# Design for Manufacturing Tolerance Review Checklist > Source: https://netray.co/tools/design-for-manufacturing-tolerance-review-checklist > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: Free Tools ## Short answer A pre-release checklist for reviewing tolerances on a drawing for manufacturability, function and inspectability. ## Category engineering-plm ## Industry Discrete Manufacturing ## Audience - Design engineer - Manufacturing engineer - Quality engineer - Drafter ## Tool **Kind:** checklist **Groups:** #### General tolerances and notes **Items:** **Text:** A general tolerance note is present and complete (for example ISO 2768-mK) with the standard named **Critical:** true The general tolerance class matches what the intended process can hold Unit of measure and projection method are shown in the title block **Text:** Material, finish, coating and heat treat callouts are present with their specifications **Critical:** true Surface finish requirements are stated only where function needs them Edge break and sharp edge rules are stated for unspecified edges **Text:** Drawing revision and release status match the item master in the ERP **Critical:** true #### Fits, datums and geometric tolerances **Items:** **Text:** Mating features have explicit limits, not general tolerances **Critical:** true Fits are selected from a standard system (ISO 286 or equivalent) and checked for clearance or interference **Text:** Datum features are real, accessible surfaces that represent how the part mounts **Critical:** true The datum reference frame has a clear primary, secondary and tertiary order Feature control frames use the correct modifiers (MMC, LMC, projected zone) only when justified Theoretical exact dimensions are boxed wherever position or profile is used Position and profile tolerances reference a datum frame that can be reproduced in fixturing Form tolerances are smaller than the size tolerance where the envelope is intended #### Manufacturability **Items:** **Text:** Each tight tolerance has a functional reason documented **Critical:** true Tolerances are compared with the typical capability of the planned process **Text:** Tolerance stacks for critical assemblies are checked, worst case or statistical **Critical:** true Features are reachable by the tool and can be clamped without distortion Thin walls and long slender features have realistic flatness and straightness values Thread and hole callouts give both thread depth and drill depth Tolerances allow for finish, coating thickness or plating build-up Castings and forgings have machining stock on all mating surfaces #### Inspectability and release **Items:** **Text:** Every critical dimension can be measured with an available gauge or CMM program **Critical:** true Measurement uncertainty is small compared with the tolerance on the tightest features **Text:** Key and critical characteristics are flagged and balloon-numbered for the inspection plan **Critical:** true Sample or first article inspection requirements are stated for the customer or program Features that cannot be measured after assembly are identified for in-process inspection A 3D model exists, matches the drawing and is clearly marked as reference or authority Supplier-facing notes do not conflict with purchase order terms Peer review is recorded with name, date and open items **Scoring Note:** Any unticked critical item should block release. For non-critical items, record an owner and due date for each gap before the drawing is issued to production or a supplier. ## Content **Intro:** A drawing is the contract between design and manufacturing, and tolerance mistakes are expensive once metal is cut. Use this checklist in the peer review before release, so function, cost and inspection are all considered. **Sections:** #### How to use the checklist **Body:** Run the review with someone from manufacturing or quality, not only the designer. Go through each group, tick what is satisfied and leave a note for each gap. Critical items are those that, if missed, usually cause scrap, rework or a failed assembly. Print or export the finished list and attach it to the engineering change or release record so there is evidence the review took place. **Bullets:** - Review drawings in the same units your supplier uses - Mark each tight tolerance with its functional reason - Record the reviewer and date on the exported copy #### Why tolerance review pays off **Body:** Cost rises steeply as tolerances tighten, because tighter limits usually mean slower machining, finishing operations, more inspection and lower yield. A review often finds tolerances that were copied from a previous drawing without a functional need. It also catches the opposite case, where a mating feature relied on a general tolerance. Both are far cheaper to fix on screen than on the shop floor. #### Linking to standards **Body:** The checklist assumes you follow a standard such as ASME Y14.5 or ISO GPS for geometric tolerancing, ISO 286 for fits and ISO 2768 for general tolerances. The standard named in your title block governs how a symbol is read, so mixing conventions on one drawing is a defect in its own right. If you supply to aerospace or defense, check customer flow-down requirements for drawing practice as well. #### Common mistakes **Body:** Frequent findings include missing general tolerance notes, datums that cannot be reproduced in a fixture, position tolerances on features with no datum frame, and callouts that ignore plating thickness. Another common one is a tolerance that is achievable in theory but cannot be measured with the available equipment, which makes acceptance a debate. Fix these during review and record the decision. **Cta:** Netray can help connect drawing review outcomes to ERP engineering change and inspection plan data, so what was agreed in review carries through to the shop floor. **Faq:** #### Who should attend a tolerance review? **Answer:** At minimum the designer, a manufacturing or process engineer and a quality or inspection representative. For critical assemblies, add the supplier or the machinist who will run the part. Different roles catch different problems, so a single reviewer is rarely enough. #### When should the review happen? **Answer:** Before drawing release and again when a significant change is made. Reviewing early, while the model can still change, is cheaper. A second pass after the first quote is useful, because suppliers often point to tolerances that drive price. #### Should every dimension have a functional reason? **Answer:** Not every dimension, but every tight tolerance should. General tolerances cover non-critical features. Documenting the reason for tight limits helps later changes, since someone can tell whether the limit is safe to relax. #### Does this replace a full GD&T audit? **Answer:** No. It is a practical release checklist and does not replace detailed checking against ASME Y14.5 or ISO GPS rules. For complex parts or program requirements, have a trained GD&T professional check the feature control frames. ## Search terms tolerance review checklist, drawing review checklist gd&t, dfm checklist tolerances, engineering drawing checklist manufacturing, design for manufacturability tolerance, drawing release checklist, tolerance feasibility review, gdt drawing check --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json