Cell Clustering

Question 1

cell manufacturing

Answer 1

is the physical division of the manufacturing facilities
into production cells

Question 2

Similarity
Coefficients (𝑺𝒊𝒋)

Answer 2

𝑺𝒊𝒋 = 𝒙𝒊𝒋 / 𝒙𝒊𝒋 + 𝒙𝒋𝒋

number of parts
visiting both machines (𝒙𝒊𝒋)

number of parts
visiting one (𝒙𝒋𝒋)

Question 3

how do you work out which manufacturing processes should be placed together

Answer 3

work out their Similarity
Coefficients then divide into families

Question 4

Sometimes more than one parts family need a key machine

Answer 4

Engineers must decide to either replicate the common machine or share it
between the cells

Question 5

what are the maximum possible number of clusters

Answer 5

(N-1)N / 2

number of parts (N)

Question 6

process layout vs group layout

Answer 6

Process (Functional) layout:
* Arranges equipment and workstations by similar processes or functions.
* Lower initial setup costs but higher operational costs due to inefficiencies, items moving between departments as needed
* Low production volume with high product variability
* e.g., custom machine parts

Group (cellular) layout
* Combines equipment and workstations into groups (or cells) to process a specific family of products
* Higher initial setup costs but lower operational costs once optimized
* Moderate to high production volume of similar products.

Question 7

advantages of manufacturing cells

Answer 7

• reduced material handling
• reduced in-process inventory (waiting for a batch to be done before moving on to next process)
• improved human relations
• simplified layout

Question 8

disadvantages of manufacturing cells

Answer 8

• reduced flexibility (cells are designed for producing specified parts)
• reliance on the whole system (one breakdown causes the whole line to stop)
• operators must be experts in several fields (compared to a single one in process manufacturing)

Question 9

layout design considerations

Answer 9

• part family (use of similar material, tool, etc)
• production volumes (expected demand)
• manning requirements (how many operatives are needed)
• cell layout
• cell control (management of cell operations)

Question 10

performance criteria

Answer 10

• production volume (total no. of parts over time)
• production costs (costs over no. of units)
• on-time delivery (on-time delivered over total delivered)
• first time right (no. of good units over total units)
• revenue per employee ( total revenue over no. of employee)

Question 11

how does FMS differ from normal cell-based systems

Answer 11

*Automation: all elements of FMS are linked, controlled and managed by a central computer
*Complexity: FMS is more complex, integrating machines and software
*Production Volume: FMS handles medium to low volume with high variety, whereas cell-based systems are optimized for high volume and low variety.
*Cost: FMS requires a higher investment
*Efficiency: FMS offers high efficiency with complex scheduling
*Maintenance: FMS has complex maintenance needs