Which class of shop does your frame need?
A fabricator is limited by three things you cannot see on its website: the crane in the bay, the length of the stress-relief furnace and the travel of the machine that finishes the part. Enter your piece and see what it demands of a shop, before you ask anyone to quote.
The classes the tool uses
Typical equipment classes seen in heavy fabrication shops. They are thresholds for screening, not a specification, and a shop can sit between them. The shop that quotes confirms its own numbers.
| Shop class | Crane | Stress-relief furnace | Machine table |
|---|---|---|---|
| Light | Up to 10 t single hook | Up to about 4 x 2.5 x 2.5 m | Up to 3 m travel |
| Medium | Up to 20 t, often two cranes for tandem lifts | Up to about 8 x 3.5 x 3.5 m | Up to 6 m travel |
| Heavy | Up to 50 t, or 2 x 32 t tandem | Up to about 12 x 5 x 4.5 m | Up to 12 m gantry mill or large HBM |
| Specialist | Above 50 t, or 100 t tandem with a lift plan | Larger furnace, or local or vibratory relief agreed by the designer | Above 12 m, or machining on site |
Crane demand is the finished weight times 1.25 for rigging, spreader beam and the fixture the piece is welded on. A piece that fits the crane in the fabrication bay may still not fit the crane in the machining bay; ask about both.
Furnace fit is checked against the piece dimensions plus 300 mm each way for supports and thermocouples. Machine table fit uses the longest machined span against the machine's travel; the piece may sit on the table even if only part of it is machined.
Go deeper
- Shipping envelope checker: will it fit a container once it is built?
- Stress relief for welded machine bases: when thermal is required and when it is not.
- Flatness tolerance on large machined weldments: what the machine table has to hold.
- Assessing heavy fabrication capacity in Vietnam: how we check these numbers in the building.
- How we vet: the five-stage process behind every shortlist.
Want the shortlist done for you?
Send the drawing and the destination port. Within 24 business hours we tell you which shops in the network clear the crane, furnace and machine table your piece needs, and up to three of them quote you directly.
We reply within 24 business hours.