Inspection fixtures and gauges

FIXTURES AND GAUGES DESIGN

The design office of Metronom Pacific Pty. Ltd. offers their clients a comprehensive range of services to carry out the projects for the design and acquisition of inspection gauges and fixtures. The specifications, tolerances and the scope of the project are determined in close consultation with the client. Based on this information and on the broad experience of our company, a gauging or measurement concept is worked out within days, which then is presented for discussion and improvement to the customer. With the development of the concept also an accurate assessment of the overall costs of the project is achieved. The design is performed in CATIA V5. Extensive CAD libraries of modular fixturing systems, like for instance ALUFIX, streamline the design process and give the project engineer the overall costs to assemble a particular design. The parametric design and the use of modular components for the assembly and construction of inspection gauges and fixtures facilitate changes, modification and improvements during the realisation of a project. The modularity and reusability of the majority of the fixture components not only reduces the design time but also offers a substantial cost reduction potential to the industry.

 

Among the many different gauges and fixtures that Metronom Pacific Pty. Ltd. Designs and supplies are the following:

 

HOLDING, MEASUREMENT AND INSPECTION FIXTURES:

 

Inspection fixtures are mainly used in combination with coordinate measuring systems (CMM). The component is fixed rigidly on the fixture, however, without distorting it, so that the CMM, either automatically or manually, can measure the relevant features of the part.

 

This type of fixtures simulates the mounting points of the component in the car. Usually the design of the fixture is performed in such a way that the part is mounted in car position and an easy alignment of the fixture to the car grid is possible.

 

The Geometric Design & Tolerancing (GD&T) specifications are strictly observed during the design phase, determining the required final positioning accuracy of the mounting points, as well as their dimensions and forms.

 

Fast and repeatable mounting of the part on the fixture, probe accessibility to all the measurement areas of the component, distortion-free clamping, weight of the fixture are some of the many aspects that are considered when designing inspection fixtures.

 

Fixture design structure for car accessories

MEASURING FIXTURES:

 

In some instances, a method to measure a component accurately without having to rely on an expensive coordinate measuring system is needed. These fixtures offer a stable and repeatable mounting system for the part in order to be dimensional checked using gauges or fixed dial indicators.

 

Measuring Fixture for a steering wheel

 

INSPECTION GAUGES

 

Inspection gauges have to comply, similarly as the inspection fixtures, with all the requirements of accessibility, distortion free clamping, ease of alignment with the car-grid, rigidity and GD&T compliance. However, they have an additional functionality: they offer the possibility of inspecting and/or measuring the part in reference to its surroundings.

 

The gauging components usually are attached to the fixture frame but they have to be designed in such a way that they do not hinder the easy and fast mounting and clamping of the component to the gauge. The surrounding gauging blades can machined in engineering plastics like Ureol or in aluminium. Mounting points and gauging blades are calibrated on a CMM during the validation of the gauge.

 

Inspection gauge with tail light

 

PRODUCTION GAUGES

 

The inspection gauges can be used in the metrology area as well as on the production floor. They also give the operator the possibility to perform dimensional inspection of the part using hand-held dial indicators or feeler gauges without having to rely on a coordinate measuring system.

 

The part can also be visually inspected facilitating fault detection. All the mounting points as well as the gauging components are designed to be adjusted for calibration and validation of the gauge.

 

Production gauge structure

 

 

DATA CONTROL MODELS

 

A data control model is a 1:1 physical reproduction of the CAD data, typically machined on a milling centre to very tight surface tolerances. The physical models, depending on the customer’s specification, are manufactured in Ureol or in aluminium. It gives the design team the possibility to inspect the design, review it and assess it form the styling point of view. In some instances a tolerance impact analysis is required, which is performed by adjusting the position of the components in relation to the surrounding parts. To be able to move the components they are mounted on adjustable elements, which can be moved in one, two or three orthogonal directions. The supporting frame has to be rigid and accurate to facilitate the complex part mounting as well as tits calibration and adjustment.

 

Data control model for Holden Commodore Data control model for Beetle
Data Control Model for Holden VY Project
Data Control Model VW New Beetle

 

INTERNAL AND EXTERNAL CUBING

 

Internal cubing sample

 

The cubing technique plays an important role in the automotive industry. The cubings are used to mount the real components (sheet metal parts, assemblies, moulded parts, etc.) as they it will be on the real vehicle. Therefore, the cubing is an accurate simulation of the mounting points in the vehicle giving the engineer the possibility to verify off-tool elements as well perform first part analysis and assess the component with the surrounding elements in its vicinity.

 

 

Complete cubing from a truck

There can be partial cubings, where only a particular region of the vehicle is assessed. The cubing offers also the possibility to mount gauging elements to validate real elements with its surroundings. The gauging elements can be manufactured in aluminium or in engineering plastics like Ureol.

 

 

Complete cubings are accurate frames where al the external or internal components of a vehicle can be mounted for evaluation, inspection and measurement. Cubings give the engineering teams a valuable tool to evaluate components in vehicle position.

Complete cubing system