Effective production management is no longer able to tolerate leaving high productivity machine tools with expensive hourly ratings standing idle. Here, common problems arise while waiting for decisions to proceed while inspection and measurement, ‘solution hop’ and move parts from one piece of specialist measuring instrument or device to another in order to fully satisfy the needs of the feature to be checked.
Not only is this time consuming with the added delays from work queuing, the chances of error are magnified from having to re-datum to reference points plus possible loss of working tolerance between one point and another. Further problems can also be created from personal interpretation of results leading to a significant source of additional downtime while results are collated.
Traditionally routines of the inspector revolve around the use of hard gauges, verniers, micrometers, depth and height gauges, clocks, hand and slip gauges, checking fixtures, optical projectors plus surface measurement and specialist kit for applications such involute form checking on gearing. The problem is that each is an individual task and many of the functions simply give ‘go’ and ‘no-go’ status.
As a result, important information such as trends or providing on-going intelligence for process control is negated. Indeed, what action can be taken or references given through traceability when the customer says “it’s wrong or won’t fit?” Even the CMM can be limited in 3D measurement and much of the operator’s duty is devoted to sitting at a terminal programming and then moving the part to another piece of equipment for specific tasks.
Here, non-contact measuring specialist OGP’s philosophy to create a single multi-feature measuring centre with the capability to move a part through five-axes of orientation pays off. It is able to combine traditional 3-D co-ordinate measurement using touch and feather probes with non-contact video measurement having the added advantage of a zoom capability.
Furthermore, features such as interferometric laser scanning can be carried out on profiles, internal features and surface texture, all combined into a single setting of the component to be measured.
According to Andrew Fulton, managing director of OGP UK: “The challenges to improve lead time, throughput, measuring ability and accuracy are no different in the measuring room to the production area. Most engineers will agree how development of new sensors, measuring devices and related metrology software is moving forward at a pace, and here, OGP’s ‘Future Proofing’ or forward thinking compatibility to integrate these elements and capability with existing OGP products is paramount.”
The OGP rationale is no-different to the latest multi-axis machine tools. Having secured the part, its measuring centres can be programmed in three, four or five axes of movement. The measuring process too can then be switched between different elements from the measuring bank of sensor based systems held on the same machine frame to suit the feature requirement without any need to re-datum.
Also, by working with a totally integrated measuring process an important gain can be made in making full use of process tolerances, combining different geometric and feature relationships and critical attention drawn to non-conformity to out-of-tolerance elements which can be immediately highlighted without having to delve through lines upon lines of data.
In the latest version of OGP’s SmartScope Vantage measuring centre which has a capacity up to 610 mm by 660 mm by 400 mm, integration of the different sensors and measuring elements is seamless. These include video, touch, micro and feather probe tactile measurement, digital range laser sensors, laser scanning of surfaces and cavities and the latest Rainbow white light probe for highly polished surfaces. Each is able to capture measuring data combined with multi-axis positioning to create a single cycle measuring system.
Each individual measuring and or sensor can be programmed into the measuring routine without the need to re-datum or calibrate. Also, either as an original supply option or as a retrofit upgrade, fully programmable variants of illumination can be added to suit the subject feature being checked. This can include substage profile lighting with electronic iris control able to synchronise with any magnification of a feature as well as coaxial through-the-lens surface lighting and OGP’s patented white light and non-heat generating programmable LED SmartRingTM lighting.
Tactile or touch trigger probes can include Renishaw touch and scanning probes to measure features that are difficult to image or have surface boundaries that are inaccessible to video. There are also 0.1 mm stylus feather probes for contacting fragile work and deformable surfaces with a miniscule measuring force of less than 1 mg.
The TeleStar TTL interferometric laser scanning system has a two micron spot size and an exceptionally long working distance with the ability to scan within cavities up to 200 mm deep and measure inside ultra-small micron sized hole
A major benefit is the ability to quickly capture large amounts of data over diffused, polished and mirrored surfaces, domed and porous parts as well as scanning internal features on single beam configuration features. Also, near vertical surfaces can be scanned even against a steep wall of up to 80 deg from the horizontal.
The OGP Rainbow white probe allows features on highly polished or translucent surface components such as optical mirrors or contact lenses to be measured providing surface characteristics to nanometre accuracies.
Key to OGP’s operating system is the powerful MeasureMind 3-D MultiSensor metrology software which uses Microsoft Windows XP or Windows 7 operating systems that incorporate a flexible 3-D datum environment. It will provide single reference calibration, levelling, rotation and origin definition while having the ability to quickly switch between the different sensor types at any point in the measuring routine. By incorporating dual rotary motion (5-axis positioning), continuous data can be captured from complex forms such as turbine blades, vanes and airfoils. l