Welding tooling · Buyer's guide
A fixture has two jobs that must be checked separately: locate the unwelded parts, then manage movement as the joint heats and shrinks. The buying decision is whether the assembly can be loaded, welded and removed with the required dimensions after release—not simply whether the clamps hold it tightly.
01
The four component groups below describe a functional welding-fixture assembly. Their quantities, part numbers and material grades depend on the actual drawing. They are not a manufacturing BOM for one supplier’s model. Carr Lane supports the locating and force-path explanation; Siegmund illustrates the modular table arrangement. [2] [1]
| Component / BOM reference | What it does | Material and purchasing detail |
|---|---|---|
| Base plate or modular table | Carries the locating/support arrangement and establishes the mounting surface. A modular bore pattern accepts the system’s fixing elements. [1] | Order the actual table/base material, surface treatment, flatness, dimensions and mounting arrangement. The system comparison gives plate dimensions and load guidance, not one universal steel grade. [1] |
| Locating pins and stops | Establish the position from the specified holes, edges or faces. A relieved second pin can avoid redundant location from two holes. [2] [6] | Specify contact geometry, fit, replaceability and the selected catalogue part or drawing. “Hardened steel” alone does not identify a grade, hardness or service replacement. No universal pin material is assigned here. |
| Clamping arms and contact pads | Seat and retain the work against its supports and locating references. Clamp direction and contact position affect part bending. [2] | Identify the manual/powered mechanism, pad and contact material, force at the working position and mounting hardware. A generic steel label is not evidence for the supplied arm or pad. |
| Support blocks / rest points | Support the part at the required height and back up clamp force; distinguish a datum contact from a support added for stiffness. [2] | Specify height, adjustment/locking method and contact material. Check the supporting arrangement with the part drawing; no Q235, 45-steel or 40Cr grade is assumed. |
For a dedicated station, request the actual assembly drawing and itemised parts list, including actuators, sensors and interlocks where supplied. The four functional groups above do not establish the quantity or safety configuration of an automated cell.
02
Modular welding tables use a grid of bores and standard bolts, stops and clamps. Siegmund, a German table maker, defines its three systems by bore size [1].
Mission describes dedicated automotive fixtures and robotic workstations, including interference checks and cycle-time analysis. Compare that scope with a modular table when the work involves repeated datum locations, robot access or variant changeover. A production quantity alone does not establish the economic break-even point; ask each builder to quote the required loading, welding and unloading sequence. [5]
| System 16 | System 22 | System 28 | |
|---|---|---|---|
| Bore | Ø16 mm | Ø22 mm | Ø28 mm |
| Grid | 50 × 50 mm | 100 × 100 mm or diagonal | 100 × 100 mm or diagonal |
| Plate thickness | approx. 11.5–13 mm | approx. 17–19 mm | approx. 24.5–27 mm |
| Table side height | 100 / 150 mm | 150 / 250 mm | 200 / 300 mm |
| Recommended load | up to 2,000 kg | up to 3,000 kg | up to 6,000 kg |
| Typical use | Fine, precise fixtures with little distortion | General metalwork, moderate distortion forces | Heavy steel structures, high clamping and distortion forces |
These are Siegmund catalogue comparisons, not universal specifications for every welding table. Recommended loads depend on the type and number of legs. Siegmund also offers connecting elements between systems: different bore sizes are not directly interchangeable, but “only within one system” would overlook those purpose-designed connectors. Confirm the actual table, leg, bolt and accessory configuration. [1]
03
Carr Lane’s guide explains workpiece location in a general fixture-design context. Its machining-force examples are not estimates of weld shrinkage force. Apply the locating principles to the weldment drawing and assess the thermal behaviour separately with the welding process. [2] [3]
Show which faces, edges and holes establish the coordinate system, and how the fixture and inspection setup relate to those features. [2]
Carr Lane describes one round pin with one diamond pin for location from two holes without binding. The diamond pin locates in one axis. Its orientation and fit still belong on the fixture drawing. [6]
Check how parts seat before welding. Unplanned interference needs investigation; intentionally pre-springing a part is a different, engineered distortion-control method described by TWI. Do not reject every forced offset as a tolerance mistake, or accept an unexplained one as a process setting. [3]
04
TWI, the UK welding research organisation, describes three assembly methods to limit distortion when design changes are not possible [3].
