Welding knowledge for enclosure buyers
TIG Welding Sheet Metal: An OEM Enclosure Guide
TIG welding can be a good choice for thin stainless steel, aluminum and visible enclosure joints when control and appearance matter. It is not automatically the best or lowest-cost process for every seam; material, access, production volume, distortion risk and finishing expectations should decide the route.
Buyer summary
TIG Welding at a Glance: Fit, Risk and Inspection Focus
| Best-fit questions | Material, thickness, joint access, cosmetic face and annual quantity |
|---|---|
| Drawing information | Weld location, symbol, required appearance and critical post-weld geometry |
| Main production risks | Fit-up variation, burn-through, heat distortion and excess grinding |
| Inspection focus | Joint continuity, visible defects and drawing-defined dimensions |
When TIG Welding Fits a Sheet Metal Enclosure
TIG welding gives the operator close control of the arc and filler addition. That can be useful around thin stainless panels, aluminum assemblies, corners and joints that remain visible after fabrication.
For repeat OEM work, however, the decision should also consider cycle time and fixture stability. A long cosmetic seam on a thin door may look straightforward in CAD but accumulate heat and pull the panel out of flatness. In some designs, a shorter weld pattern, additional formed features or mechanical fastening produces a more stable result.
The Drawing Must Define More Than “TIG Weld”
A useful fabrication drawing identifies the joint location, weld length or continuity, accessible side, visible face, grinding scope and the geometry that must remain controlled after welding. If penetration or a specific weld standard matters, the buyer should state the applicable requirement and evidence.
Gaps caused by inconsistent laser cutting or bending cannot be repaired economically by adding more weld. Fit-up, tack sequence and fixture contact are part of the welding process, so the factory needs the assembly drawing as well as individual part drawings.
How We Reduce Distortion and Cosmetic Risk
The practical controls are joint fit-up, restraint, tack order, balanced sequence, limited heat input and checking the assembly while correction is still possible. Grinding should be limited to the faces that truly require it because excessive dressing can thin the sheet and create waves.
For a prototype, the first article should verify squareness, door fit, mounting interfaces and the final appearance after cleaning or coating. Once those points are approved, the same fixture, sequence and revision become the basis for the repeat batch.
When Another Process Welds the Same Seam Better
TIG is not a default setting. It costs cycle time, so it should pay for itself in appearance, leak-tightness or heat control. On a long straight seam above about 3 mm that will sit behind a panel, MIG deposits metal several times faster and the bead shape does not matter. On high-volume lap joints in thin sheet, laser welding puts far less total heat into the part and needs no filler, which usually means less correction afterwards. Where the assembly has to come apart for service, or where two dissimilar materials will not weld cleanly, a PEM fastener or a rivet is the more honest answer.
The test we apply is simple: multiply the annual quantity by the total welded length per unit. When that number is high and the joint is not visible, TIG is usually the wrong route. When it is low, or the seam sits on a face the end user will look at, TIG earns its place. Full comparison in TIG vs MIG vs laser welding.
From Weld Bead to Finished Surface
The weld is not the last operation, and what happens between the arc and the final finish decides whether a joint looks deliberate or looks repaired. On stainless, heat tint has to come off before the part can passivate; left in place it becomes the first place rust appears even though the base metal is stainless. The drawing should state how far dressing goes — ground flush, blended, or as-welded — because grinding a thin panel removes thickness and can leave a visible dish. Direction matters too: on a brushed face, a scratch pattern running across the grain reads as a defect under the same lighting that hides it elsewhere on the panel.
Coating exposes what grinding hides. Gas porosity that looked acceptable on bare metal tends to open as pinholes after powder coating, because trapped gas expands in the cure oven. That is why the cosmetic standard is worth agreeing on a finished sample rather than on a raw weld. See surface preparation before coating and common welding defects.
Buyer questions
TIG Welding Questions Buyers Ask Before Approving a Sample
These answers define the discussion points. Final values and acceptance criteria are confirmed against the project drawing and purchase requirements.
