How to choose a welding robot? Eight types of needs explained at once.

Different materials, plate thicknesses, batch sizes, and workpiece structures place completely different demands on a robotic welding solution. This article looks at typical scenarios such as thin-sheet low-heat-input welding, aluminum alloy welding, multi-layer multi-pass welding of medium-thick plate, seam tracking, multi-axis coordination, collaborative welding, and vision-based teach-free welding. It reviews welding robot products and process capabilities to help manufacturers move from "the welding challenge" to a better-fit automation solution. When buying a welding robot, don't compare robot specifications alone. Evaluate the whole welding capability made up of the robot, welding power source, process, seam sensing, external axes, and expert database.

"What kind of welding robot suits our workpiece?" This is one of the questions manufacturers ask most often when preparing for welding automation.

But anyone who has actually run a robotic welding project knows the answer can't be found by looking only at "how much payload the robot has or how long its arm is."

Even among welding robots, 0.5 mm sheet and 50 mm plate call for two entirely different technical approaches. Standardized workpieces and small-batch non-standard structures place different demands on an automation system. Carbon steel, stainless steel, galvanized sheet, and aluminum alloy also differ markedly in heat input, droplet transfer, spatter, penetration depth, and distortion control.

So when a company buys a welding robot, what it really needs to choose is not a single robot, but a complete welding solution made up of the robot itself, the welding power source, the welding process, seam sensing, external axes, and the software system.

So how should you choose for different manufacturing scenarios?

This is one of the most common problems in hardware, automotive parts, sheet metal, and stainless steel fabrication.

The core conflict in thin-sheet welding is that you must ensure the weld fuses, without letting excessive heat input cause burn-through, sagging, distortion, or heavy spatter.

The traditional approach is to reduce current and travel speed, but this can lead to lower welding efficiency, unstable arc starts, or poor bead formation.

For these scenarios, CRP currently offers two main types of solutions.

The first type is the Pro and Nynhan series, which use integrated control between the robot and welding power source to improve low-spatter and thin-sheet welding capability.

For example, the new-generation Pro series has been upgraded for thin-sheet processes, and offers a 0.6 mm ultra-thin sheet straight-polarity process.

The Nynhan series focuses on ultra-low spatter, fast programming, integrated design, and high-speed motion. Its matching welding power source uses 100 kHz high-frequency control and maintains good spatter control even at 200 A. It also supports thin-sheet processes, short-arc pulse, and flux-cored wire welding.

The second type is cold arc welding / CMT-type low-heat-input solutions, for applications with higher requirements on thin sheet.

CRP's cold arc welding uses a servo wire-feeding torch to control wire retraction at high frequency. Combining physical and electromagnetic control, it achieves gentler droplet transfer and thereby lowers overall heat input. The technology features near-zero spatter, low heat input, stable arc length, strong gap-bridging capability, and high-speed welding.

Yes, but the process limits differ from material to material.

CRP's cold arc welding robots now cover carbon steel, stainless steel, galvanized sheet, aluminum, and copper, among other materials. Typical applicable ranges are: carbon steel about 0.5–5 mm, stainless steel about 1.0–5 mm, galvanized sheet about 0.5–5 mm, copper 1–5 mm, and aluminum about 1 mm and above.

In process testing, cold arc welding has achieved butt welding of 0.5 mm ultra-thin carbon steel sheet. In special cases it has gone further, welding 0.4 mm ultra-thin carbon steel sheet, and the weld has been verified under two shielding gases: 80% Ar + 20% CO₂ and 100% CO₂. Compared with ordinary gas-shielded welding, cold arc welding reduces heat input by about 20%, which effectively reduces welding distortion.

For galvanized sheet, low heat input is equally important. The zinc coating burns off easily under high heat, which can also increase porosity and spatter. In CRP's cold arc tests, compared with conventional low-spatter processes, some galvanized sheet test scenarios showed porosity reduced by more than 20%, spatter reduced by more than 10%, and penetration depth increased by more than 30%.

Aluminum welding has always been a scenario that tests the process capability of a welding robot.

The reasons go beyond aluminum alloy's fast heat conduction. They also include wire-feeding stability, arc starting, droplet control, bead formation, and the oxide film. So aluminum welding cannot be understood as simply "swapping in a spool of aluminum wire."

