What are conformance classes?
A large Application Protocol like AP-238 is divided into conformance
classes to make it easier for vendors and users to decide what types
of functionality they want to support in their systems. AP-238 has
four conformance classes.
What is Conformance Class 1?
CC1 is the easiest conformance class to implement. This conformance
class defines a CNC program as a series of working steps that are each
defined by a CNC independent tool path expressed as Tool Cut Point
data. There is no requirement to include any geometry, GD&T or feature
data in the file. A "quick and dirty" CC1 translator for a CAM system
can be implemented by translating APT CL data to the AP-238 format.
The STEP-NC Write Library is a
simple, open-source library for doing this.
What is Conformance Class 2?
CC2 is also easy to implement because it is a combination of CC1 and
AP-203 edition 1. This conformance class enables intelligent set-up by
including models of the as-is and to-be products, safe areas for the
fixtures, as well as the tool holder and cutting data in the exchange
file. With this information and its own internal data a CNC can do
complete checking of the tool path data.
What is Conformance Class 3?
CC3 is the first conformance class to enable generation and
modification of the part program. In this conformance class the
definition of the removal volumes defined in the CAM system is
included in the data. Therefore, a smart CNC can use this same data to
re-generate the paths if some condition changes or another CAM system
can read the data and make the changes. Implementing CC3 of AP-238 is
harder than CC1 and CC2 but all of the necessary data is already in
most CAM systems so it does not require any process changes by the end
user.
What is Conformance Class 4?
Conformance class 4 is the ultimate goal. The data in this class
enables full generative path planning on the control using intelligent
software. It includes everything in the AP and requires the upstream
systems to supply at least the GD&T information for the part and
better still the part feature (AP-224) information.