Putai Main Tee Roll Forming Machine: Profile Design, Load Capacity and Line Setup
What is a Main Tee Roll Forming Machine
A main tee roll forming machine produces the load-bearing main runner of a suspended ceiling grid — normally a 24 × 32 mm or 24 × 38 mm section formed from 0.4–0.5 mm galvanized strip. A well-specified main tee roll forming machine holds camber within 1.5 mm over 1.2 m, punches cross-tee slots at a fixed pitch, and runs 20–40 m/min. A main runner roll forming machine differs from a cross tee line mainly in section depth, die design and the number of calibration passes, which is why the two are rarely interchangeable without new tooling.
What a Main Tee Actually Does in a Ceiling System
The main tee — ASTM C635 calls it the main runner — is the member hung from the structural slab by hanger wire, usually at 1,200 mm centres. Everything else clips to it. Cross tees sit in its slots at 600 mm or 1,200 mm centres, wall angles close the perimeter, and acoustic tile or metal panel rests on the resulting grid. Because the whole ceiling load passes through this one profile, its depth and gauge are engineering decisions, not cosmetic ones.
That is also why a dedicated main tee roll forming machine exists as a category. A cross tee line forms a shallow channel and punches a hook; a main runner needs a deeper section, a splice detail at every 3 m or 3.6 m joint, and slots that stay on pitch across a full bundle. In most ceiling factories the main tee production line is also the constraint on delivery, because it is the slowest line per meter of finished grid.
Profile Geometry: What 32 mm and 38 mm Really Change
The face width is almost always 24 mm, because that is what standard tile edge details and clip systems expect. Depth is where the engineering happens.
| Profile | Typical gauge | Where it is used |
|---|---|---|
| 24 × 24 mm main runner | 0.35–0.4 mm | Light commercial, short spans, low tile weight |
| 24 × 32 mm main runner | 0.4–0.45 mm | General commercial offices, retail |
| 24 × 38 mm main runner | 0.45–0.5 mm | Longer hanger spans, heavier tile, services above ceiling |
Depth raises the section modulus roughly with the square of the increase, so 38 mm buys noticeably more stiffness than 32 mm at the same gauge. That is the lever a buyer pulls first when a project specifies a higher load class — before spending on thicker strip. A main runner roll forming machine configured for 38 mm depth with 22 stations will also run 32 mm with the matching tooling, which is why depth range belongs in the quotation rather than in a later change order.
Line Configuration for a Main Tee Roll Forming Machine
The forming section is only part of the answer. On a main runner roll forming machine, four units decide whether the profile holds its shape at the end of the shift.
- Decoiler and leveler. A 5 t hydraulic decoiler with a seven-roll leveler removes coil set. Skip the leveler and the camber problem is built in before the first stand.
- Servo feed and punching. Slot pitch at 600 mm and 1,200 mm is set here. A servo feed accurate to ±0.1 mm keeps cumulative drift under control across a 3.6 m length.
- Forming stands (18–22). Shafts of 50–60 mm with GCr15 rollers at HRC 58–62. The last four stands should be calibration passes, not bending passes.
- Flying shear and stacker. A servo-tracked shear cuts without stopping the strip; the stacker keeps bundles square so the splice ends are not damaged in transit.
Power on a main runner roll forming machine sits around 11–15 kW for a 38 mm profile at 40 m/min, and connected load including hydraulics usually lands between 25 and 35 kW. A main tee production line quoted with a much smaller motor for the same speed and depth is usually buying that speed by cutting calibration passes, which is where camber starts.
Main Tee vs Cross Tee: One Line or Two
A combined main runner roll forming machine is the usual first purchase, because capital is finite and orders arrive mixed. A dedicated main tee roll forming machine becomes the better second purchase once main runner passes roughly 60 percent of volume. Changeover stops eating the shift, the calibration stands can be optimised for one profile instead of compromised for two, and a second main tee production line frees the combined machine for cross tee work.
Cross tees can be produced on the same frame with a different tooling set, or on a dedicated cross tee line once volume justifies it. The technical rule is straightforward: the shallower the profile, the fewer stations needed, so a cross tee set running on a main runner roll forming machine is usually over-engineered rather than under-capable.
Frequently Asked Questions
1. What is the difference between a main tee and a cross tee?
A main tee, also called a main runner, is the load-bearing member hung from the slab and usually 24 × 32 mm or 24 × 38 mm in section. A cross tee locks into its slots at 600 mm or 1,200 mm centres and is smaller, typically 24 × 24 mm or 24 × 26 mm.
2. What steel thickness should a main tee use?
Most commercial main runners run 0.4–0.5 mm hot-dip galvanized steel, with 0.45 mm the common middle ground. Heavier gauge raises load capacity but also raises forming force, motor size and coil cost, so depth is usually the cheaper lever.
3. How many forming stations does a main tee roll forming machine need?
Eighteen to twenty-two stations is the practical range for a 24 × 38 main runner. Fewer stations force each pass to bend more angle, which raises residual stress and shows up later as camber and twist.
4. Can one machine produce both main tee and cross tee?
Yes, with separate tooling sets. Changeover between the two profiles typically takes 20–40 minutes, so a combined line suits batch production rather than daily small runs.
5. What causes camber in main tees?
Camber usually comes from uneven strip tension, an out-of-adjustment leveler, asymmetric roll gaps, or too few forming passes. Measure over 1.2 m with a straight edge before blaming the coil.
6. How fast does a main tee production line run?
Most main runner lines run 20–40 m/min, with heavier gauge and dense slot patterns pulling the effective average down. At 30 m/min and 85 percent OEE, expect roughly 12,240 m per eight-hour shift.
7. How much does a main tee production line cost?
Configuration sets the price far more than brand: station count, shaft diameter, punching tonnage, shear type, automation level and the number of tooling sets. Compare quotes on the same profile list and the same acceptance test, otherwise the numbers are not comparable.
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