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Sheet Metal Fabrication

Sheet Metal Fabrication — CNC, Tubular Pipe Frames & Assembly

A procurement engineer's guide to sourcing sheet metal fabrication in India — from CNC cutting and bending capabilities to welding, tubular pipe frame specialisation, tolerances, prototype-to-production workflows and the quality systems that separate OEM-grade fabricators from job shops.

Sheet Metal Fabrication 8 min read Published Jul 5, 2023 · Updated Apr 2026 Pantnagar · Rudrapur · NCR

Sheet metal fabrication is the physical foundation underneath virtually every engineered product in Indian manufacturing — from automotive chassis and agricultural implements to architectural facades and solar mounting. At Autotek Steel Engineers, 36+ years of precision fabrication have shaped a manufacturing capability that handles everything from single-piece prototypes to large-volume production runs, with tubular pipe frame specialisation that few Indian fabricators match. This guide walks through what we do, how we do it, and how procurement engineers should benchmark a fabrication supplier.

Our fabrication capabilities

Cutting

  • CNC laser cutting — precision profile cutting on sheet up to 20mm thick; excellent edge quality, minimal heat-affected zone.
  • CNC plasma cutting — cost-effective on heavier sections.
  • Shearing — high-volume straight-cut operations.
  • Mechanical sawing — tube and section cutting.

Forming

  • CNC press brake bending — multi-axis back gauge, programmable sequences for complex bend patterns.
  • Tube bending — mandrel and rotary draw bending for tubular pipe frames.
  • Rolling — cylinders, curves and architectural radii.

Joining

  • MIG / MAG welding — production welding of steel sheet and tube structures.
  • TIG welding — precision and stainless-steel work.
  • Spot / resistance welding — high-volume thin sheet assembly.
  • Mechanical fastening — riveting, clinching, self-piercing rivets.

Integrated surface finishing

Tubular pipe frame specialisation

Tubular pipe frames — the welded tube structures that form agricultural implement frames, automotive seat structures, two-wheeler sub-frames, furniture skeletons and architectural handrails — demand specialised fabrication competence. Unlike flat sheet metal, tube fabrication requires:

  • Accurate tube mitring — computer-generated fishmouth cuts for clean, strong joints.
  • Jig-based welding — purpose-built fixtures to hold geometry true during heat distortion.
  • Post-weld stress relief where structural tolerance demands it.
  • Inspection and geometry verification — CMM or laser tracker checks against 3D model.

Our Rudrapur facility (Sai Auto Industries) is specifically equipped for high-volume tubular pipe frame fabrication supporting automotive and agricultural OEM supply chains.

Prototype to production workflow

  1. RFQ & drawing review — 24-48 hour turnaround on technical quotes, including DFM feedback.
  2. Prototype — single-piece and low-volume builds on shared CNC time; first-article inspection report delivered.
  3. Pilot run — 50-200 piece validation batch; process capability study (Cp, Cpk) on critical dimensions.
  4. Production run — dedicated scheduling; SPC monitoring on key dimensions.
  5. Finishing & delivery — integrated coating + packaged-for-delivery.

Tolerances & standards

Typical sheet-metal fabrication tolerances achievable in our lines:

±0.1mmCNC cut accuracy
±0.5°Press brake bend angle
±0.5mmOverall tubular frame

Tolerances are tied to ISO 2768 (general tolerance medium class) by default; tighter tolerances on specific features available per customer drawing.

Quality systems

  • ISO 9001-2008 certified quality management system.
  • In-house CMM inspection for critical features.
  • Process capability studies — Cp/Cpk reporting on dedicated production runs.
  • First-article inspection on every new part number.
  • Traceability — material certificates, heat numbers preserved through production.

Industries we fabricate for

  • Automotive & two-wheeler OEMs — chassis brackets, tubular frames, body panels, fasteners.
  • Agricultural & construction equipment — implement frames, tractor hoods, excavator covers.
  • Architectural & construction — facade panels, railings, louvres, canopy structures.
  • Furniture manufacturers — tubular office chair and desk bases, filing cabinet frames.
  • Renewable energy — solar mounting structures, wind-tower hardware.
  • Aerospace & defence-grade work — precision sub-assemblies with traceability.
Quick answers

Sheet Metal Fabrication FAQ

Do you handle prototypes or only volume production?
Both. Our sheet metal fabrication lines are specifically set up to handle prototypes, low-volume pilot runs and large-scale production. Prototype work typically runs on shared CNC time with full first-article inspection reports.
What material thicknesses can you fabricate?
Standard capability is 0.5mm to 20mm on CNC laser cutting; heavier sections up to 40mm on plasma. Press brake bending handles sheets up to 6mm thick across common widths. Tube fabrication supports diameters from 12mm up to 100mm OD in common wall thicknesses.
Are your fabrications ISO certified?
Yes. Our quality management system is ISO 9001-2008 certified, covering all fabrication, welding, inspection and traceability processes. Full material certification and dimensional inspection reports accompany deliveries on customer request.
Do you specialise in any particular fabrication?
Yes — tubular pipe frame fabrication is a specific specialisation at our Sai Auto Industries unit in Rudrapur, supporting high-volume automotive and agricultural OEM programs with jig-based welding and geometry-verified assemblies.
Can fabrication and coating be combined in one purchase order?
Yes — most customer orders combine fabrication and finishing (powder coating, CED, zinc plating, etc.) under a single PO. Single-source delivery avoids logistics hand-offs, reduces lead time and simplifies quality traceability.

Need a fabrication partner?

Share your drawings, quantities and tolerance specs — our CNC lines and assembly capabilities support prototype through large-scale production for automotive, aerospace and architectural applications.

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