Tool life management systems have come a long way in the past few years. The best systems can handle just about any tool life problems you can think of. And with the growing popularity of open architecture, personal computer-based controls, tool life management systems should continue to improve.
First and foremost, tool life management systems should assist you in your pursuit of moving all tool maintenance tasks off-line (the subject of last month's Tech Talk column). You must have the ability to specify tool groups instead of individual cutting tool stations. For example, instead of specifying a 0.5-inch diameter drill in station number one, with tool life management you will be able to specify a group of 0.5-inch diameter drills. Most tool life management systems are not limited when it comes to the number of tools in a group, allowing at least 25 tools per group. And station numbers corresponding to each tool in each group can be easily specified. However, tool life management systems vary substantially with regard to the flexibility they offer for managing each tool in the group. Here are some things to look for.
Tool life period—You'll want the ability to specify tool life in time. Watch out for systems that allow only number of cycles. It is common to need your tool life management system to work for you over the course of several production runs, and of course tools will be running for different amounts of time in each job.
Tool exhausted notation—You'll want your operators to have an easy way to determine when tools are dull. Of course, the tool life management system will automatically move on to the next tool in the group when a tool is dull. You'll also want the operator to have a simple way of informing the tool life management system when a tool is replaced. And he or she must have the ability to do this while the machine is in cycle.
Offset data numbers and entry—Offset values will change with each cutting tool in a given tool group. Many tool life management systems allow you to enter tool offset data on the same display page as your tool life data, which minimizes the potential for data entry mistakes.
Automatic offset update for tool wear—As a tool wears, the surfaces it machines may vary. Conventional methods dictate that the CNC operator measures the surface and updates the appropriate offsets manually. As long as tool wear is consistent (due to consistent workpiece material from one piece to the next), your tool life management system should have the ability to automatically change offset values during a tool's life to hold size. This ability is especially important to companies intending to run their CNC machines unattended.
Handling cutting tool material variations—Your tool life management system should have the ability to modify speeds and feeds based on variations in cutting tool material. In the 0.5-inch drill tool group mentioned above, for example, you may have some cobalt drills and some high speed steel drills, which, of course, will require different speeds and feeds.
Program, store, and retrieve tool life data—Since you will likely have to run the same workpiece at some future date, you must have the ability to save the tool life data to keep from having to enter it every time you change setups. To minimize initial setup time, it is also helpful to be able to program off-line.