Setup in Micro-Precision Cutting
Setup in cutting refers to the work of fixing the material (called “work”) to the machine tool and preparing it for machining. Fixing the material (clamping), paralleling/originating, tool preparation, NC program creation/editing are the setup work. Setup is the main work performed by the operator in cutting. It is a process that requires skill as a processing craftsman, and the quality of this setup greatly affects the processing accuracy.
6 Steps of Setup in Micro-Precision Cutting
1. Fixing the material
Fix the material to the table. There are several standard fixing methods depending on the shape of the material and the processing content. Since there is parallel work of the material, fix it first temporarily. Please refer to the following for the fixing method.
1-2. How to fix the material
There are several standard ways to secure a workpiece to a machine tool.
This is the easiest way to fix the workpiece directly to the table surface using a general-purpose clamp tool. A space is required to hang the tip of the clamp tool on the top of the work. In addition, the clamp tool may pop out from the top surface of the work, which may interfere with machining.
1-2-2. Precision vise
This is a method of fixing the work with a precision vise for machining.
It is possible to open the upper part of the work. Since it is necessary to attach a precision vise to the table and parallelize it, it is larger than fixing with a clamp tool. The work must be shaped so that it can be pinched by the base of the vise. By processing the base of the vise according to the shape, it can be fixed even if it is not flat to some extent.
1-2-3. Scroll chuck
This is a method of fixing the work using the scroll chuck. Convenient for fixing cylindrical workpieces such as round bars.
1-2-4. Jig plate
This is a fixing method that uses a general-purpose jig plate. Since the circumference of the work can be left open, it is useful when the upper part or side of the work needs to be processed. However, a screw hole for attaching to the jig plate is required on the bottom of the work.
2. Parallel output
Align the orientation of the material with the axial direction of the machine tool. A tool called a test indicator is used to measure the deviation of the side of the material. Adjust the tilt of the material so that the memory of the test indicator is within the allowable range, and repeat the measurement of deviation. After adjusting to the allowable range, fully tighten the clamp to completely fix the material piece to the table.
3. Pointing out the origin
Next, using a tool called a point master, the center position of the material is determined and input to the machine tool with that as the origin. The origin setting by the point master is a typical example among many methods. The point master is a mechanism that lights up the lamp and makes a sound when you touch an object. If you hit the point master from both sides of the material and know each point, the midpoint will be the center of the material. Determine the center position of each of the X and Y directions and use it as the origin position.
4. Installation and length measurement of end mill
Attach the end mill to the spindle. The end mill is usually mounted on the spindle via a milling chuck (or holder). When attaching the end mill to the milling chuck, adjust the amount of protrusion as instructed. If the amount of protrusion is too short, the holder may interfere with the material, and if it is too long, the runout of the end mill will increase during machining and a rough surface (chatter) will occur on the machined surface. After installing the spindle, check the end mill for “runout” by applying a test indicator to the end mill and rotating it. Using a tool called a pre-setter, measure the tip position of the end mill and input it to the machine tool as a reference in the Z direction. The pre-setter is pushed in the height direction, and when the height reaches a fixed height, the memory becomes “0”. In this case, it indicates that the tip of the end mill is located 50 from the table surface. Since the tip of the end mill determines the height direction of machining, it is possible to input the reference position in the Z direction to the machine tool.
5. Creating an NC program
Create an NC program to operate the machine tool. A simple program is created by directly inputting it on the control device of the machine tool. Complex programs are created using applications such as CAM, and data is transferred to the control device for processing.
When everything is ready, press the start switch of the machine tool to perform automatic machining. The machine tool operates according to the instructions of the NC program and performs the prescribed machining. This completes the machining with this tool in this setup. In order to process with another tool and process the other surface, release the fixing once, turn the material over, fix it again, and proceed with the same setup. Changing the direction of the work and performing the setup work again in this way is called “setup change”.