MRP

– MRP-II (Manufacturing Resource Planning)

• Ketiganya merupakan tahap

perkembangan MRP

UMY

Mechanical

Engineering

(3)

• MRP-I

: Digunakan untuk menghitung jumlah

• MRP-I

: Digunakan untuk menghitung jumlah

kebutuhan material, tanggal dibutuhkan, dan jadwal

pelaksanaan produksi (planed order release).

• Closed-loop MRP

: Merupakan pengembangan

sistem pengendalian produksi di mana di dalamnya

terdapat proses perencanaan kebutuhan kapasitas

dan umpan balik informasi perkembangan produksi.

• MRP-II → Disebut juga perencanaan sumber bisnis

‘business resource planning’

• Merupakan sistem informasi yang mengintegrasikan

pemasaran, finansial, dan operasi.

• Mengkoordinasikan penjualan dan rencana produksi agar

konsisten dan juga mengkonversikan kebutuhan sumber

daya menjadi kebutuhan finansial.

UMY

Mechanical

Engineering

(4)

Tujuan MRP:

• Merupakan rencana produksi atau rencana

pemesanan

komponen

dan

material

yang

pemesanan

komponen

dan

material

yang

diperlukan

untuk

mendukung

Master

Production

Schedule

(MPS).

Rencana

ini

Production

Schedule

(MPS).

Rencana

ini

meliputi identifikasi produk yang harus dipesan,

identifikasi jumlah dan menjadwalkan saat

dibutuhkan

(order

release)

dan

batas

penyerahan (due date).

• Menentukan

prioritas

berdasarkan

batas

pemesanan dengan berubah-ubahnya sistem.

• Menjadi masukkan perencanaan kebutuhan

kapasitas

untuk

memprediksi

kebutuhan

sumber yang diperlukan untuk mencapai MPS.

UMY

Mechanical

Engineering

(5)

INPUT untuk MRP

Informasi yang menjadi masukkan untuk MRP

yaitu:

• MPS (Master Production Schedule)

• Struktur produk dan BOM (Bill Of Material)

• Informasi lain dari item master file:

– Inventory status / status persediaan

– Lead time / waktu ancang

– Safety Stock/ persediaan cadangan

– Order quantity / jumlah pesanan / ukuran lot

UMY

Mechanical

Engineering

(6)

Karakteristik MRP

Inventory replacement berdasarkan

pada permintaan yang akan datang

Inventory replenishment selambat

mungkin (as late as possible)

Permintaan yang akan datang terhitung

Memerlukan struktur produk

UMY

Mechanical

Engineering

(7)

Karakteristik MRP

Memperhitungkan ketergantungan

antar item

Berhubungan dengan master plan

Lead

time

diketahui

dan

tidak

tergantung pada kapasitas yang

tersedia

UMY

Mechanical

Engineering

(8)

Karakteristik MRP

Sangat cocok untuk kondisi dimana:

Permintaan yang bervariasi dan produk

yang kompleks tetapi bisa diprediksi

(dependent demand)

Penambahan nilai yang tinggi pada

order entry

Memerlukan ketepatan data yang tinggi

Dapat diterapkan dalam perencanaan maintenance

UMY

Mechanical

Engineering

(9)

Struktur Input-output MRP

MPS

Customer

orders

_MPS

Forecast

_demand

MRP

Bill of

materials

Inventory

records

materials

records

Materials

Purchase

Materials

Works

plan

Purchase

orders

Works

orders

UMY

Mechanical

Engineering

(10)

Production Domain

Maintenance Domain

Production Domain

Maintenance Domain

*MRSRP : Man Resources & Spares

Requirements Planning

UMY

Mechanical

Engineering

(11)

Logika MRP

Gross

BOM

Gross

Planned orders

requirement

BOM

Planned orders

replanning

Inventory

Net

Planned order

Lead

Planned order release

Inventory

Net

requirement

Planned order

release

Lead

time

Orders in

_{Planned order}

Order

Batch sizing

Orders in

process

Planned order

receipt

Order

quantity

Batch sizing

method

UMY

Mechanical

Engineering

(12)

MRP Matrix/Grid

Order quantity __________

Safety stock ___________

Low level Code _________

Lead Time _____________

Period

1

2

3

4

5

6

7

8 Gross requirement

Gross requirement

Scheduled Receipts

Projected on Hand

X

Projected on Hand

Net requirements

Planned order receipts

Planned order release

(13)

MRP Grid

Order quantity __________

Lot size/Order quantity - kebutuhan minimum order quantity,

ditentukan oleh tinjauan ekonomis dari proses produksi.

