Optimization of hole-making operations in manufacturing industry plays a vital role. Tool travel and tool switch planning are the two major issues in hole-making operations. Many industrial applications such as moulds, dies, engine block, automotive parts etc. requires machining of large number of holes. Large number of machining operations like drilling, enlargement or tapping/reaming are required to achieve the final size of individual hole, which gives rise to number of possible sequences to complete hole-making operations on the part depending upon the location of hole and tool sequence to be followed. It is necessary to find the optimal sequence of operations which minimizes the total processing cost of hole-making operations. In this work, therefore an attempt is made to reduce the total processing cost of hole-making operations by applying relatively new optimization algorithms known as shuffled frog leaping algorithm and proposed modified shuffled frog leaping algorithm for the determination of optimal sequence of hole-making operations. An industrial application example of ejector plate of injection mould is considered in this work to demonstrate the proposed approach. The obtained results by the shuffled frog leaping algorithm and proposed modified shuffled frog leaping algorithm are compared with each other. It is seen from the obtained results that the results of proposed modified shuffled frog leaping algorithm are superior to those obtained using shuffled frog leaping algorithm. New position of frog Previous position of frog Random number values between 0 to 1 Position of best frog among the memeplexes Position of worst frog among the memeplexes Position of global best frog in search space which best among all frogs. Inertia weight Search acceleration factor with positive values Search acceleration factor with positive values The total holes to be machined in the part are the co-ordinates of point d are the co-ordinates of point e Non-productive tool travel time required for moving tool from the point d to the in rectilinear direction Tool type index in ascending order according to the tool diameters, d=1,…,D Hole index, e=1,…,E f=1,…,E ndex for the last tool to be used on hole e Combined tool and machining costs when tool type d is used on hole e. Cost per unit tool switch time Cost per unit non-productive traveling time he total operations required for hole d., d=1,2,…,D m 1+m 2+…+ m D , the total of operations in the part The tool required for operation e of hole d. The tool travel time for traveling from hole d to hole d’ The time required for switching the tool T d’e’ when tool T de is in spindle 1 if operation e of hole d is machined in position f of operation order, otherwise 0, where 1,2,…,D, e=1,2,…, m i , f=1,2,…, M 1 if T de ≠T d’e’ , otherwise 0 
Tool path planning of hole-making operations in ejector plate of injection mould using modified shuffled frog leaping algorithm