CNC tool setting is a vital aspect of the overall process to produce accurately machined precision-made parts. Not only must CNC tools be set accurately, but this process must be handled quickly and efficiently to facilitate speedy overall manufacturing rates. CNC tool setting involves coordinating the positions of the workbench, tools, and workpieces for maximum accuracy during the machining process. Each piece must maintain an exact precision dimensional relationship with the others, and this requires special CNC tool setting procedures.
CNC tool setting should only be undertaken by trained and experienced CNC machine operators, as there is much to know and accomplish to ensure accuracy. The brief explanations of CNC tool setting below are in no way an exhaustive set of instructions.
1. Trial Cutting and Knife Alignment
This is a simple and very basic method of CNC tool setting that leaves traces of cutting from the knife tool on the workpiece. After adjusting the knife settings in the x and y-axis, install a workpiece and find the center. Initiate a cut into the side of the workpiece at a slow speed, then remove the workpiece and record the x and y coordinate values. You can also install a milling cutter and perform a trial cut to obtain the z-axis coordinate value.
2. Tool Alignment of Feeler Gauge
This CNC tool setting method sets a feeler gauge between the tool and the workpiece but does not rotate the tool, so no traces or markings are left on the workpiece. Remember to subtract the thickness of the feeler gauge when calculating the coordinates. This is not a highly accurate method for measuring tool alignment.
3. CNC Tool Setting Alignment with Edge Finder or Eccentric Bar
A very common and accurate method for CNC tool setting alignment uses an edge finder or an eccentric bar instead of a knife in the trial cutting method. Make sure the steel ball part slightly contacts the workpiece. Choose a workpiece that is a good conductor and ensure the positioning surface is rough for a good reference.
4. Top Knife Setting Method
This method of CNC tool setting is similar to the trial cutting and knife alignment method above, except that it cuts into the top of the workpiece and not the side. Adjust the knife settings in the x and y-axis, install a workpiece and find the center. Initiate a cut into the top of the workpiece at a slow speed, then remove the workpiece and record the x and y coordinate values.
5. Transfer (indirect) Knife Alignment
CNC machining often uses more than a single tool, and the length of the second tool is often inconsistent with the length of the first tool. This makes it necessary to re-zero the original tool plus the additional tool. The indirect zero method is often used to process the zero points for both x and y axes without damaging the machined surface of the workpiece.
6. Tool Alignment with a Special Tool Aligner
Traditional CNC tool setting methods have poor security, take up time, and have significant risks for error, often breaking a steady machining rhythm and slowing productivity. A special tool aligner device makes for a much safer and more efficient toll-setting process, simplifying the work and producing much higher accuracy and overall efficiency.
7. Dial Indicator Tool Setting
This method of CNC tool setting uses a dial indicator mounted on the tool spindle. Move the worktable, so the center line of the spindle is approximately moved to the center of the workpiece, and adjust the magnetic seat. Slowly rotate the spindle by hand, so the contact of the dial indicator rotates along the circumferential surface of the workpiece and observe its track. Then, install a knife in place of the dial indicator and follow the trial cutting method or feeler gauge method to obtain both x and y-axis coordinates.
Accurate Machine Tool Services can help with CNC machine tool setting adjustments and testing, as well as mechanical and electrical repairs and preventive maintenance. Contact us today to learn more.