Consider these elements:
- C-frame design
- High-grade cast iron components
- Special linear recirculating bearings in hardened and ground tracks
- Large, recirculating ballscrews mounted central to each axis
- Pre-loaded double-row angular compact bears for the ballscrews.
Add them all up, and you’ve got yourself something that is a machine tool, something that can sit out on the factory floor with all of the conditions that are characteristic of that terrain (which is where things like high-grade cast iron components come onto their own).
What is more notable about these things is the fact that this is not a machine tool in the common parlance of something that cuts or forms metal. Rather, they are key parts of the SF ACTIV from Brown & Sharpe (North Kingstown, RI).
Yes, this is a measuring machine. Or, it could be considered in the context of a factory (especially an assembly operation) a flexible gage.
The unit provides a measuring range of 600 x 430 x 470 mm, so an array of workpieces can be handled. There is a sheet metal cabinet enclosure with a sliding front door. The unit is configured so that it can be integrated, via a parts-handling system, into an automated manufacturing system. Or, if the application demands it (e.g., transfer line operations), the enclosure can be removed.
It is equipped with a high-accuracy, high-speed analog scanning probe. Which, of course, means that it can scan such things as contoured parts. But the probe can be set up so that it performs in a point-to-point. And, as this is a flexible piece of equipment, it provides the wherewithal to change heads and styli: analog, touch trigger or laser probes can be employed.
About that “ACTIV.” It’s an acronym. For Adaptive Compensation of Temperature Induced Variations. Simply put: it provides real-time, 3D volumetric performance compensation of the measuring machine to adjust to ambient thermal conditions . . . which perhaps isn’t too simple. So think of it this way. There are a series of thermal sensors on the structure. The data collected are processed through an algorithm, which determines how temperature affects the structure. That, then, is used by linear and structural compensation software, which results in adjustments so that what’s measured isn’t thrown off by temperature variations.
The Sharpe 32Z control (housed in a sealed, air conditioned cabinet) runs PC-DMIS for Windows measurement and inspection software. Windows, of course, is becoming almost as familiar on the factory floor as it is in the office environment. The SF ACTIV also has what’s known as a “Shop Smart” graphical user interface, which can be tailored to meet specific operational needs (i.e., depending on the level of operator proficiency).
Manual & Mobile
Carl Zeiss IMT Corp.(Minneapolis, MN) has long been a proponent of the importance of data collection via scanning. It has been rolling out an assortment of coordinate measuring machines (CMMs) with scanning capabilities, machines that are suited for laboratory use and machines that are useful (and affordable) to people who have been using conventional touch-trigger CMMs.
One piece of equipment that it rolled out a few years ago (literally, as you’ll see in a moment) and which it has been providing upgrades to since is called the ScanMax, which is a repeatable, flexible, manual scanning gage. This unit is designed for obtaining data related to size, form and location of parts that can fit within its 20-in. spherical measurement range.
Essentially, workpieces (weighing up to 150 kg—or 332 lb) are set up on the worktable (which, incidentally, can swivel and tilt) and the operator (metrology engineer; shop floor associate; whomever) manually maneuvers an articulating arm so that it follows the contour of the part. The X, Y, Z measuring area, depending on probe length used, is either 850 x 400 x 400 mm or 850 x 400 x 470 mm. The probe used on the ScanMax is based on the Zeiss VAST (Variable Accuracy and Speed Technology) head: it permits scanning; Profil software permits the acquisition of up to 200 points per second. There is automatic probe identification software used by the gage to minimize the possibility of operator error. The gage provides an accuracy to 2 µm and repeatability to 1 µm.
Because this is a manual device, Zeiss engineers paid close attention to ergonomic issues, not only with regard to making the articulated arm easy to move (ScanMax is built with carbon fiber reinforced plastic and ceramics, which not only make it light, but also thermally stable and vibration-resistant), but also from the standpoint of making sure that the operator has the ability to see the part, probe and monitor.
About that aforementioned rolling: ScanMax really gets around: it rides on wheels.
Beyond CAD/CAM: CAMM
“Computer-aided manufacturing measurement is the third and final stage of the computer-aided revolution,” claims Simon Raab, president, FARO Technologies, Inc. (Lake Mary, FL). The other two volleys in the revolution are computer-aided design (CAD) and computer-aided manufacturing (CAM). Raab goes on to say, “The difference is that this piece of the computer-aided tool set is for manufacturing engineers and assembly technicians who must design, build, and operate the lines that put parts together.”
Raab explains, “By using computer-aided manufacturing measurement (CAMM) software and hardware, manufacturing engineers can exploit the original design data to build tooling, troubleshoot fit problems in both pilot and production operations, and analyze trends in production for long-term quality control. While designing an assembly line, manufacturing engineering can design, build, and test tools electronically with simulation software. Once a pilot plant is built, the CAD data can serve as a standard for measuring the prototype parts with soft gages—also known as flexible gages, such as portable, articulated measurement arms. If manufacturing engineers identify any errors or inefficiencies, then they can modify the tools, equipment, and process control devices to correct them. The ability to compare tools and prototype assemblies to the original CAD data not only simplifies many measurements but also allows engineers to make more design iterations and fine-tune processes in less time.
“Besides using CAMM as a process design tool, engineers and assembly technicians also can use it to troubleshoot problems once the line is in production. As wear and abuse take their toll, manufacturing can deploy the same CAMM tools to troubleshoot fit problems as they occur and to analyze process feedback for identifying trends for planning corrective action and making improvements.”
FARO provides both hardware (e.g., its FaroArm measuring unit) and software (CAM2) for CAMM. The company estimates that just 5% of industry uses CAMM techniques. Presumably, those who use it earlier will gain competitive advantages.
The Surtronic DUO from Taylor Hobson (Rolling Meadows, IL) is engineered for performing surface roughness measurements—Ra and Rz—but because of its design, it is probably something that people are likely to take to, as it is a combination of two small ovals (the entire unit measures just 5 x 3 x 1.5 in.) that is designed for easy manual manipulation. It just looks like it might actually be fun to use, even though it is a precision instrument.
The bottom half contains the traverse mechanism (traverse distance = 0.200 in.) and a diamond stylus with a 200-µ in. radius. The top half has an LCD display and start and inch/metric conversion buttons.
One clever aspect of the device is that it uses an infrared—IrDA, to be precise—link between the two units. The top and bottom can be separated by as much as 40 in. and the measurements are picked up and reported.
The DUO provides a gaging range of 0.0078 in. and an electronic resolution of 0.4µ in (the display resolution is 1µ in).