A machinist makes a batch of parts perfectly — to the wrong drawing. It's one of the most frustrating and costly errors in manufacturing, and it's almost always caused by weak revision control: an old print left at the machine, a revision emailed to the wrong person, a customer drawing updated without anyone noticing. Good drawing control makes sure everyone works to the current, approved revision.
What revision control means
Every drawing has a number and a revision. When the drawing changes, the revision changes. Revision control ensures that each revision is approved before use, that everyone who needs it gets the new revision, that old revisions are withdrawn from use, and that history is kept so you know which revision applied to which parts.
Numbering and revision schemes
Use a consistent drawing number format, ideally linked to the part number. Choose a revision scheme — letters or numbers — and stick to it. Record the revision on the drawing title block, in the drawing register and in the BOM or part master, so all three always agree.
Approval and release
A new drawing or revision moves through draft, check, approve and release. Only released revisions should reach purchasing, production and quality. Recording who checked and approved, and when, provides accountability and supports audits.
Distribution: getting the right revision to the right people
Paper distribution relies on everyone receiving, filing and replacing prints correctly — and someone collecting old ones. It rarely works perfectly. Digital distribution — drawings available on screens, always at the current revision — removes most of the risk. When a revision is released, everyone viewing the drawing sees the new one immediately.
Drawings on the shop floor
Tablets at workstations, or QR codes on job cards that open the drawing, give operators the right revision for the job they are running. Because the job card is linked to a specific part and revision, there is no ambiguity. Operators can zoom into details on screen and, where needed, view 3D models or work instructions alongside.
Controlled paper copies
Where paper is still needed — harsh environments, large-format drawings — print controlled copies with a stamp or watermark, record where each copy is, and replace and collect them when revisions change. Uncontrolled photocopies should be prohibited.
Customer drawings
Many job shops and suppliers work to customer drawings. Register each customer drawing with the customer's number and revision, link it to your internal part number, and check incoming drawings against the register whenever a customer sends an update. Customers often update drawings without highlighting changes; a revision check on every new order prevents surprises.
Linking drawings to jobs and inspection
Linking each job card to the drawing revision makes the revision part of the production record. Inspection plans should also reference the revision, so inspectors measure against the right tolerances. If a problem appears later, you know exactly which revision the parts were made to.
Revision changes and work in progress
When a revision changes while jobs are in progress, decide what happens to them: finish at the old revision, rework to the new one, or stop and scrap. This is part of the engineering change process and should be recorded against each affected job. See engineering change management.
Common problems
- Old prints left at machines.
- Drawings stored on individual laptops.
- Customer revisions not noticed.
- Drawing register out of sync with the BOM.
- No record of which revision a batch was made to.
Getting started
- Build a drawing register with numbers, revisions and status.
- Store released drawings in one controlled repository.
- Link drawings to part numbers and job cards.
- Provide shop-floor access on tablets.
- Withdraw uncontrolled paper copies.
Corposol builds drawing management software linked to job cards and inspection. Talk to us.
Supplier drawings and purchase orders
When parts are bought to your drawings, the purchase order should state the drawing number and revision. Suppliers should acknowledge revisions, and incoming inspection should check parts against the revision on the order. When a revision changes, open purchase orders must be reviewed and suppliers informed. Many costly receiving disputes come from suppliers making parts to a revision you have already replaced.
Viewing and markup
Production and quality staff often need to comment on drawings — unclear dimensions, tolerances that are hard to achieve, suggested improvements. Allowing markups on a copy, linked to an engineering change request, captures this feedback without altering the controlled drawing.
Frequently asked questions
What revision scheme should we use?
Common schemes use letters (A, B, C) or numbers (01, 02). Choose one, document it and use it consistently; some businesses use numbers for pre-release and letters after release.
How do we handle customer drawings?
Register customer drawings with the customer's number and revision, link them to your part numbers, and control them just like internal drawings.
Can we stop paper prints entirely?
Many shops move to tablets for most drawings. Where prints are still needed, mark them as controlled copies and collect old ones when revisions change.
What happens to jobs already in progress when a drawing changes?
The engineering change process decides — complete at old revision, rework, or stop — and the decision is recorded against the job.
Can operators see only the current revision?
Yes. Shop-floor access shows only the released revision linked to the job, with older revisions accessible only to authorised users.
Who should be allowed to release drawings?
Only designated engineering or design staff after checking and approval. Production and quality can view and request changes but should not be able to release new revisions.
How long should old revisions be kept?
Keep them for as long as products made to them may need service, investigation or audit evidence — often many years. They should be clearly marked as superseded.