Order quantity __________

Safety stock ___________

Low level Code _________

Safety stock – level terendah dari inventory yang

diperbolehkan dalam garis projected on-hand.

ditentukan oleh tinjauan ekonomis dari proses produksi.

Low level Code _________

Lead Time _____________

diperbolehkan dalam garis projected on-hand.

Lead time - waktu antara pengeluaran order dan penyelesaian

atau pengiriman permintaan.

Period

1

2

3

4

5

6

7

8 Gross requirement

Gross requirement

Scheduled Receipts

Projected on Hand

X

Projected on Hand

Net requirements

Planned order receipts

Planned order release

(14)

Lead Times

• Lead time of a manufactured item consists of:

1. Queue time (menunggu untuk diproses)

2. Running/assembly time (pemprosesan batch)

3. Setup time (penggantian peralatan dari satu item ke

item yang lain)

4. Move time (including waiting to move next operation)

5. Preproduction time (preparation to release order)

• Lead time of a purchased item includes the time

between order release and its retreival.

UMY

Mechanical

Engineering

(15)

Time-Phased Product Structure

Product structure tree

Lead Time

Product structure tree

Lead Time

Time-Phased Product Structure

UMY

Mechanical

Engineering

(16)

Time-Phased Product Structure

D dan E harus sudah selesai

Start production of

D

_{1 week}

D dan E harus sudah selesai

pada titik ini sehingga produksi B

dapat dimulai

D

1 week

B

2 weeks to

produce

A

E

2 weeks

B

3 weeks

2 weeks

E

A

1 week

C

G

2 weeks

3 weeks

F

C

G

D

1 week

1

2

3

4

5

6

7

8 D

1

2

3

4

5

6

7

8 Dengan backward scheduling - item A dijadwalkan dulu, kemudian penjadwalan item

yang lain menyesuaikan sehingga item A dapat diproduksi tepat waktu.

(17)

MRP Grid

GR ( Gross Requirement)

Kebutuhan kotor yang ditentukan atau diperoleh dari MPS

Period

1

2

3

4

5

6

7

8 Gross requirement

Gross requirement

Scheduled Receipts

Projected on Hand

X

Projected on Hand

Net requirements

Planned order receipts

Planned order release

(18)

MRP Grid

SR (Schedule Receipts)

Jadwal penerimaan dimana pemesanan order telah

dilakukan pada tahap perencanaan sebelumnya,

sehingga pada perencanaan yang berjalan hanya atau

tinggal menerima order tsb

Period

1

2

3

4

5

6

7

8 Gross requirement

Gross requirement

Scheduled Receipts

Projected on Hand

X

Projected on Hand

Net requirements

Planned order receipts

Planned order release

(19)

MRP Grid

POH ( Projected on hand)

Banyaknya simpanan atau inventory yang ada pada tahap

awal perencanaan  inventory status

Period

1

2

3

4

5

6

7

8 Gross requirement

Gross requirement

Scheduled Receipts

Projected on Hand

X

Projected on Hand

Net requirements

Planned order receipts

Planned order release

(20)

MRP Grid

N R ( Net Requirement)

Kebutuhan bersih ( kebutuhan sesungguhnya pada

perencanaan tersebut untuk tiap-tiap periode)

NR = GR – SR – POH

Period

1

2

3

4

5

6

7

8 Gross requirement

Gross requirement

Scheduled Receipts

Projected on Hand

X

Projected on Hand

Net requirements

Planned order receipts

Planned order release

(21)

MRP Grid

PO Rec ( Plan Order Receipts)

