Round Table Legs Welding Fixture First Article Inspection: What to Check Before Batch Production
A welding fixture first article inspection should answer two questions before repeat production begins: can the fixture locate and hold the parts as intended, and does the first welded assembly meet its released drawing after it leaves the fixture? Check the setup, the tacked assembly, the cooled weldment and the free-state part separately. A good result while every clamp is tight does not by itself approve the finished weldment.
For an overseas buyer, the useful deliverable is more than a photo of a frame on a 3D table. Ask for a fixture layout, the drawing revision, measured features with acceptance limits, the inspection stage for each feature, and a record of any adjustment made after the first piece. That evidence lets your shop repeat the setup and tells you what to question before ordering a larger tooling set.
Define what the first article is approving
Keep three approvals distinct. The welding table is the mounting platform; the fixture is the arrangement of stops, supports, bolts and clamps; the first article is the welded part produced with that arrangement. A supplier’s table specification cannot substitute for measurement of your finished assembly. Likewise, a weldment that passes once may not demonstrate that the fixture can be reset consistently after a changeover.
Before cutting or welding, agree which drawing revision controls, which dimensions and weld requirements are critical, who supplies the raw parts, and whether inspection is required in the clamped state, the released state, or both. If your contract calls for a named first-article standard or customer form, use that requirement in addition to this shop-floor checklist. Do not treat an informal fixture check as a claim of certification.
Freeze the reference setup before measuring parts
Record the table and hole system
Identify the actual table model, usable surface, hole system and grid pitch on the setup sheet. For example, the TA282010N D28 table is listed with a 2000 × 1000 mm working surface, a 100 × 100 mm tabletop hole grid and top and side mounting holes. Its product page lists Q355B steel and nitriding/oxidation for that model. These are platform specifications, not a promised tolerance for your weldment.
Mark the hole positions actually used, including any side-face mounting, then record the accessory identifiers and orientations. A D28 hole name alone does not tell another operator which edge of a stop is the contact face or which way a clamp swings. Use a top-view sketch and two or three labeled photos; keep the image set as an inspection record rather than putting decorative images into the purchasing document.
Separate locators, supports and clamps
List the surface each locator contacts and the feature it controls. Supports carry the work at planned heights; clamps push it against defined contacts. If a clamp becomes the only thing establishing a dimension, the part can move when pressure changes. Our datum setup guide explains how to choose reference faces before placing accessories on the grid. The first-article check then tests whether those intended contacts were used on the real parts.
Note shims, adjustable supports, replacement bolts and any temporary spacer. The as-built list matters more than the first CAD layout if the team changed hardware during the trial. Never silently carry a trial shim into production without revising the setup sheet.
Inspect at four moments, not only at the end
The inspection plan should follow the point at which a problem can still be corrected. The stages below are a practical starting sequence; the released drawing and agreed welding procedure decide the exact acceptance checks.
| Stage | What to check | Why it matters |
|---|---|---|
| Loaded, before tacking | Part identity and revision, contact at intended datums, joint gap, support height, clamp clearance and weld access | Finds a poor fit or a misplaced locator before heat locks the assembly together |
| After tacking | Critical overall dimensions, diagonals or angles specified on the drawing, joint position and any lifted contact | Shows whether the planned tack sequence preserved the setup |
| After welding and cooling | Features that can change with heat, visible weld condition and remaining access for measurement | Separates welding effects from the initial fixture setting |
| After clamp release | Free-state geometry, fit to mating parts where specified, and repeatability on a second loading if required | Reveals a part held to shape only by clamp pressure |
Do not put a pass mark against “flatness” or “squareness” without saying which surface, length and method were measured. If the drawing controls a frame diagonal, record both measured diagonals and the stated limit. If no tolerance has been supplied, ask the buyer for one; do not invent an acceptable difference because the table looks flat.
Make the measurement report usable
For every controlled feature, show the drawing callout, nominal value, tolerance, actual result, instrument or gauge, inspection stage and pass/fail decision. Record whether the weldment was supported, clamped or free when measured. A measurement taken against a stop is not interchangeable with the same dimension on a released part unless the drawing or agreed method says it is.
