Makino has recently introduced the Hyper-i control for the EDBV-series EDM drilling machines. This marks the complete unification of a common control system for all Makino EDM products, and provides new levels of user-friendliness and operator efficiency. The addition of the Hyper-i control for the EDBV-series machines brings enhancements in machining capability for programming, process monitoring, and electrode depth control and electrode management.
As addressed in our last blog entry, there exist two solutions for 3D leveling of workpieces using Makino’s Hyper-i control. Both methods capture and record three data points along the top surface of a workpiece to establish a 3D plane, which is then used to calculate and adjust the U/V axes to be perpendicular with the workpiece conditions. Our first entry on this subject focused on the optional touch probe system method. For part two of this series, we will look at using the dial indicator method.
3D Leveling using a Dial Test Indicator
The ability to perform 3D part leveling is a very attractive time saving function for wire EDM, but the reality is that the full touch probe option is rather expensive.
Makino has developed a new standard setup 3D Plane Find function for the Hyper-i control that is used to skew the U/V axis to be perpendicular to the workpiece conditions using a standard dial test indicator. This function performs in the same manner as with the touch probe option, but uses tools that a shop typically already has at its disposal.
Using a simple dial test indicator,operators can easily capture three points along the top of the workpiece, or four points along the vertical side wall of the workpiece to establish a 3D plane for U/V angle calculation. The operator manually positions the machine to different locations and moves the machine so that the dial indicator is at the same zero point on the dial, and then presses the [Get Position] button to automatically record each location. Once the data points are collected, a [Compute Angle] button is pressed to calculate a new U/V axis location that will be perpendicular to the workpiece condition. This 3D Plane Find function is slower and not as accurate as the more expensive touch probe system, but it provides a very cost-effective means of achieving part alignment using standard shop tools.
There are two solutions for 3D leveling of workpieces on Makino’s Hyper-i control—a standard feature that utilizes a dial indicator, and an optional touch probe system. Both methods capture and record three data points on a workpiece’s top surface to establish a 3D plane. The measurement data is then used to calculate and adjust the U/V axes to be perpendicular with the workpiece conditions.
If the top of the workpiece is contoured and not flat, there are provisions within the setup routines that allow for capturing of four data points to establish a 3D Plane in the XZ or YZ direction using the vertical side wall of a workpiece. This function that utilizes four data points will simultaneously adjust and align U/V for parallelism and also establish an X/Y rotation value. For this blog post, we will focus on the touch probe method.
Touch Probe System
Makino does offer a full 3D probe option that uses a high-accuracy Renishaw MP250 probe. The system provides the ability to establish a 3D plane (leveling of the workpiece in Z-Axis–care of establishing perpendicularity of U/V through three points on the top or side of the workpiece), can be used to measure workpiece feature sizes and alignment locations (center find of holes/squares/rectangles, edge find, corner find, workpiece rotation, etc.), and can also be used for the alignment of rotary C-axis applications.
The system’s design places the probe in the center of the wire path, allowing the probe to reach any location that the machine can reach in operation. The probe system is removed from the machine for operation and utilizes an EROWA ITS chuck for easy clamping and removal of the probe system. There is also a calibration standard that is provided with the system that is used to establish a correlation between the center of the wire and the center of the probe stylus. The 3D probe system is a higher cost option, but the use of the Renishaw MP250 probe interface will provide the highest level of workpiece setup accuracy.
The video below shows the Touch Probe system in action to where it will capture (3) points on the top of the work piece, and (3) points on the one side of the work piece, and (2) point on another side wall. Once complete, the point data is used to automatically establish an origin point on the corner of the work piece along with a work rotation value and 3D leveling.
Q: What are the advantages to using a Spindle Ball and Table Ball for part setup and probing?
A: Using ball-to-ball pick-up methods helps to improve the accuracy of the workpiece and electrode pick-ups. Tooling balls minimize the contact area for touch probing, and minimize the potential for an inaccurate pick-up caused by any debris or burrs between the part and electrode when aligning using the full area of the electrode. Besides pick-up accuracy improvement, the ball-to-ball alignment method also allows the ability for automatic and unattended setups.
A spindle ball tool holder is used in the Z-axis of the machine to establish workpiece size and location data, and a table ball is used for the size and location alignment of the electrode. Both pick-up methods use standard canned pick-up cycles within the control, and the machine establishes an offset and location data between the workpiece and electrode through a correlation measure cycle between the spindle ball and table ball.
The Hyper-i control contains a special ball-to-ball setup cycle located on the [Preparation] screen that is used to measure and establish the offset and correlation between the table ball and spindle ball tooling. The Hyper-i control also collects and records all size and position data that is determined through the measurement pick-up cycles, and this data can be exported from the machine for statistical process tracking purposes.
Achieving consistent side wall surface finishes is an operational need that becomes more critical when machining to finer finishes. Producing consistent vertical side wall surface quality increases in difficulty with deeper cavity depths and/or smaller and thinner electrode details. Due to a hydraulic effect that is created with the di-electric oil during orbiting routines, some electrodes can exhibit flexing or vibration using standard orbiting speeds, which can degrade the final produced surface quality.
There are some process and programming techniques that can be utilized to improve the consistency of the side wall surface finish. Makino machines with the MGH and Hyper-i control system allow for program control of the orbiting speeds using the G132 special settings command.
Using the G132 program line, an input value for Item-D will control the overall machine speed during orbiting. Item-D has a 5-digit number value, and setting this to a 20,000 or 30,000 value will slow the orbiting speed down. This method may increase cycle time slightly, but it will help to ensure proper finishing and will produce a more even and consistent side wall surface finish. Please reference the Machining Techniques manual (Section 5-6) or contact Makino Technical Support at 888-MAKINO4 for more information.