Simple Solutions That Work! Issue 7

38 The sixth step involves defining the external level of expertise available in your local labor pool. The facts of whether you have an abundance of CNC experienced workers in your area versus robotic experienced workers, or vice-versa, may help guide the direction of your decision on an Automatic Grinding machine solution. Most local foundry labor pools have a greater availability of CNC experience than robotic experience, but you must evaluate your individual area before making this decision. The seventh step is evaluating your current cycle times versus the projected cycle times of the solution, or the desired cycle times. If you want more speed and power, then the CNC could be the solution. If you want to achieve a 100% grind and the speed is not the driving issue, then the robotic solution can be more effective. Either solution will cut your existing cycle times significantly. Step eight is appraising if you want or need the additional productivity offered by a pallet changer. This allows the operator to load/unload while the machine is grinding, instead of stopping the machine between parts to allow an operator to load/unload the machine. The use of a pallet changer provides you the option to run part A while part B is being loaded, or run OP 10 on one side and OP 20 on the other. It also allows you to maximize or balance the productivity of the operator and machine because if you set the program to clean 90-95% of the casting, the operator can be doing some small hand cleaning and inspection of the remaining 5-10% while waiting for the machine that is grinding the next part. The use of a pallet changer allows you to lower cycle times and increase productivity while insuring the operator’s safety and productivity. Step nine would be assessing your grinding area’s need for improved consistency and quality. Do you have issues with over grind and under grind or consistent quality? The use of a laser on the CNC or robotic solution can cure all of this. The laser will identify the casting, make sure it is in the correct position for grinding and it will also modify the grind program based on identifiable casting irregularities. This will guarantee that every casting is ground exactly the same way and insure repeatability. Step ten is to calculate the number of tools necessary to insure a quality grind. What operations do you want to do inside the machine? Do you want to grind only, cut risers and gating, grind the face of a casting, grind small windows, or drill and tap holes? The CNC solution will allow the use of 4 to 6 tools that can perform these functions while the robotic solution can utilize from 2 to 9 tools. The CNC will have a main cutting wheel and a main grinding wheel, a milling cutter and a small horizontal grinding wheel. The larger CNC machine will have a facing wheel and possibly an additional milling cutter or drill. It can also be set up to use a riser conveyor to remove risers and gating from the machine. The robotic solution can also be set up with a variety of tools that can be changed out by the robot inside the cell using a tool magazine. Step eleven is the estimation of the total cost of ownership and the ROI. This is the evaluation of the maintenance costs and durability of the solution, as well as how long it will take to recoup your investment. Can the machine reliability meet the productivity demands of your operation? Is the machine design and construction robust enough to handle the constant forces of power, speed and vibration on a daily basis? Will you achieve the Overall Equipment Effectiveness (OEE)