Greg Blackman speaks to Markus Maurer about a new standard specification sheet the VDI and VDMA Machine Vision are designing to help integrate vision systems
The Association of German Engineers, the VDI, in cooperation with the machine vision chapter of the VDMA, are developing a standard specification sheet for making a ‘factory acceptance test’, planned for release in 2015.
VDI/VDE 2632 part 3, for specifying a factory acceptance test to determine the functionality of machine vision in production equipment, is the third part of standard information sheets designed to aid end-users and machine vision suppliers when integrating vision in production machinery. VDI/VDE 2632 part 1, ‘Machine vision: Basics, terms and definitions’, was released in April 2010, while part 2 of the standard, ‘Machine vision: Guidelines for the preparation of a requirement specification and a system specification’, came out in September 2013.
While there are many standards for machine vision components, such as the interface standards, there is very little in the way of standard documents for suppliers of complex systems. These VDI specification sheets define what needs to be known by both sides – the end-user and the vision supplier – to integrate machine vision successfully into production equipment.
‘The target group is the end user of machine vision in various industries, as well as machine builders that are thinking about integrating vision in their machines,’ explained Markus Maurer at Vitronic, who is active in the standard working group. The specifications give the end customer an idea of the types of questions they should be asking in order to install an effective machine vision system.
He added that the VDI standard is also designed for suppliers of machine vision components, so that they can quote for or design an inspection system. ‘The specification is so that both sides understand the other side a little bit better,’ Maurer said.
The end customer should be aware of factors like vision cycle time and inspection rate, while machine vision companies need to have an idea of the types of defect the vision system will have to pick up, as well as the environmental conditions it will have to work under – does the system require shielding from external light, for example?
VDI/VDE 2632 part 3, which the group is currently working on, will define what is needed for an effective factory acceptance test, such as how many parts should be checked, the type of part, and the criteria to decide which defects are relevant, among other issues. ‘If you use the same sample parts for the acceptance test as were used for the setup of the system, then of course you’ll pass the test. But maybe actual production is a little bit different,’ noted Maurer, adding that real components from the production line should be used in acceptance tests.
‘There is sometimes a lack of communication and sometimes a lack of understanding of what each side wants,’ Maurer continued. ‘As a machine vision company, you are dealing with many different end customers from different sectors, and it’s not always easy to understand their requirements. The end-customer might have many different production techniques, with machine vision only being a small portion of overall equipment. The end-user might also not be aware of what influences the optical system and the inspection results, and what is important to achieve high throughput and reliable inspection. This is what we are trying to define.’
VDI/VDE 2632 parts 1 and 2 are currently available at Beuth (http://www.beuth.de/en), with part 3 expected to be published next year. The VDMA Machine Vision group has also produced a video that explains the benefits of part 2 of the standard.
Further information
