CMM vs. Vision System – Five questions to ask when choosing your measurement method

We’re often asked how our customers choose which of the various measurement systems to use for the inspection jobs they handle.  It often comes down to a decision between CMMs or our Vision Systems – now that CMM style probing has become a more commonly used tool for vision systems, making the decision on which system to use becomes less cut and dry.  This article attempts to make your decision an easier one.

Four factors to consider when deciding on your inspection system:

  1. Speed: Is your inspection a one-time event or an ongoing sampling?
  2. What size is your smallest feature?
  3. Do three of your datums appear in one view?
  4. Variety: Do you need probing and vision capabilities on the same part?

Also includes a pictorial part guide, analysis of reporting and accuracy. 

  1. Speed factor: Is your inspection a one-time event or an ongoing sampling?

Since vision systems are less dependent on moving probes, probe approach speeds and (**another downside of CMMs**), Vision has the potential to be much faster and even more accurate.

  1. What size is your smallest feature?

Both CMMs and Vision systems can handle larger features.  As features get smaller than 3-5mm, we start leaning towards using a vision system.

  1. Do three of your datums appear in one view of your print?

In the past, vision systems have been assigned to 2-D applications, however, the newer ability to use vision and CMM probing interchangeably and on the same machine, makes vision systems a more common choice in 2½-D and 3-D applications.  In any event, if the main datums appear on one view of your print, we would consider the part 2-D in nature and would lean towards the vision system.

  1. Variety factor: Do you need probing and vision capabilities on the same part?

The nature of the characteristics you need to measure is a key consideration

It’s not always obvious which system to use.  Feel free to contact SPC Next for advice.