Üretim 8.2-mrp structure
TRANSCRIPT
-
8/2/2019 retim 8.2-MRP Structure
1/44
MRP Structure (Contd)
-
8/2/2019 retim 8.2-MRP Structure
2/44
Example 2 The Firm in Example 1 produces all
items in Product A.
Using Lead times and MPS, weconstruct the Gross MaterialRequirements Planas follows:
-
8/2/2019 retim 8.2-MRP Structure
3/44
Example 2
-
8/2/2019 retim 8.2-MRP Structure
4/44
Example 2 So far we assumed there is no
Inventory on hand.
If there is inventory on handfor aParent item, The requirements for theparent item and all its components will
decrease.
-
8/2/2019 retim 8.2-MRP Structure
5/44
Example 3
Given the
following on-handinventory, Weconstruct a Net
RequirementsPlan:
-
8/2/2019 retim 8.2-MRP Structure
6/44
Example 3 Net Requirements plan includes
following:
1) Gross Requirements, 2) On handinventory, 3) Net requirements, 4)Planned Order Receipt, and 5) Planned
Order Release for each item.
-
8/2/2019 retim 8.2-MRP Structure
7/44
Example 3 We now begin with A and work
backward through the components:
-
8/2/2019 retim 8.2-MRP Structure
8/44
-
8/2/2019 retim 8.2-MRP Structure
9/44
Example 3A: We need 80 units of B at week 7
because we need 40 units of A at this
week, and one unit of A requires 2 unitsof B. Therefore 2 times 40 = 80.
-
8/2/2019 retim 8.2-MRP Structure
10/44
Example 3
-
8/2/2019 retim 8.2-MRP Structure
11/44
Example 3 Scheduled receipts are empty because
it is the products that we get from
Outside. In this example, we assume that we do
not buy any of the parts.
-
8/2/2019 retim 8.2-MRP Structure
12/44
Example 3
-
8/2/2019 retim 8.2-MRP Structure
13/44
Example 3
-
8/2/2019 retim 8.2-MRP Structure
14/44
Example 3
-
8/2/2019 retim 8.2-MRP Structure
15/44
Example 3
-
8/2/2019 retim 8.2-MRP Structure
16/44
Example 3
This example considered only product A.
Normally, there is demand for many
products. Scheduled program of each product
contributes to the Master Schedule ANDultimately to the Net Material RequirementsPlan(which includes all components for allproducts).
-
8/2/2019 retim 8.2-MRP Structure
17/44
Example
Lets combine several products into asingle plan.
Assume that product B is used inmaking products of A and S.
It is also sold directly to the market.
-
8/2/2019 retim 8.2-MRP Structure
18/44
Example
Now we will prepare a GrossRequirements Plan for B,
by combining the master schedules ofA,S, and B
Master schedules for A, S, and B are as
follows:
-
8/2/2019 retim 8.2-MRP Structure
19/44
Example
-
8/2/2019 retim 8.2-MRP Structure
20/44
Example
Now we will combine all three schedules ANDcreate Gross Requirements for B:
At period 1: we sell 10 units of B directly,therefore we should produce 10 units B.
At period 2: we sell 10 units of B directly.Plus, We also need 40 units of B forproducing A at period 6. Because lead timefor A is 4 periods.
-
8/2/2019 retim 8.2-MRP Structure
21/44
Example
At period 3: we need 40 units of Bbecause we will use them to produce 40
units of S at period 9.
Therefore:
Gross Requirements for B is as follows:
-
8/2/2019 retim 8.2-MRP Structure
22/44
Example
Period 1 2 3 4 5 67 8
Gross Req. 10 50 40 50 2045
-
8/2/2019 retim 8.2-MRP Structure
23/44
Example
In this example, we calculated only thegross requirements for B.
However, Remember that:
Net Requirements = (Gross Req.) -[(On hand) + (Scheduled Receipts)]
-
8/2/2019 retim 8.2-MRP Structure
24/44
Example
Therefore, we should also consider theInventory on hand for B AND also
Scheduled Receipts for B (if we buysome of B from other suppliers).
Remember that, Scheduled receipts are
the ones we do not produce and buyfrom Outside.
-
8/2/2019 retim 8.2-MRP Structure
25/44
Example
Scrapped components, Missed receivingdates, and Machine breakdowns
May Cause changes in the MaterialRequirements Plan.
