For example, low-cost machine tools are proliferating. “A number of [machine tool] companies are pioneering lower-cost machining centers,” explained Jean Zangao, product manager for Hexagon Metrology (North Kingstown, RI). “Today you can find, for example, VMCs in the $75,000 range. If you compare that to standard tool setting units that cost $3000–$5000, including installation, that is a significant fraction of the cost of the machine.” In response, the Hexa- gon brand m&h launched their new Tool Setter TS35.20. For roughly a third of the cost of higher end systems that feature RF or IR wireless communication, they are aimed squarely at the low-cost VMC market. “You would want a wireless system for machines with more than three-axis or more complicated than a VMC,” explained Zangao. According to the company, they fix the TS35.20 to the table in the machine, sending its signals by cable to the control unit. The company reports deflection force down to 2.2 N•m,
Tool Break Detector (TBD) that uses laser beam triangula- tion. The system projects a laser beam onto the tool surface that reflects onto a receiver. The company says that even in the presence of coolant, its algorithm for detecting break- age will “accurately analyze the reflected light signal created by a rotating tool.” The probe works with tools operating at 200–5000 rpm, with diameters as small as 0.2 mm. Tools may be positioned at a distance of between 0.3 m to 2.0 m from the TBD unit based on the installation. The unit requires a wire connection to the machine tool and is suitable only for center cutting or solid tools, according to Sharad Munda, Mida probes product manager for Marposs.
Machining Goes Small
The TT460 Probe for on-machine tool measurement transmits in either RF, IR or both (Heidenhain).
which the company says allows users to measure tools with a diameter as small as 0.1 mm to a system accuracy of 0.5 µm. Measuring is done at speeds of up to 3 m/min. To measure ever-smaller tools, m&h recently launched the Laser Tool Setter LTS35.65-23, specifically designed for machines with small footprints. It boasts an accuracy of 0.2 µm and measures lengths and radii on parts with a minimum diameter of 25 µm. In another nod to the low-cost end of the market, Marposs (Auburn Hills, MI) also recently introduced its Mida brand
Machining smaller is another trend to which metrology providers need to adapt. Marposs responded to this trend by recently launching its new higher precision Mida ML75HP noncontact laser tool-setting system for on-machine tool checking. This is a variation on its existing Mida ML75P laser tool setter. This unit features a laser beam that checks tools as small as 10 µm in diameter. “To set this in context, our ML75Pico is good for measuring tools that are greater than 30 µm and the standard ML75P is good for tools greater than 50 µm in size,” said Munda. “We have a customer in San Francisco measuring tools to a repeatability of 0.2 µm that are 25 µm in diameter.” The ML75HP generates a laser
beam between an emitter and a receiver mounted inside the machine tool working area. When a tool mounted on the spindle interrupts the laser beam, the laser system outputs a signal to the machine CNC. Checks the system performs include tool length and radius measure; tool wear compensa- tion; tool breakage detection; insert/cutting edge integrity; insert/cutting edge profile; and thermal drift compensation. To avoid issues with lasers in machine tool environments, GF AgieCharmilles (Lincolnshire, IL) offers its Intelligent Tool