Jul. 18, 2024
As the name implies, the tool magazine is used to store tools. It is one of the main components of the automatic tool changer in the machining center. According to the number of tools stored in the tool magazine and the way to take the tools, the tool magazine can be designed into different types.
The more common types are disc tool magazines and chain tool magazines. The chain tool magazine has a larger capacity for storing tools. The tool changer exchanges tools between the machine tool spindle and the tool magazine. The most common one is a manipulator;
there are also those that do not have a manipulator and the spindle directly exchanges tools with the tool magazine, which is called an armless tool changer.
The disc tool magazine should be called a fixed address tool changer, that is, each tool position is numbered, generally from 1 to 12, 18, 20, 24, etc., which is the tool number address.
After the operator installs a tool into a certain tool position, no matter how many times the tool is changed, it is always in that tool position.
Features:
1. Low manufacturing cost. The main components are the tool magazine body and the indexing plate. As long as the machining accuracy of these two parts is guaranteed, the indexing of the tool magazine in the moving parts uses a very classic "Marsh mechanism". The front and back,
up and down movement mainly use cylinders. Assembly and adjustment are relatively convenient, and maintenance is simple. Generally, machine tool manufacturers can make it themselves.
2. The tool magazine must "return to zero" every time the machine tool is turned on. When the tool magazine is rotating, as long as the baffle is close to the contactless switch (the distance is about 0.3mm), the CNC system defaults to tool No. 1. And use this as the counting basis.
The number of times the "Marsh mechanism" rotates is the current number of tools. As long as the machine tool is not shut down, the current tool number is memorized. When the tool is replaced, it is generally rotated according to the principle of the closest distance,
and the tool number is numbered in the counterclockwise direction. If the number of tool magazines is 18, the current tool number is 8, and the tool No. 6 is to be replaced, according to the principle of the closest distance tool change, the tool magazine rotates counterclockwise.
If you want to change to tool No. 10, the tool magazine rotates clockwise. The tool memory is cleared after the machine tool is shut down.
3. The tool change time of the fixed address tool magazine is relatively long. Domestic machine tools generally take more than 8 seconds (from one cutting to another cutting).
4. The total number of tools in the disc tool magazine is limited and should not be too many. Generally, the 40# tool handle does not exceed 24, and the 50# tool handle does not exceed 20. Large gantry machine tools also have discs converted to chain structures, with up to 60 tools.
The chain tool magazine changes tools at random addresses. There is no number on each tool sleeve. Its advantage is fast and reliable tool change.
Features:
1. High manufacturing cost. The tool magazine has a chain combination of tool sleeves, and the robot tool change action is controlled by a cam mechanism. The processing of parts is relatively complicated. Assembly and debugging are also relatively complicated.
It is generally produced by professional manufacturers, and machine tool manufacturers generally do not make it themselves.
2. The counting principle of tool number. Like the fixed address tool selection, it also has a base tool number: tool No. 1. But we can only understand it as tool sleeve No. 1, not tool No. 1 in the part program: T1. There is a tool table in the system. It has two columns.
One column is the tool set number, and the other column is the current program tool number corresponding to the tool set number. If we program a three-tool machining program, the placement of the tools starts with tool set 1 T1 (tool 1), tool set 2 T2, and tool set 3 T3.
We know that when T1 is machining on the spindle, tool T2 is ready. After the tool is changed, T1 is replaced in tool set 2. Similarly, when T3 is machining, T2 is installed in tool set 3. After one cycle, the previous tool is installed in the tool set of the next tool.
The CNC system has a long-term memory of the tool set number and tool number. After shutting down and restarting the tool magazine, the state before shutting down can be restored without "returning to zero". If "returning to zero",
the corresponding tool number in the tool set number must be modified in the tool table.
3. The tool change time of the robot tool magazine is generally 4 seconds (from one cutting to another cutting).
4. The number of tools is generally more than that of the disc tool magazine, usually 18, 20, 30, 40, 60, etc.
5. The cam box of the tool magazine should be regularly replaced with gear oil for lubrication and cooling