Similarly, changes occur in MRP When
MPS changes.
-
8/2/2019 retim 8.2-MRP Structure
26/44
Example
Computerized programs perform all thecalculations and such changes.
So far we assumed that we produceexactly What we Need. No more or No
less.
-
8/2/2019 retim 8.2-MRP Structure
27/44
Example
The objective in an MRP system is toproduce units only as needed, With no
safety stock AND no anticipation offurther orders.
Such a procedure is consistent with
small lot sizes, frequent orders, lowinventory, and dependent demand.
-
8/2/2019 retim 8.2-MRP Structure
28/44
Example
However, when independent demandexists, A lot sizing technique called
Economic Order Quantity ispreferable.
EOQ technique provides a formula that
averages (or smooths) demand over anextended time horizon.
-
8/2/2019 retim 8.2-MRP Structure
29/44
Example
Now we will compare the traditionalMRP technique (produce as needed)
with EOQ technique in the followingexample:
-
8/2/2019 retim 8.2-MRP Structure
30/44
Example 4
Suppose that for product B, lead time is1 week, and inventory on hand is 35
units. We will first apply the produce as
needed approach. (traditional MRP)
-
8/2/2019 retim 8.2-MRP Structure
31/44
Example 4
-
8/2/2019 retim 8.2-MRP Structure
32/44
Example 4
Now we will apply the EOQ formula:
Economic Order Quantity (Q*) = [(2 D
S) / H]
-
8/2/2019 retim 8.2-MRP Structure
33/44
Example 4
Here, D is annual demand for B = 1404units
S is annual Setup cost = $100
H is annual inventory Holding cost =$52
-
8/2/2019 retim 8.2-MRP Structure
34/44
Example 4
Therefore: Q* = [(2 (1404) (100)) /52] = 73 units per order.
This means that, every time we give aproduction order, it should be 73 units.
In this case, Order releases for product
B will be as follows:
-
8/2/2019 retim 8.2-MRP Structure
35/44
Example 4
-
8/2/2019 retim 8.2-MRP Structure
36/44
Closed-Loop MRP
This implies an MRP system thatprovides Feedback to scheduling from
the Inventory Control System.All new and sophisticated computerized
MRP systems are now closed-loop
systems.
-
8/2/2019 retim 8.2-MRP Structure
37/44
Closed-Loop MRP
A closed-loop MRP system also providesfeedback to the 1) Capacity Plan, 2)
Master Production Schedule, andultimately 3) to the Production Plan.
In the Capacity Planning, For each work
center, Load reports are required.
-
8/2/2019 retim 8.2-MRP Structure
38/44
Closed-Loop MRP
Load reports show the ResourceRequirements (in hours) in a work
center For all work currently assigned tothat work center.
For example, suppose that initial load of
a work center exceeds the capacity ofthat work center (say 150hours/period).
-
8/2/2019 retim 8.2-MRP Structure
39/44
Closed-Loop MRP
Here, closed loop MRP systems allowproduction planners to Move the work
to other periods IN ORDER TO smooththe work load in each period.
-
8/2/2019 retim 8.2-MRP Structure
40/44
Closed-Loop MRP
-
8/2/2019 retim 8.2-MRP Structure
41/44
Closed-Loop MRP
Some tactics for Smoothing the workload are as follows:
1) Sending a lot to two differentmachines for the same operation. Thisis called splitting the lot. This process
involves additional setup for themachines, but results in a shorter time.
-
8/2/2019 retim 8.2-MRP Structure
42/44
Closed-Loop MRP
2) Moving the entire lot to anotherperiod which is near to the current
period. Today, the most sophisticated version
of Material Requirements Planning
(which is called MRP II) has substantialapplications beyond Scheduling andInventory Management.
-
8/2/2019 retim 8.2-MRP Structure
43/44
Closed-Loop MRP
Once a firm has MRP system, Inventorydata can be changed by Labor Hours,
by Material Costs, by Capital Cost, or byany Resource Variable.
When MRP is used in this manner, It is
usually referred as Material RESOURCEPlanning.
-
8/2/2019 retim 8.2-MRP Structure
44/44
Closed-Loop MRP
MRP II computer programs aregenerally tied into other computer
programs. It receives such data as Order Entry,
Inventory, Billing, Purchasing,
Scheduling, Capacity Planning,Accounting, Warehouse Management,etc.