Gantry Robot Lines vs Articulated Robots for ASEAN Production: Machines Served, Speed by Payload and the Repeatability Question

Choose a gantry when one robot has to serve three or more machines in a fixed row and you have clear height to hang steel overhead. Choose an articulated arm — on a floor rail if it has to travel — when you are tending one or two machines, reorienting parts, or cannot touch the roof structure. Payload is the wrong first question: across one manufacturer's gantry range the payload spans about 92x while the number of machines served spans 18x, and it is the second number that sets your cost per machine. Before comparing quotes, settle one thing in writing: which rated load the quoted repeatability was measured at.

Machines per robot is the number that moves your cost

Gantry lines are sold in tiers, and the tiers are defined less by payload than by how much of your shop one robot covers. From the published specification tables for the [TZ gantry robot line range](/en/products?category=pr-gantry-robot-line) on this site:

| Tier | Max end load | Standard machines served | Axis ceiling | |---|---|---|---| | [TZ-SZ / TZ-HZ](/en/products/jiangsu-qingzhi-zhihua-technology-tz-sz-high-speed-intelligent-gantry-robot-production-line) | 12 | 2 | 3 standard, up to 8 | | [TZ-HG / TZ-HB](/en/products/jiangsu-qingzhi-zhihua-technology-tz-hg-high-speed-intelligent-gantry-robot-production-line) | 20/30 | 2 | 4/5/6 optional, up to 32 | | [TZ-MG / TZ-MZ / TZ-MB](/en/products/jiangsu-qingzhi-zhihua-technology-tz-mg-high-speed-intelligent-gantry-robot-production-line) | 20/100 KG | up to 20 | 4/5/6/7 optional, up to 128 | | [TZ-MU](/en/products/jiangsu-qingzhi-zhihua-technology-tz-mu-ultra-heavy-duty-intelligent-gantry-robot-production-line) | 100/300/500/800/1100 | up to 36 | 5/6/7 optional, up to 128 |

From 12 kg to 1,100 kg is roughly a 92-fold jump in payload. From 2 machines to 36 is 18-fold. Notice that the axis ceiling tracks the machine count rather than the payload: 8 axes for 2 machines, 128 for twenty or more, which works out to roughly four to six axes consumed per station. That ratio is the useful one, because it tells you what expansion you are actually buying. A line at 8 axes serving 2 machines has nowhere to put a third; the same layout on a 128-axis controller does.

An articulated arm cannot follow that curve on its own. Its envelope is a sphere around a fixed base, so it typically reaches one or two machines, and the standard fix is a floor rail — the "seventh axis" — which is the arm industry paying for the one thing a gantry has by design: extendable linear travel.

One note on units. In the published tables only the 20/100 KG row still carries its unit. Chinese parameter tables lose the unit column in transcription often enough that you should have kilograms and metres per minute confirmed in the quotation rather than inferred from a sibling row.

The speed on the datasheet belongs to the lightest configuration

Same range, same published tables. The 12 kg tier lists a Y-axis speed of 90 m/min. The 20/100 kg tier lists "60/40 (20KG/100KG)" — one machine, two speeds: 60 m/min at 20 kg, 40 m/min at 100 kg. The [heavy tier](/en/products/jiangsu-qingzhi-zhihua-technology-tz-mu-ultra-heavy-duty-intelligent-gantry-robot-production-line) lists 40 m/min on Y.

So traverse speed falls from 90 to 40 m/min across the range, a factor of 2.25, as payload rises. Within a single model it drops 33% as soon as you load it to the capacity you probably bought it for. If a supplier puts "90 m/min" and "100 kg" in the same sentence, those two numbers came from different machines.

This also settles the gantry-versus-rail speed argument. Vendor figures for seventh-axis rails commonly sit at 1–2 m/s, which is 60–120 m/min — the same band. Traverse speed is not what separates the two architectures. Overhead space versus floor space is.

Ask which rated load the repeatability belongs to

ISO 9283:1998, the performance standard for manipulating industrial robots, is explicit about test conditions: "All tests shall be executed with a test load equal to 100 % of rated load conditions, i.e. mass, position of centre of gravity, moments of inertia, according to the manufacturer's specification." It defines pose repeatability as "the closeness of agreement between the attained poses after n repeat visits to the same command pose in the same direction", measured over 30 cycles.

Now read that against a machine sold at both 20 kg and 100 kg. A single repeatability figure cannot describe both configurations, because the standard requires the test at 100% of whichever rated load applies. Datasheets in this class frequently print the row label — "repeat positioning accuracy" — and leave the number to the quotation stage.

So make it a written question rather than an assumption:

• Repeatability per ISO 9283, stated together with the rated load it was measured at, over 30 cycles
• The same figure for the payload **you** will actually run, if it differs
• Whether the figure is per-axis or measured at the tool

Measure clear height, not roof height

Published column heights across this range run 2,000–4,500 mm, with Z-axis travel of 1,300–3,500 mm. A gantry needs that height free above the machine tools, and in ASEAN the binding constraint is rarely the roof apex — it is the lowest thing hanging from it.

Before you pick a column height, measure to the lowest obstruction along the intended run: sprinkler pipework, crane rails, lighting, ducting, and [HVLS fans](/en/news/hvls-fan-guide-southeast-asia-tropical), which occupy exactly the overhead volume a gantry wants. If the unit is leased, the right to anchor steel to the roof structure is a landlord question and belongs in the letter of intent, not in commissioning week.

An articulated arm inverts the trade: it leaves the ceiling alone and takes floor area instead, including guarded area nobody can walk through.

What to put in the purchase order

A gantry production line is an integration, not a machine, so the terms matter more than the brochure.

• **Integrator of record.** ISO 10218-2:2025 is the safety standard for industrial robot applications and robot cells — the integrator's half of the pair, alongside ISO 10218-1:2025 for the robot builder. The 2025 edition replaced the 2011 version and absorbed the collaborative-robot requirements previously published separately as ISO/TS 15066. Name the standard, and name who carries responsibility for conformity.
• **Axes consumed versus axis ceiling** for your specific layout, in writing.
• **Machines served**, standard and maximum, with the station hardware each addition requires.
• **Auxiliary stations priced separately.** Workpiece rotating, inspection, cleaning, storage and laser marking stations are listed as options across this range, not inclusions.
• **Spares and service in-region**, with response times.

For the machine side of the cell, see our [CNC machining centre buying guide](/en/news/cnc-machining-center-buying-guide-asean) and [gantry machining centre versus VMC](/en/news/gantry-machining-center-vs-vmc-asean). For payback method, use the [industrial robot ROI guide](/en/news/industrial-robot-roi-asean-factories).

Conclusion

Count machines and measure clear height before you compare payloads, then settle the repeatability question on paper. [Browse the gantry robot line range](/en/products?category=pr-gantry-robot-line), see [China sourcing support](/en/china-sourcing), or [talk to our team](/en/contact).

Standards references are current as of September 2026. Confirm editions and conformity responsibility with your supplier before ordering.