Type
Welded frames, portal frames and cage frames
Open frames of hollow section or plate that carry something rather than stand under a machine: portal frames and arches, lattice and truss frames, cage frames of square tube, rotating gantry rings, lift frames with pivot lugs, reel stands with a bored tower. The common thread is the weld, not the machining: most of these frames are welded out, blasted and painted, and only a bore or a pad is machined.
This type is the widest in the group, from a handling frame of a metre and a quarter to a lattice girder frame close to six metres.
What the drawing must show
A part like this is priced from the drawing. The quotation is fastest when it carries:
- The section sizes and the wall thicknesses, with the material grade
- The squareness and straightness the frame must hold, if tighter than the general tolerance
- Which lugs, bores or pads are machined, and their tolerances
- Weld symbols on the joints that carry load, and the inspection level
- The finish, and whether the frame is painted or hot-dip galvanised
17 models of this type
Real structures that came through this company as built jobs, quoted enquiries or designs from our own office, shown as anonymous models with their measured size. Open one for its description.
- Overall size, L x W x H
- 6 437 x 2 730 x 1 869 mm
A portal frame weldment built from tapered box section arms joined at a flat plate crown, with small brackets and lugs along the top and a braced linkage frame hanging under one arm. The sloped arm ends in a bored pivot eye, stiffened by a row of gussets at the open end. It measures about 6.4 m long, 2.7 m wide and 1.9 m high. Parts like this are tack welded on a fixture and welded out, with every bore and pad cut after welding.
- Overall size, L x W x H
- 3 270 x 2 160 x 1 515 mm
A lift frame built around two curved cheek plates set at a kinked angle, with a row of straight grille bars spanning the opening between them. Pivot lugs with bored eyes sit at both ends, a cylindrical bore runs along one arm, and small mounting lugs sit on the cheek faces. It measures about 3.3 m long, 2.2 m wide and 1.5 m high. A part like this is tack welded on a fixture and welded out, with the bores and pads machined after welding.
- Overall size, L x W x H
- 3 490 x 2 260 x 2 267 mm
A reel stand weldment made from two stacked plated box sections on a sloped, rib-stiffened base, carried on two long beam feet joined by cross bars and footplates. A large round bore through the upper box, triangular stiffening ribs on the sloped face, a rear access opening and top lifting lugs stand out. It measures about 3.5 m long, 2.3 m wide and 2.3 m high. Parts like this are welded out on a fixture, with the bores and pads machined after welding.
- Overall size, L x W x H
- 5 690 x 1 980 x 1 230 mm
A lattice girder frame formed from two parallel box-section girders with diagonal bracing, tied together by cross beams across the top to close out a rigid box structure. One end carries thick drilled end plates and flange pads with bolt patterns, with projecting brackets at the corners for connection. It measures about 5.7 m long, 2.0 m wide and 1.2 m high. A piece like this is welded out on a fixture, with every bore and pad cut after welding.
- Overall size, L x W x H
- 2 783 x 762 x 2 095 mm
A rotating gantry frame built from rectangular hollow section, forming an open portal with raked legs, diagonal corner braces and a top rail carrying small mounting lugs. A foot rail joins the base, with pivot brackets at each lower corner where a bored seat lines up each side for rotation. It measures about 2.8 m long, 0.8 m wide and 2.1 m high. Such a part is run on the 14 m robotic welding track when the batch allows, with the bores and pads machined after welding.
- Overall size, L x W x H
- 3 155 x 2 573 x 1 425 mm
A braced truss frame made of two long folded side panels tilted on an incline, held apart by cross tubes and diagonal bracing, with pivot lugs and mounting brackets at both ends. The folded top edge of each panel and the crossed bracing underneath stand out, keeping the whole frame square and rigid. It measures about 3.2 m long, 2.6 m wide and 1.4 m high. Parts like this are folded on the press brake and welded out on a fixture.
- Overall size, L x W x H
- 1 855 x 1 250 x 1 284 mm
A heavy front frame of this kind combines a ribbed box base with angled gussets and bolting lugs at the corners, carrying two tall cheek plates pierced with pin bores and stiffened by curved ribs. A bored circular seat sits on the rear face, with lifting lugs and small mounting flanges nearby for pins and brackets. It measures about 1.9 m long, 1.3 m wide and 1.3 m high. Such parts are welded out on a fixture, then machined after welding on a horizontal boring mill.
- Overall size, L x W x H
- 3 130 x 2 125 x 2 200 mm
A side frame pair like this carries two tall plate uprights joined across by three long tie bars. Each plate has a stepped, notched outline with large and small bores, mounting pads and brackets along its edges, matched on both sides. The stepped profile and dense bore pattern stand out, giving mounting points at several heights. It measures about 3.1 by 2.1 by 2.2 m. Here a part like this is cut from plate on the laser bed and tack welded on a fixture and welded out.