TWI notes that "when MMA or MIG welding butt joints, the joint gap will normally close ahead of welding", while with submerged arc welding the joint may open up during welding [3]. Fixtures and tack sequences must allow for the process used.
TWI calls for considering balanced welding and easy removal from the fixture. Ask the builder to show the loading, tack/weld and unloading sequence, including the condition at which dimensional acceptance takes place. The part’s position while clamped does not prove its dimensions after release. [3]
The public abstract for ISO 13920:2023, edition 2, covers general linear, angular, shape and position tolerances in four classes, chosen for functional requirements. Individually specified drawing tolerances take precedence. It does not provide a fixture’s positioning accuracy or certify weld quality. The paid numerical tolerance tables were not used for this page. [4]
| Method | How it works | Trade-off |
|---|---|---|
| Pre-setting | Parts are set at an offset and left free, so shrinkage pulls them into line [3] | Low residual stress and no costly equipment, but the offset is hard to predict and needs representative trial welds [3] |
| Pre-bending | Parts are pre-sprung, for example with strongbacks and wedges, to counter shrinkage [3] | Effective for angular distortion in thin plate [3] |
| Restraint | Clamps, jigs and fixtures hold parts during welding [3] | TWI calls it "the more widely practised technique"; some movement on release from locked-in stress, and higher residual stress that can cause cracking in susceptible materials [3] |
05
Use these fields to define an order and acceptance check. The modular-system dimensions above are sourced catalogue data; the unfilled fields below require the selected fixture’s drawing or test plan. A clamp, a bare table and a complete welding cell do not share one rating.
| Specification field | Unit / basis | What the quotation must identify |
|---|---|---|
| Clamping force | N or kN at the work contact | Force, direction, arm position and supporting contact. More restraint is not automatically better distortion control. [2] [3] |
| Clamping stroke | mm | Working travel and clearance for inserting/removing the part. Ask the builder to demonstrate the full motion with the actual assembly. |
| Positioning accuracy | mm against named datums | The feature measured, permitted error and inspection condition. Do not substitute Mission’s undefined machining-accuracy statement for locator-position acceptance. [5] |
| Operating temperature | °C; component and exposure stated | Permitted conditions for the selected contacts, actuators and sensors; distinguish local welding heat from room ambient. No category-wide temperature limit is verified here. |
| Operating pressure | MPa or bar, for powered clamps only | Supply requirement and allowable range from the selected actuator documentation. Manual clamps have no pneumatic supply requirement; no generic 0.4–0.8 MPa range is established. |
| Material grade | Drawing / component specification | Base, locating contacts, support blocks and clamping elements listed separately, with heat treatment where required. A single steel grade for the whole fixture is insufficient. |
| Surface treatment | Process and affected surfaces | Identify treatment, masking and dimensional allowance on locating contacts. An anodizing claim alone does not establish a final positional tolerance. [5] |
| Fixture weight | kg; included equipment stated | Separate tooling mass from workpiece mass and any positioner. Do not equate greater mass with a verified stiffness or load rating. |
| Base-plate dimensions | L × W × thickness, mm | Provide usable area, mounting pattern and support/leg arrangement. The Siegmund system data illustrate why plate thickness and leg configuration must accompany a table selection. [1] |
| Adjustment range | mm / degrees; axis identified | Identify the adjustable locator or clamp, locking method and setup references. A general range does not define usable access for every weld. |
| Repeatability | mm; repeated loading/setup test | Agree the measured features, loading/clamping procedure, number of trials and thermal condition. Repeatable location in the jig is separate from the released welded-part tolerance. [2] [3] |
| Duty cycle | Defined operating cycle / parts per shift | State load, clamp, weld, cool/release and unload timing for the intended process. Do not assign “continuous duty” to an unspecified actuator or station. |
06
Mission’s robotic welding-cell page supplies a real example of a builder’s published scope. Its staffing, site and lead-time figures are undated website statements, not a current capacity audit or a delivery commitment. [5]
Mission also states machining accuracy of 0.008 mm before anodizing and 0.0005 mm after anodizing, without defining the measured feature or method. Preserve those as an unresolved supplier claim, not an expected accuracy improvement after coating. Ask for a locator inspection report against the agreed datum scheme, followed by a trial on representative welded parts measured after release. These are proposed purchase acceptance steps, to be agreed with the builder. [5]
07
Carr Lane’s fixture-design guidance calls for accessible, cleanable locating features and avoiding locations where debris interferes with seating. In a welding application, use that principle to plan inspection and cleaning access around the reference contacts. This is a design check, not a prescribed maintenance interval. [2]
08
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Supply boundary: [modular table / dedicated jig / complete welding cell]; quantity [ ] Part drawing and revision: [ ]; CAD, materials and thicknesses: [ ] Drawing datums, critical dimensions and acceptance condition after release: [ ] Welding process and procedure: [ ]; manual / robot: [ ]; access restrictions: [ ] Part variants and production target: [ ]; loading and changeover method: [ ] Proposed locating, support and clamp scheme: [ ]; clamp drive / utilities: [ ] Distortion plan: [pre-setting / pre-bending / restraint]; representative trial parts: [ ] Modular option: bore system, table size, leg configuration, part load and accessories: [ ] Required documents: assembly BOM, locator inspection, operating/maintenance instructions: [ ] Acceptance: agreed fixture checks and trial-weld measurements after release: [ ] Cell option: positioner / robot / guarding / interlocks / integration responsibility: [ ] Delivery location, design approval and trial dates: [ ]
Dedicated automotive tooling and a modular welding table are different purchases. The companies below are described from the published scope of each website.
