Facilities Design

Alvin Adi K (2509100056)Rama P. Renspandy (2509100060)Andi Reza R (2509100063)Ikhsan Salman (2509100079)Arif Z. W (2509100147)

CRAFT(COMPUTERIZED RELATIVE ALLOCATION OF FACILITIES TECHNIQUE)

Definition

Computerized Relative Allocation of Facilities Technique (CRAFT) is a tool that used to help improve the existing layout of the facilities. The facility is improved by swaping two or more departments to help arrange the facility to an optimal floor plan.

Inputs of CRAFT

• From-To Chart

• Cost Matrix

• Distance (Determined)

• Initial Layout

When will CRAFT be used?

CRAFT is used when the number of departments is enormous that the manual computation would be nearly impossible to do.

CRAFT is basically used with process layout approach, which also known as a functional layout that usually used in job shops or a batch production facility.

What does the CRAFT do?

CRAFT do uses a pair wise exchange algorithm that maynot return the optimal result because the final solutiondepends on the initial layout of the plant.

Rather than examine all the possible swaps, CRAFTconsiders the swap of only adjacent department pairor pairs that have the same area.

Steps of using CRAFT :

Basic step of CRAFT has been modified a number of

times, but we use COFAD (Tompkins and Reed, 1976) as

a reference, a four step algorithm, tackles the selection of

MHS and layout. These are the following steps:

1. Determines an initial layout.

2. Selects an MHS for the layout obtained in the first step

from a candidate list of equipment.

3. Calculates and revise the cost of each move based on

material handling equipment to each move. (These three

first step is repeated until a satisfactory solution obtained)

To get a good-quality final solution, the user must

provide different starting solution, evaluate the final solution

obtained by CRAFT for each of these and choose the best

one.

Example of CRAFT :

This software (add-ins in

Ms. Excel) needs several

inputs to be defined, such as

layout information, facility

information, department

information, flow matrix, and

transportation cost. The

input (in Ms. Excel) will be

like:

Cont’

Cont’

The next step will be generate the end layout, by clicking

the ‘define facility’ button.

Cont’

By clicking the ‘define facility’ button, the software will

generate you the final solution layout :

Cont’

Then, based on final

solution layout, the last part

is evaluated the final

solution for each of these

and choose the best one.

The output file generated

layout itself can be

classified into 3 parts:

Cont’

This part will give the detail information, such as area required, area

defined, x-centroid, y-centroid, and the sequence. What method that

used, how the assumption of the layout, the measure of the department

distance also mentioned at the upper part.

Cont’

Six buttons can be utilized to enhance the visual layout,

for instance, pressing the solve button will give the visual

layout how the end solution visual layout look like :

Cont’

The last part explain how many iteration used and how

much do it cost to make the layout :

Advantages of CRAFT :

1. The fact that the calculation is done by computer –

sophisticated calculating machine – is clearly

advantages that save a lot both time and money in the

process.

2. It gives us rooms to define the variable and constraints

that we have out here in the real world.

3. Flexibility can be seen as there are 6 buttons that can be

utilized to generate series of different end solution (in

figure 1.4)

Disadvantages of CRAFT :

1. Inefficient

2. Jobs time occured

Jobs do not flow through in an orderly fashion, therefore

backtracking occurs often. Idle time, more idle time may be

experienced while workers are waiting for more work to arrive

from different departments.

3. The (not) end result.

End result may need to be modified, because once CRAFT

has determined a solution it may need to be managed to

create a layout that fits in the plant.

4. Greedy algorithm.

It is the algorithm that always takes the best immediate

solution. In contrary, a job shop that flow through the system

is not always constant and causes fluctuations in the process.

THANK YOU