Kuliah 3 LSiPro – FT Untirta Muhammad Adha Ilhami 3rd Edition 2014 PERENCANAAN AGREGAT Kuliah 3 LSiPro – FT Untirta Muhammad Adha Ilhami 3rd Edition 2014 Muhammad Adha Ilhami

Tujuan Pembelajaran Mahasiswa mampu menggunakan teknik agregasi Mahasiswa mampu menyusun Master Production Schedule (MPS) atau Jadwal Induk Produksi (JIP). Muhammad Adha Ilhami

Pemahaman Dasar Bahwa aggregate plan (AP) merupakan tahap perencanaan awal dimana hasilnya adalah MPS (Top Level Production Plan) dan dilakukan oleh Top Level Business Plan. AP memperhatikan kapasitas dan kapabilitas perusahaan. Analisa AP dilakukan dalam kelompok produk (product family) dengan unit agregat. AP melibatkan pemilihan strategi manufaktur. AP berperan dalam sebagai interface antara perusahaan/sistem manufaktur dan pasar produknya. Muhammad Adha Ilhami

Company Top Level Plan Alur informasi dalam AP. Data (input) dan Hasil (output) AP. Muhammad Adha Ilhami

Planning Horizon Aggregate planning: Perencanaan kapasitas jangka menengah, biasanya dilakukan untuk 2 sampai 12 bulan. AP prinsipnya menyesuaikan kapasitas dan permintaan Short range Intermediate range Long range Now 2 months 1 Year Muhammad Adha Ilhami

Demarkasi Strategic & Tactical Plan Strategic planning is the process of establishing corporate goals and objectives along with the plans to accomplish them. Tactical planning is the process selecting the methods of achieving organizational objectives. Muhammad Adha Ilhami

Pertanyaan Dasar Dengan hasil peramalan yang ada, perusahaan akan menetapkan kapasitas (kemampuan produksi) perusahaan berapa dalam 1 tahun ke depan? Bagaimana konsekuensi terhadap perusahaan? Pilihan penambahan tenaga kerja, mesin, jumlah shift dll? > = < Demand Muhammad Adha Ilhami

Overview of Planning Level Short-range plans (Detailed plans) Machine loading Job assignments Intermediate plans (General levels) or medium-range (aggregate) plans Employment Output Long-range plans Long term capacity Location / layout Product/Process design Muhammad Adha Ilhami

Why Aggregate Plan? Detil lebih sulit diperoleh untuk waktu yang lebih panjang Detil membawa banyak ketidakpastian: agregasi yang dilakukan ditujukan mengurangi variabilitas Permintaan total pakaian lebih sedikit mengandung bias dibandingkan permintaan kaos, celana, dan kemeja. Jika terdapat variabilitas kenapa repot-repot membuat rencana detil, bagaimanapun juga input dapat berubah. Buat rencana yang fleksibel Fleksibilitas dan agregasi biasanya sejalan Muhammad Adha Ilhami

Rencana Agregat Strategi perencanaan dalam tahapan Perencanaan dan Pengendalian Produksi yang bermuara pada perencanaan kapasitas yang optimal. Proses agregasi (aggregation) ialah pengelompokan beberapa jenis item menjadi product family. Proses disagregasi (disaggregation) adalah proses derivasi product family menjadi item. Muhammad Adha Ilhami

Istilah Berkaitan dengan Produk Type: kelompok beberapa product families. Product family: kelompok beberapa items. Item: produk akhir individual yang dibeli (digunakan) oleh konsumen. Biasanya hirarki tersebut dimulai dari product family, karena bila sebuah pabrik membuat lebih dari satu jenis type maka operasi perusahaan itu akan menjadi sangat kompleks. Pengelompokan sejumlah item ke dalam sebuah product family dilakukan dengan teknik Group Technology (GT). Muhammad Adha Ilhami

Satuan Agregat Unit agregat yang biasa digunakan dalam proses agregasi : Jam kerja buruh, mesin atau resource lainnya. Waktu standar. Harga jual, Ongkos produksi. Satuan agregat dummy (pseudo product). Muhammad Adha Ilhami

Aggregate plan units At this level of planning, there is not a lot of detail. Individual end product identity is typically not present. Instead, planning is performed for a composite, or average unit of product in a particular family of similar products. For example, we may plan for units of hair dryers, without regard for whether they are 1500 watt dryers, 1600 watt dryers, 1875 watt dryers, travel dryers, etc. Decisions are typically aggregated into monthly time periods. Weekly or daily detail is not needed at this level of decision making. Those finer time breakdowns will be made at lower levels of decision making still to come. Muhammad Adha Ilhami

