Many potential suppliers state that they are ready to produce components according to specified requirements as they are familiar with the ISO GPS system tools for dimensional and geometrical tolerancing. Regrettably, in many instances, this is not true. This paper discusses a survey developed to assess the geometrical dimensioning and tolerancing skills and results derived from this survey executed among 15 potential suppliers. The investigation aims to preselect potential suppliers and evaluate how much support the suppliers will require while also assessing the risks associated with placing an order with a particular supplier. The survey is based on the online test comprised of 27 closed-end questions used to identify strengths, weaknesses, and knowledge of a candidate supplier's personnel. Five different answers are given for each question. The respondent shall indicate one correct answer. The inquiry is practically oriented. Most of the questions include drawings with indicated selected tolerance as well as drawings of the possible actual parts with exaggerated geometrical deviations. The associated question is whether an actual part is made according to the specification. The main conclusion is that most responders disclose a low level of understanding of the ISO GPS system. Urgent education is needed.

The inconsistencies between tolerances for aluminium profiles as specified in EN 755-9:2016 along with EN 12020-2:2016 and tolerance concepts defined in ISO 1101:2017 are demonstrated. It is shown that the standards defining requirements for extruded profiles have been developed without considering provisions in the ISO GPS system. A number of ambiguities in EN 755-9 and EN 12020-2 that were overcome in the ISO GPS system are shown. For example, broad application of plus/minus tolerancing for step dimensions does not provide unique verification of aluminium alloy-extruded profiles. It is pointed out that some terms univocally defined in the ISO GPS system are used incorrectly in both standards. It makes it difficult for a customer to verify on CMM whether or not extruded profiles satisfy the requirements specified in the order. Finally, significant changes regarding geometrical tolerancing in standards for the aluminium alloy-extruded profiles are proposed.