GlossaryKind of term: Manufacturing termRevision
What is a revision?
A revision is a released version of a drawing or model, marked by a letter or number that moves on with every released change.
The revision index sits in the title block, B, J or 03 for example, and tells you which version you are holding. When something changes, the drawing gets a new index and a row is added to the revision table: what changed, when, and who released it. A model can carry a revision of its own that does not automatically move in step with the drawing.
When does a drawing get a new revision?
When a drawing gets a new revision is decided by the change control of whoever owns it, not by a fixed rule. Many companies give a change that does not affect interchangeability a new revision, and a change to form, fit or function a new part number, so that old and new parts cannot be mixed up. Whether a material change, a different finish or a tighter tolerance falls under that varies by company. Drawing and model revisions are often managed in a PDM or PLM system; a change made outside that system sometimes never reaches the revision table.
How does a revision work in practice?
A quoted price belongs to one revision. A new revision can look the same and still call for an extra operation, setup or inspection, or drop one. On a new revision you therefore read the revision table first and then compare drawing and model with the version you priced before, because not every change makes it into the table. State in your quote which revision your price rests on, so that a later difference can be traced.
What is a revision often confused with?
A revision is not a quote version: the revision is a version of the customer's drawing, the quote version a version of your answer. It also differs from a drawing change: the change is what differs between two revisions, the revision is the recorded state that results.
How do you see a revision in Blake?
Blake keeps revisions per part. The drawing values appear as proposals, and each confirmation or correction shows who made it and when. More on requests.
Frequently asked questions
Can I reuse an old quote for a new revision?
Not without comparing. A small change, such as a tighter tolerance or a moved datum, can add an operation, setup or inspection. Compare drawing and model with the revision you priced and carry over only what demonstrably stayed the same.
What if the drawing and the model carry different revisions?
Ask the customer which combination applies and record the answer on the part. Pricing on two revisions at once gives a price that belongs to neither.
How do I find a change that is not in the revision table?
By setting drawing and model beside the previous version: dimensions, tolerances, notes and title block. A model comparison in CAD helps with the geometry; on the drawing you compare feature by feature.