GlossaryKind of term: Manufacturing termFeature
What is a feature?
A feature is a region of a part's geometry with its own manufacturing meaning, such as a hole, pocket, slot or chamfer, made by one or more operations.
Geometrically it is a connected set of faces that together form one machinable shape; a step or a boss counts as well. The 3D model consists of faces and edges; a feature groups them into a shape with dimensions, such as diameter and depth, and with the requirements placed on it. That makes the feature a common unit to which you attach operations, tools and time. A ⌀12 H7 hole with Ra 1.6 µm is one feature with two requirements, made for example by drilling and reaming.
How does a feature work in practice?
Many estimates are built feature by feature: count the features by kind, assign an operation and a time to each, and add up. That is an estimating method, not a law: two holes that look identical in the model can take different times. One may be a clearance hole, the other a fitted bore with a position tolerance to a datum, made where possible in the same setup as that datum. Access matters too, not just the count: from which direction each feature can be machined, and which setup that implies. A missed feature is a missing line in the estimate.
What is a feature often confused with?
A feature is not a requirement: the bore is the feature, H7 the requirement on it. Nor is it an operation: reaming is what you do to meet H7. A design feature in CAD, such as an extrusion or a cut in the model tree, does not necessarily match a manufacturing feature: one cut can hold a pocket and three holes. And in the tolerancing standards a feature is any surface, line or derived element of the part, a broader sense than the shop's.
How do you see a feature in Blake?
In Blake the requirements from the drawing, such as tolerances, roughness and threads, sit with the part as proposals. You confirm or correct them; who did so and when stays visible, with a note if you add one. Milling, turning, drilling and tapping are separate lines in the estimate, each labelled as an estimate. More on requests.
Frequently asked questions
Is a face also a feature?
When it has its own manufacturing meaning, yes: a top face you face-mill, a sealing face with a flatness requirement, a clamping face. A face with no requirement or operation of its own is geometry that belongs to another feature.
How do I avoid missing a feature?
Work through model and drawing view by view and count by kind: holes, threaded holes, pockets, slots, edges. A list with each feature's requirement and operation serves as the check; what is not on the list is not in the estimate.