Production Activity Control

Question 1

PAC

Answer 1

production activity control

Question 2

Production Activity Control in the MPC System

Answer 2

Shop-floor Scheduling and Control (SFC)

Vendor Scheduling and Follow-Up

Question 3

Production activity control (PAC) defined

Answer 3

Production activity control (PAC) concerns the execution of material plans.
PAC includes shop-floor scheduling and control (SFC). Many firms also assign vendor scheduling and follow-up to PAC. Order release is becoming more a part of PAC.

Question 4

Linkage between MRP/CRP and PAC

Answer 4

MRP/CRP TO PAC is maaterial and capacity plans

PAC TO MRP/CRP IS Status information: Completions of operations, order closeout
Warning signals: Inadequacies in material and capacity plans

Question 5

Shop-Floor Scheduling and Control (SFC) Activities DEFINED AS

Answer 5

Schedule start and completion dates for each work order (or shop order) at each work center

Ensure the required materials, tools, personnel, and information are available when needed

Monitor and control the progress of work orders

Report work center efficiency, operation times, scrap, and so on

Question 6

SFC Data Requirements

Answer 6

Item master
Item number/description, lead time, lot size

Bill of materials
Product structure

Work center master
Work center number, number of shifts per week, number of machine/labor hours per shift

Routing

Question 7

Routing

Answer 7

Routing data for each part are essential inputs

Lead times for each operation typically consist of four elements

Question 8

Routing data for each part are essential inputs

QUESTIONS

Answer 8

What operations are performed to make the part
Which work center will perform each operation
How long each operation will take

Question 9

Lead times for each operation typically consist of four elements

Answer 9

Queue time (time spent waiting to be processed)
Setup time (time to prepare the work center)
Run time (operation time per piece × lot size)
Move time (delay waiting to be moved plus time spent moving to the next work center)

Question 10

Production Activity Control Technique

Answer 10

Operation setback chart
Gantt chart
Priority sequencing rules

Question 11

Priority Sequencing Rules

Answer 11

Sequencing: Determining the order of job processing at a work center

Priority sequencing rules (or priority rules) are simple heuristics used to select the order in which jobs will be processed

Commonly used priority sequencing rules
Earliest due date 
Shortest processing time
Order slack 
Slack per operation
Critical ratio

Question 12

Priority Sequencing Rules

Earliest part due date:

Answer 12

Schedule the job with the earliest due date of the part first

Question 13

Priority Sequencing Rules

Earliest operation due date:

Answer 13

Schedule the job with the earliest due date of the current operation first

Question 14

Priority Sequencing Rules

Shortest processing time (or shortest operation next):

Answer 14

Schedule the job with the shortest processing time first

Question 15

Order slack:

Answer 15

Schedule the job with the least order slack first
Order slack = Time until the part due date – Total processing time remaining

Total processing time remaining is the sum of the setup times and run times of all remaining operations

Question 16

Slack per operation:

Answer 16

Divide the order slack by the number of remaining operations, and then schedule the job with smallest value first

Question 17

Critical ratio:

Answer 17

Schedule the job with the lowest critical ratio first

Critical ratio = “Time until the part due date” /”Lead time remaining “

Lead time remaining includes all elements of manufacturing lead time (queue, setup, run, and move times) for all operations that have not been completed

Sometimes total processing time remaining is used instead of lead time remaining