Publishes dedicated arc/spot fixtures and robotic welding workstations. Clarify fixture-only versus complete-cell delivery and require project-specific locator and trial-weld acceptance; its machining-accuracy statement is not a welded-part guarantee.
Product scope checked 2026-10-10
Publishes battery-box/tray welding fixtures and robotic welding integration. Ask for the part-specific support, clamping and robot-access layout rather than treating a battery-box example as a universal fixture.
Product scope checked 2026-10-10
Lists 3D welding fixture tables and castings. This supports a modular-table offering; a dedicated jig, actuators or a complete robot cell must be separately confirmed.
Product scope checked 2026-10-10
Publishes a welding-fixtures product page within vehicle production equipment, but provides little technical specification. The product footer names Henan Xunche while the contact page names China Vehicle Industry; confirm the quotation issuer, manufacturer and exact deliverables.
Product scope checked 2026-10-10
Describes welding fixture design, positioners and workstation integration, including process engineering. Establish the delivered fixture/cell boundary and local commissioning responsibility. The published contact address is in Taoyuan.
Product scope checked 2026-10-10
Publishes automotive checking fixtures, welding jigs and body-in-white welding lines. A checking fixture is a separate inspection tool; specify whether the order is for weld tooling, inspection tooling or a complete production line.
Product scope checked 2026-10-10
Lists 3D welding platforms and welding-fixture workbenches. Confirm the actual table/bore system, supporting structure and included clamps; a table listing does not establish an automated welding station.
Product scope checked 2026-10-10
Publishes 2D/3D welding tables with clamping and locating accessories. Request the configuration drawing and compatible accessory list; the general product range does not establish the load rating of a particular assembly.
Product scope checked 2026-10-10
Lists an Alignment Nest (LH & RH) under Welding Fixtures, alongside its broader automotive tooling offering. The detail page does not give a dimensional specification; request the actual jig drawing and trial acceptance, rather than substituting checking-fixture accuracy for a post-weld result.
Product scope checked 2026-10-10
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
Select for part geometry, access, fixture forces and the complete table/support load configuration. Siegmund identifies System 16 by 16 mm bores and a 50 mm grid, and System 28 by 28 mm bores with 100 mm or diagonal layouts. Check the catalogue configuration and compatible accessories, including any approved cross-system connectors. [1]
Three primary, two secondary and one tertiary locating contacts establish the reference arrangement in Carr Lane’s example; clamps seat the part. It is a locating principle, not a claim that every weldment needs six separate components or no additional support. [2]
No. TWI explains that restraint limits movement but can leave residual stress, movement on release and cracking risk in susceptible materials. The appropriate clamp arrangement depends on the part and qualified welding approach, not a universal maximum force. [3]
Into the locators or supports, so the clamping force does not bend the part. [2]
Sources checked 2026-10-10. Standards bodies and regulations define the requirements; manufacturer pages show published ranges for those models only. CNFX does not certify products or suppliers.
Ask for use case, specification boundaries, supplier type, and RFQ preparation information for this product.
Compare manufacturer profiles with relevant product and process capability.