Manufacturers looking to transition from manual metrology to utilizing a CNC coordinate measuring machine (CMM) now have a fresh option to explore—the recently introduced ALTO 6.5.5 by CMM manufacturer LK Metrology, based in Derby, UK. Targeting the entry-level segment of the CMM market, this machine boasts guideways constructed from aluminium, thus reducing the initial investment compared to models featuring ceramic components, which is the norm for many LK CMMs. Through several innovative design elements, the ALTO 6.5.5 achieves a remarkably compact form factor while maintaining the high precision and swift throughput typically associated with more expensive CMM systems.

The CMM adopts a half-gantry design, enhancing accuracy by shortening one side of the supporting leg for the bridge. Additionally, a fixed aperture beneath the shortened leg streamlines the loading and unloading of components from that side of the machine. Employing micro-machining techniques on the aluminium components, achieved by fly-cutting them while unclamped, eliminates potential distortion often encountered when releasing conventional workholding fixtures post-milling. Prior to assembly, all aluminium parts undergo hard anodization, resulting in a durable 50 µm thick layer that offers exceptional resistance to corrosion.

Rapid 5-Axis Touch-Trigger Measurement 

Designed exclusively for touch-trigger probing, the CMM excels in capturing precise measurements rapidly, facilitated by the integration of a motorized PH20 5-axis probe head from Renishaw, which triples inspection speed. Continuous angular rotation and infinite positioning, akin to the company’s top-tier REVO2 probing system, obviate the need for high-speed movements of the machine’s X, Y, and Z axes, thus minimizing dynamic errors. In certain measurement scenarios, movement of the linear axes may not be necessary at all, resulting in enhanced accuracy and repeatability.

Moreover, the 5-axis motion capability enables the measurement of larger parts by minimizing the space required for head rotation around the part. While the PH20 represents the most expensive probe head option, mindful of cost constraints for prospective ALTO buyers, LK also offers lower-cost motorized and manual head alternatives. Additionally, a variety of surface roughness probing solutions are available, along with stylus change racks featuring self-calibration and automatic tip correction upon changeover.

Advanced CMM Construction 

The design of the ALTO revolves around the necessity for a compact CMM with linear travels measuring 600 x 500 x 500 mm. All electronics, including the PC system, are integrated within the base, ensuring a small footprint, while the guideways do not extend beyond the table, differing from other designs.

With aluminium replacing ceramic for the guideways, no compromises have been made in the construction of the new machine, which incorporates all the top-end features of LK’s other CMMs. These features include a 100 mm thick granite table, low-maintenance pre-loaded air bearings, and zero-hysteresis friction drives in all axes, ensuring smooth motion and precise positioning. Standard equipment includes a sub-micron optical measuring scale system with dynamic signal processing for stability, pneumatic counterbalance in the Z-axis, and multi-sensor thermal compensation. The machine minimizes inspection cycle times with rapid acceleration up to 1,500 mm/s² and axis speeds of 500 mm/s.

The machine achieves a length measurement accuracy of 2.5 + 3.0L/1000 μm with high repeatability in an environment temperature controlled between 16 and 26°C. An optional shop-floor pack, featuring a pneumatic anti-vibration system and extended operational temperature range between 15 and 35°C, is available for deployment in harsher or uncontrolled production environments outside a quality control room.

Intuitive One-Touch Software

The ALTO comes equipped with TouchDMIS, the world’s first all-touch CMM software, simplifying CMM programming and measuring through its user-friendly interface. Requiring minimal training for operators to become proficient, TouchDMIS offers native import of STEP and IGES files, along with full CAD capability.

Ergonomically designed to maximize productivity for both novice and expert users, the touchscreen graphical user interface incorporates floating toolbars to optimize the graphical area, with all primary software actions accessible via eight large buttons. TouchDMIS eliminates drop-down menus or stacked toolbars, ensuring all functionality is easily accessible with a single touch. Multiple reporting options are available to suit user preferences.

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