Rencana kedatangan order pada periode bersangkutan

(yang besarnya ditentukan oleh ukuran lot)

Period

1

2

3

4

5

6

7

8 Gross requirement

Gross requirement

Scheduled Receipts

Projected on Hand

X

Projected on Hand

Net requirements

Planned order receipts

Planned order release

(22)

MRP Grid

POR (Plan Order Release)

Rencana pe-release-an / memulai pembuatan / memulai pesan dari

sesuatu order yg dikaitkan dengan Lead Time-nya) sehingga ketika

dibutuhkan pada suatu periode telah terlaksana

Besarnya PO Rel = PO Rec

Periode PO Rel = Periode PO Rec - LT

Period

1

2

3

4

5

6

7

8 Gross requirement

Gross requirement

Scheduled Receipts

Projected on Hand

X

Projected on Hand

Net requirements

Planned order receipts

Planned order release

(23)

Bill of Materials

Seat cushion

Back slats

Seat-frame

Leg supports

Seat-frame

boards

Front

Back

Leg supports

Front

legs

A

Back

legs

A

Ladder-back

chair

Figure 12.3

chair

(24)

Bill of Materials

A A Ladder Ladder--backback chair chair C (1) Seat D (2) Front B (1) Ladder-back E (4) Leg Seat subassembly Front legs Ladder-back subassembly Leg supports I (1) Seat cushion H (1) Seat frame G (4) Back slats F (2) Back

legs slats frame cushion legs

J (4) Seat-frame

boards

(25)

Master Production Schedul

Master Production Schedule

e

Master Production Schedul

Master Production Schedule

e

(MPS)

April

May

Ladder-back chair

1

2

3

4

5

6

7

8

150

150 Ladder-back chair

Kitchen chair

150

120

150

120

200 Desk chair

200

670

670 Aggregate

production plan

for chair family

670

(26)

Inventory Record

Figure 12.5

Item: C

Description: Seat subassembly

Lot Size: 230 units Lead Time: 2 weeks

Week 1 2 3 4 5 6 7 8 Week Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected on-hand inventory Planned 37 Planned receipts Planned order releases releases

(27)

Inventory Record

Figure 12.5

Item: C

Week 1 2 3 4 5 6 7 8 Week Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected on-hand inventory Planned 37

Gross requirements adalah permintaan total

Planned receipts

Planned order releases

Gross requirements adalah permintaan total

untuk dua jenis kursi.

Projected on-hand inventory pada minggu

ke 1 adalah 37 + 230 – 150

(28)

Inventory Record

Figure 12.5

Item: C

Week 1 2 3 4 5 6 7 8 Week Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 Planned receipts Planned order releases

Gross requirements adalah permintaan total

untuk dua jenis kursi.

Projected on-hand inventory pada minggu 1

releases

Projected on-hand inventory pada minggu 1

(29)

Inventory Record

Figure 12.5

Item: C

Week 1 2 3 4 5 6 7 8 Week Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 Planned receipts Planned order releases Projected on-hand inventory balance pada akhir minggu

Inventory on hand pada akhir minggu Gross requirements pada Scheduled / planned receipts pada

=

+

–

releases pada akhir minggu ke t akhir minggu ke t - 1 pada minggu t pada minggu t

(30)

Inventory Record

Figure 12.5

Item: C

Week 1 2 3 4 5 6 7 8 Week Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 117117 117117 –– 33 –– 33 ––153153 ––273273 ––273273 Planned receipts Planned order releases Projected on-hand inventory balance pada akhir minggu

Inventory on hand pada akhir minggu Gross requirements pada Scheduled / planned receipts pada

=

+

–

releases pada akhir minggu ke t akhir minggu ke t - 1 pada minggu t pada minggu t

(31)

Planned Orders

Figure 12.5

Keterangan:

_{Item: C}

Week

Keterangan:

Tanpa order baru di minggu ke 4,

akan ada kekurangan 3 unit:

1 2 3 4 5 6 7 8

Week

akan ada kekurangan 3 unit:

117 + 0 + 0 – 120 = – 3 units.

Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 117117 117117 ––33 –– 33 ––153153 –– 273273 –– 273273 Planned receipts Planned order releases releases

(32)

Planned Orders

Figure 12.5

Item: C

Week 1 2 3 4 5 6 7 8 Week Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 117117 117117 Planned receipts Planned order releases releases

(33)

Planned Orders

Figure 12.5

Keterangan:

_{Item: C}

Week

Keterangan:

Dengan penambahan planned

receipt akan mengakibatkan

1 2 3 4 5 6 7 8

Week

receipt akan mengakibatkan

kesetimbangan menjadi

117 + 0 +

230

230 – 120 = 227 units.

Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 117117 117117 227227 230 230 Planned receipts Planned order releases 230 230 releases

(34)

Planned Orders

Figure 12.5

Dengan penambahan planned

_{Item: C}

Week

Dengan penambahan planned

receipt akan mengakibatkan

kesetimbangan menjadi

1 2 3 4 5 6 7 8 Week

kesetimbangan menjadi

117 + 0 +

230

230 – 120 = 227 units.

Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 117117 117117 227227 230 230 Planned receipts Planned order releases 230 230 releases

(35)

Planned Orders

Figure 12.6

Mengingat lead time 2 minggu

_{Item: C}

Week

Mengingat lead time 2 minggu

maka planned order release

ditempatkan mundur 2 minggu,

1 2 3 4 5 6 7 8

Week

ditempatkan mundur 2 minggu,

menjadi minggu ke 2.

Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 117117 117117 227227 230 230 Planned receipts Planned order releases 230 230 230 230 releases 230230

(36)

Planned Orders

Figure 12.6

Mengingat lead time 2 minggu

_{Item: C}

Week

Mengingat lead time 2 minggu

maka planned order release

ditempatkan mundur 2 minggu

1 2 3 4 5 6 7 8

Week

ditempatkan mundur 2 minggu

menjadi minggu ke 2.

Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 117117 117117 227227 230 230 Planned receipts Planned order releases 230 230 230 230 releases 230230

(37)

Planned Orders

Figure 12.6

Planned order pertama akan

_{Item: C}

Week

Planned order pertama akan

habis hingga minggu ke 7,

ketika projected inventory turun

1 2 3 4 5 6 7 8

Week

ketika projected inventory turun

menjadi – 43.

Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 117117 117117 227227 230 230 227 227 7777 ––4343 Planned receipts Planned order releases 230 230 230 230 releases 230230

(38)

Planned Orders

Figure 12.6

Dengan penambahan planned

_{Item: C}

Week

Dengan penambahan planned

receipt kedua mengakibatkan

kesetimbangan menjadi

1 2 3 4 5 6 7 8 Week

kesetimbangan menjadi

77 + 0 +

230

230 – 120 = 187.

Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 117117 117117 227227 230 230 227 227 7777 230 230 Planned receipts Planned order releases 230 230 230 230 230 230 releases 230230

(39)

Planned Orders

Figure 12.6

Dengan penambahan planned

_{Item: C}

Week

Dengan penambahan planned

receipt kedua mengakibatkan

kesetimbangan menjadi

1 2 3 4 5 6 7 8 Week

kesetimbangan menjadi

77 + 0 +

230

230 – 120 = 187.

Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 117117 117117 227227 230 230 227 227 7777 230 230 187 187 Planned receipts Planned order releases 230 230 230 230 230 230 releases 230230

(40)

Planned Orders

Figure 12.6

Keterangan:

_{Item: C}

Week

Keterangan:

Planned order release kedua

ditempatkan pada minggu ke 5

1 2 3 4 5 6 7 8

Week

ditempatkan pada minggu ke 5

Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 117117 117117 227227 230 230 227 227 7777 230 230 187 187 Planned receipts Planned order releases 230 230 230 230 230 230 230 230 releases 230230 230230

(41)

Planned Orders

Figure 12.6

Item: C

Week 1 2 3 4 5 6 7 8 Week Gross requirements 150150 00 00 120120 150150 120120 Scheduled 0 0 0 0 230 230 00 00 00 00 00 00 00 Scheduled receipts Projected 117 117 on-hand inventory Planned 37 117117 117117 227227 230 230 227 227 7777 230 230 187 187 187187 Planned receipts Planned order releases 230 230 230 230 230 230 230 230 releases 230230 230230

(42)

• Speaker Kits, Inc., mempunyai produk berupa

speaker kit (merk dagang “Awesome”). Satu kit

“Awesome” (A) terdiri atas:

– 2 standard 12-inch speaker kits (B) dan 3 speaker kit

dengan amp-boosters (C).

