Question

help..

Given: Cycle time = 5 min. Number Hand motion/cycle = 200 % Grip Force = 0.3 Posture Factor = 0.9 Miscellaneous Factor= 0.3 11. Calculate the CTD Risk Index. Is it Acceptable? 2. If you can increase productivity by 20% and reduce % Grip Force by 50%, calculate the new CTD Risk Index. Is it Acceptable?

Answer 1

The CTD Risk index is calculated as part of a cumulative trauma disorder risk assessment model for the upper extremities. The variables and score in the CTD Risk Index are derived from physiological, biomechanical, and epidemiological principles.
Have a look at the photo below, for the entire calculation methodology used to calculate CTD Risk Index. The acceptable value of CTD Index is upto 1. Anything above that is not acceptable.

CTD Risk Index Job Title: VCR Counter No Date: Job Description Department Analyst Cyclo me (in minutes obtain from videotape Cycle Day (480 Lanch.Brnaks) Cleme Parts / Day Gif known) Handmations Cycle Handmations / Day (axa) Frequency Factor (Divide by 10.000) Yes (Circle appropriate condition POT Working Posture Stand Hand Posture 1: Puip Pinch No Hand Posture 2: Lateral Pinch No Yes Hand Posture 3: Palm Pinch Yes Hand Posture 4: Finger Press No Hand Posture Power Grip Yes Type of Reach HorizontalU p/Down Up/Down Hand Deviation 1: Flexion Hand Deviation 2: Extension No Yes Hand Deviation 3: Radial Dev. No Yes Hand Deviation 4: Ulnar Dev. Forearm Rotation Neutral In/Out Elbow Angle 90E 90E Shoulder Abduction <45E <90E 90E Shoulder Flexion <90E <180E 1 BUE Back Neck Angle <45E <90E 90E Balance No Total the Points for the Circled Conditions Posture Factor (Dividee by 10) Yes Grip or Pinch Force Used on Task Max Grip or Pinch Force Te i se Divide bye: Force Factor (Divide e by.15) (Circle appropriate condition) Sharp Edge No Yes Yes NO Vibration Dyna Warm Intermittent Static Cold Total The Points for the Circled Conditionsle Miscellaneous Factor (Divide e by 3) - STD Risk Index Frequency. PostureForce Factors .1 x Miscellaneous Factory CTD Risk Index = 3x + +.1x1

The final formula for calculation is as follows:
CTD Risk Index = .3 x (Frequency + Posture + Force Factors) + .1 x (Miscellaneous Factor)

Let's answer the given questions now:

Q1)
Posture and Miscellaneous factors have already been provided in the question. Let's calculate Frequency and Force Factors.

Frequency factor calculation:

• #Cycle/day = 480/5 = 96
  [Please note that, since no break and lunch times have been provided in the question, we have ignored them and not subtracted anything from 480 which is the standard value for number of minutes in a workday]
• #Hand motions/cycle = 200
• #Hand motions/day = 96 x 200 = 19800
• Frequency factor = 19800/10000 = 1.98

Force factor calculation:

• % Grip Force = 0.3
• Force Factor = 0.3/0.15 = 2

We have all the values we need now. Let's calculate the CTD Risk Index.

CTD Risk Index = .3 x (Frequency + Posture + Force Factors) + .1 x (Miscellaneous Factor)
CTD Risk Index = 0.3 (1.98 + 0.9 + 2) + 0.1 x (0.3)
CTD Risk Index = 0.3 (4.88) + 0.03
CTD Risk Index = 1.464 + 0.03
CTD Risk Index = 1.494

The current job produces a CTD risk index of 1.494, which is significantly higher than the acceptable value of 1. Hence, we can say that current CTD Risk Index is Unacceptable.

Q2)
Now, If we increase productivity by 20% and reduce % Grip force by 50%, we need to recalculate frequency and force factors.

New Frequency factor calculation:

• 20% increase in productivity means 20% decrese in cycle time
• New Cycle time = 5 min - 20%* 5 min = 5 min - 1 min = 4 min
• New #Cycle/day = 480/4 = 120
  [Please note that, since no break and lunch times have been provided in the question, we have ignored them and not subtracted anything from 480 which is the standard value for number of minutes in a workday]
• New #Hand motions/cycle = 200
• New #Hand motions/day = 120 x 200 = 24000
• New Frequency factor = 24000/10000 = 2.4

New Force factor calculation:

• There's Reduction in % Grip force by 50%
• New % Grip Force = 0.3/2 = 0.15
• New Force Factor = 0.15/0.15 = 1

We have all the values we need now. Let's calculate the New CTD Risk Index.

New CTD Risk Index = .3 x (Frequency + Posture + Force Factors) + .1 x (Miscellaneous Factor)
New CTD Risk Index = 0.3 (2.4 + 0.9 + 1) + 0.1 x (0.3)
New CTD Risk Index = 0.3 (4.3) + 0.03
New CTD Risk Index = 1.29 + 0.03
New CTD Risk Index = 1.32

Note that the New CTD Risk Index is also well above the acceptable value of 1, hence the new CTD Risk Index is also unacceptable.