CRP's cold arc welding solution uses a servo push-pull wire feed with arc length control, so that wire motion and arc state are coordinated more precisely. It has developed a variety of aluminum welding processes and can produce fish-scale weld beads.

For customers, two questions matter most: whether the wire-feeding system can handle the wire stably, and whether there are mature process parameters that can be called up directly for different plate thicknesses, joint types, and weld appearance requirements.

If heat input is the hardest problem in thin-sheet welding, then for medium-thick plate the hardest problems are penetration, fusion, stability, and consistency across multiple layers and passes.

Construction machinery, agricultural machinery, steel structures, and large equipment often involve V-, K-, and J-groove joints. The thicker the plate, the more weld passes need to be filled, and the higher the demands on robot path planning, welding sequence, and parameter management.

One of the positioning goals of CRP's RH series is medium-thick plate and multi-axis extended applications, with support for seam finding, arc tracking, multi-layer multi-pass welding, and external-axis coordination.

More importantly, CRP is not merely solving "can a robot weld thick plate?" It is building an expert database for medium-thick plate.

In actual use, operators can enter information such as plate thickness, wire, shielding gas, groove type, and leg size, and have the system generate the corresponding multi-layer multi-pass parameter set. After generation, it can be reviewed, modified, and saved back, so that the same type of weld can be called up repeatedly.

This gradually turns welding process from "dependent on personal experience" into "a replicable data asset."

In the ultra-thick plate field, CRP has also done fairly systematic process exploration. Under CO₂ and mixed-gas welding conditions, it has carried out research on automatic multi-layer multi-pass welding of 10–100 mm ultra-thick plate with a variety of groove forms, covering V-, K-, and J-grooves.

This is a problem that must be solved once robotic welding moves from the lab into a real factory.

However high a robot's repeat positioning accuracy, it only guarantees that "the robot repeats the taught path." But the actual weld is not always in the same position.

Plate cutting errors, fixture errors, groove deviation, cumulative errors from upstream processes, and thermal distortion can all make the actual weld deviate from the theoretical path.

So the robot also needs to "sense." CRP's current welding solutions already form a combination of technologies: touch sensing, arc tracking, laser tracking, vision, and multi-axis coordination.

Touch sensing suits finding the actual weld position before welding; arc tracking dynamically corrects the path during welding based on the arc signal.

CRP's arc tracking system can track stably at a current of about 120 A and a weave width of about 1 mm, and automatically corrects the welding path.

Laser tracking scans the groove profile in real time with a laser sensor and dynamically corrects torch posture and path, offering better adaptability to gaps and misalignment.

CRP can also build a digital workstation from a 3D model, use the expert database to match the process, and correct the path in real time through process arc tracking.

In construction machinery, steel structures, agricultural machinery, and large equipment manufacturing, a six-axis robot alone is often not enough.

A large workpiece can span several meters, so the robot must cover a larger working area while keeping the weld in a favorable welding position. This calls for the robot to work together with external axes such as a ground track and a positioner.

A single robot supports up to 6+6, a total of 12-axis, expansion, and supports combinations such as linear rails and two-axis positioners.

For example, one agricultural machinery project has already used 11-axis coordination: a 6-axis robot + 3 external-axis mechanisms + a 2-axis positioner, combined with touch sensing, arc tracking, and multi-layer multi-pass functions to complete complex medium-thick plate welding.

The value of such a system is not just that "the robot can reach farther." The positioner actively changes the workpiece posture, turning some vertical and overhead welding positions into more favorable welding postures, which helps improve quality stability.

In the past, many companies believed that robotic welding suits large-volume standard parts like those in automotive plants, while manual welding is more flexible for small-batch non-standard parts.

That judgment is changing. CRP currently has two technical routes to address this.

One route is the collaborative welding robot. CRP's collaborative welding models currently include the RC09-05-W, RC13-10-W, and RC18-05-W.

The greatest value of collaborative welding is not only that the robot is lighter and more flexible. It makes welding programming and changeover simpler, reducing companies' dependence on specialized robot programmers.

Operators can directly drag the robot to near the target point, then fine-tune in six directions (up/down, left/right, forward/back) using a joystick on the end effector, and record points, lines, arcs, welding, and weaving commands directly at the end effector.

