What is a machine vision inspection system?

In essence machine vision systems make use of a high specification video camera (the term CCD is frequently used which refers to the chip technology) to take an image of the part being inspected, a light source which picks out the relevant features to be inspected (this is a very important aspect of a successful installation), and a processing unit to analyse the image taken. There are many variants of this ranging from intelligent cameras with a processing unit built-in (more suited to dedicated, simple applications) to specially designed processors that can take multiple cameras, running different inspection tasks simultaneously. And of course there is a lot in between. The details are not important here it is sufficient to note that there are different systems for different applications.

What can be inspected?

A great deal has been made of the utilisation of machine vision in the electronics industry especially semiconductor manufacturing where very small geometries and the requirement for a clean room environment can take great advantage of the technology, but a vast number of applications are possible and virtually any manufacturing industry including metal stamping, plastic moulding, pharmaceutical, healthcare, food and drink, packaging and automotive can take advantage of automated inspection.

Machine vision can be used for dimensional checks, grading by size and shape, detecting surface flaws, verifying mechanical assembly, checking packaging integrity, checking date and lot codes. More applications...

How fast can it inspect?

This depends on the type of camera used, the processor and the software. Many cameras used in machine vision applications are capable of acquiring 60+ full frame images per second and with 'partial scanning' rates can be much higher. This does not translate directly into the rate at which parts can be inspected, this will also depend on a number of factors but some applications are currently running well in excess of 10,000 parts per minute.

Who programs it?

A vision system needs an applications program to perform the required task. This may be done by the system supplier, a machine vision integrator or the end user. Today it is very rare that a specialist software company is needed as this produces very dedicated solutions that are difficult and expensive to modify. Nearly all machine vision systems today have a user interface but these vary greatly in the skills required to use them. Inspection Builder form PPT is unique in that it combines very powerful inspection algorithms and a simple technique to create the application. All that is needed for the end user to modify or produce his own inspection programs is a familiarity with Windows, a short training class, and a knowledge of what is to be inspected. Despite its simplicity the PPT software is very powerful and flexible.

What if my needs change?

If the vision system is flexible and has a simple programming environment, modifying an inspection task if the specification changes or creating a program for a new product is well within the capabilities of both the system and the user. So you don't have to worry about the vision system being obsolete at the end of your product's life. It may be necessary to change the lighting and the parts handling may of course be different but the vision system can normally be adapted quite simply. This may not be the case for more dedicated systems.

Isn't lighting very important?

YES! but a carefully designed application will not be affected by changing ambient light. Correct lighting will be determined by the supplier or systems integrator.

How do I find out if my application is feasible?

A company that provides a complete machine vision system solution will advise you after asking lots of questions and taking samples for evaluation. A good partner is one who has the knowledge of parts presentation, lighting, and experience of a variety of inspection applications. The more precisely you can define your problem and what you want to achieve, the more successful will be the outcome. You should then be provided with a proposal outlining what can be done, how it will be achieved and at what cost. Some companies, but not all, will charge you for this.