Question

CHOCHITO, S.A homemade sweets factory wants to determine the normal time and standard time for packaging and packaging of its variety of products. The following table contains the data about a recent study, regarding the measurement of the elements to be carried out. A measurement is considered incorrect if it has a variability greater than +/- 10%, therefore it must be eliminated from the calculation. Knowing that the company grants its workers 30 minutes for the necessary delay and fatigue:

Work elements    Cycles in minutes R

1. Take a container	1.7	1.8	2.2	1.7	2.3	1.9	2.1	1.8	2.2	1.7	130%
2. Fill the container	4.3	5.7	4.4	5.6	4.6	5.5	4.6	5.4	4.7	5.3	120%
3. Cover the container	3.4	4.6	3.5	4.5	3.6	4.4	3.7	4.3	3.8	4.2	110%
4. Place the label	1.9	2.1	1.8	2.2	1.7	2.3	1.8	2.2	1.7	2.3	120%
5. Place 24 containers per box	2.3	1.8	2.2	1.7	2.3	1.9	2.1	1.8	2.2	1.7	140%
6. Stack the full boxes	7	9	6.8	9.2	6.9	9.1	7.1	8.9	7.2	8.8	120%

Calculate:

a. Normal time and standard time

b. Calculate the number of boxes per worker

Answer 1

Assumptions

Company runs for 8 hours per day (i.e 1 shift per day) excluding Lunch Break

Allowance (TA) offered by company is 30 minutes per shift (Personal allowance (PA) + Fatigue Allowance (FA))

Solution

Let Available Time (AT) = 8 hours per day

Total Allowance (TA) per worker = 30 mins per day

Work Element is denoted by WE

Step 1:

Average Time for WE1 =

  

=

=   

T_WE1 = 1.94 min

Similarly,

T_WE2 = 5.01 min

T_WE3 = 4 min

T_WE4 = 2 min

T_WE5 = 2 min

T_WE6 = 8 min

Step 2:

Elimination of Variability ± 10%

10% of T_WE1 = 0.19

therefore, observations only in the range of 1.94 ± 0.19 (1.7 min to 2.1)

Now TWE1 =

T_WE1 = 1.9 min

repeating the same procedure for other work elements,

the average time turns out to be the following

Take a Container	Fill the Container	Cover the Container	Place the Label	Place 24 Containers per box	Stack the full Boxes
X	X	X	1.9	X	X
1.8	5.7	X	2.1	1.8	X
X	X	X	1.8	2.2	X
X	5.6	X	2.2	X	X
X	X	3.6	X	X	X
X	5.5	4.4	X	1.9	X
2.1	X	3.7	1.8	2.1	X
1.8	5.4	4.3	2.2	1.8	8.9
X	X	3.8	X	2.2	7.2
X	5.3	4.2	X	X	8.8
TWE1 = 1.9 min	TWE2 = 5.5 min	TWE2 = 4 min	TWE2 = 2 min	TWE2 = 2 min	TWE2 = 8.3 min

Nominal Time (NT) = Observed Time (T_WE) X Rating Factor (R) / 100

NT₁ = T_WE1 * 130 / 100

NT₁ = 2.47 min

Similarly

NT₂ = 6.6 min

NT₃ = 4.4 min

NT₄ = 2.4 min

NT₅ = 2.8 min

NT₆ = 9.96 min

Step 3:

Standard Time (ST) Calculation

Standard Time (ST) =

Allowance Factor = Total Allowance time / Total working time

= 30 / (8 * 60)

= 0.0625

ST for container process =

ST = 16.92 min

Standard Time for complete Cntainer process is 16.92 mins

Standard Time for Packing Box is 2.98 mins

STandard Time Stacking the Box is 10.62 mins