What is a Tool Frame?
The robot is a collection of axes that each have a specific range of motion and distance from one another. The processor calculates the position of the robot’s Tool Center Point (TCP) by the angle of each axis and the known distance to the next.
By default, FANUC robots calculate position in the real world by the center of the plate on the end of the last actuator. When you attach a tool, you must tell the robot where the effective end of the tool is, relative to the tool center plate.
This can be done through direct entry of measurements taken from the TCP but the FANUC software includes useful utilities for automatically calculating a new tool center point with minimal effort.
|Tool||Where the center of the effective point on the tool is, relative to the tool plate. Optionally, orientation can be defined.|
|User||Where the work area’s origin (zero) point is located, as well as the direction of each cartesian axis.|
The Three-Point Method
The three-point method for tool frames is to teach the positional data of the effective end of the tool. This does not teach the orientation, but for many uses is sufficient.
|Start by opening the menu with the MENU button on the keypad.
Using the arrow keys, cursor down to SETUP and select the submenu item “Frames”.
|The SETUP Frames page will be displayed, but depending on which frame was last edited, may not yet be on Tool Frames.
The image on the left shows that User Frame is selected. We want to switch to Tool Frame.
|Open the menu for selecting frame types by hitting the |OTHER| softkey.
|The method that appears may not be our desired Three-Point Method. To change methods, hit the softkey |METHOD| and select “Three Point”.
The Details page for your selected Tool Frame will appear.
Notice the asterisks filling the Comment field. This indicates the field is uninitialized. Select it and hit the hard key ENTER.
Name your Tool Frame with your initials and the month.
What did you name your Tool Frame? ________________________
Note: Use Alphanumeric characters and start with a letter.
|Notice the name you gave it shows up in the Comment Field.
Notice each Approach Point contains UNINIT. This means no points have been taught yet.
Select Approach point 1.
|Jog the robot so that the center of the robot’s tool touches the teaching object. Align it as best you can without disturbing the object.
Holding SHIFT, hit the soft key RECORD.
Jog the robot’s tool away from the teaching object so there is no risk of bumping it.
Select Approach point 2.
|Jog in Yaw, Pitch, and Roll to move the robot’s tool to a significantly different orientation, such as pictured.
Jog in X, Y, and Z to once again touch the center of the tool with the teaching object.
Hold SHIFT and press the softkey RECORD.
|Jog the robot’s tool away from the teaching object so that there is no risk of bumping it.
Select Approach point 3.
Jog again in Yaw, Pitch, and Roll to move the robot’s tool to a different orientation. Ensure you are not 180 degrees from either previous point you have taught. Jog in X, Y, and Z to once again touch the center of the tool with the teaching object.
|With all 3 of the approach points taught, the robot will calculate the position of the tool’s center relative to the center of the tool plate. This information will be displayed at the top.
Confirm your tool frame is correctly configured by moving the robot into an empty area of its envelope and jogging around in Yaw, Pitch, and Roll. If correctly taught, jogging in orientation will result in no translational movement whatsoever.
The Direct-Entry Method
It may often be desirable to simply measure the tool's position relative to the center plate, and enter it manually. For instance, a tool may have interchangeable effectors - such as a milling bit - and the only difference from the last was length, which can be edited in the Z field.
In this lab, we will take the tool frame we just created and edit it to include a suction cup we will place on the end of the tool.
|We start by taking a measurement from a known fixed point to our previously taught tool tip. Since these are digital calipers, we need only take it to that point and then zero it out. This creates a reference point we can measure from.|
|Once it is zeroed out, we add our suction cup. This cup sticks out a bit from the original brass piece by 4.9mm, as shown in the image.
|The useful end of the suction cup is actually about 1mm inside the cup, as it should be pressed down on the object slightly to make proper contact for negative pressure to develop. We take the 4.9mm measured, subtract the 1mm from it and get 3.9mm for our changes.
|Select the Z value on screen and enter the new number you have come up with. Press enter to submit the change.|