Choose a method that can resolve the tolerance you are judging. A tape measure may establish gross envelope size but may be unsuitable for a tightly controlled hole location. A long diagonal can be affected by where the operator places the tool. Agree contact points and repeat the method on subsequent parts. Where traceability is required, document the measuring equipment and calibration chain for the result; NIST’s metrological traceability guidance explains why traceability and measurement uncertainty belong to the result rather than to a calibration sticker alone.
Keep the table’s hole grid out of the acceptance column unless it is explicitly part of the drawing’s measurement method. The grid helps position tooling; the weldment drawing defines the part. For large frames, agree whether measurement occurs on the table, on independent supports or in an assembly trial, and record that condition so the buyer can reproduce it.
Run the build sequence as the operator will use it
Have the production operator load the first set of components using the proposed instructions. Watch for parts that must be forced into place, clamps that cover a weld, stops that block removal, and bolts that have to be loosened before the final weld is complete. The fixture can be dimensionally sound yet awkward enough to invite a different, undocumented sequence on the next shift.
Place a marked copy of the weld-access plan beside the setup sheet. Check the actual torch or gun path through tacking, final welding, cleaning and inspection. Confirm that measuring tools can reach controlled features at the stated stage. If a clamp must move, specify when it moves and whether the part still has enough locating contacts after the move.
Make one controlled adjustment at a time during the trial. If the team moves a stop, changes tack order and adds a shim together, a passing part will not reveal which change mattered. After adjustment, update the hole map, accessory list and inspection record before calling the fixture ready.
Decide whether the fixture is ready for a batch
A pass decision needs both a conforming part and a stable method. Review the measured first article against the drawing, then ask whether another operator could produce the next one with the recorded hardware and sequence. If repeatability is a critical contract requirement, schedule a second loading or changeover trial rather than inferring it from one welded part.
When a feature fails, keep the nonconforming part identified and record the actual value. Work back through material cut length, fit-up, contact faces, support heights, tack sequence, weld sequence and clamp release. Do not “correct” a weldment by pushing harder with a clamp and then report only the in-fixture result. Revise the fixture or process, weld another controlled first piece, and inspect the affected features again.
This is also the point to decide whether a custom fixture is justified or whether modular hardware is enough. A family of similar frames may benefit from a documented hole map and adjustable stops. A repeated part with difficult free-state geometry may need dedicated locators or a different welding sequence. The first-article report gives you evidence for that decision; the catalog alone cannot.
Send a clear approval pack to the buyer
For a remote purchasing team, request a compact pack rather than a large unlabelled photo folder:
- Released weldment drawing and revision, with the inspected features marked.
- Table model, hole system, grid pitch, accessory part numbers and the as-built hole map.
- Loading, clamping, tack, weld, inspection and removal sequence.
- First-article results showing limits, actual values, inspection state and equipment used.
- Photos labeled by stage, plus a list of changes made after the first trial.
- Disposition of any failed feature and the results of the corrective trial.
Ask who owns future setup revisions and how replacement accessories will be identified. If the fixture will be shipped overseas, agree how the hardware and documentation are packed and labeled so the receiving shop can rebuild the approved arrangement. The pre-shipment inspection checklist covers the separate table and delivery checks; it does not replace inspection of your welded first piece.
Common buyer questions
Does a flat welding table prove the welded part will pass?
No. Table condition, locator placement, component fit-up, welding sequence and clamp release all affect the final geometry. Inspect the actual part against its drawing at the agreed stage.
Can a first article pass while it is still clamped?
Only if the agreed drawing or inspection method specifies that constrained condition for the feature in question. Otherwise, add a free-state check after the assembly has cooled and the clamps have been removed.
Get the fixture brief checked before ordering
If you are buying a D28 table or a fixture for a repeat weldment, send the drawing revision, material and section sizes, critical dimensions, expected welding sequence, destination and required approval records with your request for a quote. We can then discuss the table size, hole layout and accessory list against your actual part, with any unconfirmed tolerances or inspection obligations left visible for agreement before the order.