Contoh Proses Agregasi IBM memproduksi komputer laptop, desktop, notebook dan mesin teknologi tinggi lainnya. Proses agregasi adalah pengelompokkan jenis – jenis komputer tersebut ke dalam family product (misalnya famili komputer). Sebuah rumah sakit bisa melakukan agregasi jasa yang diberikan menjadi jumlah perawat atau dokter yang dibutuhkan. PT. Telkomsel bisa melakukan agregasi jumlah unit penjualan kartu prabayar (kartu simpati) dan kartu pascabayar (kartu hallo) menjadi jumlah rupiah penjualan yang diterima. Kartu hallo juga terdiri dari beberapa item. Muhammad Adha Ilhami

Prinsip Aggregate Plan Aggregate planning: General plan Combined products = aggregate product Short and long sleeve shirts = shirt Single product Pooled capacities = aggregated capacity Dedicated machine and general machine = machine Single capacity Time periods = time buckets Consider all the demand and production of a given month together Quite a few time buckets When does the demand or production take place in a time bucket? Muhammad Adha Ilhami

Aggregate Plan Input Biaya-biaya Sumber daya Biaya inventori Biaya back order Biaya Hiring/firing Biaya Overtime Biaya subkontrak Sumber daya Tenaga Kerja Fasilitas Ramalan Permintaan Statemen Kebijakan Perusahaan Subkontrak Overtime Tingkat Persediaan Back order Muhammad Adha Ilhami

Aggregate Plan Output Biaya total Perusahaan Projected levels of inventory Inventory Output Employment Subcontracting Backordering Muhammad Adha Ilhami

Strategi Umum AP Proactive Reactive Mixed Mengubah demand menyamai kapasitas. Reactive Mengubah kapasitas menyamai permintaan. Mixed Gabungan proaktif dan reaktif Muhammad Adha Ilhami

NATURE OF THE AGGREGATE PLANNING PROBLEM Units of “Aggregate” Product Time 1 year Demand Forecast Regular (or Normal) Capacity Limit Muhammad Adha Ilhami

AGGREGATE PLANNING STRATEGIES Operations Oriented Marketing Oriented Leveling strategy Chase strategy Shifting demand Counter seasonal products Muhammad Adha Ilhami

Operation Oriented Strategi untuk mengatasi demand yang berfluktuasi dikategorikan sebagai strategi berorientasi operasi atau berorientasi market/pasar. Leveling strategy: Maintain output at a constant (level) rate throughout the planning horizon. Accommodate seasonal variations in demand through the accumulation and depletion of inventories.   Chase strategy: Vary the output rate to match the seasonal variations in demand. Output rate can be varied by (1) hiring and firing workers, (2) utilizing overtime and idle time, or (3) subcontracting. Hybrid strategy: A cost effective aggregate plan may require the use of a combination of the pure strategies listed above. Such a plan is referred to as a hybrid plan. Muhammad Adha Ilhami

Marketing Oriented Strategi/taktik marketing berhubungan dengan demand siklis. Ilustrasi : Biasanya produksi tertentu (tetap) namun jika demand berada di bawah produksi, maka marketing harus diandalkan sehingga demand setara dengan produksi. Muhammad Adha Ilhami

Alur Proses Pengolahan Data – Peramalan – Rencana Agregat Item Family Family Data Data Produk A B C Peramalan Family Perancangan Agregat Disagregasi MPS Agregasi Data Data family A B C Peramalan Family Perancangan Agregat Disagregasi MPS Agregasi Muhammad Adha Ilhami

Contoh Hasil Peramalan Permintaan (Dalam agregat) Month JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Demand Forecast 100 150 250 400 50 90 160 260 390 240 60 Additional Data Hiring cost: $200 per worker hired Firing cost: $100 per worker fired Regular pay: $5000 per worker per month Overtime pay: 1.5 times regular pay Inventory carrying cost: $10 per unit (based on end of month balances) Backorder cost: $20 per unit (based on end of month shortage) Productivity: 10 units per worker per month (this has also been scaled down from what was originally expressed in thousands of units per month) Beginning workforce size: 20 workers (available at the beginning of January) Beginning inventory: 0 units (no inventory available at the beginning of January) Muhammad Adha Ilhami

LEVEL STRATEGY WITH INVENTORY AND BACKORDERS Total annual demand = 2,400 units. Average monthly production needed = 2,400 units/12 months = 200 units per month. Current work force size is 20 workers. This is just enough (because productivity = 10 units per worker per month). Month JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Demand Forecast 100 150 250 400 50 90 160 260 390 240 60 Production 200 Beginning Inv. -100 -150 110 -140 Ending Inv. Carrying Cost 1000 1500 1100 900 Backorder Cost 2000 3000 2800 Regular Labor Cost 100,000 Overtime Cost Total Inventory Carrying Cost: $7,000 Total Backorder Cost: $9,800 Total Hiring Cost Total Firing Cost Total Regular Payroll Cost: $1,200,000 Total Overtime Payroll Cost: Total Annual Cost: $1,216,800 Muhammad Adha Ilhami