– Tiap B terdiri atas 2 12” speaker (D) dan 2 bok karton

yang dilengkapi installation kit (E).

– Tiap amp-boosters speaker kit (C) mempunyai 2

speaker booster (F) dan 2 installation kit (E).

– Tiap speaker booster (F) terdiri atas 2 12” speaker (D),

dan 1 amp-booster (G).

• Bila terdapat permintaan 50 “Awesome” tentukan

MRP nya.

(43)

(44)

• Untuk 50 unit A dibutuhkan:

Part B: 2 x # A = (2)(50) = 100

Part C: 3 x # A = (3)(50) = 150

Part F: 2 x # C = (2)(150) = 300

Part E: 2 x # B + 2 x # C = (2)(100) + (2)(150)

= 500

Part G: 1 x # F = (1)(300) = 300

Part D: 2 x # B + 2 x # F = (2)(100) + (2)(300)

= 800

• Sehingga untuk 50 unit A, diperlukan 100 unit B, 150 unit

(45)

• Bila diketahui lead time untuk tiap komponen adalah

sbb:

(46)

Time-Phased Product Structure untuk “Awesome”

D dan E harus sudah selesai

pada titik ini sehingga produksi B

Time-Phased Product Structure untuk “Awesome”

Start production of

D

1 week

2 weeks to

pada titik ini sehingga produksi B

dapat dimulai

2 weeks

D

1 week

B

2 weeks to

produce

2 weeks

E

A

1 week

E

2 weeks

3 weeks

2 weeks

E

1 week

C

G

2 weeks

3 weeks

F

C

D

1 week

1

2

3

4

5

6

7

8 D

(47)

• Langkah berikutnya adalah membangun gross material requirements

plan dan membuat jadwal produksi untuk memenuhi permintaan 50 unit

A pada minggu ke 8.

(48)

• Bila diketahui on-hand inventory adalah

sebagai berikut

• Maka net requirement plan dan planned

(49)

Item: A

Description: “Awesome”

Lot Size: LFL

Lead Time: 1 weeks

Week 1 2 3 4 5 6 7 8 Week Gross requirements

0

Scheduled

50

0

Scheduled receipts Projected

10

on-hand inventory Planned

10

40

Planned receipts Planned order releases

40

releases

40

(50)

Item: B

Description: Standard speaker kit

Lot Size: LFL

80

Scheduled A Scheduled receipts Projected

15

65

releases

65

(51)

Item: C

Description: Amp-booster speaker kit

Lot Size: LFL

120

Scheduled A Scheduled receipts Projected

20

100

releases

100

(52)

Item: F

Description: Speaker booster

Lot Size: LFL

Week 1 2 3 4 5 6 7 8 Week Gross requirements Scheduled C

200

Scheduled receipts Projected

5

195

releases

195

(53)

Item: E

Description: Karton bok & Installation kit

Lot Size: LFL

Week 1 2 3 4 5 6 7 8 Week Gross requirements Scheduled C

200

130

B Scheduled receipts Projected

10

200

120

200

120

200

releases

120

200

(54)

Item: D

Description: 12” speaker

Lot Size: LFL

Week 1 2 3 4 5 6 7 8 Week Gross requirements Scheduled F

390

130

B Scheduled receipts Projected

10

130

380

130

380

releases

380

130

(55)

Item: G

Description: Amp. booster

Lot Size: LFL

Week 1 2 3 4 5 6 7 8 Week Gross requirements Scheduled

195

F Scheduled receipts Projected on-hand inventory Planned