The challenge
Robot arms mounted on mobile platforms, known as mobile manipulators, let a single arm do useful work in more than one place. The arm travels on an Autonomous Mobile Robot (AMR) between a storage area and a production cell, so one asset covers tasks that would otherwise need several fixed cells.
That flexibility comes with a hard constraint. Everything the mobile manipulator carries has to be paid for out of a payload budget already committed to the arm, the battery, and the platform itself. Tooling mass is the easiest place for that budget to leak.
Our customer requirement was specific. The tool had to retrieve large bins weighing 15 kg, holding assembly components, from storage racks, and deliver them to an assembly station where they had to be positioned accurately enough to be worked from directly.
There is a second, less obvious problem with a mobile manipulator. The base is not bolted to the floor. Any tool that requires the arm to reach deep into a rack shifts the combined centre of mass and works against platform stability. Reach and stability pull in opposite directions.
Our solution
Our engineering team designed a custom gripper that conforms to the geometry of the bin and produced it in Nylon PA12 by selective laser sintering on an EOS P396.
The gripper is shaped to the bin, not to a generic tote
Because the tool is printed, the contact geometry could be matched to the specific bin in use rather than compromised into a shape a machining operation could produce. A conforming interface spreads the 15 kg load across a broad contact area instead of concentrating it at two clamping points, which is what makes a secure hold possible without heavy clamping hardware.
A piston-driven extension mechanism handles the reach
Rather than asking the arm to drive deep into the rack, the tool extends to engage the bin and retracts to bring it in close to the platform before travel. This is the part of the design that resolves the reach versus stability conflict. The load spends the journey pulled in tight to the mobile base, where it does the least damage to the centre of mass.
Twelve printed components replace a much larger bolted assembly
Consolidating the mechanism into twelve printed parts eliminates the bracket and fastener stack a conventional build would need. Fewer joints means fewer things to loosen on a machine that spends its life driving over floor joints and thresholds.
A note on the name
Inside our engineering team and with the customer, this tool is known as the Bin Picking Tool. Be aware that the same phrase means something different in the wider robotics industry. The distinction is explained in the questions below.
Full specifications
| Material | Nylon PA12 |
|---|---|
| Machine | EOS P396 |
| Layer thickness | 120 microns |
| Build time | 22 hours |
| Post processing | Black dye |
| Number of components in the assembly | 12 |
| Tool weight | 3.0 kg |
| Bin payload | 15 kg |
| Mechanism | Piston-driven extension and retraction |
| Application | Mobile manipulator, AMR mounted robot arm |
Results
At 3.0 kg the tool leaves the mobile manipulator with meaningful capacity for the 15 kg bin and a margin on top of it.
Retracting the load in close to the platform before travel keeps the combined centre of mass where the AMR can handle it.
The bin arrives at the assembly station positioned to be worked from directly, with no manual repositioning step.
Frequently asked questions
Is this the same as robotic bin picking?
No, and the distinction matters. In robotics, bin picking normally refers to a vision guided system that identifies and retrieves randomly oriented individual parts from inside a bin, which is a 3D machine vision problem. This tool does something different. It picks up the bin itself, a loaded 15 kg tote, from a storage rack and moves it to an assembly station. The correct term for that is tote handling or bin handling.
What is a mobile manipulator?
A mobile manipulator is a robot arm mounted on an autonomous mobile robot. Instead of being fixed to one workstation, the arm travels between locations, so a single arm can perform tasks across a facility. The trade-off is that everything the platform carries, including the tooling, comes out of a shared payload and battery budget.
Why does tool weight matter so much on an AMR?
Because the payload budget is shared. Tooling mass is subtracted from the product the platform can carry, it draws down battery runtime on every move, and it shifts the combined centre of mass in ways that affect how fast the platform can accelerate and turn safely.
How heavy a bin can a printed gripper handle?
This tool is rated for the 15 kg bins in the customer application. Nylon PA12 produced by selective laser sintering is a genuine engineering material, and printed tooling routinely handles loads in this range and above. The limiting factor is usually the rated payload of the robot rather than the tool.
Can the gripper be adapted to a different bin or tote?
Yes. The conforming interface is designed around a specific bin geometry, so a different tote means a design revision and a new print. There is no hard tooling to amortise, which is what makes bespoke geometry economical in the first place.
Have a similar application?
Send us the part, the payload, and the cycle time. Our engineering team will scope the tool with you and tell you honestly whether additive manufacturing is the right answer for it.