LEVEL STRATEGY WITH SUBCONTRACT Total annual demand = 2,400 units. Average monthly production needed = 2,400 units/12 months = 200 units per month. Current work force size is 20 workers. This is just enough (because productivity = 10 units per worker per month). Subcontract fee is $30 per unit. Month JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Demand Forecast 100 150 250 400 50 90 160 260 390 240 60 Production 200 Beginning Inv. 360 300 110 70 Ending Inv. -100 -50 210 Carrying Cost 1000 1500 2600 3600 3000 1100 700 2100 Subcontract Cost Regular Labor Cost 100,000 Overtime Cost Total Inventory Carrying Cost: $18,100 Total Subcontract Cost: $4,500 Total Hiring Cost Total Firing Cost Total Regular Payroll Cost: $1,200,000 Total Overtime Payroll Cost: Total Annual Cost: $1,222,600 Muhammad Adha Ilhami

CHASE STRATEGY WITH HIRING AND FIRING Total annual demand = 2,400 units. Average monthly production needed = 2,400 units/12 months = 200 units per month. Current work force size is 20 workers. This is just enough (because productivity = 10 units per worker per month). Month JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Demand Forecast 100 150 250 400 50 90 160 260 390 240 60 Workers Needed 10 15 25 40 5 9 16 26 39 24 6 Number Hired 4 7 13 Number Fired 20 18 Hiring Cost 1,000 2,000 3,000 800 1,400 2,600 Firing Cost 1,500 1,800 Labor Cost 50,000 75,000 125,000 200,000 25,000 45,000 80,000 130,000 195,000 120,000 30,000 Overtime Cost Total Inventory Carrying Cost: Total Backorder Cost: Total Hiring Cost $12,800 Total Firing Cost $7,800 Total Regular Payroll Cost: $1,200,000 Total Overtime Payroll Cost: Total Annual Cost: $1,220,600 Muhammad Adha Ilhami

CHASE STRATEGY WITH OVERTIME AND IDLE TIME Total annual demand = 2,400 units. Average monthly production needed = 2,400 units/12 months = 200 units per month. Current work force size is 20 workers. This is just enough (because productivity = 10 units per worker per month). Month JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Demand Forecast 100 150 250 400 50 90 160 260 390 240 60 Capacity * 20 Capacity Needed * 10 15 25 40 5 9 16 26 39 24 6 Overtime * 19 4 Idle Time * 11 14 Regular Labor Cost 100,000 Overtime Cost 37,500 150,000 45,000 142,500 30,000 Total Inventory Carrying Cost: Total Backorder Cost: Total Hiring Cost Total Firing Cost Total Regular Payroll Cost: $1,200,000 Total Overtime Payroll Cost: $442,500 Total Annual Cost: $1,642,500 Muhammad Adha Ilhami

Pilih Yang Mana? Apa Konsekwensinya? Total Inventory Carrying Cost: $7,000 Total Backorder Cost: $9,800 Total Hiring Cost Total Firing Cost Total Regular Payroll Cost: $1,200,000 Total Overtime Payroll Cost: Total Annual Cost: $1,216,800 Total Inventory Carrying Cost: Total Backorder Cost: Total Hiring Cost $12,800 Total Firing Cost $7,800 Total Regular Payroll Cost: $1,200,000 Total Overtime Payroll Cost: Total Annual Cost: $1,220,600 Level Inventory & Backorder Chase Fired & Hired Total Inventory Carrying Cost: Total Backorder Cost: Total Hiring Cost Total Firing Cost Total Regular Payroll Cost: $1,200,000 Total Overtime Payroll Cost: $442,500 Total Annual Cost: $1,642,500 Total Inventory Carrying Cost: $7,000 Total Backorder Cost: $14,200 Total Hiring Cost Total Firing Cost Total Regular Payroll Cost: $1,200,000 Total Overtime Payroll Cost: Total Annual Cost: $1,221,200 Chase Overtime & Idletime Level Subcontract Apa Konsekwensinya? Muhammad Adha Ilhami

Linear Programming Keterangan: r : ongkos produksi per unit reg time P : jumlah unit yang diproduksi reg time h : ongkos kenaikan per unit produk At : jumlah unit kenaikan produksi f : ongkos penurunan per unit produk Rt : jumlah unit penurunan produksi v : ongkos produksi per unit overtime Ot : jumlah unit diproduksi overtime c : ongkos inventori per unit Muhammad Adha Ilhami