available three excavators a 315DL 320D Japan and 324D Japan
Solution
Maximum bucket capacity for the given three hydraulic excavators are tabulated as under.
Hydraulic Excavator (Type)
Maximum bucket capacity
315DL
1.2 yd3
320D(Japan)
1.6 yd3
324D(Japan)
1.96 yd3
As shown in table above it was found that the maximum rated bucket capacity of the 315DL is the lowest and for 324D is highest among three hydraulic excavators.
In terms of cost the data for the three hydraulic excavator is tabulated as below.
Hydraulic Excavator (Type)
Lease/operational cost
315DL
$150/hr
320D(Japan)
$225/hr
324D(Japan)
$300/hr
From above table it was found that 315DL has low operational cost while 324D has high operational cost.
Condition:
Scooping out 5000 yd3 using maximum rated capacity for each hydraulic excavator.
Assumption:
Each excavator has adequate reach capacity at front and side.
As the work requires to scoop the dirt from the flood control channel the hydraulic excavator requires sufficient net power too. And when comparing the cost of operation it must be on economical side too.
In table below the calculated no. of bucketing operation required is shown,
Hydraulic Excavator (Type)
No. of bucketing operation
315DL
4167
320D(Japan)
3125
324D(Japan)
2551
Operational cost wise 315 DL has low cost and 324D(Japan) has high cost, but the bucket of the 320D(Japan) and 324D(Japan) are more resistive to the moderately abrasive materials like dirt. And the task completion is faster in 320D and 324D when compared to 315DL. Thus it can be concluded that 320D(Japan) has lower operational cost as well as sufficient net power and has adequate maximum range capacity too. Thus 320D(Japan) is suitable for scooping out 5000yd3 at operational cost of $225/hr.
| Hydraulic Excavator (Type) | Maximum bucket capacity | 
| 315DL | 1.2 yd3 | 
| 320D(Japan) | 1.6 yd3 | 
| 324D(Japan) | 1.96 yd3 | 