CRP collaborative welding also supports welding software functions such as weaving, multi-layer multi-pass, seam finding, and arc tracking, and offers collision detection, UPS, and gravity compensation.

For deployment, CRP collaborative welding robots support several forms, including a mobile cart, a magnetic base, and external-axis extension. The mobile cart has been iterated to its second generation and is better suited to real production floors; the standard magnetic base fits the CRP-RC09-05-W and CRP-RC13-10-W. For projects that need a larger working range or an added positioner, collaborative robots can likewise extend up to 5 external axes.

This is already becoming an important direction for the next stage of welding automation.

CRP has now developed several intelligent welding solutions driven by vision and models.

For example, for small-batch, multi-variety structural parts, the system can scan the workpiece and reverse-model it, without needing drawings in advance. It supports more than 10 structural forms such as H-beams, and automatically generates the corresponding welding paths.

For inner and outer ring seams on pipe fittings, a vision teach-free system can scan the weld, reverse-model it, and automatically generate the welding program, while coordinating with external axes and planning positioner angles.

In power transmission steel tower scenarios, the CRP solution can also use a line laser point cloud to identify the weld, automatically welding steel pipe towers 600–2000 mm in diameter, and automatically match welding processes from the multi-layer multi-pass expert parameter database.

In addition, in standard stainless steel tube-sheet scenarios such as boilers and heat exchangers, automated welding can be completed through a combination of CAD drawings, 3D vision, a dedicated TIG torch, and arc tracking.

Not necessarily. Welding speed must be built on stable weld quality.

Especially in thin-sheet welding, if you chase speed and end up with arc breaks, undercut, porosity, or poor bead formation, the rework cost may end up higher.

A feature of CRP's cold arc technology is that it corrects arc length through continuous closed-loop control, keeping the arc stable even when welding speed and wire stick-out change.

In some process tests, compared with low-spatter welding, cold arc welding speed increased by 10%–20% or more, and by more than 50% under high-current, high-speed welding conditions.

Because the robot only solves "how to move." What really determines weld quality also includes the welding power source, the wire-feeding system, the control algorithm, and the welding process.

Take Nynhan as an example: the robot and welder use integrated control, so welder parameters can be set and saved directly on the robot's teach pendant, and simplified parameters reduce the difficulty for operators in adjusting the process.

The cold arc solution goes a step further, designing the robot, servo wire-feeding torch, welder, and control algorithm as one complete system.

For example, in arc length control, the system monitors wire retraction length in real time and adjusts wire feed speed through closed-loop control. This keeps current and arc length stable when stick-out changes, producing consistent penetration depth and weld formation.

This also points to a critical selection principle: an industrial robot can be a general-purpose device, but a welding robot cannot have only general-purpose motion capability. For welding customers, what matters more is how much real welding process experience the manufacturer has accumulated.

"Our sheet is too thin, manual welding burns through easily, and afterward we need heavy grinding and shape correction." For this kind of customer, the first thing to look at is the ability to control heat input and droplet transfer, not just robot precision.

Once you have thought these conditions through, you will find that today "getting the robot to move along a taught path" is no longer the hardest problem. The real difficulties are: how to control heat input on thin sheet; how to achieve stable penetration on medium-thick plate; how to complete multi-layer multi-pass welding on 50 mm or 100 mm thick plate; how to find the weld when the workpiece deviates; how to achieve multi-axis coordination on large structures; how to lower programming costs for small batches and many variants; how to guarantee weld quality on special materials such as aluminum alloy and galvanized sheet; and how to turn the years of accumulated experience of excellent welders into replicable process parameters and expert databases.

From the low-spatter, high-performance welding of Pro and Nynhan, to the medium-thick plate and multi-axis coordination of the RH series; from the low heat input of cold arc welding/CMT, to the flexible deployment of collaborative welding; and on to vision-based teach-free operation, external-axis coordination, and expert databases, CRP is gradually integrating robot control, welding power sources, welding processes, and intelligent sensing into one complete welding technology system.

For manufacturers, when choosing a welding robot, instead of only asking "How much does this robot cost?", it is better to first ask, "Where exactly is my workpiece hard to weld?" What ultimately determines quality, cost, and efficiency is not the robot alone, but the entire technology system behind it: the welding power source, process, sensors, and intelligent software. And this is the key to moving welding automation from "robots replacing labor" toward "process intelligence."