Is TIG always the best process for thin sheet metal?
No. Joint access, appearance, material, thickness, heat sensitivity and production volume determine whether TIG or another joining route is more practical.
What should a drawing say about visible welds?
Identify cosmetic faces, weld locations, grinding scope and the approved appearance reference. A general note such as "smooth weld" is not an objective acceptance standard.
How is distortion evaluated?
We review the completed assembly against agreed datums, flatness, squareness, door gaps and mating dimensions rather than judging the weld bead alone.
RFQ checklist
What to Send With a TIG Welding RFQ
- Send material grade and actual thickness
- Mark visible and non-visible welds
- Define continuous, intermittent or sealed joints
- Identify post-weld flatness and squareness needs
- State finish, grinding and inspection expectations
Tungsten, Current and Gas Settings That Hold on Thin Sheet
TIG is chosen for sheet metal when the weld is visible, when the joint has to be leak-tight, or when the heat-affected zone has to stay narrow. The values below are the starting window our welders tune from on a sample coupon before production. They are not finished procedure values: polarity, tungsten grind, backing and joint fit-up each move them.
| Material and thickness | Tungsten | Polarity / current | Filler wire | Argon flow (L/min) |
|---|---|---|---|---|
| Carbon steel 0.8-1.5 mm | Lanthanated 1.6 mm | DCEN 35-70 A | ER70S-2 or ER70S-6, 0.8-1.0 mm | 6-8 |
| Carbon steel 2.0-3.0 mm | Lanthanated 2.4 mm | DCEN 80-130 A | ER70S-6, 1.6 mm | 8-10 |
| Stainless 304/316 0.8-1.5 mm | Lanthanated or ceriated 1.6 mm | DCEN 30-65 A | ER308L or ER316L, 0.8-1.0 mm | 6-8, plus back purge on roots |
| Stainless 304/316 2.0-3.0 mm | Lanthanated 2.4 mm | DCEN 75-120 A | ER308L or ER316L, 1.6 mm | 8-10, plus back purge |
| Aluminium 1.0-2.0 mm | Zirconiated or lanthanated 2.4 mm | AC, balanced towards cleaning, 60-110 A | ER4043 or ER5356, 1.6 mm | 8-10 |
| Aluminium 3.0-4.0 mm | Zirconiated or lanthanated 3.2 mm | AC 110-170 A | ER5356 for strength, ER4043 for crack resistance, 2.4 mm | 10-14 |
Two disciplines carry more weight than any number in that table. Keep the tungsten grind consistent, because a blunt or contaminated tip wanders and widens the bead beyond what the current setting predicts. And keep the gas shield intact until the bead has cooled below the point where it oxidises — post-flow is not optional on stainless. Both are the usual explanation for grey, sugared beads that fail a cosmetic inspection while every parameter on the sheet looks correct.
From research to RFQ
Send the Welded Assembly for a TIG Review
Send the current files, quantity, material, finish and assembly context. We will identify the questions needed for a practical manufacturing review.
What stands behind this quotation
- Manufacturing since 20162,500 m² Ningbo plant — 3 laser cutting machines (including newer TRUMPF), 4 CNC press brakes and 10 welding stations.
- Shipped to more than 30 export marketsEnclosures, cabinets and formed parts supplied to OEM buyers across Europe, North America and Asia.
- 123 documented product casesMedical device housings, HVAC and heat pump enclosures, agricultural and livestock equipment, industrial hydraulics, material handling trolleys and EV charging cabinets.
- Factory evidence you can checkTUV Rheinland audit reference MIC-ASI243729 and Bureau Veritas reference MIC-ASR263630 available for buyer review on request.
Before you send drawings: project confidentiality is default · first-article inspection is carried out before a batch continues · pricing is staged from prototype quantity to repeat volume · pre-shipment photos and packing records are prepared when the project needs them.