Elevator counterweight frame manufacturing

A counterweight frame holds stacked weights, runs on guide shoes and survives a shaft environment that is often damp. Ganesh makes counterweight frames for TKE and Eros Elevators as complete coated assemblies: laser cut, formed, fixture welded, pretreated and powder coated. The table below is the working specification; the customer drawing always takes precedence where the two differ.

Cut. Laser cut side plates, cross members and gussets. Control: 12 kW fibre laser, ±0.5 mm part tolerance.

Form. Press brake returns and stiffening flanges. Control: 200 T / 4,450 mm brake, stored program.

Weld. Fixture MIG welding of frame and shoe mounts. Control: Robotic or fixture manual, dimensional check.

Finish. Shot blast where required, seven tank, powder coat. Control: DFT and adhesion checked.

Inspect. Diagonal, hole position, coating, packing. Control: Recorded per batch.

Material grade and thickness, the tolerance on every functional feature, the finish and colour, masking requirements, weld size or symbol where relevant, the inspection level, and the packing method. Where a standard applies, name it and the revision. Three missing items on a drawing cause most quotation errors: material grade, finish specification and annual quantity.

The three failures that reach the shaft are a twisted frame from welding without a fixture, a hole pattern that drifts because it was match-drilled rather than jig-bored, and coating breakdown at the shoe mount where pretreatment could not reach. Each is prevented before the first weld: fixture, drawing tolerance and part design for drainage.

Cost is dominated by weld length and fixture time, not by material. A frame with 4 m of weld costs far more to make than a frame with 1.5 m, even at the same weight, because fit-up and weld time scale with joint length.

The frame carries the block, it does not resist the load itself. That changes the material decision: 4–6 mm CRCA or mild steel is enough for the frame members because the block supplies the mass, and going thicker adds handling weight on site without adding safety. What matters is the bearing area under the block, the flatness of the base member and the position of the shoe mounts relative to the rail. A frame that is 2 mm out of flat puts the shoes into a bind that no amount of adjustment at commissioning will fully remove.

Shafts are damp, dusty and difficult to access. Drainage matters more than the drawing usually says: a closed box member with a horizontal weld and no drain hole will hold water and rust from the inside out. Ganesh raises this at the manufacturability review, because it is a design decision, not a fabrication one. Coatings are specified against the shaft environment rather than a generic RAL code, and masked areas are agreed so the shoe mounting faces stay clean.

The frame is checked on diagonal, overall height and width, shoe mount position and block bearing flatness. General tolerances follow ISO 2768-m unless the drawing is tighter; hole positions that locate shoes or rails are inspected on a fixture rather than with a tape. The inspection record travels with the batch, which is what a lift OEM audits at supplier review.

If the frame is being re-quoted because it is consistently out of tolerance, the fix is usually the fixture or the weld sequence, not thicker steel. If it is being re-quoted because installation is slow, the fix is usually a slotted shoe mount or a locating tab that lets the fitter adjust without a hammer. Both are cheaper than a redesign.

Send the assembly drawing at its current revision, the frame material and thickness, the block size and weight, the shoe type and mounting interface, the coating specification, the annual quantity and the delivery plant. If a frame already exists and is being re-sourced, send one physical sample or a full dimensional report: matching an existing frame is faster when the actual geometry is known, not just the nominal drawing.

Ganesh operates under ISO 9001:2015 and ISO 14001:2015, with an independent inspection function, material traceability to mill certificates and in-process inspection records. First article inspection reports and PPAP documentation are available where the programme requires them.