- Overall size, L x W x H
- 2 244 x 1 850 x 824 mm
A braced frame with side panels forms two sloping plate panels with folded top edges, set on a tube base with diagonal cross braces, gussets, pivot lugs and mounting brackets at the corners. The triangulated struts under each panel give an open trestle form, with bored lugs at both ends for pivot pins. It measures about 2.2 m long, 1.9 m wide and 0.8 m high. Here a part like this is set on a fixture, tacked and welded out, then machined after welding on a horizontal boring mill.
- Overall size, L x W x H
- 2 819 x 1 603 x 986 mm
A kinked frame like this starts as a rectangular base of channel and box rail, braced across with tubes, then rises into two upright posts tied by a cross member before kinking upward into a long boxed arm carrying welded hook brackets and lugs along its length. The row of mounting brackets on the raised arm stands out most. It measures about 2.8 m long, 1.6 m wide and 1.0 m high. A piece like this is set on a fixture, tacked and welded out.
- Overall size, L x W x H
- 4 000 x 2 181 x 1 158 mm
A welded box section frame forms a long rectangular ladder base with cross members. Plated corner brackets sit at each end, and rows of hook shaped lugs and small stiffener ribs stand up along both long sides, with bored pin holes through several brackets. The hook fronts and angled end brackets stand out most. It measures about 4.0 by 2.2 m, and 1.2 m high. Parts like this are set on a fixture, tacked and welded out, with every bore and pad cut after welding.
- Overall size, L x W x H
- 2 136 x 1 639 x 1 033 mm
A base frame of rectangular tube rails and cross braces forms a flat, open base with gusseted corners and a row of mounting bores along the rails. Two cranked, bored plate arms rise from one end, each with a small lug bracket, and a pair of short twin lugs sits at the other end. The stepped, bored arms stand out. It measures about 2.1 by 1.6 m, roughly 1.0 m high. Such parts are tack welded on a fixture and welded out.
- Overall size, L x W x H
- 1 809 x 1 701 x 931 mm
A welded frame built from rectangular tube rails and crossmembers, with a pair of curved tube arms rising from one end, braced by diagonal struts and gusset plates. Drilled lugs, clevis eyes and a flat mounting pad sit along the rails and arm tips, giving it a hook-like profile from both sides. It measures about 1.8 m long, 1.7 m wide and 0.9 m high. A piece like this is welded out on a fixture, with the bores and pads machined after welding.
- Overall size, L x W x H
- 1 740 x 1 620 x 937 mm
An open cube frame made from square hollow section posts and rails, with four parallel tube rails spanning the top and a lower ring of rails near the floor. Each corner post carries a bored, bolted plate for joining to adjoining frames, and short brackets sit partway up two posts. It measures about 1.7 by 1.6 m and stands 0.9 m high. A piece like this is tack welded on a fixture and welded out, then machined after welding on a horizontal boring mill.
- Overall size, L x W x H
- 2 067 x 1 110 x 740 mm
A cage frame built from square hollow section posts and rails, three open box frames nested together, the middle box taller and set forward of the two flanking ones. Top and bottom rails carry cross slats, corner posts stay open for access, and small brackets sit on one upright near the centre post. It measures about 2.1 m long, 1.1 m wide and 0.7 m high. Pieces like this are tack welded on a fixture and welded out, then blasted and painted in the booths on site.
- Overall size, L x W x H
- 2 100 x 340 x 1 267 mm
A cage frame unit built up from square hollow section uprights, cross members and a slim top rail set on raised stand-offs running the full length. One tier steps down into an open diagonal brace that closes the lower corner, and a bolted bracket plate sits into one of the uprights. The welded frame measures about 2.1 m long, 0.3 m wide and 1.3 m high. In this hall a part like this is welded out on a fixture, with every bore and pad cut after welding.
- Overall size, L x W x H
- 1 245 x 1 187 x 1 965 mm
A tall welded handling frame built from folded steel plate, with large cut-out window openings on two faces and a perforated grid panel across the top. One upright edge carries a row of small round holes, and the lower panel on the back face has a recessed rectangular cutout. It stands about 1.2 by 1.2 m in plan and 2.0 m high. Such a part is bent on the 400 t press brake and welded on the 14 m robotic track for a series, by hand for a one-off.
Each model is rendered from its own geometry in raw steel, without paint, and is shown as a still. Customer names, machine designations and drawing numbers are not published; part lists and files are not offered. The interactive model above this section is a parametric example, not one of these.
How a part like this goes through the hall
Tubes and sections are cut to length, plates are laser cut on a 2 000 x 4 000 mm bed, and the frame is set up on a table or a jig so it comes out square. Welding is by hand or on the robotic track for a series. A frame that stays within the envelope of the blasting chamber, 8 000 x 5 000 x 3 000 mm, is blasted and painted in house; galvanising is arranged on request.
Where this fits
Capabilities it runs through
Industries that order it
Notes from the blog
Other types in this group
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